ACID-BASE DISORDERS
Normal Acid-Base Balance
pH, 7.4; Pco2, 40; O2 sat, 98–100%.
The notation commonly used for blood gases whether arterial or venous is: pH/Pco2/PO2/calculated HCO3/calculated SaO2—bicarbonate may also be included.
DIAGNOSIS
Diagnose acid-base disorders by obtaining an arterial blood gas (ABG—pH and Pco2) and an electrolyte panel (HCO3–).
Assess the acid-base disorder step by step:
Is the primary disorder an acidosis (pH < 7.4) or alkalosis (pH > 7.4)?
Is the disorder respiratory (pH and Pco2 move in opposite directions)?
Is the disorder metabolic (pH and Pco2 move in the same direction)?
Is the disorder a simple or mixed disorder?
Acidosis
Acidosis induces ion shifts at the cellular level that cause hyperkalemia and hypercalcemia. This can manifest clinically as a cardiac arrhythmia.
There is a right shift of the O2-Hg dissociation curve, which means 
affinity resulting in 
oxygen release of oxygen to the tissues
cerebral blood flow, but pulmonary blood flow.
ABG = 7.35–7.45/35–45/80–100/18–23
VBG = 7.25–7.35/41–51/35–40/18–23
METABOLIC ACIDOSIS
serum pH caused by a in plasma HCO3–. It is important to identify the underlying cause of metabolic acidosis by calculating the anion gap (AG).
AG = [Na+] – ([Cl–] + [HCO3–]). Normal AG = 8–16 mEq/L, and reflects unmeasured serum ions (organic acids, phosphates, etc.).
Normal AG metabolic acidosis results when the low HCO3– levels are balanced by a compensatory in renal Cl– reabsorption, keeping the AG in range. This is also commonly referred to as a hyperchloremic metabolic acidosis.
Diarrhea is the most common cause of normal AG metabolic acidosis, and is due to excessive gastrointestinal HCO3– loss. Renal tubular acidosis is another metabolic disturbance caused by ineffective reabsorption of HCO3–(proximal), or excretion of H+ (distal).
AG metabolic acidosis can be due to serum H+ from exogenous sources (MUDPILES), or endogenous production (lactic acidosis/ketoacidosis/renal failure).
Treat metabolic acidosis by correcting the underlying disorder. Severe metabolic acidosis (pH < 7.2) results in compensatory hyperventilation (Kussmaul’s breathing), and diminished responsiveness to catecholamines that results in cardiac output and tissue perfusion. Treat patients with pH < 7.15 with Na+HCO3–.
RESPIRATORY ACIDOSIS
serum pH due to pulmonary retention of CO2 (PaCO2 > 40 mmHg).
Renal compensation consists of increasing reabsorption of HCO3–.
Acute compensation occurs at a rate of 1 mmol/L per 10 mmHg in PaCO2.
Causes of anion gap metabolic acidosis:
MUDPILES
Methanol
Uremia
Diabetic ketoacidosis (DKA)
Paraldehyde
Isoniazid
Lactate
Ethylene glycol
Salicylates
Chronic compensation occurs at a rate of 4 mmol/L per 10 mmHg in PaCO2.
Make sure the airway is patent.
Correct potential reversible causes.
PaCO2 is expected to as a result of compensatory hyperventilation in metabolic acidosis.
Alkalosis
Alkalosis induces ion shifts at the cellular level that cause hypokalemia and hypocalcemia.
There is a left shift of the O2-Hg dissociation curve, resulting in oxygen delivery to the tissue.
cerebral blood flow.
Expected PaCO2 should be calculated with Winter’s formula and compared with measured Pco2 to see if compensation is appropriate.
Expected Pco2 = 1.5 (measured HCO3–) + 8 ± 2
Failure of compensation is indicative of an additional primary acid-base disorder.
METABOLIC ALKALOSIS
A 6-week-old child has a 2-week history of projectile vomiting that is not bile-stained. He is dehydrated and slightly jaundiced. Think: Pyloric stenosis.
The initial symptom of pyloric stenosis is nonbilious vomiting. Progressive vomiting results in hypochloremic hypokalemic metabolic alkalosis. Most likely lab findings: Na 138, K 3.0, Cl 88, HCO3 35, pH 7.52. Jaundice due to level of glucuronyl transferase may be present, which resolves after relief of the obstruction. awareness has resulted in earlier diagnosis.
serum pH due to an plasma HCO3–.
Mechanism relies on fact that the renal system cannot excrete excess HCO3–.
In children, metabolic alkalosis is caused by excessive loss of H+ (vomiting).
Urinalysis (UA) is the best initial step in evaluation to determine if the extracellular fluid (ECF) volume is contracted or expanded:
If urine Cl– is < 10 mEq/L, ECF contraction, hypokalemia, and is saline sensitive.
If urine Cl– is > 20 mEq/L, ECF expansion, hypertension, and is saline resistant.
PaCO2 is expected to as a result of compensatory hypoventilation in metabolic alkalosis.
Failure to compensate indicates an additional underlying primary respiratory alkalosis.
Treat the underlying cause.
Volume repletion in cases of ECF volume contraction will correct the alkalosis, and diuretics should be used when ECF volume is expanded.
Watch for the possibility of two concurrent primary disturbances. In salicylate toxicity, both primary respiratory alkalosis and metabolic acidosis exist.
RESPIRATORY ALKALOSIS
serum pH due to plasma CO2.
Caused by hyperventilation (anxiety, asthma, pulmonary embolism, pneumonia, hypoxia).
Renal compensation (excretion of HCO3–) occurs over a period of several hours:
Acute compensation HCO3– 2 mEq/L, for every 10 mmHg in PaCO2.
If an asthmatic has respiratory distress that is expected to have respiratory alkalosis, has a normal pH and normal Pco2, beware of impending respiratory failure.
Chronic compensation HCO3– 6 mEq/L, for every 10 mmHg in PaCO2.
Treat respiratory alkalosis by treating the underlying disorder. Breathing into a paper bag can be useful in cases of psychogenic hyperventilation.
RENAL TUBULAR ACIDOSIS (RTA)
A 1-year-old child is brought into the emergency department (ED) with vomiting, constipation, and urine production. The child is found to have normal anion gap metabolic acidosis. A renal ultrasound reveals medullary nephrocalcinosis. Think: Renal tubular acidosis.
Renal tubular acidosis is characterized by normal anion gap metabolic acidosis. A urine pH < 5.5 suggests proximal RTA, whereas in distal RTA urine pH > 6.0. Presence of nephrocalcinosis and hypercalciuria are suggestive of distal RTA.
DEFINITION
A renal tubular disorder resulting in normal anion gap hyperchloremic acidosis, due to impaired urinary acidification.
Presence of acidemia and alkaline urine, with preserved glomerular function.
Hyperchloremic metabolic acidosis with a high urinary pH.
RTA type 1 is the most common form.
ETIOLOGY
Three types: 1, 2, and 4. Type 3 RTA is exceedingly rare.
Type 1—distal RTA:
Hyperchloremic metabolic acidosis with a high urinary pH.
Inability to secrete H+ by the distal tubule and collecting duct (bicarbonate cannot be generated) 
metabolic acidosis with alkaline urine (> 5.5).
Compensatory in excretion of other cations causing hypokalemia and hypercalciuria.
Can be complicated by rickets, secondary to phosphate wasting.
Type 1 RTA is the only type associated with renal stones.
Type 2—proximal RTA:
Caused by proximal tubular reabsorption of bicarbonate.
The mechanisms of H+ secretion in the distal tubule are overwhelmed HCO3 loss in urine.
