2007 Flashcards
During maximal water reabsorption, the concentration of calcium within the kidney is highest in:
A. Bowman’s space
B. Henle’s loop
C. the proximal convoluted tubule
D. the distal convoluted tubule
E. the collecting duct
E
Maximal water reabsorption and maximal concentrations of urinary constituents (solutes), including calcium, occur in the collecting ducts.
A patient has recurrent nephrolithiasis and Type I renal tubular acidosis. Urolithiasis is most likely secondary to which metabolic problem:
A. excessive production of 1,25-dihydroxyvitamin D
B. lack of osteopontin
C. hypocitraturia
D. hyperoxaluria
E. hyperuricosuria
C
Hypocitraturia is present in > 75% of patients with renal tubular acidosis (Type 1) and associated nephrolithiasis. Osteopontin is an inhibitor of calcium oxalate crystallization, but is not a major factor in renal tubular acidosis. Hypercalciuria does occur in this setting, and may contribute to stone formation. Hyperoxaluria and hyperuricosuria are not associated with renal tubular acidosis.
During transurethral resection of a papillary bladder tumor on the left lateral wall, the patient has an obturator reflex. The bladder wall is thinned, but the tumor remains intact. Prior to resuming resection, the next step is:
A. reduce cutting current and distend bladder to minimize movement.
B. increase cutting current to minimize contact time and reduce bladder volume.
C. witch irrigating fluid from glycine to water to reduce conductivity.
D. Reduce cutting current and bladder volume
E. switch cutting current from pure to blend and secure left leg.
D.
Obturator nerve reflex may be evoked while resecting lesions on the lower lateral wall and bladder neck area, particularly in a thin patient. This reflex results in adductor spasms of the leg, as well as inward movement of the bladder wall during resection that could result in perforation. The obturator reflex may be prevented by decreasing the cutting current and avoiding distension of the bladder during resection. If this is not effective, paralytic agents can be used during general anesthesia, or in some cases an obturator nerve block can be administered.
Four months after a pubovaginal sling procedure, a woman requires CIC for persistent urinary retention. The next step is:
A. alpha-blocker
B. bethanechol
C. urethral dilation
D. continue CIC
E. urethrolysis.
E.
Lifelong CIC, although effective, is inappropriate if corrective surgery can restore normal voiding. Oral bethanechol has not been shown to effectively improve bladder contractility and is not indicated in the presence of bladder outlet obstruction. Alpha-blockers such as terazosin and urethral dilation are options but represent suboptimal therapy when compared to anatomic correction by urethrolysis. The ability of videourodynamics to predict surgical success and whether repeat anti-incontinence surgery should be performed at the same time as urethrolysis is controversial. Most patients however resume normal voiding and are continent without repeat surgery. If urinary retention occurs in someone undergoing a mid-urethral sling, sling incision should be undertaken much sooner.
An asymptomatic, 72-year-old man has a fever of 102° F of one week duration. A urine culture shows Aerobacter aerogenes greater than 10^5 col/ml. His WBC is 18,000. CT scan of the abdomen reveals an ill-defined mass in the upper pole of his right kidney on both the pre- and post-contrast studies. Ultrasound shows internal echoes in the mass. The mass is most likely:
A. segmental renal infarct
B. segmental pyelonephritis
C. renal tumor
D. xanthogranulomatous pyelonephritis.
E. Renal abscess.
E.
The clinical and radiographic findings are most consistent with renal abscess. Segmental pyelonephritis would have a normal pre-contrast study. In xanthogranulomatous pyelonephritis, a stone is usually present and the organism is most commonly an E. coli or Proteus. Given the clinical and radiographic findings, tumor is less likely.
A 65-year-old man has urinary incontinence. Three years earlier, he underwent radical retropubic prostatectomy for prostate cancer followed by adjuvant external beam radiation. His serum PSA is now undetectable. PVR is minimal. His urodynamic evaluation while taking anticholinergics is shown in the exhibit. The next step is:
A. transurethral collagen injection.
B. perineal sling.
C. artificial urinary sphincter.
D. augmentation cystoplasty.
E. augmentation cystoplasty and artificial urinary sphincter.
E.
