Step 1 Q&A Flashcards
- A 25-year-old woman with asthma presents to the ED in severe cardiovascular distress after taking a theophylline overdose in an attempt to commit suicide. At presentation, she is convulsing, her blood pressure is
80/40 mm Hg, and she has developed a cardiac arrhythmia. Considering the mechanism of action of theophylline, which drugs may be used to counteract its effects?
- The correct answer is: β-Blockers.
An overdose of theophylline will cause a decrease in the hydrolysis of cAMP to adenosine monophosphate, resulting in an increasing and potentially toxic level of cAMP. β-Agonists activate adenylate cyclase, which converts ATP to cAMP, so β-blockers may be given to stop this process and reduce cAMP levels.
- On a routine check-up, a 65-year-old woman with recently diagnosed adenocarcinoma of the lung is found to have drooping of the right eyelid. Pupillary examination reveals anisocoria with the right pupil smaller than the left. Upon further questioning she reveals that after exerting herself she has to mop the sweat off of her left brow, but does not notice any sweat on her right side. What is the most likely etiology of the patient’s symptoms?
- The correct answer is: Apical lung tumor.
A tumor at the apex of the lung, or superior sulcus, is known as a Pancoast’s tumor. Due to its location, it can sometimes compress the cervical sympathetic plexus, resulting in Horner’s syndrome (ptosis, miosis, enophthalmos, and anhidrosis), as seen in this patient.
- A 50-year-old man is treated for septic shock with multiple antibiotics. Seven days later, the patient is alert and oriented, and his tissue perfusion has returned to normal. However, he describes a terrible feeling that “the world is spinning.” Which therapeutic agent is most likely responsible for this patient’s symptom?
- The correct answer is: Gentamicin.
Gentamicin is an aminoglycoside antibiotic used in the treatment of gram-negative rod infections. It is often combined with β-lactam antibiotics because it acts synergistically. Aminoglycosides can cause nephrotoxicity and nonoliguric acute tubular necrosis, or ototoxicity, which can present as either vestibular or cochlear damage. Vestibular toxicity may result in vertigo, nausea, vomiting, or ataxia, whereas cochlear damage causes tinnitus or hearing loss. The patient in this question is experiencing vertigo.
- A homeless man who is an alcoholic is brought to the ED after being found unconscious by the side of the road. Films taken on arrival show some old trauma to the
jaw. X-ray of the chest and CT of the chest reveal a mass lesion in the right lower lobe with spiculation, which appears to extend into the pleural space and involve an adjacent rib. A biopsy specimen of the mass-like lesion is shown in the image. Histologic specimens of bronchial lavage fluid after biopsy contain numerous
hyphae but no malignant cells. What should be included in the treatment regimen for this man’s condition?
- The correct answer is: Penicillin G
This man likely has actinomycosis from infection with Actinomyces israelii, a gram-positive anaerobic bacterium with a branching filamentous appearance. The image shows what is known as a “sulfur granule” formed by a colony of Actinomyces fi laments solidified with tissue exudates. The bacteria are generally normal inhabitants of the oral cavity and are found in dental caries. Poor oral hygiene coupled with trauma increases the risk of aspiration of the organism leading to infection. Infections with Actinomyces tend to be chronic and extend through multiple tissue planes. Actinomyces species appear to be susceptible to a wide range of β-lactam agents, which are regarded as agents of first choice in treatment.
- A 55-year-old woman with a history of schizophrenia
presents to the emergency department with paranoia and active hallucinations. Her agitation is so severe that she has to be restrained for several days. She is started on haloperidol. A few days later she becomes tachycardic and complains of sharp right-sided chest pain. What step should be taken next in the care of this patient?
- The correct answer is: Start IV Heparin.
Her symptoms of tachycardia and sharp chest pain make it most likely that the patient has developed a pulmonary embolism secondary to being restrained for several days. The best treatment for this would be an anticoagulant.
- A 25-year-old medical student presents with a nonproductive cough, low-grade fever, and malaise of 3 weeks’ duration. He says that a few of the people he studies with have been feeling the same way. Sputum cultures come back negative. The patient denies exposure to farm animals, travel, or HIV. The physician decides to treat for an atypical pneumonia. What method could identify the organism responsible for such a pneumonia?
- The correct answer is: Cold agglutinin testing.
Mycoplasma pneumoniae is the most common cause of interstitial (atypical) pneumonia, along with viruses. It cannot be cultured and is diagnosed by the cold agglutinin test, which measures the agglutination of immunoglobulins when they are cooled.
- A 50-year-old man complains of shortness of breath on exertion of a few months’ duration. On inspection there is an increased anteroposterior diameter of the chest, pursed lips, and dyspnea with no scleral icterus or jaundice. The patient has a 75-pack-year history of smoking. On physical examination, the patient is
tachycardic and has hyperresonant lungs with decreased breath sounds. There is no evidence of hepatomegaly or liver nodules on palpation. What is the most likely diagnosis?
- The correct answer is: Centriacinar emphysema.
The patient presents as a classic “pink puffer,” making emphysema the most likely diagnosis. Because smoking is closely linked to centriacinar emphysema, this is the best answer choice. The stem mentions an absence of jaundice and liver problems, making α1-antitrypsin deficiency, and the associated panacinar emphysema, unlikely.
- A 13-year-old white girl with a past medical history
of nasal polyps develops severe bronchoconstriction
and wheezing after taking a large dose of aspirin, having mistaken it for a cold medication. After presenting to the ED, she is found to have a past history of aspirin allergy. Which medication can be used effectively to stop the bronchoconstriction resulting from her aspirin allergy?
- The correct answer is: Zileuton.
Aspirin serves to inhibit the cyclooxygenase enzymes. An allergy to aspirin is thought to result from the diversion of arachidonic acid to the leukotriene pathway when the cyclooxygenase-catalyzed prostaglandin pathway is blocked. The resulting increase in leukotriene synthesis leads to the bronchoconstriction that is typical of an aspirin allergy. Zileuton is an effective inhibitor of the 5-lipoxygenase pathway and thus blocks the conversion of arachidonic acid to leukotrienes. Because of this, zileuton can be used in the treatment of aspirin allergy.
- A 60-year-old white man presents to his physician with a productive cough of a few months’ duration. The patient reports having three of these episodes over the past 2 years, with each episode lasting 4 months. On physical examination the patient is cyanotic, wheezing, and has crackles in the lungs upon auscultation. Lung biopsy reveals hypertrophy of mucussecreting glands in the bronchioles, with a Reid index >50%. Other than smoking, what is associated with the most likely diagnosis?
- The correct answer is: Air pollution.
Although cigarette smoking is the most common cause of chronic bronchitis, air pollution is also associated with this diagnosis.
- During dental procedures, it is possible that small fragments may be aspirated into the trachea and cause aspiration pneumonia. If the patient is sitting upright during the procedure, which of the following is the most common site of aspiration pneumonia?
- The correct answer is: R Lower lobe.
The right main bronchus is more vertical and wider than the left, and aspirated particles are more likely to lodge at the junction of the right inferior and right middle bronchi. Because of this, aspiration pneumonia contracted when an individual is in an upright position is most common in the right lower and middle lobes.
