A 67-year-old man is brought to the emergency department by his wife due to progressive lethargy over the last 24 hours. Before going to bed, he had a fever, chills, headache, and neck pain and was "feeling tired." His wife had difficulty waking him up this morning. The patient has had no sick contacts, recent travel, flu-like symptoms, or skin rashes. He has a history of type 2 diabetes mellitus, hypertension, hyperlipidemia, and ischemic stroke with a complete recovery of neurologic deficits. The patient takes aspirin, metformin, chlorthalidone, lisinopril, and atorvastatin. He is a retired school teacher and has no history of tobacco, alcohol, or illicit drug use.
Temperature is 39.1 C (102.3 F), blood pressure is 140/90 mm Hg, pulse is 110/min, and respirations are 16/min. Pulse oximetry shows an oxygen saturation of 97% on room air. The patient is obtunded and does not follow commands but is able to localize to pain in the upper extremities and withdraw the lower extremities to noxious stimuli. Physical examination is otherwise unremarkable. Fingerstick glucose level is 190 mg/dL. Blood cultures are drawn.
Which of the following is the best next step in immediate management of this patient?

Question

A 67-year-old man is brought to the emergency department by his wife due to progressive lethargy over the last 24 hours.  Before going to bed, he had a fever, chills, headache, and neck pain and was "feeling tired."  His wife had difficulty waking him up this morning.  The patient has had no sick contacts, recent travel, flu-like symptoms, or skin rashes.  He has a history of type 2 diabetes mellitus, hypertension, hyperlipidemia, and ischemic stroke with a complete recovery of neurologic deficits.  The patient takes aspirin, metformin, chlorthalidone, lisinopril, and atorvastatin.  He is a retired school teacher and has no history of tobacco, alcohol, or illicit drug use.
Temperature is 39.1 C (102.3 F), blood pressure is 140/90 mm Hg, pulse is 110/min, and respirations are 16/min.  Pulse oximetry shows an oxygen saturation of 97% on room air.  The patient is obtunded and does not follow commands but is able to localize to pain in the upper extremities and withdraw the lower extremities to noxious stimuli.  Physical examination is otherwise unremarkable.  Fingerstick glucose level is 190 mg/dL.  Blood cultures are drawn.
Which of the following is the best next step in immediate management of this patient?

Quizplus · Accepted Answer

This patient has high fever, neck pain, and altered mental status, the 3 classic manifestations of acute bacterial meningitis. Most cases are caused by Streptococcus pneumoniae, but Neisseria meningitis, group B streptococci, Haemophilus influenzae, and Listeria monocytogenes (in patients age >50) are also frequently isolated. Blood cultures and lumbar puncture (LP) are required for definitive diagnosis. Blood cultures successfully identify the underlying pathogen in 50%-90% of cases and should always be drawn prior to antimicrobials to maximize their yield. The timing of LP is more nuanced as patients with any of the following require a preceding noncontrast head CT scan: Altered mental status (as in this patient)Immunocompromised stateHistory of central nervous system diseaseNew-onset seizurePapilledemaFocal neurologic deficit Altered mental status (as in this patient) Immunocompromised state History of central nervous system disease New-onset seizure Papilledema Focal neurologic deficit Head CT scan often results in treatment delays of up to 6 hours, which can increase the risk of death and neurologic sequelae. As such, patients with suspected bacterial meningitis who require a head CT scan prior to LP should first receive empiric treatment with antibiotics and adjuvant dexamethasone (Choices D and E). Antimicrobial treatment prior to LP can reduce the yield of cerebrospinal fluid gram stain and culture, but most pathogens can still be successfully cultivated for 4-10 hours after antibiotic initiation. Patients who do not require a head CT scan prior to LP should undergo LP before the administration of antimicrobials. Most patients with suspected bacterial meningitis are also treated with empiric acyclovir to cover for possible herpes simplex encephalitis. (Choice A) Bedside electroencephalogram monitoring is often used to evaluate for nonconvulsive status epilepticus, which can occur in the setting of an infectious encephalopathy and lead to mental status changes. However, this patient should first receive empiric antibiotics; electroencephalogram can be considered if there is no mental status improvement. (Choice B) Brain MRI takes longer to perform than a head CT scan. Therefore, urgent noncontrast head CT scan is preferred in patients with acute mental status changes to rule out space-occupying lesions. Educational objective: Patients with suspected acute bacterial meningitis require early treatment with empiric antibiotics and dexamethasone to limit neurologic sequelae and death. Those who need a head CT scan (eg, altered mental state, focal neurologic deficit, immunocompromised state, new-onset seizure, papilledema, history of central nervous system disease) prior to lumbar puncture should first receive blood cultures, antibiotics, and dexamethasone. Patients who do not require a head CT scan should receive blood cultures and lumbar puncture prior to treatment. __________ References: Dexamethasone in adults with bacterial meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/12432041) Bacterial meningitis: current therapy and possible future treatment options. (http://www.ncbi.nlm.nih.gov/pubmed/22029523) Practice guidelines for the management of bacterial meningitis. (http://www.ncbi.nlm.nih.gov/pubmed/15494903)

A 67-Year-Old Man Is Brought to the Emergency Department by His