The urodynamic tracing provided demonstrates evidence of poor compliance as indicated by a steady rise in the detrusor pressure with filling, and intrinsic sphincter deficiency as indicated by leakage of urine with increases in abdominal pressure. Adequate treatment of the incontinence requires improving the bladder compliance and increasing outlet resistance. This is best accomplished by an augmentation cystoplasty and artificial urinary sphincter. Placement of an artificial sphincter or sling alone risks damage to the upper urinary tract and continued incontinence despite the concomitant anticholinergic treatment because of persistently poor compliance. Augmentation cystoplasty alone will not resolve the stress urinary incontinence. Transurethral collagen injection is ineffective at increasing outlet resistance and will not address the compliance abnormality.
Widespread and indiscriminate human immunodeficiency virus (HIV) antibody testing is not recommended because the:
A. assays are not sensitive
B. false-negative rate is too high
C. false-positive rate is too high
D. risk of infection is low
E. prevalence of infection is high
C
Screening programs for HIV infection use a sequence of tests that start with an enzyme immunoassay (EIA) that has a sensitivity > 99%; the probability of a false-negative test result is remote. The specificity of current EIA tests is approximately 99% if repeated tests are positive. In this situation, more sensitive assays, such as a Western blot, are performed. A positive confirmatory test is considered evidence of HIV infection. The problem with indiscriminate testing is the non-zero, false-positive rate. Screening a population in which the prevalence of HIV is low will lead to the identification of more individuals who have falsely positive tests than individuals who actually have an infection. Selective screening of high-risk individuals or groups is more likely to accurately identify infected patients.
Relaxation of the external sphincter during a bladder contraction requires the presence of intact neural pathways between the pontine micturition center and the:
A. basal ganglia
B. cerebral cortex
C. sympathetic ganglia
D. anterior horn cell nucleus in the thoracolumbar spinal cord
E. Onuf’s nucleus in the sacral spinal cord
E.
Coordinated relaxation of the external urinary sphincter while voiding requires intact neurons between the pontine micturition center and the sacral spinal cord. Projections from the pons to Onuf’s nucleus in the sacral cord allows relaxation of the intrinsic portion of the external sphincter termed the rhabdosphincter. In addition, anterior horn cells in the sacral cord responsible for the pudendal nerve are modulated by the pons so that pelvic floor musculature (i.e. levator ani) do not contract during micturition. Interruptions of pathways between the pons and sacral spinal cord, such as with spinal cord injury and multiple sclerosis, can lead to the development of detrusor external sphincter dyssynergia. Suprapontine areas such as the cerebral cortex and cerebellum are not required for coordinated voiding, however can lead to detrusor overactivity when injured. Sympathetic innervation originates in the thoracolumbar spinal cord and is responsible for coordinating internal sphincter activity.
A 55-year-old man with bladder cancer undergoes a radical cystectomy with a planned orthotopic neobladder. Intraoperative frozen-section reveals negative lymph nodes but invasive TCC is detected at the prostatic apical margin. The best management is:
A. ileal neobladder
B. ileal neobladder and adjuvant pelvic radiotherapy
C. ileal neobladder and adjuvant chemotherapy
D. ileal conduit
E. continent cutaneous pouch
E.
The presence of invasive transitional cell carcinoma of the prostate carries a high risk of urethral recurrence and is a contraindication to orthotopic bladder replacement. All patients undergoing cystectomy should be counseled about the possibility that intra-operative findings might change the planned form of urinary diversion and all of the alternatives should be discussed prior to surgery. Of the choices listed, the continent cutaneous pouch is the best option for a patient expecting to awake with a continent diversion, although rectal pouches are also acceptable.
An otherwise healthy 65-year-old man elects active surveillance for T1c, PSA 8.2 ng/dl, Gleason score 6 (1 of 12 cores positive) prostate cancer. His digital rectal examination remains normal and subsequent serial PSA values of 7.1, 10.2, and 8.9 ng/dl at 6, 12, and 18 months respectively. The next step is:”
A. endorectal MRI scan
B. TRUS and prostate biopsy
C. bone scan
D. ProstaScint® scan
E. definitive local therapy
B.
This patient has favorable risk (normal digital rectal examination, PSA <10, Gleason score < 7, and minimal core involvement) clinically localized prostate cancer. Although there is no clinical or biochemical evidence at this point of disease progression, a repeat prostate biopsy at 18 months can provide important information useful in management. This is especially true for men electing active surveillance who have a life-expectancy > 10 to 15 years and are otherwise candidates for definitive therapy. A repeat biopsy may provide information that would lead one to consider local therapy. This includes grade progression and an increase in the percentage of the biopsy specimen involved with cancer.