The bicarbonate is replaced in the circulation by Cl hyperchloremia.
sodium delivery to the distal tubule aldosterone secretion hypokalemia.
Isolated disorder.
Generalized defect in proximal tubular transport (Fanconi syndrome). Nephrocalcinosis and nephrolithiasis do not occur despite urinary calcium (urinary citrate levels are not reduced).
Plasma HCO3– remains at 15–20 mEq/L.
Type 4—mineralocorticoid deficiency RTA.
Aldosterone deficiency or resistance.
aldosterone production by the adrenal gland (Addison disease, congenital adrenal hyperplasia, primary hypoaldosteronism).
production of renin by the juxtaglomerular apparatus (interstitial damage).
Nephrocalcinosis and nephrolithiasis are rarely seen.
Characteristic features: Hyperkalemia, acidic urine—urinary pH < 5.5 (distal tubule H+ pump functions normally).
SIGNS AND SYMPTOMS
Polyuria, dehydration, anorexia, vomiting, constipation, and hypotonia.
Children often present with growth failure.
TREATMENT
Correct acidosis:
Sodium bicarbonate (alkalinize the urine, correct the sodium defect, lower aldosterone, and raise the potassium).
Potassium citrate (augments urinary citrate and inhibits stone formation).
Caution! NaHCO3 in Type II can correct the condition but can further hypokalemia, and potassium supplements may also be required.
Correct electrolyte abnormalities to maintain bicarbonate and potassium levels: Potassium citrate therapy is able to correct the metabolic acidosis and hypokalemia in distal renal tubular acidosis.
The primary defect in distal renal tubular acidosis is a defect in secretion of hydrogen ions.
PROGNOSIS
Distal RTA can be a lifelong disease and may renal failure.
Proximal RTA and mineralocorticoid RTA usually resolve within 12 months.
ACUTE RENAL FAILURE (ARF)
A 4-year-old boy develops oliguria 12 hours after operation for a ruptured appendix. Creatinine (Cr) is 0.5 mg/dL, blood urea nitrogen (BUN) is 23 mg/dL, urine sodium is 12 mEq/L. Think: Prerenal azotemia.
Oliguria is most often due to dehydration. Historical features are vomiting, diarrhea, and poor oral intake. A BUN-to-serum creatinine ratio of > 20:1 is suggestive of prerenal azotemia. Other features are concentration of urinary sodium, urinary excretion of creatinine, and a high urine osmolality. The precipitating event for prerenal azotemia is renal hypoperfusion. Give physiologic saline for blood volume expansion. Reversibility with treatment of the underlying cause is the hallmark.
A 2-year-old boy develops bloody diarrhea a few days after eating in a fast-food restaurant. A few days later, he develops facial edema, pallor, lethargy, and urine output. Blood work shows a low hematocrit and platelet count. A UA reveals blood and protein in the urine. Think: HUS secondary to Escherichia coli O157:H7 infection.
This infection is commonly acquired by eating undercooked red meat (hamburgers). It is usually preceded by either gastroenteritis (usually diarrheal) or an upper respiratory tract infection. Sudden onset of pallor, lethargy, and oliguria suggest HUS. Microangiopathic hemolytic anemia and thrombocytopenia support the diagnosis of HUS. The peripheral smear may show helmet cells, burr cells, and fragmented red cells.
A 5-year-old patient with ARF has an electrocardiogram (ECG) that shows peaked T waves and a widened QRS complex. Think: Hyperkalemia.
Hyperkalemia occurs due to impaired renal excretion. As K+ levels rise, peaked T waves are the first ECG changes. Further rise results in widening of the QRS complex. All patients with suspected hyperkalemia should be placed on a cardiac monitor. The initial treatment includes administration of calcium chloride or gluconate to treat hemodynamic instability, and initiation of measures to lower serum K+.
DEFINITION
ARF develops when renal function is diminished to the point where body fluid homeostasis can no longer be maintained.
Acute rise in BUN, serum creatinine, or both.
Three main types: prerenal, renal, and postrenal.
ARF results in azotemia (elevated BUN).
May present with symptoms of oliguria, anuria, or insidiously without oliguria.
PATHOPHYSIOLOGY
Prerenal:
Caused by hypoperfusion of the kidneys secondary to hemorrhage, sepsis, heart failure, or salt/protein-wasting disease.
This is the most common cause of ARF.
Potentially reversible if blood flow is restored prior to progression to acute tubular necrosis (ATN).
Oliguria is always present.
Gastroenteritis is the most common cause of hypovolemia.
Renal:
Caused by renal parenchyma damage, usually from tubular disease (most commonly ATN), glomerular disease (Wegener, Goodpasture, systemic lupus erythematosus [SLE]), vascular disease (HUS or renal vein thrombosis), and interstitial disease (medications).
The most common cause of ARF in toddlers is hemolytic-uremic syndrome (HUS).
The kidneys are unable to concentrate urine effectively.
Usually presents with edema.
Consider poststreptococcal glomerulonephritis in a child presenting with hypertension, edema, hematuria, and renal failure.
Postrenal:
Caused by any significant obstruction of the urinary tract (posterior urethral valves, bilateral uretropelvic or uretrovesical obstruction).
Almost always associated with infection.
Nephritic syndrome: Hematuria, edema, and hypertension.
SIGNS AND SYMPTOMS
Oliguria.
Edema (salt and water overload).
Hypertension (HTN).
Congestive heart failure (CHF).
Seizures.
Normal urinary output: 2–4 ml/kg/hr
DIAGNOSIS
Find out the duration, and attempt to get a baseline Cr level.
Obtain a careful history to determine the cause of renal failure.
Serum and urine chemistry are useful tests for differentiating the cause.
Prerenal: BUN:Cr > 20:1 with FeNa < 1%.
Renal: BUN:Cr < 20:1 and FeNa > 2–3%.
In children with postrenal ARF, a renal ultrasound will show dilation of the renal pelvis and collecting system.
Oliguria: < 0.5 mL/kg/hr urine production
TREATMENT
Catheterize the patient to monitor urine output and relieve obstruction.
Treat patients with hypovolemia with volume replacement.
Treat patients who fail to produce adequate urine output with fluid restriction.
Avoid drugs that can precipitate prerenal failure (such as nonsteroidal anti-inflammatories [NSAIDs]) in patients with renal perfusion.
Children with renal failure may have a normal urinary output.
COMPLICATIONS OF UNTREATED ARF
Hyperkalemia can develop secondary to impaired renal tubule function and ion shifts due to acidosis. A serum potassium level > 7 mEq/L must be treated emergently. Give calcium gluconate to stabilize the myocardium, bicarbonate, glucose and insulin, Kayexalate (sodium polystyrene), and albuterol. Cardiac arrest from hyperkalemia is a life-threatening complication of untreated ARF.
Hypocalcemia and hyperphospatemia may result from parathyroid hormone (PTH) resistance and loss of ability to hydroxylate vitamin D into an active form. Severe hypocalcemia manifests as tetany, and is treated by lowering phosphate and replacing active vitamin D.
Anemia is often caused by lowered erythropoietin levels. Erythropoietin can be supplemented.
Hyponatremia secondary to excessive administration of hypotonic fluids to oliguric patients. Patients with a serum sodium < 120 are at risk for developing cerebral edema and central nervous system (CNS) hemorrhage. Partial correction should be undertaken to raise the Na level to at least 120 mEq Na.
Patients with ARF could be either volume overloaded or volume depleted. Always assess a patient’s hydration status.
Required = (Desired Na concentration – Observed Na concentration) × Body weight (Kg) × 0.6
Treat patients with water restriction.
