A 22-year-old African American man is evaluated for gross hematuria. He has had 5 days of grossly bloody urine every time he urinates. He denies associated flank or abdominal pain, back or abdominal trauma, fever, chills, or dysuria. There is no family history of either a bleeding disorder or kidney disease. He had a similar episode one year ago which lasted 5-10 days and resolved spontaneously. During that time, he had an unremarkable ultrasound of his kidneys. He has had no recent illnesses and he takes no medications. He had an uncomplicated knee surgery two years ago for a torn ligament. He had two girlfriends over the last year, and he used condoms occasionally.
He is very muscular with a BMI of 25 kg/m². His blood pressure is 133/82 mm Hg and pulse is 89 /min. He has no costovertebral angle tenderness. Abdominal exam is unremarkable. Laboratory results are as follows:

Which of the following is most likely to confirm this patient's diagnosis?

Question

A 22-year-old African American man is evaluated for gross hematuria. He has had 5 days of grossly bloody urine every time he urinates. He denies associated flank or abdominal pain, back or abdominal trauma, fever, chills, or dysuria. There is no family history of either a bleeding disorder or kidney disease. He had a similar episode one year ago which lasted 5-10 days and resolved spontaneously. During that time, he had an unremarkable ultrasound of his kidneys. He has had no recent illnesses and he takes no medications. He had an uncomplicated knee surgery two years ago for a torn ligament. He had two girlfriends over the last year, and he used condoms occasionally.
He is very muscular with a BMI of 25 kg/m². His blood pressure is 133/82 mm Hg and pulse is 89 /min. He has no costovertebral angle tenderness. Abdominal exam is unremarkable. Laboratory results are as follows:

Which of the following is most likely to confirm this patient's diagnosis?

Quizplus · Accepted Answer

This patient presents with recurrent gross hematuria. The absence of active urinary sediment makes intrinsic glomerular disease less likely. The normal ultrasound findings and lack of clinical symptoms also makes a structural kidney lesion, kidney stone, or urinary tract infection less likely. Since he is a young African American, there is a high probability of sickle cell trait causing his gross hematuria, and the diagnosis can be confirmed with hemoglobin electrophoresis. Hematuria and impaired ability to maximally concentrate the urine are two renal abnormalities encountered in patients with sickle cell trait. The renal papilla is a hypoxic and hypertonic environment, and papillary blood velocity is relatively slow - all conditions which favor sickling of cells. This results in renal papillary infarction and possible papillary necrosis. (Choice A) This patient has no symptoms of a systemic autoimmune disorder, red blood cell casts, or significant proteinuria on urinalysis to suggest the possibility of an autoimmune disorder and associated glomerulonephritis. (Choice B) Coagulation studies for gross hematuria would be less helpful in this patient not taking anti-coagulants and no other bleeding or bruising to suggest an inherited bleeding disorder. (Choice C) This patient has no symptoms to suggest bladder pathology, and he is not at high risk for bladder cancer. The cystoscopy may establish bleeding from above the bladder, but likely not a definitive diagnosis. (Choice E) Renal biopsy would be indicated for patients with dysmorphic red cells on urinalysis, red blood cell casts, significant proteinuria, or reduced glomerular filtration rate. This patient has none of the above indications. Educational objective: Hematuria and impaired ability to maximally concentrate the urine are two renal abnormalities encountered in patients with sickle cell trait. A hemoglobin electrophoresis can confirm the diagnosis. A rare complication of sickle trait is the development of renal medullary carcinoma, a highly malignant cancer that is seen almost exclusively in young patients with sickle cell trait. __________ References: Complications associated with sickle cell trait: a brief narrative review. (http://www.ncbi.nlm.nih.gov/pubmed/19393983)

A 22-Year-Old African American Man Is Evaluated for Gross Hematuria