The combination of severe acute flank pain and microscopic hematuria is suggestive of
A. Urinary bladder tumorB. Choledocholithiasis
C. Kidney tumor
D. Urolithiasis
Answer.
D. Urolithiasis
The combination
of severe flank pain (renal colic) and hematuria is highly suggestive of
urolithiasis. The formation of urinary stones relates to decreased urine volume
and increased urine concentrations of certain substances. Most stones contain
calcium (either calcium oxalate or calcium phosphate) and are seen in patients
with hypercalcinuria (with or without hypercalcemia), such as with
hyperparathyroidism or diffuse bone disease. Magnesium ammonium phosphate
stones are formed in alkaline urine as the result of ureaseproducing
(urea-splitting) bacteria such as Proteus. The ammonia released from the
breakdown of urea combines with magnesium and phosphate. These stones are large
and may fill the renal pelvis (staghorn or struvite calculi). Examination of
the urine with a dipstick reveals alkaline urine that is positive for esterase
(from the leukocytes in the urine) and nitrite (since Proteus reduces nitrate).
Uric acid stones may form in patients with hyperuricemia, such as patients with
gout or patients being treated for leukemias or lymphomas. Cystine stones are
rare, but may be found in children with hereditary defects in the renal
transport of some amino acids.