Metabolic acidosis is due to excretion of hydrogen and ammonia.
Infection is a common and serious complication.
CHRONIC RENAL FAILURE (CRF)
On a routine exam, a 10-year-old girl has HTN that is confirmed by repeated measurements. Her blood pressure (BP) is 160/90 in the right arm and similar in the left arm and right leg. Think: Renal disease.
BP should be measured at least twice with appropriate cuff size. A short or narrow cuff may artificially BP measurement. Renal parenchymal disease and coarctation of the aorta are common causes of hypertension in children 1–10 years of age. BP should be obtained in all four extremities to determine the presence of coarctation of the aorta. The most appropriate next diagnostic test is UA.
DEFINITION
CRF is a result of irreversible kidney damage end-stage renal failure.
ETIOLOGY
CRF in children under age 5 is most often due to anatomic abnormalities, such as renal hypoplasia, dysplasia, or malformations.
After age 5, CRF usually results from glomerular diseases such as HUS or glomerulonephritis, hereditary diseases such as Alport syndrome, or cystic diseases.
SIGNS AND SYMPTOMS
The development of uremic symptoms in chronic renal disease is usually insidious and nonspecific.
Patients may present with headache, fatigue, lethargy, anorexia, vomiting, polydipsia, polyuria, and growth failure.
Most patients with CRF are weak and have HTN, as the renin-angiotensin-aldosterone system is stimulated by diminished GFR regardless of actual volume status.
See Table 14-1 for a listing of symptoms of uremia.
Patients will often present with bleeding due to defective platelets secondary to uremia.
Uncontrolled bleeding can be treated with dialysis and desmopressin.
DIAGNOSIS
Serum Cr measurement will give a good estimate of glomerular filtration rate (GFR) as the two vary with an inverse relation.
GFR < 20% of normal is typical for CRF.
Always attempt to obtain a baseline Cr level to differentiate between ARF, CRF, and acute-on-chronic renal insufficiency/failure.
TREATMENT
Dialysis and renal transplant are indicated for patients when serum Cr is > 10 mL/dL.
TABLE 14-1. Symptoms of Uremia
Azotemia (accumulation of nitrogen products)
Acidosis
Sodium wasting
Sodium retention
Urinary concentrating defect
Hyperkalemia
Renal osteodystrophy
Growth retardation
Anemia
Bleeding tendency
Infection
Neurologic (fatigue, poor concentration, headache, drowsiness, muscle weakness, seizures, coma)
Gastrointestinal ulceration
Hypertension
Hypertriglyceridemia
Pericarditis and cardiomyopathy
Glucose intolerance
Diet: Children with CRF are growth retarded. Children should be given adequate caloric intake. Nasogastric (NG) tube feeds and recombinant human growth hormone therapy has been shown to improve linear growth. Water-soluble vitamins, zinc, and iron should be supplemented.
Renal osteodystrophy: Children with CRF are unable to excrete phosphate. The resulting hyperphosphatemia and hypocalcemia stimulate PTH. The ensuing secondary hyperparathyroidism fibrosis of the bone marrow space (osteitis fibrosis cystica). Symptoms of renal osteodystrophy include muscle weakness, bone pain, and growth retardation. Treatment includes normalization of the serum calcium and phosphorus levels.
Anemia: Anemia results from inadequate erythropoietin production by the kidneys. Children with Hgb < 6 should be transfused with packed red blood cells (RBCs). Erythropoietin can also be administered subcutaneously.
Hypertensive emergencies: HTN should be treated with salt restriction and a combination of angiotensin-converting enzyme (ACE) inhibitors and β blockers.
Absolute indications for emergent dialysis:
AEIOU
Acidosis
Electrolyte abnormalities
Toxic Ingestion
Fluid Overload
Uremia
END - STAGE RENAL DISEASE (ESRD)
An 8-year-old patient receiving peritoneal dialysis for ESRD develops abdominal pain and fever. Think: Peritonitis.
The most serious complication of peritoneal dialysis is peritonitis. It should be suspected in the presence of abdominal pain and fever in a patient who is on peritoneal dialysis. Clinical manifestations include fever and abdominal pain and tenderness. Common causative organisms are coagulase-negative staphylococci, S aureus, streptococci, Escherichia coli, Pseudomonas, and other gram-negative organisms.
DEFINITION
ESRD occurs when a patient’s renal function has been irreversibly compromised and failed (the serum Cr is typically > 10 mg/dL).
CAUSES
Congenital anatomic abnormalities are the most common cause in children < 5 years old, and glomerulonephritis is the most common culprit in children > 5 years old.
High BUN/Cr levels are not an absolute indication for dialysis.
TREATMENT
Dialysis: Peritoneal dialysis is the standard technique for infants and children. However, dialysis patients remain uremic, which restricts normal growth and development.
Renal transplant: Renal transplantation is the preferred mode of treatment of most children with ESRD. Preparation for transplantation from living donors or listing for cadaver donor transplant should begin for all children with ESRD. The contraindications for transplant include children with human immunodeficiency virus (HIV) and children with metastatic malignancy.
The most common causes of HTN in children are secondary causes—renal (75%), infection, glomerulonephritis, HUS, obstructive uropathy.
WILMS’ TUMOR
A previously healthy 2-year-old boy has a left-sided flank mass discovered by his mother. His physical examination reveals a BP of 110/70 and a large mass arising in his left flank. A UA shows 5–10 erythrocytes and 2–3 leukocytes. Think: Wilms’ tumor.
The usual presentation of Wilms’ tumor is an abdominal mass, and it is not uncommon for the parent to discover this mass. Other features may include abdominal pain, fever, anemia, hematuria, and HTN. The most appropriate next diagnostic test is an ultrasound of the abdomen and urinary tract. Because Wilms’ tumor metastasizes to the lungs, a chest radiograph should be obtained.
DEFINITION
Nephroblastoma.
Embryonal neural crest cell origin.
It most commonly presents between the ages of 1 and 4 years (median age at diagnosis: 3.5 years).
The most common type of renal tumor in children.
ETIOLOGY
Wilms’ tumors are associated with mutations of the p53 tumor suppressor gene on chromosome 11.
SIGNS AND SYMPTOMS
Abdominal/flank mass (typically asymptomatic):
The most common presentation.
Rarely crosses the midline, as opposed to neuroblastoma.
Vomiting.
May present with gross hematuria, fever, and HTN due to obstruction of renal artery.
Associated with aniridia, genitourinary malformation (cryptorchidism), mental retardation, hemihypertrophy, and Beckwith-Wiedemann syndrome (macroglossia, omphalocele, visceromegaly).
Can be bilateral (5–10%).
PATHOLOGY
Stage 1: Tumor limited to kidneys and can be removed with an intact capsule.
Stage 2: Grows beyond the kidney but can be completely removed.
Stage 3: Nonhematogenous extension into the abdomen.
Stage 4: Hematogenous metastases.
Stage 5: Bilateral renal metastasis.
SPREAD
Contiguous invasion of adjacent organs.
Extension into the renal vein and inferior vena cava.
Distant spread: Lung and liver.
DIAGNOSIS
Renal ultrasound (US): Echogenic intrarenal masses that may contain cystic areas.
Computed tomography (CT): To determine the origin and extent of spread.
Biopsy: To determine cell type.
TREATMENT
Stage 1–3 tumors are treated with nephrectomy and chemotherapy with or without radiation.
Stage 4 tumors are treated with pulmonary irradiation and three-drug combination chemotherapy in addition to above.
