USMLE step 1 : Q 26-28 : Answers

Question Number 26

Correct Answer: A

Explanation:
A urethral stricture occurs when scar tissue forms in the urethra. The stricture blocks the urethra and may cause the urinary stream to slow to the point where the patient cannot urinate. Causes for urethral stricture formation include trauma ( sharp blow to the base of the penis), gonorrhea, or previous instrumentation of the urinary tract On questioning, the patient stated that he underwent cystoscopy 2 months previously. . Gonococcal strictures are the commonest cause of infective urethral strictures but rarely cause fistulas. Fistulas are typically secondary to TB infection and may be multiple. The genital involvement in Behcet's syndrome are ulceration of the labia or scrotum

 

Question Number 27

Correct Answer: A

Explanation:
Individuals with urinary lithiasis rarely can find comfort in any position. They sit, stand, pace, recline, and move continuously in an attempt to shake off whatever it is that is creating discomfort. Fever is not present unless urinary infection occurs along with the calculus. Pulse rate and blood pressure may be elevated because of pain and agitation. Examination of the abdomen reveals moderate deep tenderness on palpation over the location of the calculus and the area of the loin. Urinalysis in most patients with urinary lithiasis reveals the presence of microscopic or gross hematuria.

 

Question Number 28

Correct Answer: B

Explanation:
Hematuria and irritative bladder symptoms, such as dysuria or urinary frequency, are the most common presenting symptoms of bladder cancer. Most patients have hematuria, which is frequently gross but occasionally microscopic. The hematuria can be episodic. Irritative urinary symptoms, such as urgency, dysuria, and frequency without hematuria, particularly in the absence of infection, should lead to an evaluation for bladder cancer. Larger tumors may cause bladder outlet obstruction or ureteral obstruction resulting in hydronephrosis. Bilateral ureteral obstruction leading to azotemia is rare. Bladder tumors may cause pelvic pain by infiltrating regional nerves or bone, may cause lymphedema as a result of lymphatic obstruction from lymph node metastasis, or may present as manifestations of metastatic disease to bone, lungs, or liver. If bladder cancer is suspected, an intravenous pyelogram (IVP) should be undertaken to locate filling defects in the bladder and in the upper tracts. In addition, cystoscopy should be performed to locate the tumor and to facilitate biopsy for pathologic confirmation and to determine depth of invasion. Urinary cytologic analysis is a useful adjunct in the initial assessment and follow-up evaluation. Newer tests including an evaluation of the urine for bladder cancer antigens, such as bladder tumor antigen and nuclear matrix protein 22, and the genetic fingerprinting of exfoliated cells is under study. Evaluation of metastatic sites is essential, including abdominal pelvic CT, chest radiograph, and bone scan.