Encephalitis: The Daily PANCE Blueprint
A 35-year-old woman is brought to the emergency department with confusion and a first-time seizure. Her family reports that she has been having headaches and a low-grade fever for the past few days. The patient has no history of seizures, drug use, or medication use. On physical examination, she is found to have neck stiffness and photophobia. A neurological examination reveals hyperreflexia and a positive Kernig sign. What is the next best step in diagnosing viral encephalitis?
A. CT scan of the head without contrast
B. Electroencephalogram (EEG)
C. Lumbar puncture with cerebrospinal fluid analysis
D. Magnetic resonance imaging (MRI) of the brain
E. Blood cultures
Answer and topic summary
The answer is C. Lumbar puncture with cerebrospinal fluid analysis
A lumbar puncture is the most appropriate next step for diagnosing viral encephalitis. The procedure allows for the analysis of cerebrospinal fluid (CSF), which can reveal pleocytosis, increased protein levels, and normal glucose levels, all suggestive of viral encephalitis. PCR testing of the CSF can help identify specific viral pathogens, such as herpes simplex virus (HSV), which is a common cause of viral encephalitis.
Incorrect Answers:
- A. CT scan of the head without contrast – This imaging study may be useful to rule out other causes of neurological symptoms, such as hemorrhage or mass effect, but it is not specific for diagnosing viral encephalitis.
- B. Electroencephalogram (EEG) – EEG can be helpful in assessing seizure activity or encephalopathy, but it does not confirm the diagnosis of viral encephalitis.
- D. Magnetic resonance imaging (MRI) of the brain – While MRI can show characteristic findings in cases of viral encephalitis (e.g., temporal lobe involvement in HSV encephalitis), it does not provide a definitive diagnosis without CSF analysis.
- E. Blood cultures – Blood cultures are not typically diagnostic for viral encephalitis, as the infection usually resides in the central nervous system rather than the bloodstream.
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Smarty PANCE Content Blueprint Review:
Covered under ⇒ PANCE Blueprint Neurology ⇒ ⇒
Also covered as part of the Emergency Medicine EOR and Internal Medicine EOR topic lists