POLYCYSTIC KIDNEY DISEASE (PKD)
An 8-month-old girl has an easily palpable kidney. US shows cystic kidneys, hepatic fibrosis, and portal HTN. Think: Autosomal-recessive polycystic kidney disease.
Classic presentation: Bilateral flank masses during the neonatal period or early infancy. Ultrasound may show uniformly hyperechogenic kidneys. Presence of hepatic fibrosis supports this diagnosis. Associations: oligohydramnios, pulmonary hypoplasia, respiratory distress, and spontaneous pneumothorax.
DEFINITION
Bilateral renal cysts without dysplasia.
Congenital malformation of the urinary tract resulting in cysts within the kidneys.
PATHOPHYSIOLOGY
Autosomal-recessive PKD (ARPKD; previously known “infantile polycystic disease”): Cysts are a dilation of the collecting ducts. Many patients also have cysts in the liver, cirrhosis, and portal HTN.
Autosomal-dominant PKD (ADPKD; previously known “adult polycystic disease”): Cortical and medullary cysts that are primarily dilated tubules. Although most patients are identified between 30 and 50 years of age, the condition has been recognized in newborn.
Currently, the nomenclature of infantile versus adult is no longer used.
SIGNS AND SYMPTOMS
ARPKD
urine formation by the fetus oligohydramnios, Potter syndrome (flat nose, recessed chin, epicanthal folds, low-set abnormal ears, limb abnormalities), and pulmonary hypoplasia.
At birth, infants may present with renal insufficiency or HTN. Children will also present with bilateral flank masses at birth.
ADPKD
Commonly presents in the fourth or fifth decade of life with hematuria, bilateral flank pain or masses, and HTN.
Also associated with hepatic cysts and aneurysms of the cerebral circulation.
ARPKD—innumerable tiny cysts
ADPKD—large cysts
DIAGNOSIS
US of the kidneys reveals enlarged and hyperechogenic kidneys.
TREATMENT
Treatment is supportive. PKD results in ESRD. Treat patients with ESRD with dialysis and kidney transplant.
RENAL DYSPLASIA
DEFINITION
Abnormal metanephric differentiation resulting in nonrenal components affecting all or part of the kidney. A dysplastic kidney can contain nonrenal elements such as cartilage.
RENAL HYPOPLASIA
A 1-week-old male newborn has a wrinkled abdomen that lacks anterior abdominal musculature. He also has clubfeet and is in respiratory distress. His bladder is distended and easily palpable, and neither testis is in his scrotum. Lab findings include BUN 30, Cr 2, and HCO3 15. Think: Prune belly syndrome.
Triad: Absent abdominal wall muscles, undescended testes, and renal dysplasia. The renal collecting system is dilated. The bladder usually enlarged with a pseudodiverticulum at the urachus. Respiratory distress may be related to pulmonary hypoplasia due to severe oligohydramnios.
DEFINITION
Nondysplastic small kidney that has decreased calyces and nephrons.
Children with bilateral hypoplasia usually present with chronic renal failure.
This is the leading cause of ESRD during the first decade of life.
FANCONI SYNDROME
DEFINITION
Rare disorder characterized by wasting of variable amounts of phosphate, glucose, amino acid, and bicarbonate by the proximal renal tubule.
ETIOLOGY
Inherited.
Cystinosis (defect of cystine metabolism that results in deposition of cystine in major organs of body, especially kidney, liver, eye, and brain).
Galactosemia.
Fructosemia.
Lowe syndrome (X-linked disorder with congenital cataracts, mental retardation, and Fanconi syndrome).
Tyrosinemia.
Wilson disease.
Acquired secondary to exposure to:
Chemotherapeutic/immunosuppressive agents (ifosfamide, tacrolimus, cyclosporine).
Heavy metals.
Gentamicin or outdated tetracycline.
Cystinosis is the most common cause of Fanconi syndrome.
Fanconi syndrome is one of the causes of proximal RTA.
SIGNS AND SYMPTOMS
Growth retardation
Rickets
Polyuria
Dehydration
Anorexia
Vomiting
It is important to distinguish Fanconi syndrome from Fanconi’s anemia. Fanconi’s anemia is an inherited disorder of bone marrow failure, whereas Fanconi syndrome is a disorder of renal tubules.
DIAGNOSIS
Elevated levels of glucose and electrolytes (phosphate, sodium, potassium, bicarbonate) in the urine.
Evidence of renal insufficiency.
TREATMENT
Bicarbonate therapy is mainstay.
Replacement of phosphate.
HORSESHOE KIDNEY
DEFINITION
Midline fusion of the lower kidney poles.
The major pathologic finding in congenital nephrotic syndrome is dilation of the proximal tubules.
EPIDEMIOLOGY
Seven percent of horseshoe kidneys are associated with Turner syndrome and are four times more common in children with Wilms’ tumor.
Horseshoe kidneys occur in 1 in 500 births.
NEPHROTIC SYNDROME
A 2-year-old boy has a 1-week history of edema. On examination, his BP is 100/60 and he has generalized edema and ascites. Lab values show Cr 0.4, albumin 1.4 g/dL, and cholesterol 569 mg/dL. A UA shows 4+ protein and no blood. Think: Nephrotic syndrome.
The common age of presentation is 2–6 years. Minimal change disease is the most common pattern of nephrotic syndrome in children. Typical presentation: periorbital and peripheral edema. Additional findings may include HTN and microscopic hematuria. Histopathologic examination shows no glomerular abnormalities on light microscopy in minimal change disease.
Nephrotic range proteinuria = Protein excretion of > 40 mg/m2/hr.
Random urine protein/creatinine ratio > 3.0.
DEFINITION
Nephrotic syndrome is characterized by proteinuria, hypoalbuminemia, edema, and hyperlipidemia.
Patients can develop a hypercoagulable state due to nephrotic loss of antithrombin III.
ETIOLOGY
Eighty-five percent of nephrotic syndrome in children is caused by minimal change disease.
Other causes of nephrotic syndrome include mesangial proliferation and focal segmental glomerulosclerosis.
Renal Biopsy
Age < 1 year or > 8 years
Recurrent gross hematuria
Family history of kidney disease
Laboratory findings suggestive of secondary nephrotic syndrome:
Sustained elevation in serum creatinine levels
Low C3/C4 levels
Positive antinuclear antibody (ANA) findings
Positive anti-double-stranded DNA antibody
PATHOPHYSIOLOGY
A loss of negatively charged glycoproteins in the capillary walls causes an in basement membrane permeability.
EPIDEMIOLOGY
More common in boys than girls (2:1).
Most common in children between 2 and 6 years of age, and commonly follows a viral illness.
SIGNS AND SYMPTOMS
Pitting edema (most common clinical finding).
Periorbital edema.
Oliguria.
Anasarca.
DIAGNOSIS
The diagnosis is usually made clinically, with supportive laboratory values.
Proteinuria > 3.5 g/24 hr.
Serum albumin < 2.5 g/dL.
Hyperlipidemia.
A confirmatory renal biopsy shows fusion of the epithelial foot process by electron microscopy.
TREATMENT
Most children will respond to steroids (4–6 weeks of prednisone).
Relapses can be treated with steroids or alternative agents like cyclophosphamide or cyclosporine if steroid resistant.
Salt/fluid restriction to edema.
The majority of children will have relapses with age, most resolving by the end of the second decade.
Urine dipstick is not an accurate measure of protein excretion.
COMPLICATIONS
Infection is most common, especially spontaneous bacterial peritonitis. Two organisms: Streptococcus pneumoniae and Escherichia coli.
Thromboembolism:
Higher in secondary nephrotic syndrome and membranous nephrotic syndrome.
