1—D. This question illustrates the common clinical scenario of an asymptomatic patient with supratherapeutic warfarin levels. The American College of Chest Physicians' guidelines for INRs greater than 5 but less than 9 in patients without significant bleeding include omitting the next 1 or 2 doses of warfarin and more frequent INR checks. In patients with an increased risk of bleeding, oral vitamin K can be considered. In a prospective, randomized, controlled trial of asymptomatic patients with supratherapeutic INRs, however, 1 mg of oral vitamin K was found to lower INR levels more rapidly than 1 mg of subcutaneous vitamin K. Hence, oral vitamin K is the correct approach.
Sources: Ansell J, Hirsh J, Poller L, et al. The pharmacology and management of the vitamin K antagonists: the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy [published correction appears in Chest. 2005; 127:415-416]. Chest. 2004;126(suppl 3):204S-233S. Crowther MA, Douketis JD, Schnurr T, et al. Oral vitamin K lowers the international normalized ratio more rapidly than subcutaneous vitamin K in the treatment of warfarin-associated coagulopathy. A randomized, controlled trial. Ann Intern Med. 2002;137:251-254.
2—B. Acute pharyngitis is one of the most common illnesses for which patients visit primary care physicians. Various bacterial and viral organisms are capable of inducing pharyngitis, either as a single manifestation or as part of a more generalized illness (eg, subtypes of rhinovirus, coronavirus, or adenovirus; Streptococcus pyogenes [group A beta-hemolytic], group C beta-hemolytic streptococci).
Group A streptococcus is the leading bacterial cause of acute pharyngitis, accounting for approximately 15% to 30% of cases in children and 5% to 10% of cases in adults. In addition, group A streptococcal pharyngitis is the only common form of the disease for which antibiotic therapy is definitely indicated. Therefore, when a patient is being evaluated for an acute sore throat, the most important clinical task is to decide whether or not the patient has "strep throat" and requires antibiotic treatment.
A throat culture is the gold standard for the diagnosis of group A streptococcal pharyngitis. However, obtaining definitive results from the throat culture takes between 24 and 48 hours. Although delaying antibiotic treatment for this period will not diminish its efficacy in preventing rheumatic fever, it is often difficult to explain this to the patient. In a patient who is acutely ill and has a high pretest probability for streptococcal pharyngitis, it is not unreasonable to start antibiotic treatment while awaiting the culture results. If the culture is negative, treatment should be promptly discontinued.
These problems can be averted by using the rapid antigen-detection test, which can confirm the presence of group A streptococcal carbohydrate antigen on a throat swab in a matter of minutes. The available tests, which use enzyme-immunoassay methods, are highly specific for the presence of group A streptococci. Therefore, a positive rapid test does not require confirmation by a culture, and treatment should be initiated based on the results. Because the sensitivity of these tests ranges between 80% and 90% compared with cultures, it is recommended that negative rapid tests in children and adolescents be confirmed with a conventional throat culture.
Physicians who rely on clinical impression alone to diagnose streptococcal pharyngitis are likely to overtreat patients for fear of missing an infection that may lead to rheumatic fever or invasive disease.
The incidence of streptococcal pharyngitis in persons older than 20 years is low, and their risk of developing acute rheumatic fever is minimal. It is therefore reasonable to base the decision to treat acute pharyngitis in adults on either throat culture or high-sensitivity rapid antigen-detection testing (no confirmation by culture required), which helps prevent unnecessary use of antibiotics.
Penicillin remains the treatment of choice for group A streptococcal pharyngitis, because of its proven efficacy, narrow spectrum, safety, and low cost. For oral therapy, a full 10-day course of treatment is recommended (250 mg every 6 h, or 500 mg every 12 h for adolescents/adults) to ensure a maximal rate of infection eradication from the pharynx.
Treatment with azithromycin (Zithromax), cefuroxime (Ceftin), cefdinir (Omnicef), cefixime (Suprax), and cefpodoxime (Vantin) has been shown to result in similar infection eradication rates at 5 days compared with penicillin at 10 days, but cost and emerging patterns of resistance must still be considered.
Source: Bisno AL. Acute pharyngitis. N Engl J Med. 2001; 344:205-211.
3—C. This lesion has all the classic warning signs of melanoma, known as ABCDE:
- Asymmetry
- Border irregularity
- Color variation
- Diameter >6 mm
- Evolution over time.
