| ||||
 | ||||
 | ||||
TEACHING TOPICS from the New England Journal of Medicine
| ||||
Teaching Topics | July 19, 2012
BPH: How does one approach the treatment of benign prostatic hyperplasia (BPH)?
Ingestion of an Unknown Substance: What are the toxic effects of antimony ingestion?
| ||||
| ||||
Teaching Topic
BPH
Clinical Practice
A.V. Sarma and J.T. Wei
  
BPH, a histologic diagnosis, is a condition that occurs with aging; the prevalence increases from 25% among men 40 to 49 years of age to more than 80% among men 70 to 79 years of age.
Clinical Pearls
 What are the lower urinary tract symptoms associated with BPH?
The symptoms are classified as obstructive voiding or bladder storage symptoms. Obstructive voiding symptoms include urinary hesitancy, delay in initiating micturition, intermittency, involuntary interruption of voiding, weak urinary stream, straining to void, a sensation of incomplete emptying, and terminal dribbling. Storage symptoms include urinary frequency, nocturia, urgency, incontinence, and bladder pain or dysuria.
What are the risk factors for developing BPH?
In addition to increased age, additional risk factors include black (vs. white) race, obesity, diabetes, high levels of alcohol consumption, and physical inactivity; mechanisms underlying these associations remain poorly understood. Physiological markers associated with an increased risk of benign prostatic hyperplasia include levels of endogenous testosterone and dihydrotestosterone as well as increased levels of dehydroepiandrosterone and estradiol, insulin-like growth factors, and inflammatory markers (e.g., C-reactive protein).
Morning Report Questions
Q. What office evaluation should be performed when a diagnosis of BPH is being considered?
A. Evaluation includes a complete history to rule out alternative causes of lower urinary tract symptoms, including consideration of excess fluid and caffeine intake and the use of diuretics or medications with antihistaminic effects that may weaken bladder detrusor function. A digital examination of the prostate should be performed and a PSA measurement obtained. A urinalysis should be ordered to screen for urinary tract infection and to look for hematuria, which might indicate urolithiasis or cancer of the kidney, bladder, or prostate. Urinary tract infections should be treated. Evaluation should also include the use of the American Urological Association Symptom Index, a quantitative measure of the severity of lower urinary tract symptoms. If the patient reports a sense of incomplete bladder emptying or has a palpable bladder on abdominal examination, a post-voiding residual urine measurement should be obtained to rule out “silent” urinary retention (normal residual urine volume, <100 ml).
Q. How does one approach the treatment of BPH?
A. A reasonable approach would be to initiate an alpha-blocker (doxazosin), and then to increase the dose based on symptom response. If symptoms are still bothersome, a 5α-reductase inhibitor can be added as long as the PSA level is higher than 1.5 ng per milliliter (indicating prostatic enlargement). Another option, particularly if the patient also has erectile dysfunction for which he desires treatment, would be to prescribe a phosphodiesterase-5 inhibitor (currently only tadalafil is approved for these symptoms), since this agent could address both problems. In a randomized, placebo-controlled trial comparing doxazosin, a 5α-reductase inhibitor (finasteride), and the combination of the two, type 1 5α-reductase inhibitors (with or without alpha-blocker therapy), but not alpha-blocker therapy alone, significantly reduced rates of secondary outcomes of urinary retention and the need for invasive therapy for BPH.
|
Teaching Topic
Ingestion of an Unknown Substance
Case Records of the Massachusetts General Hospital
W. Macías Konstantopoulos, M. Burns Ewald, and D.S. Pratt
Patients with exposures to poisons commonly present to emergency departments. Unintentional poisoning was second only to motor vehicle accidents as a cause of accidental injury or death for all ages in 2009 and accounted for more than 830,000 visits to the emergency department in 2010.
Clinical Pearls
What initial testing is useful in the care of a patient with suspected poisoning?