Renal vein thrombosis, deep vein thrombosis, and pulmonary embolism.
POSTSTREPTOCOCCAL GLOMERULONEPHRITIS (PSGN)
A 4-year-old girl presents with malaise, periorbital edema, and smoky-colored urine. She had a strep throat infection 2 weeks prior. A serum complement level is , and an antistreptolysin O (ASO) titer is . Think: PSGN.
PSGN occurs after an infection of the throat or skin by group A β-hemolytic streptococci. It is manifested as an acute nephritic syndrome or as isolated hematuria and proteinuria. It is mediated by immune complexes, which is suggested by low complement level. The ASO is elevated. Urinalysis shows red blood cells and RBC casts.
Proteinuria
Normal protein excretion = ≤ 4mg/m2/hr
Normal urine protein/creatinine ratio = < 0.5 (< 2 year) < 0.2 (> 2 year)
Transient
Fever
Dehydration
Exercise
Orthostatic proteinuria (most common cause):
Obtain two samples of urine (one in recumbent and the other in ambulatory position).
Practically first morning urine and another sample later in the day.
24-hour urinary protein excretion < 1000 mg/day.
Persistent (> 1+ on > 1 occasion).
Requires further evaluation.
DEFINITION
Immune complex disease caused by group A β-hemolytic streptococcus types 12 and 49.
Typically occurs 10–14 days following strep pharyngitis or a skin infection (impetigo).
DIAGNOSIS
Positive throat cultures or antibody titers to streptococcal antigen.
UA: RBC casts, RBCs, protein.
Light microscopy: Enlarged glomeruli with mesangial proliferation and exudation of neutrophils.
Immunofluorescent microscopy: Granular pattern of immunoglobulin deposition.
Electron microscopy: Electron microscopy reveals electron-dense humps (immune complexes) on the epithelial side of the glomerular basement membrane (GBM).
TREATMENT
Treat with penicillin for 10 days to prevent spread of nephrogenic strain of group A β-hemolytic streptococci.
Treat renal and cardiac failure with peritoneal dialysis.
Microscopic hematuria may take up to 1 year to resolve.
RAPIDLY PROGRESSIVE GLOMERULONEPHRITIS (RPGN)
DEFINITION
Acute glomerulonephritis = hematuria, proteinuria, and HTN.
Severe glomerulonephritis that rapidly progresses to acute renal failure if left untreated.
The underlying abnormality is the presence of crescent-shaped scars in the majority of the glomeruli.
SIGNS AND SYMPTOMS
RPGN presents like nephritic syndrome with nephrotic range proteinuria and rapidly progresses to ARF within weeks to months after onset.
Gross hematuria and/or edema is the most common presentation.
Causes of gross hematuria:
OUCH RED URINE HURTS
Oncologic agents
Urethrorrhagia (secondary to squamous metaplasia of urethra)
Coagulopathy
Hydronephrosis
Renal vein thrombosis
Exercise
Dead papillae (papillary necrosis)
Urolithiasis
Renal contusion
Infections
Neoplasm
External manipulation (masturbation)
Hypercalciuria
Urethral injury
Renal custs
Trauma
Sickle cell
DIAGNOSIS
Complement C3 and C5 are usually decreased. The complement levels generally return to normal after 6–8 weeks.
Light, immunofluorescent, and electron microscopy reveal presence of crescents on the inside of Bowman’s capsule. The crescents are composed of the proliferative epithelial cells of the capsule, fibrin, and macrophages.
TREATMENT
Although some patients respond to corticosteroids or cyclophosphamide, prognosis is generally very poor, with most patients requiring dialysis.
MEMBRANOPROLIFERATIVE GLOMERULONEPHRITIS
A patient presents with hemoptysis, sinusitis, and glomerulonephritis. Think: Wegener’s granulomatosis.
Wegener’s granulomatosis involves the upper and lower airways and kidneys. Triad: Necrotizing granulomatous lesions in the respiratory tracts, necrotizing vasculitis, and focal glomerulonephritis. It is rare before adolescence. Most patients present with respiratory symptoms. The radiographic findings may include nodular infiltrates, pulmonary nodule, cavitation, and diffuse alveolar hemorrhage.
DEFINITION
Most common cause of chronic glomerulonephritis in older children.
SIGNS AND SYMPTOMS
Nephrotic syndrome
Hematuria
HTN
DIAGNOSIS
Light microscopy: Glomeruli arranged in a lobular pattern, often appearing duplicated with a “tram tracking” appearance.
Immunofluorescent microscopy: Lobular deposits of C3 and immunoglobulins.
Electron microscopy: Immune complex deposits in mesangial and subendothelial regions.
TREATMENT AND PROGNOSIS
Poor prognosis. Fifty percent of patients will develop chronic renal failure within 10 years.
There is no definitive therapy, although some patients respond to prednisone.
MEMBRANOUS GLOMERULONEPHRITIS
A patient presents with dyspnea, hemoptysis, and ARF. Think: Goodpasture syndrome.
Goodpasture syndrome is an antiglomerular basement membrane disease. Triad: glomerulonephritis, pulmonary hemorrhage, and antibody to basement membrane antigens. Respiratory manifestations: cough, dyspnea, and hemoptysis associated with pulmonary hemorrhage. Renal manifestations: acute nephritic syndrome with hematuria, proteinuria, and HTN. UA may show active sediment with RBCs and RBC casts.
DEFINITION
Membranous glomerulonephritis is an immune complex disease of the kidney.
EPIDEMIOLOGY
It is the most common cause of nephrotic syndrome in adults and is uncommon in children.
Can be idiopathic or secondary (SLE 10–20% of lupus nephritis).
The most common cause of gross hematuria in children is IgA nephropathy.
SIGNS AND SYMPTOMS
Presents as a nephrotic syndrome.
Some patients have microscopic hematuria.
DIAGNOSIS
Light microscopy: Diffuse thickening of the GBM without proliferative changes.
Immunofluorescent microscopy: Granular deposits of immunoglobulin G (IgG) and C3.
Electron microscopy: Deposits of IgG and C3 located on the epithelial side of the membrane.
TREATMENT
Most cases resolve spontaneously in children, although some children will have persistent proteinuria.
Nephrotic syndrome is best controlled with salt restriction and diuretics.
Electron microscopy of membranous glomerulonephritis shows a “spike-and-dome” pattern on the epithelial side of the GBM.
FEVER/EXERCISE/POSTURAL PROTEINURIA
DEFINITION
Proteinuria up to 150 mg/day may be normal.
Proteinuria consists of plasma, albumin, and Tamm-Horsfall proteins.
Postural proteinuria: Proteinuria is from lying in supine to upright position due to unknown cause.
Febrile proteinuria: Proteinuria caused by fever > 101°F (41.1°C). Febrile proteinuria will normalize after fever resolves.
Exercise proteinuria: Proteinuria following vigorous exercise. Usually resolves after 48 hours of rest.
Persistent proteinuria = glomerular lesion.
The most common cause of proteinuria in children is orthostatic proteinuria.
Degrees of Proteinuria
1+: 30 mg/dL
2+: 100 mg/dL
3+: 300 mg/dL
4+: > 2,000 mg/dL
INTERSTITIAL NEPHRITIS–ACUTE AND CHRONIC
DEFINITION
Inflammation in the interstitium between the glomeruli in the areas surrounding the tubules.
RISK FACTORS
Acute: Allergy to medications (penicillin, cephalosporins, sulfonamides, rifampin, phenytoin, thiazides, furosemide, allopurinol, amphotericin B, NSAIDs) is the most common cause. Infections (especially in children), sarcoidosis, glomerulonephritis, and transplant rejection are also risk factors.
