THE NEUROPSYCHIATRY OF INFECTIOUS DISEASE
- Psychiatric Annals. 2001;31(3):193-204
- Posted March 1, 2001
Acute viial encephalitis typically presents with the sudden onset of fever accompanied by headache, altered consciousness, disorientation, behavior and speech disturbances, and generalized or focal neurologic signs.1″3 In some cases, signs of central nervous system (CNS) involvement may not become apparent until the delayed development of immune-mediated postinfectious encephalitis.1″3 Early diagnosis is critical in detecting treatable nonviral causes of encephalitis, and in detenriining whether to adrninister specific antiviral therapy.
Occasionally, acute encephalitis initially presents as a behavioral syndrome simulating classic psychotic or mood disorders.4**6 In the absence of prominent neurologic signs, such patients are often misdiagnosed and prescribed psychotropic drugs. This can seriously delay appropriate neurologic evaluation and antiviral treatment, and further stigmatize patients. Furthermore, clinical evidence suggests that patients with encephalitis may be at increased risk for adverse reactions to neuroleptic treatment, including neurolepticinduced catatonia, extrapyramidal side effects, neuroleptic malignant syndrome, and seizures that can complicate management and worsen outcome.18,22,30,38,40-42,47-63 In fact, suspicion of encephalitis as the underlying cause of psychosis often arises in these cases only after the development of neuroleptic-induced side effects prompts a more thorough laboratory and radiologic search for the cause of deterioration.47
Although viral encephalitis presenting as a psychiatric disorder is uncommon, it is often missed and probably underreported. In addition, recent advances in the diagnosis and treatment of viral infections of the CNS have not been adequately covered in the psychiatric literature. Most psychiatrists are aware of human immunodeficiency virus (HTV) and herpes simplex virus type 1 (HSV-I), but have limited knowledge of the broad array of common human viruses that have been associated with neuropsychiatrie manifestations of encephalitis.
This article reviews the clinical signs, epidemiology, virology, neuropathology, and treatment of psychiatric disorders due to acute viral encephalitis, based on cases reported in the literature. Specific goals are to determine whether patients presenting with initial psychiatric manifestations differ from other patients with encephalitis; to identify clinical or demographic variables helpful in diagnosing covert encephalitis in psychiatric patients; to determine whether there is a typical profile of psychiatric symptoms specific to encephalitis; and to determine whether specific viruses are associated with psychiatric presentations.
Cases of psychiatric disorders due to viral encephalitis that were published in English since 1955 were obtained through a citation service and from a MEDLINE search cross-referencing encephalitis with psychosis, catatonia, mania, depression, and neuroleptics. References in articles were scanned to find earlier citations. Published cases were included if the patients initially presented with psychiatric disorders that were attributed to viral encephalitis based on histopathology or histochemical staining of specimens obtained by biopsy or at autopsy, viral cultures of neural tissue or cerebrospinal fluid, antibodies in serum or cerebrospinal fluid, local epidemics, or clinical findings. Although the pathogenesis of subacute sclerosing panencephalitis is complex and chronic in relation to that of measles virus infection,1’2 patients with subacute sclerosing panencephalitis presenting with misdiagnosed psychiatric disorders were included. Patients with probable postinfectious encephalitis following systemic viral illness were also included when psychiatric presentations were reported. Although reflecting different underlying mechanisms,1’2 acute viral encephalitis and postinfectious encephalitis can be difficult to distinguish clinically.
One hundred eight previously published cases of psychiatric disorders due to suspected or confirmed viral infections of the CNS were found (Table I).4″66 In nearly half (43%) of the cases, no infectious agent could be identified, although the reliability of the laboratory investigations varied depending on the detail of reporting and the technology available at the time of the report. In 62 cases (57%), a specific virus was implicated. Eleven different viruses were suspected or confirmed.
Overall, more women (60%) than men (40%) were described with viruses, although gender…
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