The characteristic that distinguishes primary hypoadrenalism from secondary (pituitary) hypoadrenalism is:
A. hypotension
B. metabolic alkalosis
C. cutaneous hyperpigmentation
D. hypernatremia
E. hyperkalemia.
C.
Since the amino acids of ACTH are identical to the terminal amino acids of melanocyte stimulating hormone (MSH), over-production of ACTH results in cutaneous hyperpigmentation. Adrenal loss results in lack of negative feedback and over-production of ACTH. Pituitary failure, on the other hand, results in a lack of ACTH. Vitiligo may also be seen in these patients.
A 62-year-old diabetic man had inflatable penile prosthesis cylinders removed for infection. Six months later, he requests prosthesis reimplantation. He has suprapubic discomfort. On physical exam, the corpora are extremely fibrotic. Pelvic CT scan is shown in the exhibit. The next step is:
A. pelvic exploration, reimplant at later date
B. pelvic exploration, immediate reimplantation
C. reimplant multi-component inflatable prosthesis
D. I.V. antibiotics for two weeks, then reimplant multi-component prosthesis
E. implant malleable prosthesis only
A.
The CT scan shows a retained prosthesis reservoir, situated adjacent to the bladder. The reservoir should have been removed at the time of the explant. Prior to reimplantation, the reservoir should be removed as a first stage. The risk is high that the retained foreign body harbors bacteria that will secondarily infect a new prosthesis if the reservoir is left in place or is removed simultaneous with device reimplantation, even if the patient was asymptomatic. There should be at least 4-6 weeks between the reservoir explantation and placement of a new prosthesis.
The agent that has proven efficacy for prevention of acute urinary retention and the need for surgery in men with BPH is:
A. saw palmetto
B. flutamide.
C. finasteride
D. tamsulosin
E. doxazosin.
C.
Although all of these agents can be used to treat BPH, the only one that has demonstrated efficacy in preventing acute urinary retention and a need for surgery is finasteride. Alpha-adrenergic antagonists, in particular doxazosin, have been recently found to delay retention and need for surgery over the short-term but ultimately perform similar to placebo.
Which of the following correlates with improved patency and pregnancy rates after vasectomy reversal:
A. absence of sperm granuloma
B. increased diameter of proximal vas
C. a multi-layered anastomosis
D. the length of the proximal vas
E. an increase in cross-sectional tubular area of the testis.”,
D.
Improved patency and pregnancy after vasectomy reversal are correlated with a short time interval between vasectomy and reversal. It has been demonstrated that a proximal vas segment in excess of 2.7 cm predicts the presence of vasal fluid with whole sperm. It is generally believed that the presence of a granuloma and a smaller luminal diameter are favorable, as pressure below the level of the vasectomy may be less. Testicular specimens obtained after vasectomy reveal increased thickness of the seminiferous tubules, reduction in the number of Sertoli cells and spermatids, and an increase in the cross-sectional tubular area. The presence of interstitial fibrosis has an adverse effect on post-vasovasostomy fertility.
A 55-year-old obese woman with multiple medical problems is scheduled for a cystectomy and urinary diversion. Pre-operative CT urogram shows mild bilateral hydroureteronephrosis. At the time of cystectomy the mesentery of the bowel is shortened and infiltrated with fat. The most appropriate type of diversion is:
A. continent cutaneous diversion
B. bilateral cutaneous ureterostomies.
C. antirefluxing transverse colon conduit
D. ileal conduit with loop stoma (Turnbull)
E. antirefluxing sigmoid colon conduit
D.
The Turnbull loop stoma is the most appropriate diversion in this obese patient with a short mesentery. There will be less tension on the mesentery as it traverses the abdominal wall and it will be easier to obtain a good stomal bud above skin level. Cutaneous ureterostomy requires a ureter dilated to at least 1 cm, thick walled and well vascularized. In adults with normal ureters there is a high incidence of stricture from ischemia of the cutaneous portion of the nondilated ureter. There is a higher incidence of ureterointestinal stricture using an antireflux technique with the transverse colon. The sigmoid colon may not be the best choice with cystectomy as some surgeons ligate the internal iliac arteries which may compromise rectal blood supply. The short mesentery would also preclude using an ileal or ileo-cecal continent reservoir.
