A 35-year-old woman comes to the office due to blood in her urine. She has been working in her yard for 2 days creating a new garden. Review of systems is positive for recurrent bilateral flank discomfort. The patient has no fever, chills, vomiting, dysuria, or urinary frequency. She has never had blood in her urine before. She is sexually active with a male partner and uses condoms for contraception. The patient does not use tobacco, alcohol, or illicit drugs. Her father died from kidney disease at age 40. Temperature is 37 C (98.6 F), blood pressure is 180/120 mm Hg in both arms, and pulse is 82/min and regular. BMI is 40 kg/m². Cardiopulmonary examination shows no abnormalities. The abdomen is soft and without bruits. Laboratory results are as follows: Which of the following is the most likely diagnosis?

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11ec25c8_d867_c922_bc81_a5436c982e3d_MD0003_00 This patient most likely has autosomal dominant polycystic kidney disease (ADPKD). Patients begin developing renal cysts early in life; by mid-adulthood the cysts become large and numerous enough to cause clinical disease. Recurrent flank pain and hematuria are common in patients with ADPKD; these symptoms often result from cyst rupture that can be triggered by activities involving bending and exertion (eg, yard work). Hypertension is a typical early disease manifestation that results from localized renal ischemia with increased renin secretion. As the disease advances, patients experience progressive renal dysfunction (eg, elevated creatinine in this patient) that eventually leads to end-stage renal disease. Early in the disease process, patients also develop a urinary concentrating defect (evidenced by low specific gravity on urinalysis), likely due to renal tubular destruction. In effect, a mild nephrogenic diabetes insipidus is created with resulting increased circulating vasopressin levels. The high vasopressin levels may encourage renal cyst growth, and vasopressin-2 receptor antagonists (eg, tolvaptan) have been shown to slow ADPKD progression in some patients. Other treatments for ADPKD are mostly supportive and involve minimizing risk factors for worsening of chronic kidney disease. (Choice A) Bladder cancer most commonly presents with hematuria but typically occurs in older patients with significant smoking history. It is unlikely in this young woman with no smoking history and would not explain her renal dysfunction. (Choice B) Glomerulonephritis can occur due to rheumatologic disease (eg, systemic lupus erythematosus) or vasculitis (eg, polyangiitis with granulomatosis) and may affect young patients. Although hematuria and hypertension are a common presentation, red blood cell casts and protein are expected on urinalysis. (Choice C) Nephrolithiasis is a common manifestation of ADPKD and typically presents with hematuria and flank pain. However, nephrolithiasis alone would not explain this patient's early-onset hypertension and family history of early death from renal disease. (Choice E) Rhabdomyolysis results from excessive skeletal muscle breakdown following injury or intense exertion. It causes myoglobinuria, which appears grossly similar to hematuria and is mistakenly detected as blood on urinalysis. However, it is not true hematuria and no red blood cells are present on urine microscopy. (Choice F) Urinary tract infection (UTI) often causes hematuria; however, leukocyte esterase, nitrites, and/or bacteria are also expected on urine studies. In addition, this patient has no dysuria or urinary frequency to suggest UTI. Educational objective: Autosomal dominant polycystic kidney disease commonly presents with hypertension, hematuria, and recurrent flank pain in patients in their 30s or 40s. Treatment is mostly supportive, although vasopressin-2 receptor antagonists (eg, tolvaptan) may slow disease progression in some patients. References: Autosomal dominant polycystic kidney disease. (http://www.ncbi.nlm.nih.gov/pubmed/30819518) Vasopressin, copeptin, and renal concentrating capacity in patients with autosomal dominant polycystic kidney disease without renal impairment. (http://www.ncbi.nlm.nih.gov/pubmed/22516290)

A 35-Year-Old Woman Comes to the Office Due to Blood