Last Minute Internal Medicine: A Concise Review for the Specialty Boards
Last Minute Internal Medicine : A Concise Review for the Specialty Boards, by Patricia A. DeLaMora, is a concise and comprehensive Internal Medicine board exam prep guide. It is organized by organ and system, and focuses on must-know facts that will appear on the exam.
Below is the text of Chapter 6, entitled Urology, contributed by Dr. Douglas Scherr. The chapter reviews urinary incontinence, erectile dysfunction, hematuria, benign prostatic hyperplasia, and scrotal pain and masses.
If you have any questions on any of these topics, do not hesitate to contact Dr. Scherr's office.
Chapter 6, Urology
Definition and Etiology: There are five types of incontinence: 1) stress, 2) urge, 3) overflow, 4) total, and 5) functional.
Epidemiology: Thirteen million people in the United States suffer from urinary incontinence, with a female to male ratio of 2:1. It is estimated that 35% of women and 22% of men over age 65 have some form of urinary incontinence.
Diagnosis: The evaluation of a patient with incontinence includes a detailed medical and voiding history, including onset, medications, surgeries, and parity. Physical examination should include evaluation for cystoceles and rectoceles, sphincter tone, pelvic masses. Urodynamic studies, including measurement of the post-void residual may be valuable as well.
Treatment: Non-pharmacologic interventions are the cornerstone of treatment and should be used even when pharmacologic agents are considered.
Table 6-1: Urinary Incontinence: Definition, Etiology and Clinical Correlates
Table 6-2: Treatment (Conservative, Medical and Surgical) of Urinary Incontinence
Definition: The inability to have or maintain an erection sufficient for penetration during sexual intercourse.
Etiology: Parasympathetic stimulation (via nitric oxide mediated cGMP mechanism) relaxes the smooth muscles of the corpora cavernosa allowing increased arterial flow into the cavernosal sinusoids. As the cavernosa distends the tunica albuginea veins draining the penis are compressed, trapping blood in the penis and potentiating rigidity. There are three main types of erectile dysfunction: 1) organic, 2) iatrogenic, and 3) psychogenic.
Epidemiology: Affects two-thirds of men over the age of 70 years.
Diagnosis: Evaluation includes a medical (coronary artery disease, vascular disease and diabetes), drug (medications, alcohol and tobacco) and erectile history. The presence of nocturnal erections suggests a psychogenic etiology. Physical examination includes peripheral neuro-vascular, genitourinary and secondary sexual characteristics examination. Laboratory tests may be beneficial.
Treatment: See Table 6-4
Table 6-3: Etiologies of Erectile Dysfunction
Table 6-4: Treatment Options for Erectile Dysfunction
Definition: Hematuria is defined as more than three red blood cells (RBC) per high-powered field on microscopic examination of urine.
Etiology: Red blood cells in the urine may originate directly from the epithelium of the genitourinary tract or may pass into the urinary stream due to a systemic medical problem that affects glomerular permeability. The RBC morphology frequently differentiates urologic from systemic medical renal causes of hematuria.
Epidemiology: Hematuria is often intermittent, with up to 39% of adults having transient hematuria. The risk of urinary tract (kidney, ureter or bladder) cancer as the cause of hematuria greatly increases after the age of 50.
Diagnosis: Associated clinical history and findings often point towards a diagnosis. If the source of hematuria is assessed to be urologic in nature, both the upper urinary tracts and the lower urinary tracts must be evaluated.
Treatment: Based on the etiology.
Table 6-5: RBC Morphology on Urinalysis, Associated Urinalysis Findings by Etiology of Hematuria
Table 6-6: Differential of Causes of Hematuria
Table 6-7: Diagnostic Tests for the Upper and Lower Genitourinary Tract for the Work-up of Hematuria
Benign Prostatic Hyperplasia (BPH)
Definition: Overgrowth of prostate tissue in the transition zone.
Etiology: The prostate is a walnut-sized gland located caudal to the bladder, composed of a glandular and stromal component. The prostate gland has three anatomical zones: the peripheral zone, the central zone, and the peri-urethral transition zone. BPH is an overgrowth of tissue in the transition zone, while prostate cancer arises from the peripheral zone. Prostatic growth is mediated by testosterone, which is converted to DHT by 5?-reductase. BPH causes a mechanical compression of the urethra resulting in bladder outlet obstruction and difficulty voiding.
Epidemiology: Although up to 50% of men over the age of 50 have histological evidence of BPH, only 25-35% of men have clinical symptoms. Prevalence increases with age.
Clinical: The patient may presents with a weak urinary stream, hesitancy, straining to pass urine, sensation of incomplete emptying, frequency, urgency, and occasionally, urinary retention.
Diagnosis: The digital rectal examination (DRE) evaluates the size and consistency of the prostate gland. Dullness to percussion over the lower abdomen suggests bladder distention, which may be due to bladder outlet obstruction. Urinalysis, urine culture, as well as serum BUN, and creatinine can be performed. Measurement of prostate serum antigen (PSA) to evaluate for occult prostatic malignancy is controversial, as PSA cannot differentiate between BPH and early prostate cancer. Measurement of the urine flow rate (< 15cc/second suggests obstruction) and the bladder post-void residual volume evaluates bladder emptying.
Treatment: Treatment includes active surveillance as well as a variety of medical and surgical approaches.
Table 6-8: Treatment of Benign Prostatic Hyperplasia
Scrotal Pain and Masses
Definition: Table 6-9
Etiology: Table 6-9
Epidemiology: Table 6-9
Clinical: Table 6-9
Diagnosis: History should evaluate for the presence of pain, onset and quality of pain, duration of symptoms, presence of urinary symptoms, and sexual history. The physical examination should assess for presence of testicular masses, size of the testes, location of the testis in the scrotum, and surgical scars. Scrotal transillumination, urinalysis, and colorflow doppler ultrasound are adjunctive studies.
For urologic cancers such as bladder, kidney, and testis please refer to the Oncology chapter.
Table 6-9: Differential Diagnosis and Treatment of Scrotal Pain and Masses