Scientists have reported preliminary evidence that monkeypox might lead to severe neurological complications including encephalitis and seizure.
Other nonspecific neurological conditions, including confusion, headache, and myalgia have also been linked to the disease, according to the research led by University College London (UCL).
Despite evidence of nervous system involvement associated with smallpox infection, possible neuropsychiatric effects of infection with the monkeypox virus have not been systematically evaluated. To find out more, the team, which also involved Barts Health NHS Trust, Guy's and St Thomas' NHS Foundation Trust, and King's College London, conducted a systematic review and meta-analysis of the available evidence.
A search of MEDLINE, EMBASE, PsycINFO, AMED, and the preprint server MedRxiv up until the end of May 2022 produced an initial list of 1705 unique studies, which were whittled down to 19 for full scrutiny. The studies, carried out the US, Nigeria, Democratic Republic of Congo, Republic of Congo, and the UK, involved 1512 participants, of which 1031 had confirmed infection. Nine of the studies confirmed the clade of monkeypox, which was mostly West African variants.
Encephalitis, Seizure, and Confusion
Of three clinical features eligible for meta-analysis, prevalence across the studies was:
- Seizure 2.7% (95% CI 0.7 to 10.2%, I2 0%)
- Confusion 2.4% (95% CI 1.1 to 5.2%, I2 0%)
- Encephalitis 2.0% (95% CI 0.5 to 8.2%, I2 55.8%)
However, the authors said that interpreting the figures should be taken in the context that evidence was drawn from medium to low quality cohort and cross-sectional studies, and that only one of the studies analysed included a control group. Also, that the review only identified 2 cases of seizures, 5 cases of encephalitis, and 6 of confusion.
Dr Jonathan Rogers from UCL's Institute of Mental Health, who led the analysis, said: "We found that severe neurological complications such as encephalitis and seizures, while rare, have been seen in enough monkeypox cases to warrant concern, so our study highlights a need for further investigation."
Headache, Fatigue, and Depression Also Noted
Other frequently reported symptoms, which included myalgia, headache, fatigue, anxiety, and depression were noted, although the quality of the evidence was insufficient for the researchers to estimate prevalence. They pointed out that headache, myalgia, and fatigue were common features of a viral infection, and likely to be a reaction to systemic illness rather than direct neurological injury. Also, discrimination and stigma from a monkeypox diagnosis could be a contributory factor, hampering the affected individual's reintegration into society and leading to low mood, they suggested.
The researchers also noted that most cases in the studies they reviewed involved hospitalised patients, and that neurological symptoms from monkeypox infection might not be as common in people with more mild cases. Additionally, none of the studies had long-term follow-up to establish whether any of the symptoms persisted longer than the acute phase of the illness.
Co-author Dr James Badenoch, from Barts Health NHS Trust, said: "As there is still limited evidence into neurological and psychiatric symptoms in the current monkeypox outbreak, there is a need to set up coordinated surveillance for such symptoms. We suggest that clinicians should be watchful of psychiatric symptoms, such as depression and anxiety, and ensure that patients have access to psychological and psychiatric care if needed."
The study, published in the journal eClinicalMedicine, was funded by the Medical Research Council and Wellcome.
Lead Image Credit: Moment/Getty Images
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