Setting: office
CC: “My kidneys are failing, do I need dialysis?”
VS: BP: 152/92 mm Hg; P: 64 beats/minute; T: 98°F; R: 22 breaths/minute
HPI: A 67-year-old man with a history of hypertension and diabetes who has had renal insufficiency for several years now comes to the office for evaluation of his kidneys. The patient is obese and has had difficulty controlling both his diabetes and high BP. He is adherent to diet and tries to exercise.
PMHX:
Hypertension for 12 years
Diabetes for 8 years
Tobacco in the past; quit 15 years ago
Medications:
Lisinopril
Nifedipine
Sitagliptin
Glyburide
PE:
General: tired, but comfortable
Extremities: edema present
Chest: basilar rales bilaterally
Cardiovascular: S4 gallop; no murmurs
Initial Orders:
CHEM-7
UA
Complete blood count (CBC)
Which is not an indication for dialysis?
a. Fatigue
b. Hyperkalemia
c. Fluid overload
d. Encephalopathy
e. Metabolic acidosis
f. Pericarditis
Answer a. Fatigue
Everyone is fatigued or tired. This is too nonspecific a finding. All the others, potassium, fluid, pericarditis, acidosis, and encephalopathy are definitely indications for immediate dialysis. Despite control of BP and diabetes, many people have worsening renal dysfunction that will need dialysis. Your job is to detect who is having worsening creatinine clearance (<30 mL/minute) and will need dialysis before their condition gets bad enough to have metabolic acidosis and these other findings.
As usual, the patient returns in 1 to 2 weeks for evaluation of his laboratory test results.
Reports:
CHEM-7: BUN 48 g/dL; creatinine 4 mg/dL; potassium 4.9 mEq/L; bicarbonate 19 mEq/L
UA: protein 2+
CBC: hematocrit 32%; mean corpuscular volume (MCV) 85 fL
Renal failure decreases erythropoietin level, resulting in anemia (Figure 6-3).
Figure 6-3. Regulation of red blood cell production by erythropoietin. If the ability of blood to carry oxygen decreases because of a fall in numbers of red blood cells (e.g., normal cell death, pathological destruction of red blood cells, bleeding, etc.), the kidney senses lower partial pressure of oxygen (PO2) levels and increases the levels of erythropoietin (EPO). EPO then signals the bone marrow to increase production of red blood cells. (Reproduced with permission from Kibble JD, Halsey CR: The Big Picture: Medical Physiology, 1st ed. New York: McGraw-Hill; 2009.)
Orders:
Vascular access placement (arteriovenous [AV] graft)
Phosphate level
Calcium level
Nephrology evaluation
Acid production: 1 mEq/kg per day
There is no other way to excrete it than through the kidneys.
What is the most common cause of death with ESRD over time, even on dialysis?
a. Infection
b. Coronary disease
c. Sodium disorder
Answer b. Coronary disease
Renal insufficiency greatly accelerates the process of atherosclerosis.
The patient is seen by a vascular surgeon to place an AV graft. The patient is tired, but otherwise not significantly different than usual.
Reports:
Calcium level low
Phosphate level high
The calcium level is low from decreased levels of 1,25 dihydroxyvitamin D.
Replace calcium and vitamin D in renal failure.
Hyperparathyroidism from low calcium levels damages bone.
Orders:
Oral vitamin D and calcium carbonate replacement
CBC
CHEM-7
Move the clock forward 4 to 6 weeks. It takes this long to place an AV fistula and to allow it time to epithelialize and “mature” enough to be usable for dialysis.
In ESRD, always get a chemistry level every time you see a patient. Nephrology is a laboratory specialty. There is no significant physical finding to follow.
Report:
Chemistry: BUN 54 g/dL; creatinine 4.5 mg/dL
CBC: hematocrit 29%
Phosphate: elevated
Phosphate-lowering medications bind phosphate in the bowel:
• Calcium carbonate
• Lanthanum
• Sevelamer
Lanthanum and sevelamer are “rare earths” that bind phosphate in the bowel without affecting calcium levels. Once you get to the level of needing oral phosphate binders, patients definitely need dialysis. This is true even if pericarditis, encephalopathy, dangerous hyperkalemia, or fluid overload have not yet occurred. Do not wait for these dangerous developments on CCS.
Orders:
Phosphate binders
Calcium
Vitamin D
Dialysis
Erythropoietin
The only anemia of chronic disease treated with dialysis is ESRD.
After 6 weeks, the graft of the AV fistula should be sufficiently mature to allow vascular access. You should expect every patient on dialysis to be on:
Calcium replacement
Vitamin D
Oral phosphate binder (calcium carbonate, sevelamer, lanthanum)
Erythropoietin
BP and lipid control
This treatment should continue permanently.