Misleading symptoms confuse management of older patients with post-HSE relapse

Research shows that teenagers and adults with immune-mediated relapse after herpes simplex encephalitis (HSE) rarely display the symptoms typically seen in children, delaying the initiation of vital immunotherapy.

All six children that the researchers studied developed classical choreoathetosis symptoms post HSE, whereas none of the eight older patients, aged between 13 and 69 years, did so.

Instead, seven of the older patients presented with acute or subacute psychiatric symptoms, such as aggressive behaviour, agitation, suicidality, confusion and delusional thoughts. The eighth patient had refractory seizures and status epilepticus.

Three of the patients had acute symptoms, suggestive of a viral relapse, and were initially given antiviral treatment, while five had worsening symptoms while still in recovery from HSE and were given antipsychotic or antidepressant drugs.

Because of this, immunotherapy was considered only in the face of progressing, treatment-resistant symptoms; the median time between symptom development and initiation of immunotherapy (chiefly steroids) was 79 days, ranging from 17 to 352 days.

Josep Dalmau (University of Pennsylvania, Philadelphia, USA) and co-researchers therefore stress that patients with HSE should be closely monitored for worsening or relapsing symptoms, and for new psychiatric symptoms, irrespective of choreoathetosis.

“Any of these symptoms should raise concern for a viral relapse or an immune-mediated complication”, they write in Neurology.

And the team stresses the “impressive” response to immunotherapy, despite the delays in its initiation. Of the seven patients treated, two made a complete or near-complete recovery and the other five had major improvements in their immune-mediated symptoms, being left only with those caused by the initial episode of HSE.

Editorialists James Bale (University of Utah School of Medicine, Salt Lake City, USA) and Renaud Du Pasquier (Centre Hospitalier-Universitaire Vaudois, Lausanne, Switzerland) say: “While permanent disability may still exist in such patients, eliminating the devastating, immune-mediated neurobehavioral effects of agitation, combativeness, and suicidal ideation has immense, long-term benefit.”

They also highlight the researchers’ finding that all six of the patients with baseline magnetic resonance imaging (MRI) scans had progressive abnormalities when rescanned at the time of relapse. These were markedly reduced or absent in scans of two patients after resolution of immune-mediated symptoms.

Dalmau et al estimate that about a quarter of patients have an immune-mediated relapse after HSE, making this an under-recognised complication. Given this, and “the apparent value of repeat neuroimaging”, Bale and Du Pasquier suggest that “follow-up MRI at scheduled intervals, say 1 month and 6 months after HSE, could become a valuable standard of care.”

Neurology 2015; Advance online publication

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