A 54-year-old woman is brought to the emergency department due to fever and lethargy. The patient has had several days of productive cough and yesterday developed severe headache, nausea, and vomiting. This morning, she became weak and confused and could not get out of bed by herself. She has a history of type 2 diabetes mellitus. The patient drinks 1 or 2 glasses of wine daily. Temperature is 39.1 C (102.4 F), blood pressure is 110/70 mm Hg, and pulse is 108/min. The patient is somnolent and requires constant physical stimuli to remain awake. She is oriented to person only. Marked neck rigidity is present. Pulmonary auscultation reveals crackles and bronchial breath sounds in the right lower lung field. There is no skin rash. Laboratory testing shows leukocytosis. CT scan of the head is normal. Lumbar puncture is performed. Which of the following organisms is most likely to be seen in the spinal fluid of this patient?

Question

A 54-year-old woman is brought to the emergency department due to fever and lethargy.  The patient has had several days of productive cough and yesterday developed severe headache, nausea, and vomiting.  This morning, she became weak and confused and could not get out of bed by herself.  She has a history of type 2 diabetes mellitus.  The patient drinks 1 or 2 glasses of wine daily.  Temperature is 39.1 C (102.4 F), blood pressure is 110/70 mm Hg, and pulse is 108/min.  The patient is somnolent and requires constant physical stimuli to remain awake.  She is oriented to person only.  Marked neck rigidity is present.  Pulmonary auscultation reveals crackles and bronchial breath sounds in the right lower lung field.  There is no skin rash.  Laboratory testing shows leukocytosis.  CT scan of the head is normal.  Lumbar puncture is performed.  Which of the following organisms is most likely to be seen in the spinal fluid of this patient?

Quizplus · Accepted Answer

Explanation: Streptococcus pneumoniae is the most common cause of community-acquired bacterial meningitis. Illness is usually secondary to hematogenous dissemination (bacteremia) and may occur with or without concurrent pneumococcal pneumonia. Bacterial meningitis should be suspected in patients with >2 of the following manifestations: Headache Fever (usually >38 C [100.4 F]) Nuchal rigidity Altered mental status Symptoms usually arise acutely and leukocytosis is common. Blood cultures are often positive, but diagnosis requires a lumbar puncture. Cerebrospinal fluid typically shows high opening pressure (>350 mm H₂O), low glucose (<40 mg/dL), high protein (>200 mg/dL), and neutrophilic leukocytosis (>1000/mm³). Urgent treatment is needed as even short delays are associated with increases in morbidity and mortality. Most patients receive a third-generation cephalosporin (eg, ceftriaxone), vancomycin, and dexamethasone (to reduce inflammatory morbidity). Ampicillin is added for patients age >50 or those who are immunocompromised due to increased risk of Listeria monocytogenes. ₂ ³ This patient likely had pneumococcal pneumonia (productive cough, right lower lung crackles) prior to the development of pneumococcal meningitis (headache, fever, altered mental status, nuchal rigidity). (Choices A, C, and D) Despite reductions in invasive pneumococcal disease following the introduction of the pneumococcal vaccine, S pneumoniae still accounts for the majority (~70%) of cases of community-acquired bacterial meningitis. Other common, less prevalent causes include Neisseria meningitidis (~12%), Hemophilus influenzae, and L monocytogenes. Hemophilus may cause pneumonia in addition to meningitis but is ~10x less common than S pneumoniae; Neisseria and Listeria are less likely to cause pulmonary symptoms. (Choice B) Klebsiella pneumoniae is an unusual cause of community-acquired meningitis but may be seen in the nosocomial setting (eg, after neurosurgery). Klebsiella pneumonia is more common in those at risk of aspiration (eg, alcoholism, neuromuscular disorders) and usually causes infiltrates in the dependent lobes (eg, right lower lobe) and foul-smelling sputum. Educational objective: The most common cause of community-acquired bacterial meningitis is Streptococcus pneumoniae. Most patients have >2 symptoms of headache, fever, nuchal rigidity, and altered mental status. Concurrent pneumococcal pneumonia may or may not be present. >

A 54-Year-Old Woman Is Brought to the Emergency Department Due