Chronic: Drugs (analgesics, lithium), infections, vesicoureteral reflux, urinary tract obstruction.
PATHOPHYSIOLOGY
Interstitial nephritis is often associated with tubular damage, edema, and necrosis between tubules.
SIGNS AND SYMPTOMS
Acute: Most patients present with ARF of generalized tubular dysfunction. Recent infections, new medications, fever, malaise, and signs of ARF should be investigated.
Chronic: Children usually present with symptoms of CRF such as nausea and vomiting, headache, fatigue, HTN, and growth failure.
DIAGNOSIS
Acute: Eosinophils in the urine suggest the diagnosis. A renal biopsy demonstrates an interstitial infiltrate of lymphocytes, plasma cells, eosinophils, and neutrophils and may help to differentiate acute interstitial nephritis (AIN) and ATN. Edema is present, and the glomeruli are typically normal.
Chronic: In chronic interstitial nephritis, the inflammatory cells consist of lymphocytes and plasma cells. Tubular fibrosis is present and the glomeruli are sclerosed secondary to ischemia. Renal papillary necrosis may be present.
TREATMENT
Treat renal failure.
Children with AIN may recover completely after withdrawal of the inciting agents. Children with chronic interstitial nephritis progress to ESRD.
SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)
DEFINITION
A systemic autoimmune disease characterized by fever, weight loss, rash, hematologic abnormalities, and arthritis.
Lupus nephritis is the most common manifestation of SLE in childhood.
PATHOPHYSIOLOGY
Immune complexes deposit into the glomeruli, causing characteristic kidney diseases.
See Table 14-2 for classification.
EPIDEMIOLOGY
Most common in adolescent females.
Uncommon in children < 8 years old.
SIGNS AND SYMPTOMS
See Table 14-2.
Renal disease is more frequent in children.
DIAGNOSIS
Elevated serum levels of anti-Smith antibodies and anti-double-stranded DNA antibodies (anti-dsDNA antibodies) are highly specific for SLE.
Markers of disease activity:
Anti-double-stranded DNA.
Complement levels C3 and C4.
TABLE 14-2. SLE Nephritis—World Health Organization (WHO) Classification and Symptoms
TREATMENT
Immunosuppressive therapy (eg, prednisone, azathioprine) is used to help reduce/prevent flare-ups but cannot cure the disease.
RENAL VEIN THROMBOSIS (RVT) IN INFANCY
DEFINITION
Thrombus formation in the renal vein.
In infants, RVT is associated with dehydration, shock, and sepsis.
Occurs in infants born to mothers with diabetes mellitus.
In older children, RVT is associated with nephrotic syndrome (membranous nephropathy), cyanotic heart disease, hypercoagulable states, and contrast agents.
SIGNS AND SYMPTOMS
Acute gross hematuria
Oliguria
Flank masses
Flank pain
DIAGNOSIS
US shows enlarged kidneys.
Doppler flow studies show impaired (little) renal function.
UA shows proteinuria and/or hematuria.
TREATMENT
Correction of fluid and electrolyte abnormalities.
Prophylactic anticoagulation with heparin.
COMPLICATIONS
ARF (especially if bilateral).
Systemic HTN.
Sudden onset of gross hematuria and unilateral or bilateral flank masses. Think: Renal vein thrombosis. Must evaluate for hypercoagulable states.
NEUROGENIC BLADDER
DEFINITION
Abnormal innervation to the bladder and sphincter muscles, associated with spinal abnormalities such as CNS tumors, spina bifida, teratomas, and myelodysplasia.
SIGNS AND SYMPTOMS
Urinary incontinence.
Urinary retention.
Urinary tract infections (UTIs).
Renal dysfunction caused by urinary reflux from bladder to kidneys (upper tract deteriorations).
TREATMENT
Intermittent catheterization.
Anticholinergic medication (oxybutinin).
Surgical correction.
UROLITHIASIS
An 8-year-old boy presents with left flank pain radiating to his left testicle. The pain does not change with movement or positioning and is colicky in nature. Urine dip is positive for blood. Think: Urolithiasis.
The pain begins in the flank, extends around the abdomen, and may radiate into the groin. Ipsilateral costovertebral tenderness may be present. Children with a history of multiple UTIs may be at risk of renal stones. UA typically shows hematuria, but absence of hematuria does not exclude the diagnosis of urolithiasis. Metabolic evaluation should include measurement of uric acid, electrolytes, creati-nine, calcium, phosphorus, and bicarbonate. Serum PTH level should be obtained in the presence of hypercalciuria, hypercalcemia, or hypophosphatemia.
DEFINITION
Accumulation of urinary calculi in the urinary tract.
EPIDEMIOLOGY
More common in boys than girls (2:1), children with metabolic abnormalities, urinary tract abnormalities, neuropathic bladder, enterocystoplasty.
Only 7% of stones occur in children < 16 years of age.
ETIOLOGY
Most stones are made of calcium, struvite, uric acid, or cystine that accumulates in the calyx or bladder.
Calcium stones: Radiopaque stones due to intestinal calcium absorption or renal absorption.
Struvite stones: Radiopaque stones composed of magnesium, ammonium, and phosphate. Most commonly secondary to chronic UTIs by urea-splitting bacteria such as Proteus.
Uric acid stones: Radiolucent stones associated with high serum uric acid levels, such as hyperuricosuria, Lesch-Nyhan syndrome, after chemotherapy, myeloproliferative disorders, and inflammatory bowel disease.
Cystine stones: Radiopaque stones associated with cystinuria, an auto-somal-recessive disorder causing decreased absorption of dibasic amino acids (cystine, lysine, arginine, and ornithine) by the renal epithelial cells.
Metabolic disorders are often the cause of pediatric stones.
Hypercalciuria is the most common metabolic cause of stones.
SIGNS AND SYMPTOMS
Microscopic or gross hematuria.
Urinary tract obstruction.
Abdominal/flank pain radiating to the genitalia (renal colic).
Recurrent UTIs.
DIAGNOSIS
Plain abdominal x-ray will show radiopaque stones (calcium and struvite). Ninety percent of stones are radiopaque.
Abdominal CT can be better at detecting stones and will also yield information on the presence of hydronephrosis.
The most sensitive test for identifying stones in the urinary system is a noncontrast helical CT scan.
TREATMENT
Pain management: NSAIDs are mainstay; opiates occasionally needed.
IV hydration.
Remove calculi if they are > 5–6 mm via urethral stent or lithotripsy, especially if they are associated with obstruction and hydronephrosis.
Calcium stones: Treat with thiazide diuretic to reduce renal calcium excretion or potassium citrate, an inhibitor of calcium stones.
Struvite stones: Treat with antibiotics to prevent recurrence of bacterial infections.
Uric acid stones: Treat with allopurinol and urine alkalization.
Cystine stones: Treat with D-penicillamine to chelate cystine.
URINARY TRACT INFECTION (UTI)
A 2-month-old male infant presents with fever, vomiting, and fluid intake. A UA reveals 100 WBCs. Think: E coli UTI.
The initial manifestations may be nonspecific and may include irritability, fever, and vomiting. E coli is the most common organism in children of all ages. Urinalysis may show positive urinary leukocyte esterase, positive urinary nitrite, pyuria (> 5 WBC/hpf) and bacteriuria.
A 7-year-old girl presents with urinary urgency, frequency, suprapubic pain, and no flank pain or mass. UA shows many leukocytes, 2–5 RBCs, and no protein or casts. Think: Next step—urine culture.
