A 72-year-old woman complains of shortness of breath on exertion. She states that she also becomes short of breath at night unless she uses three pillows to prop herself up (orthopnea). Physical examination reveals mild obesity, bilateral pitting leg edema, an enlarged liver, and fine crackling sounds on inspiration (rales). A chest x-ray shows cardiomegaly. What is the most likely cause of orthopnea in this patient?

A 36-year-old man with AIDS presents with fever, dry cough, and dyspnea. A chest x-ray shows bilateral and diffuse infiltrates. Laboratory studies reveal a low CD4+ cell count. A lung biopsy discloses a chronic interstitial pneumonitis and an intra-alveolar foamy exudate. A silver stain of a bronchoalveolar lavage is shown. Which of the following organisms is the most likely responsible for these pulmonary findings?

A 60-year-old man complained of leg cramps that are so severe that he must often stop walking. What is the underlying pathologic basis for "intermittent claudication" in this patient?

A young adult male takes advantage of the free clinic to discuss recurring symptoms with a doctor. He explains that although he feels well at the moment, he sometimes hears some sound upon exhalation, and also can experience slight chest tightness and shortness of breath on occasion. The patient states that breathing symptoms come and go but tend to worsen seasonally. Standard spirometry tests are taken before and after inhalation of an ẞ-adrenergic receptor agonist. Which of the following would be consistent with the diagnosis of asthma?

An adult who has never smoked or been around cigarette smoke is unlikely to have which of the following diseases?

A 33-year-old woman delivers a healthy neonate at 38 weeks gestation. Two days later, the mother collapses in the nursery. Examination of medical records shows that the patient's father died at age 45 due to complications of Marfan syndrome. Blood pressure is 110/50 mmHg and pulses are diminished, Cardiac auscultation reveals a diastolic murmur. Which of the following is the most likely diagnosis?

A 48-year-old man with a history of heavy smoking presents with a 3-year history of persistent cough and frequent upper respiratory infections, associated with sputum production. Analysis of arterial blood gases reveals hypoxia and CO2 retention. Which of the following is the appropriate diagnosis?

A 92-year-old woman is brought unconscious to the emergency room from a nursing home. Her blood pressure is 70/30 mm Hg. She is febrile (102°F) and breathing rapidly (tachypneic). Laboratory studies demonstrate an elevated white blood cell count with 92% segmented neutrophils. Urinalysis reveals gram-negative organisms. Which of the following types of shock most likely accounts for this patient's signs and symptoms?

A 70-year-old male is admitted after a massive anterior myocardial infarction and initially stabilizes with medical management. Several days later, he suddenly develops ventricular tachycardia followed by cardiac arrest. Histologic remodeling of the infarcted myocardium reveals fibroblast infiltration with deposition of type I collagen, replacing large numbers of necrotic cardiac myocytes. Which of the following best explains the principal cause of death in patients following a massive myocardial infarction?

Alcoholism is the single most common predisposing condition for the development of which of the following pulmonary diseases?

A 5-year-old girl had a sudden attack of suffocating cough accompanied by wheezing. There was no fever but the child appeared anxious and in distress. What is the most likely diagnosis?