CR - Renal & Urologic Disorders

Question 1

What is the most common stone composition of renal calculi?

Answer 1

Calcium (>75% of cases)
Calcium (oxalate or phosphate) is present in the majority of kidney stones

Less common are:
Struvite (magnesium-ammonia-phosphate) - associated with UTIs caused by urea-splitting organisms (e.g. proteus) and urine pH > 7
Uric acid may follow initiation of medications
Cystine-associated with inborn errors of metabolism, often reoccur and cause staghorn calcium and renal failure

Question 2

Name the most common causes of post-renal acute renal failure

Answer 2

• benign prostatic hypertrophy (older men)
• calculi (younger patients)
• cancer (prostate, bladder)
• pregnant uterus
• neurogenic bladder
• retro-peritoneal fibrosis
• meatal stenosis
• phimosis

Question 3

Clinical presentation: a 55 year old obese, diabetic male patient complains of sudden onset pain and itching “down there”. Examination reveals a scrotum that is swollen and edematous with an area of necrosis.

What is the diagnosis and what is your next step?

Answer 3

Fournier’s gangrene (idiopathic scrotal gangrene)

It is a surgical emergency and immediate urologic consultation for OR debridement is essential.

Polymicrobial by facultative organisms (e coli, klebsiella, enterococci) along with anaerobes (bacteroides, fusobacterium, clostridium, anaerobic or microaerophilic streptococci)

Question 4

If you suspect testicular torsion, what should be your next step?

Answer 4

Immediate urologic consultation

Doppler ultrasound is the test of choice to evaluate for testicular torsion, but should not delay urologic consult. If there will be a delay until urologic evaluation, manual detorsion with the “open book” method should be attempted. Salvage rate is 80-100% at less than 6 hours but nearly 0 at 24 hours

Question 5

90% of renal calculi that are up to ___ mm in diameter will pass spontaneously

Answer 5

5mm

90% of stones less than 5 mm will pass spontaneously

15% of stones 5-8 mm in size will pass spontaneously

5% of stones > 8mm in size will pass spontaneously

Question 6

Which HIV medication causes radiolucent kidney stones?

Answer 6

Indinavir

Calculi composed of pure indinavir are radiolucent. However, indinavir may also combine with other calculi-forming substances, such as calcium oxide, to produce radiopaque calculi.

Other types of radiolucent stones: uric acid stones

Question 7

What is the emergency treatment of paraphimosis if the foreskin cannot be reduced manually?

Answer 7

Dorsal slit

Local anesthesia is administered followed by a superficial dorsal midline incision of the band. This will decompress the glans and allow foreskin reduction

Question 8

What kind of urethral injury do you expect with straddle or blunt trauma to the male genitalia?

Answer 8

Anterior urethral injury should be suspected after “straddle injury” trauma. Anterior urethral injury is often missed by CT. Diagnosis for urethral injury is made by retrograde urethrogram, and should be done in any trauma patient with blood noted at the urethral meatus prior to placing a foley catheter

Question 9

What are the indications for emergent hemodialysis?

Answer 9

AEIOU

Acidosis: refractory metabolic acidosis (pH < 7.2) or severe acidosis with concomitant AKI

Electrolyte disturbance: severe refractory hyperkalemia (K > 6.5), sodium level (<115 or > 165)

Intoxication: intoxication or overdose with methanol, ethylene glycol, lithium, salicylates, isopropanol, barbituates, theophylline

Overload: fluid overload refractory to diuretics

Uremia: elevated BUN (typically > 100) with symptoms (pericarditis, encephalopathy, seizures, neuropathy, bleeding); bleeding dyscrasia secondary to uremia

Question 10

What are the main causes of priapism?

Answer 10

Medications (i.e. psychotropic medications, HTN meds like hydralazine, prazosin, CCBs, meds of impotence)

Thromboembolic (i.e. sickle cell disease)

Trauma (i.e. spinal cord injury)

Remember analgesia is important with all causees of priapism

Question 11

Clinical presentation: a 48 year old male presents for gradual onset of unilateral testicular pain. His exam yields tenderness and swelling to the posterior aspect of one testicle and pain improves with elevation of that testicle. What is the most likely diagnosis? dose his age matter? How is this treated?

Answer 11

Epididymitis

This presentation is consistent with epididymitis, but ultrasound still needs to be obtained to rule out torsion

Age matters as it affects the likely etiology and therefore treatment:

Men < 35 years old is most likely due to gonorrhea and/or chlamydia. Treat with ceftriaxone and doxycycline

Men > 35 years old is most likely due to UTI organisms such as e coli or pseudomonas. Treat with levofloxacin or ofloxacin