RENAL AND GENITOURINARY
EMERGENCIES
Uric acid stones are
radiolucent.On the boards, suspect AAA in
any patient over 50 presenting
with flank pain!SYMPTOMS/EXAM
■ Abrupt onset of extreme colicky flank pain radiating to the groin.
■ Patients frequently are unable to lay still.
■ Nausea/vomiting, urinary urgency, and frequency may occur.
■ Fevers and chills if concomitant infection.DIFFERENTIAL
■ The most critical diagnosis in differential is AAA.
■ Acute papillary necrosis
■ Ischemic necrosis of the renal papillae →sloughed papillae, which
may lead to obstruction and infection.
■ Seen most commonly in patients with diabetes mellitus, sickle cell
disease, and chronic NSAID use.
■ Other considerations include pyelonephritis, testicular torsion.DIAGNOSIS
■ Hematuria is common (gross or microscopic), but absence of RBCs does
notexclude stones.
■ Urinary pH:
■ pH > 7.6 →suspect urea-splitting organisms.
■ pH < 5 →suspect uric acid crystalluria.
■ Bacteriuria suggests infection.
■ BUN/Cr—if solitary kidney, transplant, chronic renal failure.
■ Imaging:
■ Plain radiographs—low specificity; calcium, struvite and cystine
stones are radiopaque.
■ Helical CT—standard imaging modality; can identify other pathology,
no contrast, rapid.
■ IVP—provides functional information; findings consistent with
obstruction:delayed nephrogram, columnization (entire ureter visible),
hydronephrosis;requires IV contrast.
■ Ultrasound—less reliable for small stones; can be used in pregnant or
pediatric patients.TREATMENT
■ Supportive care with IV fluids and analgesia
■ NSAIDs are first line: Shown to decrease both renal capsular pressure
(through decreased GFR) and ureterospasm
■ Stones <5 mm: Likely to pass spontaneously within 4 weeks
■ Stones >8 mm: Unlikely to pass, often require lithotripsy or surgical
intervention
■ Medical expulsive therapy may be helpful:
■ Ureteral antispasmodic: Tamsulosin (Flomax)
■ Anti-inflammatory agent: Prednisone
■ Urology follow-up
■ Admission criteria:
■ Obstruction with concomitant infection
■ Intractable pain or vomiting
■ Urinary extravasation
■ Solitary kidney
■ Acute renal insufficiency
■ Severe underlying diseaseFive sites of ureteral
obstruction:
Calyx of kidney
Ureteropelvic junction
Pelvic brim
Ureterovesicular junction
(most common)
Vesicle orifice