A44-year-old secretary presents with a fever of 103°F, headache, and stiff neck. You entertain a diagn osis of bacterial meningitis and begin antibiotics immediately. With bacterial meningitis, which of the following is a likely finding in the cerebrospinal fluid (CSF)?
Answer(s): E
The Gram stain is positive in three-fourths of bacterial meningitis cases. Leukocyte counts average between 5000 and 20,000; CSF pressure is consistently elevated usually above 180 mmH2O; glucose levels are usually lower than 40 mg/dL, or less than 40% of blood glucose; and protein levels are higher than 45 mg/dL in 90% of cases
In this otherwise healthy adult woman, what is the most likely infecting organism?
Answer(s): D
F. pneumoniae is the most common cause of adult meningitis in people over 30 and accounts for about 15% of cases. H. influenzae is the most common cause in children over 1 month old. Group B Streptococcus is an important cause of neonatal meningitis, but is very rare in adults. Staphylococcus, E.coli, and Klebsiella may be seen with penetrating head wounds or postneurosurgical procedures.
In the adult neutropenic patient, which of the following is the most likely organism to cause bacterial meningitis?
Although Listeria still represents only a fraction of total cases (about 10%) of meningitis, it is seen in diabetes and cancer patients, alcoholic, elderly, and immunocompromised patients.
A50-year-old woman complains of worsening dyspnea of 1-month duration, but is otherwise asymptomatic. Lung examination is normal; her CXR is shown in the figure below. Which of the following is the most likely diagnosis?
Answer(s): B
The CXR shown in figure contains multiple bilateral pulmonary parenchymal nodules varying in size and shape, most compatible with metastatic disease to the lungs. Other possibilities are bronchogenic carcinoma or fungal granulomas (e.g., histoplasmosis or coccidiosis). Sarcoidosis usually presents with bilateral hilar adenopathy and rarely with multiple pulmonary nodules. Tuberculosis presents with a cavitating lesion, pleural effusion, or miliary pattern. Typical findings in silicosis are diffuse nodular fibrosis and eggshell calcification of hilar or bronchopulmonary lymph nodes. The CXR of patients with mycoplasma pneumonia usually shows patchy infiltrates involving the lower lobes and spreading from the hila. The finding of metastatic nodules on CXR should prompt a search for the primary tumor.
A 63-year-old man complains of a new cough and of breathlessness after walking up a flight of stairs. Chest examination reveals late inspiratory crackles but no wheezes. There is a mild clubbing of the fingers. His CXR is shown in figure. Which of the following would be found on pulmonary function testing (PFT)?
Answer(s): C
The CXR shown in Figure shows a diffuse reticulonodular pattern consistent with ILD. The hilar nodes are enlarged, suggesting lymphadenopathy. This is a nonspecific picture and may be caused by a large number of diseases. Occupational exposure to dust, gas, or fumes; sarcoidosis; idiopathic pulmonary fibrosis; and lung disease associated with the rheumatic diseases are the more common factors. Despite the diverse causes, there is a common pathogenesis: injury leads to alveolitis, which progresses to fibrosis.Abnormalities on PFT are also similar: restrictive disease characterized by decreased lung volumes (vital capacity, TLC) and decreased compliance. Loss of the alveolar capillary bed leads to decreased carbon monoxide diffusing capacity. Arterial oxygen pressure (PaO2) may be normal at rest but is decreased with exercise. Arterial carbon dioxide pressure (PaCO2) may be normal or decreased because of hyperventilation, but it is not usually elevated in pure ILD.
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