It is also strongly suspicious for the lentigo maligna form of melanoma in situ. Although lentigo maligna may be slow to enter an invasive phase, 2 years is a too-long period to delay definitive diagnosis. A smaller lesion in a less cosmetically conspicuous site could be removed with narrow, less than 5-mm margins for pathologic diagnosis and staging. Confirmation of the diagnosis and determination of the thickness of the lesion are needed before deciding on surgical margins and the need for sentinel node biopsy. There is no risk of causing metastasis of melanoma by performing subtotal incisional biopsies, although the risk of underestimating the depth of the lesion is real if the small biopsy is not taken from the deepest portion. At least one of the biopsy samples should be obtained from the portion of the lesion with the darkest brown or blue pigment. In this case, biopsy confirmed the presence of melanoma in situ in the darkest area and atypical melanocytes in the rest (Figure 2). The patient did well after complete excision and did not require node biopsy.
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| Figure 2 |
Source: Miller AJ, Mihm MC Jr. Melanoma. N Engl J Med. 2006;355:51-65.
4—C. This presentation is most consistent with oral drug-induced esophagitis. A number of medications may injure the esophagus, presumably through prolonged mucosal contact. The most often implicated agents are NSAIDs, potassium chloride, quinidine, zidovudine (Retrovir), bisphosphonates, iron, vitamin C, and antibiotics, such as doxycycline, tetracycline HCl (Sumycin), trimethoprim/sulfamethoxazole (Bactrim, Septra), and clindamycin (Cleocin). Symptoms, including severe retrosternal chest pain, odynophagia, and dysphagia, often begin several hours after taking the tablet. The symptoms may occur suddenly and persist for days.
Endoscopy may reveal from 1 to several discrete ulcers that can be shallow or deep. Chronic injury may result in severe esophagitis with stricture formation, hemorrhage, or perforation. Healing occurs rapidly when the offending agent is eliminated. To prevent drug-induced damage, patients should take all medications with 4 oz of water and remain upright for 30 minutes after ingestion. Known offending agents should not be given to patients with esophageal dysmotility or strictures.
Stopping this man's antibiotic and monitoring symptom resolution is the appropriate first step. A barium swallow or CT of the chest would not add any useful information in this case. An endoscopy would be indicated if the symptoms did not resolve after he stopped taking the drug.
Source: Kikendall JW. Pill esophagitis. J Clin Gastroenterol. 1999;28:298-305.
5—B. This patient's symptoms are highly suggestive of erythromelalgia, a paroxysmal symmetric vasodilatory disorder of unknown etiology. Idiopathic (primary) erythromelalgia occurs in otherwise healthy persons and affects both men and women equally. A secondary type is seen in patients with polycythemia vera, hypertension, gout, or neurologic diseases. Symptoms occur in response to vasodilation produced by exercise and heat exposure. Patients are typically asymptomatic between attacks.
In primary erythromelalgia, use of aspirin, 650 mg every 4 to 6 hours, provides excellent relief and may in fact be diagnostic. Warm environments should be avoided. This patient has no clinical features suggestive of gout, and her uric acid level is normal. Calcium channel blockers have been used to treat symptoms of Raynaud's phenomenon, which is a different entity. Opioids have no role in the management of erythromelalgia. There are, however, anecdotal reports of successful treatment with beta-blockers, epidural corticosteroid injections, and lidocaine patches.
Source: Stricker LJ, Green CR. Resolution of refractory symptoms of secondary erythermalgia with intermittent epidural bupivacaine. Reg Anesth Pain Med. 2001;26:488-490.
6—B. Atrial myxoma is the most common primary cardiac tumor, but metastatic masses are 20 times more common in the absence of a primary cardiac tumor. This patient has a new lung nodule and a history of breast cancer, which support this possibility. Melanomas, lymphomas, and leukemias are often the causes of metastatic cancer. Breast and lung cancers can spread by local extension. The absence of positive blood cultures and fever in this patient makes infectious vegetation unlikely. The patient does not have any predisposing factors for atrial thrombus formation, such as arrhythmias, left atrial enlargement, or a reduced ejection fraction. Embolization, obstruction, and arrhythmogenicity are the 3 primary concerns in patients presenting with intracardiac tumors.
Source: Shapiro LM. Cardiac tumors: diagnosis and management. Heart. 2001;85:218-222. imwr