Wallach's Interpretation of Diagnostic Tests: Pathways to Arriving at a Clinical Diagnosis (537 page)

Salerno F, Gerbes A, Gines P, et al. Diagnosis, prevention and treatment of hepatorenal syndrome in cirrhosis.
Gut.
2007;56:1310–1318.

HYPERCALCEMIC NEPHROPATHY

   Definition

This renal condition is caused by increased levels of calcium in the blood due to conditions such as hyperparathyroidism, sarcoidosis, vitamin D intoxication, milkalkali syndrome, or multiple myeloma or other malignancies.

   Laboratory Findings

   Increased serum calcium level (12–15 mg/dL).

   Decreased urine osmolality due to reduced renal concentrating ability manifested by polyuria and polydipsia.

   Proteinuria is usually slight or absent.

   Later findings include decreased GFR, decreased renal blood flow, and azotemia.

   Renal insufficiency is slowly progressive and may sometimes be reversed by correcting hypercalcemia.

HYPERCALCIURIA

   See calculi in Chapter
7
, Genitourinary System Disorders.

   Hypercalciuria is the most common disorder found in patients with nephrolithiasis (40–50% of cases). It is defined as urinary calcium excretion of >300 mg/day in men and >250 mg/day in women assuming a regular, unrestricted diet. It can also be defined as urinary calcium excretion of >4 mg/kg of body weight per day (for either sex or children) or a urinary concentration of more than 200 mg of calcium per liter.

   Types of hypercalciuria:

   Renal: due to abnormal renal tubular reabsorption. It is one tenth as common as the absorptive type.

   Absorptive: due to primary increase in intestinal calcium absorption.

   Resorptive: due to primary hyperparathyroidism.