Jennifer A. Hagerty, DO
BASICS
DESCRIPTION
• Typically 1st sign of impaired renal function
• Anuria: No urine output
• Oliguria: Significantly reduced urine volume
– <1 mL/kg/h in infants
– <0.5 mL/kg/h in children
EPIDEMIOLOGY
Incidence
• 10% of newborns in the NICU (1)[C]
• 2–5% of children in the ICU (1)[C]
• 10–30% of children undergoing cardiac surgery (1)[C]
Prevalence
N/A
RISK FACTORS
• Hypovolemia
• Intrinsic renal disease
• Urinary tract obstruction
• Glomerulonephritis
• Nephrotoxic medications
Genetics
Dependent on diagnosis
PATHOPHYSIOLOGY
• Prerenal failure
– Most common cause of oliguria
– Hypoperfusion in otherwise normal kidneys
– Administration of nephrotoxic agents can precipitate oliguria when reduced renal perfusion is present
• Intrinsic renal failure
– Associated with structural kidney damage including acute tubular necrosis (ischemia, drugs, or toxins), primary glomerular diseases, or vascular lesions
– Altered tubule cell metabolism leads to ischemia, then altered metabolism and subsequently cell death
• Postrenal failure
– Obstructive uropathy
– Usually reversible with relief of the obstruction
ASSOCIATED CONDITIONS
• Pre-existing renal disease
• Obstructive uropathy
GENERAL PREVENTION
• Maintain adequate hydration
• Avoid nephrotoxic agents in children with underlying renal disease
DIAGNOSIS
HISTORY
• Age, sex
• Duration of symptoms
• Pre-existing renal disease
• Medications
• Symptoms of urinary tract obstruction
• Antenatal history
• Family history
PHYSICAL EXAM
• Signs of hypovolemia
– Tachycardia
– Hypotension
– Decreased skin turgor
– Dry mucous membranes
• Signs of hypervolemia
– Edema
• Signs of obstructive uropathy
– Palpable bladder or kidney
– Meatal stenosis
DIAGNOSTIC TESTS & INTERPRETATION
Lab
• Urinalysis
– Protein, red cells, casts: Possible glomerulonephritis
– Low specific gravity: Possible acute interstitial nephritis or intrinsic renal disease
– High specific gravity: Possible prerenal cause
– Nitrate: Suggests infection
• Basic metabolic panel
– BUN/Cr ratio: >20 suggests prerenal cause
– Evaluate renal function and electrolyte balance
Imaging
• Renal and bladder ultrasound for hydronephrosis and bladder distention and thickening of the wall
• VCUG for suspected bladder outlet obstruction
• Nuclear renal scan for function, dysplasia, and drainage
Diagnostic Procedures/Surgery
Placement of a urethral catheter
Pathologic Findings
Dependent on diagnosis
DIFFERENTIAL DIAGNOSIS
• Prerenal
– Burns
– Dehydration
– Drugs
– GI losses
– Heart disease
– Hemorrhage
– Respiratory distress syndrome
– Shock/sepsis
• Intrinsic renal disease
– Acute tubular necrosis
– Exposure to nephrotoxins (drugs, myoglobin, uric acid)
– Congenital kidney disease
– Renal vascular abnormalities
– Glomerulonephritis
• Urinary tract obstruction
– Neurogenic bladder
– Posterior urethral valves
– Meatal stenosis
– Bilateral UPJ or ureteral obstruction or unilateral in a solitary kidney
– Bilateral obstructing calculi
TREATMENT
GENERAL MEASURES
• Treatment of the underlying cause
• Appropriate medical managements for acid–base disorder, fluid imbalance, electrolyte imbalance (such as hyperkalemia, hyperphosphatemia, hypocalcemia)
• Strict volume monitoring of input and output
• Avoidance of nephrotoxic agents (NSAIDs, ARBs (angiotensin receptor blockers), ACEIs (angiotensin-converting-enzyme inhibitors))
MEDICATION
First Line
Hydration to optimize cardiac output and volume status
Second Line
• Diuretics considered if adequate intravascular volume status and patient remains oliguric
• Hemodialysis or peritoneal dialysis to be considered if severe electrolyte abnormalities or volume overload
SURGERY/OTHER PROCEDURES
Relief of obstruction with urethral catheter, ureteral stenting, or nephrostomy tube
ADDITIONAL TREATMENT
Radiation Therapy
N/A
Additional Therapies
N/A
Complementary & Alternative Therapies
None
ONGOING CARE
PROGNOSIS
• Acute oliguria is often completely reversible if recognized and treated promptly
• Small increases in serum creatinine can be indicative of worsening outcome (2)[C]
COMPLICATIONS
• Progression to permanent renal injury
• Infections secondary to uremia leading to impaired defenses
• Cardiovascular complications secondary to fluid overload and electrolyte abnormalities
• Neurologic changes: Confusion, lethargy, and seizures
• Gastrointestinal effects: Anorexia, nausea, and vomiting
FOLLOW-UP
Patient Monitoring
• Serial renal function testing until resolution of anuria/oliguria
• Imaging based on diagnosis
– Monitor renal/bladder ultrasound for obstructive uropathy
Patient Resources
• American Society of Pediatric Nephrology: www.aspneph.com
• National Kidney Foundation: www.kidney.org
REFERENCES
1. Schneider J, Khemani R, Grushkin C, et al. Serum creatinine as stratified in the RIFLE score for acute kidney injury is associated with mortality and length of stay for children in the pediatric intensive care unit. Crit Care Med. 2010;38:933–939.
2. Askenazi DJ, Feig DI, Graham NM, et al. 3–5 year longitudinal follow-up of pediatric patients after acute renal failure. Kidney Int. 2006;69:184–189.
ADDITIONAL READING
• Daniels RC, Bunchman TE. Renal Complications and therapy in the PICU: Hypertension, CKD, AKI, and RRT. Crit Care Clin. 2013;29:279–299.
• Fortenberry JD, Paden ML, Goldstein SL. Acute Kidney Injury in Children. Pediatr Clin North Am. 2013;60:669–688.
See Also (Topic, Algorithm, Media)
• Acute Kidney Injury, Adult (Renal Failure, Acute)
• Acute Kidney Injury, Pediatric
• Acute Tubular Necrosis
• Anuria and Oliguria, Adult
• Chronic Kidney Disease, Pediatric
• Posterior Urethral Valves
• Ureteropelvic Junction Obstruction
• Urinary Retention, Pediatric
CODES
ICD9
• 276.52 Hypovolemia
• 599.60 Urinary obstruction, unspecified
• 788.5 Oliguria and anuria
ICD10
• E86.1 Hypovolemia
• N13.9 Obstructive and reflux uropathy, unspecified
• R34 Anuria and oliguria
CLINICAL/SURGICAL PEARLS
• Prerenal oliguria is typically reversible with complete return of renal function within 24–72 hr.
• Avoid nephrotoxic agents in patients with underlying intrinsic renal failure.