Introduction

HIV infection is associated with a wide range of renal and metabolic disturbances [1]. Electrolyte and acid-base disorders are fairly common, particularly in hospitalized patients. These include hyponatremia, hyperkalemia, and metabolic acidosis. Acute renal failure may occur, most typically as a consequence of drug therapy. Other common syndromes include hematuria, pyuria, and proteinuria; it is important to have a plan of evaluation for each of these clinical syndromes. Glomerular disease is less common and most typically manifests as focal segmental glomerulosclerosis in African-Americans and proliferative glomerulonephritis in patients of other ethnic backgrounds.

Fluid and electrolyte disorders: water, sodium and potassium

Hyponatremia is the most common electrolyte disorder in HIV-infected patients. In a longitudinal study of pediatric HIV patients, the incidence of hyponatremia was about 25% and the major cause was the syndrome of inappropriate secretion of anti-diuretic hormone (SIADH) [2]. The other common cause is volume depletion due to gastrointestinal losses and poor fluid intake. Other causes include adrenal insufficiency and drugs, including diuretics. Evaluation of hyponatremic patients involves clinical assessment of intravascular volume status and measurement of random urine sodium and creatinine concentrations. In the setting of hyponatremia and sodium depletion (extracellular volume depletion, as manifested by orthostatic hypotension), urine sodium <10 mEq/l indicates extra-renal saline loss (e.g. diarrhea) and urine sodium >10 mEq/l suggests renal saline losses (e.g. diuretics or renal salt wasting).