Case Presentation:

A 57‐year‐old female with history of stage IVB diffuse large B‐cell lymphoma presented to the emergency department 11 weeks postchemotherapy with altered mental status. Symptoms included confusion, “staring“ episodes, imbalance, and loss of appetite, progressively worsening over 1 week. Jerking episodes of the entire body, low‐grade fevers, and urinary incontinence were also noted. Past medical history was significant for lymphoma with known involvement of the brain, muscles, lung, liver, kidney, and C1 vertebra that had responded well to chemotherapy. On physical exam, she was afebrile with a pulse of 122. Her mini‐mental status exam score was 20. She had difficulty with orientation, concentration, and memory, but had no focal neurological deficits. A CBC revealed pancytopenia, whereas CSF analysis showed pleocytosis and hypogly corrhea. An MRI of the brain revealed a new area of restricted diffusion on the right frontal lobe, suggestive of a viral encephalitis. An EEG showed diffuse moderate encephalopathy with focal neuronal dysfunction in the right parietal region. She was started on IV antibiotics for presumed bacterial meningitis, IV Keppra for concerns of seizures, and IV acyclovir for suspected HSV encephalitis. Further CSF studies including HSV PCR and bacterial and fungal cultures were all negative. The patient's mental status continued to decline, and she became unresponsive. On further consideration, CSF and serum were sent for HHV‐6 PCR, which returned elevated. After 3 weeks of treatment with valganciclovir, the patient's mental status and motor skills dramatically improved. She was discharged to a subacute facility for further rehabilitation.


HHV‐6 encephalitis occurs in approximately 4% of posttransplant patients (mostly bone marrow), resulting in a wide range of neurologic symptoms. lt is very rare in immunocompetent adults, with only few cases reported. The patient in this case was immunocompromised because of high‐grade advanced lymphoma and chemotherapy, but she was not a transplant patient. Diagnosis can be challenging. DNA detection in CSF and serum can be helpful when paired with clinical presentation and MRI findings. The CSF profile in HHV‐6 encephalitis is notable for lymphocytic pleo‐cytosis. Treatment with antiviral agents is indicated in severe cases and immunocompromised adults given the high mortality risk. With timely diagnosis and treatment, a full recovery is possible.


HHV‐6‐associated encephalitis should be suspected, not only in posttransplant patients, but also in immunocompromised patients presenting with symptoms suggestive of encephalitis. Treatment can provide significant improvement in neurological outcomes.

Author Disclosure:

R. Khateeb, none.