Older children with UTI are more likely to develop localizing symptoms such as frequency, dysuria, and abdominal or flank pain. The definitive diagnosis of UTI requires a positive urine culture from a specimen obtained with sterile techniques. An appropriately collected urinary specimen is critical to make the diagnosis of UTI.
A hospitalized 6-month-old infant with a UTI remains febrile after adequate IV antibiotic treatment. Think: The next most appropriate diagnostic procedure is a renal US.
The classic clinical manifestations of upper UTI include fever and flank pain. The persistence of fever despite antibiotics is suggestive of upper UTI (pyelonephritis). Febrile UTI in children may indicate either an underlying anatomic abnormality or vesicoureteral reflux (VUR). Ultrasound evaluation may detect underlying condition that predisposes the infant or child to infection.
DEFINITION
Infection of the urinary system by bacterial pathogens. UTIs are often ascending infections from fecal/colonic flora.
The most common bacteria are E coli, followed by Klebsiella, Proteus, enteroccci, and Staphylococcus saprophyticus (among female adolescents).
UTIs are more common in males in the first year of life and more common in females afterwards.
UTI occurs in 3–8% of girls and 1–2% of boys.
Consider nosocomial UTIs with Pseudomonas and methicillin-resistant Staphylococcus aureus in institutionalized or recently hospitalized patients.
PREDISPOSING FACTORS
Female.
Uncircumcised male.
Vesicoureteral reflux/anatomic abnormalities.
Toilet training (wiping from back to front).
Tight clothing.
Bubble baths.
Nylon panties, bathing suit.
CLASSIFICATION OF UTIS
Pyelonephritis: Infection of the kidney characterized by abdominal or flank pain, fever, malaise, nausea, vomiting, and diarrhea.
Cystitis: Infection of the bladder. Common symptoms include dysuria, urgency, frequency, suprapubic pain, incontinence, and malodorous urine. Cystitis does not cause fever.
Asymptomatic bacteriuria: Presence of > 100,000/mL of a single bacterial organism on two successive urine cultures in a patient without any UTI-like symptoms.
SIGNS AND SYMPTOMS
Symptoms vary with age:
Neonates: Failure to thrive, feeding irregularities, diarrhea, vomiting, fever, hyperbilirubinemia.
1 month–2 years: Colic, irritability, gastrointestinal (GI) complaints.
> 2 years: Urgency, frequency, dysuria, abdominal and flank pain.
DIAGNOSIS
Gold standard: Urine culture. If child is not toilet trained, specimen should be obtained via suprapubic tap or catheterization.
Presence of > 100,000 colonies of a single bacteria or > 10,000 colonies in a symptomatic child or any bacterial growth from a properly obtained specimen.
Leukocytes > 5/hpf.
Hematuria.
White cell casts.
TREATMENT
Treatment varies depending on the age of the child:
Consider sepsis < 3 months of age with UTI.
2 months–2 years: UTIs are often associated with bacteremia in this age group, and 10–14 days of parenteral antibiotics is the treatment of choice. Trimethoprim-sulfamethoxazole, fluoroquinolones, and amino-penicillins are effective.
Older children: 5–7 days of oral antibiotics.
Pyelonephritis: 14-day therapy of β-lactam/cephalosporin. Antibiotics given intravenously initially, then switched to oral when clinical improvement is seen.
Further investigations:
All children under the age of 5 and all male children should have a renal US to identify anatomic abnormalities including hydronephrosis, dilation of distal ureters, or bladder hypertrophy and to rule out pyelonephritis.
Voiding cystourethrogram (VCUG) is performed by placing a catheter through the urethra into the bladder and instilling a radionuclide testing agent until the bladder is full and the child voids. Images are taken to record reflux disease. Indications for VCUG:
Females < 5 years old with UTI.
Females > 5 years old presenting with second UTI.
All males.
Febrile UTI.
Some experts recommend waiting 4–6 weeks after febrile UTI is treated to obtain VCUG.
Indications for admission:
Toxic-appearing child.
Pyelonephritis.
Child cannot tolerate oral antibiotics.
Perform a Gram stain on urine after obtaining a clean-catch specimen. A delay of 1–2 hours after receiving the specimen may cause bacterial multiplication and false positives.
VESICOURETERAL REFLUX
DEFINITIONS
Retrograde flow of urine from the bladder to the ureter and renal pelvis.
Reflux predisposes to (renal infections) pyelonephritis by facilitating the transport of bacterial from the bladder to the upper urinary tract.
Recurrent pyelonephritis can result in renal scarring and ESRD.
See Table 14-3 for grading of vesicoureteral reflux.
TABLE 14-3. Grading of Vesicoureteral Reflux
EPIDEMIOLOGY
VUR is seen in up to 50% of children with pyelonephritis.
Eighty percent of children with reflux are female.
Average age of diagnosis: 2–3 years.
SIGNS AND SYMPTOMS
Most reflux is diagnosed by VCUG during a workup for a UTI.
DIAGNOSIS/GRADING
VCUG or radionuclide cystogram.
TREATMENT
The goal of treatment is to prevent pyelonephritis and renal injury.
Children with low-grade reflux are managed medically with low-dose antibiotic prophylaxis (one-fourth to one-third dose of trimethoprim-sulfamethoxasole or nitrofurantoin) and UA and cultures every 3–4 months.
Surgical therapy is performed in children with breakthrough UTI on antibiotic prophylaxis, unresolving reflux, and bilateral grade IV or V reflux.
OVARIAN/TESTICULAR TORSION
A 15-year-old boy presents with severe pain in his right testicle. This occurred suddenly while he was playing basketball. A physical exam reveals a tender, swollen, firm testicle with a transverse lie. There is no cremasteric reflex on the right. Think: Testicular torsion.
Diagnosis is made mainly by clinical suspicion. Classical presentation includes nausea, vomiting, and severe acute testicular pain. An absent or decreased cremasteric reflex is the most sensitive physical sign for diagnosing testicular torsion. However, its presence does not exclude the diagnosis. Abnormal testicular orientation such as transverse lie is another clue. Doppler ultrasound is helpful in making the diagnosis and would show no blood flow. Immediate surgical exploration should be performed if the suspicion is high.
A 16-year-old previously healthy boy experiences a sudden onset of abdominal and scrotal pain. A physical examination shows severe tenderness in the inguinal canal on the right, and the right side of scrotum is empty. A UA is within normal limits. Think: Testicular torsion of an undescended testicle.
Most undescended testes are found either in or just distal to the inguinal canal. Torsion may occur in an undescended testis. Torsion of testicle should be considered in a boy with inguinal pain and/or swelling with an undescended testis. The most effective management is an immediate operation. Early management of the undescended testes may avoid these complications.
A 16-year-old boy presents with lower left abdominal pain and left testicular pain for 2 weeks. Palpation of the testes is normal except for isolated tenderness of the epididymis. Cremasteric reflex is normal. Think: Epididymitis.
Patients with epididymitis experience scrotal pain of gradual onset and the tenderness is localized to the epididymis. However, history and physical findings may not reliably differentiate torsion from epididymitis. Urinalysis may show pyuria. Congenital genitourinary anomalies may be present which predispose to recurrent infection.
DEFINITION
Twisting of the ovary or testicle on its respective vascular pedicle.
EPIDEMIOLOGY
Testicular torsion is the most common cause of testicular pain in boys > 12 years and is most often due to poor fixation of the testis inside the scrotum (bell clapper deformity) due to redundancy of the tunica vaginalis.
SIGNS AND SYMPTOMS
Ovarian torsion: Acute unilateral intermittent sharp lower abdominal pain.
