hypocitraturia

Hypocitraturia refers to a condition characterized by abnormally low levels of citrate in the urine. Citrate is a metabolic intermediate that plays a crucial role in preventing the formation of calcium-containing kidney stones. It achieves this by binding to calcium ions in the urine, forming soluble complexes that are less likely to crystallize. Additionally, citrate inhibits the growth and aggregation of calcium oxalate and calcium phosphate crystals, the most common components of kidney stones.

The primary cause of hypocitraturia is often an underlying metabolic disorder or a genetic predisposition. Conditions such as distal renal tubular acidosis, certain gastrointestinal disorders leading to diarrheal states (like ileostomy or chronic diarrhea), and metabolic acidosis can contribute to reduced urinary citrate excretion. Certain medications, including diuretics and topiramate, have also been associated with hypocitraturia.

The clinical significance of hypocitraturia lies in its strong association with an increased risk of developing calcium nephrolithiasis, commonly known as kidney stones. When citrate levels are insufficient, the urine becomes supersaturated with calcium, and the inhibitory effect of citrate on crystal formation is diminished, promoting stone formation. Symptoms of kidney stones can include severe pain in the flank or back, blood in the urine, nausea, and vomiting.

Diagnosis of hypocitraturia is made through a 24-hour urine collection and analysis to measure citrate levels. Treatment focuses on addressing the underlying cause if identifiable and on increasing urinary citrate excretion. This can involve dietary modifications, such as increasing intake of fruits and vegetables, and sometimes potassium citrate supplementation. Maintaining adequate hydration is also essential in preventing kidney stone formation.