A physical exam reveals small vesicular lesions (1 to 2 cm in diameter) on an erythematous base on the left breast associated with an erythematous plaque with no evident vesicles on the left inner arm. The vesicular lesions display in a segmented pattern of dermatomal distribution.
The authors’ observations
Catatonic symptoms, coupled with psychomotor agitation in an immunocompetent middle-aged adult with a history of migraine headaches, strong family history of severe mental illness, and noncontributory findings on brain imaging, prompted a Psychiatry consultation and administration of psychotropic medications. A thorough physical exam revealing the small area of shingles and acute altered mental status prompted more aggressive investigations to explore the possibility of encephalitis.
Physicians should have a low index of suspicion for encephalitis (viral, bacterial, autoimmune, etc) and perform a lumbar puncture (LP) when necessary, despite the invasiveness of this test. A direct physical examination is often underutilized, notably in psychiatric patients, which can lead to the omission of important clinical information.2 Normal vital signs, blood workup, and MRI before admission are not sufficient to correctly guide diagnosis.
EVALUATION Additional lab results establish the diagnosis
An LP reveals Ms. L’s protein levels are 44 mg/dL, her glucose levels are 85 mg/dL, red blood cell count is 4/µL, and white blood cell count is 200/µL with 92% lymphocytes and 1% neutrophils. Ms. L’s CSF analysis profile indicates a viral CNS infection (Table 23).
The authors’ observations
Varicella-zoster virus (VZV) and herpes simplex virus (HSV) are human neurotropic alphaherpesviruses that cause lifelong infections in ganglia, and their reactivation can come in the form of encephalitis.4
Continue to: Ms. L's clinical presentation...