In most, if not all, poisoned patients, a blood chemistry panel should be obtained, along with an electrocardiogram to screen for abnormalities in the duration of the QRS complex and the QT interval, tests for the serum glucose level, and screening tests for serum acetaminophen, salicylate, and alcohol. A pregnancy test should be obtained in female patients of child-bearing age. Plain radiographs may provide additional information in cases of suspected ingestions of heavy metals, body packing (internal concealment of illicit drugs), and toxin-induced noncardiogenic pulmonary edema. The utility of toxicologic screening of the urine will hinge on the recognition of a toxidrome or the suspicion of a particular substance.
What are the toxic effects of antimony ingestion?
Trivalent antimony (tartar emetic) has a potent emetic effect as aversive therapy for substance abuse, and is sold in some countries for this purpose. Doses of as little as 200 to 1200 mg can be fatal. Antimony is rapidly absorbed from the gastrointestinal tract and undergoes enterohepatic recirculation. Ninety percent of tartar emetic is excreted during the first day after ingestion, and the remaining 10% during a slower elimination phase of 16 days after ingestion. Similarly to arsenic, antimony is thought to inhibit the pyruvate dehydrogenase complex, thus preventing acetyl coenzyme A from entering the Krebs cycle with a subsequent lack of ATP production. Many organs can be affected, including the gastrointestinal tract, liver, kidneys, heart, and central nervous system. Antimony salts are gastrointestinal irritants with local effects on enterochromaffin cells, which release serotonin that subsequently acts on 5-hydroxytryptamine type 3 receptors to stimulate vomiting, which may be severe.
Morning Report Questions
Q. How is antimony poisoning treated?
A. Antimony is excreted in bile after conjugation with glutathione; therefore, the administration of N-acetylcysteine, a synthetic precursor of glutathione, is often recommended to enhance the secretion of antimony. Chelation may also be an important part of management. The goal of chelation is to form a stable complex between antimony and the sulfur donors, or dithiols, on the chelator, preventing the antimony from chelating host enzymes. Options are dimercaprol, DMPS (2,3-dimercapto-1-propanesulfonic acid), and DMSA (2,3-dimercaptosuccinic acid). A sensation of chest constriction, as well as anxiety and hypertension, may occur within 10 to 30 minutes after the administration of dimercaprol and typically will resolve in 30 to 50 minutes.
Q. What are the indicators of poor prognosis in acute liver failure?
A. The King’s College Hospital criteria remain the most used prognostic criteria for acute liver failure. For patients with acute liver failure not induced by acetaminophen, poor prognostic factors include a prothrombin time of more than 100 seconds or any three of the following criteria: drug toxicity or indeterminate cause, an age younger than 10 years or older than 40 years, a jaundice-to-coma interval of more than 7 days, a prothrombin time of more than 50 seconds (INR, ≥3.5), and a serum bilirubin level of more than 300 μmol per liter (17.5 mg per deciliter). A study of 165 patients with acute liver failure at King’s College Hospital showed that patients with an arterial ammonia level of more than 200 μmol per liter (340.6 μg per deciliter) on admission to the ICU were at the highest risk for the development of intracranial hypertension, the main cause of death in patients with acute liver failure.
| |
quote of the week
|
IMAGE CHALLENGE
|
| |||||||||
|
| ADVERTISEMENT |
 |
Featured Job of the Week
HOSPITALIST — MARYLAND The General Internal Medicine Division of the Department of Medicine at the University of Maryland School of Medicine has openings for several full-time internists for non-tenure track faculty positions at the rank of Instructor and/or Assistant Professor as part of our inpatient Hospitalist services. Positions # 3-309-683 and 3-309-685 incorporate service at our main hospital and an affiliated hospital, both of whom are located in downtown Baltimore. This team provides 24/7 coverage for inpatient medicine floors and offers teaching opportunities. Position 3-309-689 is part of an exciting multispecialty team for our Renal Transplant Service....Looking for a new practice opportunity? View this job and other listings at NEJM CareerCenter. Search now for both permanent and locum tenens jobs in many specialties.
|
