Autosomal Dominant Polycystic Kidney Disease

A 30-year-old man presented with severe left flank pain radiating to his abdomen and gross hematuria of 5 to 10 days’ duration. He also reported a 4- to 6-month history of nausea with intermittent vomiting, anorexia, and progressive weight loss. He took no medications and had no allergies. Blood pressure was 164/103 mm Hg; heart rate, 124 beats per minute; and temperature, 39.2°C (102.5°F). Auscultation revealed a grade 2/6 systolic heart murmur and minimal bibasilar lung crackles. The patient’s abdomen was distended; palpation disclosed bilateral abdominal masses. Sodium level was 137 mEq/L; potassium, 4.2 mEq/L; bicarbonate, 17.5 mEq/L; and chloride, 106 mEq/L. Blood urea nitrogen level was 68 mg/dL; serum creatinine, 8.3 mg/dL; hemoglobin, 5.1 g/dL; and hematocrit, 15.5%. Urinalysis was notable for specific gravity of 1.009, 2+ protein, more than 20 red blood cells per high-power field, and 6 to 10 white blood cells per high-power field. The patient was admitted to the ICU. A CT scan of the abdomen revealed massive bilateral polycystic kidneys with an area of hemorrhage and possible infection within the cysts (arrow). Ursula C. Brewster, MD, of New Haven, Conn, diagnosed autosomal dominant polycystic kidney disease (ADPKD), the most common hereditary renal disease and the fourth most common cause of end-stage renal disease. From 1 in 400 to 1 in 1000 Americans are affected.1 Mutations in 3 different genes can account for its development. The PKD1 gene—which is responsible for ADPKD1, the most common disorder— is present on the short arm of chromosome 16. The PKD2 gene is located on chromosome 4, and the chromosomal location of PKD3 has not been determined. Although multiple organs are involved, ADPKD is predominantly a renal disorder with various clinical manifestations. Kidney involvement consists mainly of formation of numerous cysts of varying size. This leads to an increase in kidney size and sometimes to massive nephromegaly. Complications of renal cysts include hypertension, nephrolithiasis, renal failure, hematuria, and acute or chronic flank pain. Acute clinical manifestations, as seen in this patient, can develop from rupture, hemorrhage, or infection of the cyst. It is often difficult to distinguish these various processes without renal imaging. A CT scan can visualize hemorrhagic cysts, fluid-filled cysts, and cyst rupture; however, determination of infection within a cyst is difficult. Treatment of cyst rupture and hemorrhage is supportive and includes pain control, red blood cell transfusions, and correction of any underlying coagulopathies. Rarely, a patient may require nephrectomy. Cyst infection is treated with antibiotics (ciprofloxacin, trimethoprim-sulfamethoxazole, or chloramphenicol) that penetrate the cyst and accumulate in cyst fluid. Cyst drainage is rarely required to resolve infection. This patient was treated with intravenous ciprofloxacin for possible cyst infection. Three units of packed red blood cells was transfused, and subcutaneous erythropoietin therapy was initiated. The patient’s flank pain and fever eventually resolved, and the hematocrit stabilized. Renal replacement therapy was started. The patient remains dependent on dialysis.