Testicular torsion: Acute pain and swelling of the scrotum, absent cremasteric reflex. Testicle with horizontal lie.
DIAGNOSIS
Doppler US shows low blood flow but diagnosis should be made clinically to avoid delay in treatment.
TREATMENT
Manual detorsion, followed by surgical fixation (orchiopexy). Torsion is a surgical emergency.
Time is of the essence. The longer the ovary or testis remains torsed, the less the chance of salvaging it. Ninety percent of gonads survive if detorsion and fixation take place within 6 hours of symptom onset.
Often a bilateral condition, so opposite testes is also fixed to the posterior scrotal envelope during surgery.
POLYCYSTIC OVARIAN (PCO) SYNDROME/OVARIAN CYSTS
DEFINITION
PCO syndrome is the most commonly diagnosed ovarian cause of hirsutism.
Other causes of ovarian cysts include ovarian hyperthecosis.
PATHOPHYSIOLOGY
Anovulation:
Lack of characteristic hormonal fluctuations result in chronic anovulation and levels of progesterone due to the absence of a corpus luteum.
Unopposed estrogen results in irregular shedding of a hyperplastic endometrium.
Endometrial hyperplasia predisposes PCOS patients to endometrial carcinoma.
Elevated testosterone: levels of LH stimulate ovarian follicular theca cells to produce androgens, resulting in hirsutism.
SIGNS AND SYMPTOMS
Hirsutism, amenorrhea, anovulatory infertility, obesity, insulin resistance.
DIAGNOSIS
Elevated LH-to-FSH ratio of 3:1 (normal LH:FSH is 1.5:1)
US shows multicystic ovaries (20–100 cystic follicles in each ovary) resembling a “pearl necklace.”
TREATMENT
Ovarian suppression with combined estrogen/progestin oral contraceptive pills. The progestin component will help reduce endometrial hyperplasia.
Hirsutism can be treated with oral contraceptives, spironolactone, and electrolysis.
UNDESCENDED TESTES
DEFINITION
Failure of one or both testes to descend into the scrotum. The undescended testes are usually found in the inguinal canal, but some may be ectopic.
Cryptorchidism is the failure of the testes to descend by 6 months of age.
SIGNS AND SYMPTOMS
Cryptorchidism is associated with infertility, malignancy especially seminomas, hernias, and testicular torsion.
The risk of malignancy is even if the testes are surgically placed into the scrotum; however, repositioning the testes makes them accessible for periodic examinations.
Orchiopexy also helps to decrease the risk of testicular torsion by decreasing the mobility of the testis. Usually performed between 9 and 15 months of age.
TREATMENT
If testes are not palpated in the inguinal canal: Orchiopexy after age 12 months.
If testes are palpated in the inguinal canal: Hormonal therapy with luteinizing hormone–releasing hormone (LHRH) is controversial.
PainFUL ulcers:
Chancroid
Herpes
PainLESS ulcers:
Lymphogranuloma venereum (LGV)
Syphilis
SEXUALLY TRANSMITTED DISEASES (STDs)
A 15-year-old female presents to the ED with a fever for 1 day, dyspareunia, and vaginal discharge. She had unprotected sexual intercourse with a new male partner 2 weeks ago. Physical exam reveals adnexal tenderness, cervical motion tenderness, and a friable cervix. Think: Pelvic inflammatory disease.
Acute PID is a condition of young females. Risk factors include younger age at first intercourse and unprotected sex. The most common clinical features are lower abdominal pain, vaginal discharge, and adnexal tenderness. Empiric treatment for PID is recommended in sexually active young women with pelvic or lower abdominal pain if any one of the following minimum criteria is present (cervical motion tenderness, adnexal tenderness, or uterine tenderness).
Urethral discharge:
Gonorrhea
Chlamydia
Trichomonas
A 3-year-old girl presents with malodorous bloody vaginal discharge. Think: Foreign body.
Presentation: foul-smelling discharge or vaginal bleeding. Most common vaginal foreign body in children is toilet paper. A gentle examination should be performed. Complete history and focused physical examination are usually sufficient to make this diagnosis.
“Whiff test”: Two drops of KOH mixed with the discharge and heated onto a slide produces a fishy smell. This is characteristic of both Trichomonas and bacterial vaginosis.
See Table 14-4.
EPIDEMIOLOGY
Sexually transmitted diseases affect ∼25% of adolescents.
In infants and children, detection of an STD is an important clue to sexual abuse.
RISK FACTORS
Sexual contact with person(s) with a history of STD.
Multiple sexual partners.
More than two sexual partners during previous 12 months.
Intercourse with new partner during last 2 months.
No contraception or use of nonbarrier methods.
Street involvement (eg, homelessness).
Injection drug use.
“Survival sex” (eg, exchanging sex for money, drugs, shelter, or food).
Men who have sex with men.
Due to the high rate of concurrent gonorrhea infection with chlamydia infection (60%), treatment for gonorrhea should always be included with that for chlamydia (and vice versa).
SCREENING AND PREVENTION
All women should receive a Papanicolaou smear annually to screen for cervical dysplasia within the three years of first sexual experience or at the age of 21. In addition, screen all asymptomatic sexually active patients annually for HIV, herpes simplex virus (HSV), hepatitis B, and chlamydia.
Educate all children how to the risk of contracting STDs, such as limiting number of sexual partners, using condoms, having regular check-ups, and engaging in open discussions about STDs.
If sexual abuse is suspected, social services and law enforcement agencies must be contacted to ensure the child’s protection.
TABLE 14-4. Sexually Transmitted Diseases in Children
PHIMOSIS/PARAPHIMOSIS
DEFINITION
Phimosis: Inability to retract the prepuce (foreskin) over the glans penis. Phimosis is normal in (boys) males younger than 3 years of age. In older males, phimosis is considered pathologic and may be due to the inflammation at the tip of the foreskin.
Paraphimosis: Inability to reduce to foreskin due to venous congestion of the distal foreskin. Paraphimosis can progress to arterial compromise 
penile infarction/necrosis and gangrene.
Risk factors for phimosis/paraphimosis:
Poor hygiene recurrent balanitis.
Repeated catheterization.
Forceful retraction of the foreskin resulting in scarring/phimosis.
Penile piercing.
Do not force retraction of the foreskin in phimosis. This may paraphimosis.
SIGNS AND SYMPTOMS
Phimosis may cause urinary retention secondary to pain or obstruction of the urethra.
The most acute complication of phimosis is paraphimosis.
TREATMENT
Phimosis: Steroid cream applied to the foreskin or manual stretching to loosen the phimotic ring. Circumcision is recommended for chronic phimosis in children > 10 years old.
Paraphimosis: Lubrication and manual compression of the foreskin and glans. Superficial vertical incision of the ligating band may be needed in refractory cases. Treatment is directed at reducing penile edema and restoring the foreskin to its original position as paraphimosis is a urologic emergency.
HYPOSPADIAS
DEFINITION
Ventral opening of the urethra on the penile shaft due to incomplete development of the foreskin “dorsal hood.”
Hypospadias is sometimes associated with in vivo exposure to estrogens or antiandrogens.
Associated with cryptorchidism and chordee (congenital malformation in which the head of the penis curves downward or upward).
It is important to not circumcise children with hypospadias, as the foreskin is used in the repair.
TREATMENT
Surgical repair at 6–12 months.
EPISPADIAS
Dorsal opening of the urethra on the penile shaft.
Associated with more serious congenital abnormalities such as bifid phallus, bladder, and/or cloacal exstrophy.
TREATMENT
Surgical repair recommended within first 2 months of life.