A 60-year-old obese man complains of excessive daytime sleepiness. He has been in good health except for mild hypertension. He drinks alcohol in moderation. The patient’s wife states that he snores at night and awakens frequently. Examination of the oropharynx is normal. Which of the following studies is most appropriate?
With the history of daytime sleepiness and snoring at night, the patient requires evaluation for obstructive sleep apnea syndrome. Frequent awakenings are actually more suggestive of central sleep apnea. Polysomnography is required to assess which type of sleep apnea syndrome is present. EEG variables are recorded to identify various stages of sleep. Arterial oxygen saturation is monitored by finger or ear oximetry. Heart rate is monitored. The respiratory pattern is monitored to detect apnea and whether it is central or obstructive. Outpatient sleep monitoring with oxygen saturation studies alone might identify multiple episodes of desaturation, but negative results would not rule out a sleep apnea syndrome. Overnight oximetry alone can be used in some patients when the index of suspicion for obstructive sleep apnea is high. Polysomnography includes all of these and is the best choice.
A 60-year-old man develops acute shortness of breath, tachypnea, and tachycardia while hospitalized for congestive heart failure. On physical examination the patient is tachypneic and anxious; there is no jugular venous distention and the lungs are clear to auscultation and percussion. There is a loud P2 sound. Examination of the lower extremities shows no edema or tenderness. Which of the following is the most important diagnostic step?
For suspected pulmonary embolism, CT with intravenous contrast has surpassed the ventilation-perfusion scan as the diagnostic method of choice. New multislice scanners can detect peripheral as well as central clots. Lung scanning may be useful in selected circumstances. PE is very unlikely in patients with normal or near-normal scans, and is highly likely in patients with high-probability scans. In patients with a high clinical index of suspicion for pulmonary embolus but low-probability scan, the diagnosis becomes more difficult. Catheter-based contrast pulmonary angiography (the “gold standard”) may occasionally be necessary but is not the first step. About two-thirds of patients with pulmonary embolus have evidence of deep venous disease on venous ultrasound. Therefore, pulmonary embolus cannot be excluded by a normal study. The quantitative D-dimer enzyme-linked immunosorbent assay is positive in 90% of patients with pulmonary embolus. It has been used to rule out PE in patients with a low-probability scan. A contrast CT study is needed, however, in patients with intermediate or high pretest probability of pulmonary embolism. High-resolution CT scan of the chest is useful in the diagnosis of interstitial disease but does not adequately assess pulmonary vasculature; IV contrast is necessary to diagnose PE.
A 60-year-old man complains of shortness of breath 2 days after a cholecystectomy. He denies fever, chills, sputum production, and pleuritic chest pain. On physical examination, temperature is 37.2°C (99°F), pulse is 75, respiratory rate is 20, and blood pressure is 120/70. There are diminished breath sounds and dullness over the left base. Trachea is shifted to the left side. A chest x-ray shows a retrocardiac opacity that silhouettes the left diaphragm. Which of the following is the most likely anatomical problem in this patient?
Postoperative atelectasis or volume loss is a very common complication of surgery. General anesthesia and surgical manipulation lead to atelectasis by causing diaphragmatic immobilization. Atelectasis is usually basilar. On physical examination, shift of the trachea to the affected side suggests volume loss. On chest x-ray in this patient, loss of the left hemidiaphragm, increased density, and shift of the hilum downward would all suggest left lower lobe collapse. Atelectasis needs to be distinguished from acute consolidation of pneumonia, in which case fever, chills, and purulent sputum are more pronounced and consolidation is present without volume loss. Volume loss would not be a feature of a space-occupying mass, bronchospasm, or pneumothorax. Tension pneumothorax would push the trachea to the opposite side and would usually be associated with unilateral hyperresonance.
A 55-year-old woman with long-standing chronic lung disease and episodes of acute bronchitis complains of increasing sputum production, which now occurs on a daily basis. Sputum is thick, and daily sputum production has dramatically increased over several months. There are flecks of blood in the sputum. The patient has lost 8 lb. Fever and chills are absent, and sputum cultures have not revealed specific pathogens. Chest x-ray and CT chest are shown below. Which of the following is the most likely cause of the patient’s symptoms?
While symptoms such as sputum production and cough are nonspecific, particularly in a patient with known chronic lung disease, the high volume of daily sputum production suggests bronchiectasis. In this process, an abnormal and permanent dilatation of bronchi occurs as the muscular and elastic components of the bronchi are damaged. Clearance of secretions becomes a major problem, contributing to a cycle of bronchial inflammation and further deterioration. High-resolution CT scan, the diagnostic test of choice for this disease, shows prominent dilated bronchi and the signet ring sign of a dilated bronchus adjacent to a pulmonary artery. This CT scan picture is pathognomonic for bronchiectasis. Tuberculosis usually causes upper lobe cavitary disease. COPD causes hyperexpansion, upper lobe bullae, and nonspecific bronchial wall thickening. CT scan in anaerobic lung abscess would show an air-fluid level, usually within a shaggy inflammatory infiltrate. This CT scan shows no nodule or mass to suggest lung cancer.
A 20-year-old fireman comes to the emergency room complaining of headache and dizziness after putting out a garage fire. He does not complain of shortness of breath, and the arterial blood gas shows a normal partial pressure of oxygen. There is no cyanosis. Which of the following is the best first step in the management of this patient?
With symptoms of headache and dizziness in a fireman, the diagnosis of carbon monoxide poisoning must be addressed quickly. A venous or arterial measure of carboxyhemoglobin must first be obtained, if possible, before oxygen therapy is begun. The use of supplementary oxygen prior to obtaining the test may be a confounding factor in interpreting blood levels. Oxygen or even hyperbaric oxygen is given after blood for carboxyhemoglobin is drawn. Methemoglobinemia causes cyanosis, which is not present in this patient. EKG is unlikely to be abnormal in this young healthy patient without chest pain. Central nervous system imaging would not be indicated, and there are no diagnostic patterns that are specific to carbon monoxide poisoning. Anemia might cause dizziness, but the symptom would not occur as acutely as in this case.
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