Description of HE by Dr. Dalmau (formerly at U Penn, now at University of Barcelona, Spain)
Dr. Dalmau, one of the leading international authorities on autoimmune encephalopathy, coauthored an article that appeared in Psychiatric Times in March 2010 titled “Psychiatric Presentation of Autoimmune Encephalopathies.” As readers of this site may know all too well, many HE patients are misdiagnosed with psychiatric disorders by treaters unfamiliar with autoimmune encephalopathy, Here are excerpts from the article:
“While a biological basis for numerous psychiatric illnesses has become increasingly appreciated, few mechanistic hypotheses have gripped psychiatric researchers as strongly as an autoimmune basis for behavioral abnormalities. Perhaps the most extreme example of autoimmune phenomena that result in psychiatric changes can be found in antibody-mediated limbic encephalitis. In these syndromes, autoantibodies interfere either directly or indirectly with neuronal function, the outcome of which is striking cognitive and behavioral changes often accompanied by severe neurological symptoms…
Another group of autoimmune-mediated disorders results in limbic encephalitis but is not usually associated with an underlying neoplasm….
Hashimoto encephalopathy is an autoimmune limbic encephalitis characterized by high levels of antithyroid antibodies in serum, although usually without clinically relevant thyroid dysfunction. Patients are women in their 40s to 50s who present with waxing and waning cognitive impairment, such as memory dysfunction and speech abnormalities. Psychiatric disturbances are extremely frequent as well and include disorganized behavior with poor self-care, psychosis (often with visual hallucinations), changes in mood or personality, and sleep dysfunction.
Seizures are often associated with Hashimoto encephalopathy, but unique to this syndrome are fluctuating stroke-like episodes that span multiple different vascular territories. Other neurological symptoms such as myoclonus, tremor, ataxia, and headache have been reported in one-third of cases.
Thyroid peroxidase antibodies assist in the diagnosis of Hashimoto encephalopathy. This finding is reported in nearly all cases. However, a well-defined pathogenic role for these antibodies has not been established, and the antibodies are highly prevalent in the general population, which complicates diagnosis based on antibodies alone. Results of brain MRI scans are normal 50% of the time, and changes are nonspecific, even when abnormal.
Finally, another critical feature that supports the diagnosis of this disorder is the response to treatment: Hashimoto encephalopathy is almost uniformly responsive to a prolonged course of high-dose corticosteroids. On average, treatment continues 4 to 6 weeks before clinical recovery starts and corticosteroid taper is initiated.Multiple studies have described relapse of symptoms with early cessation of therapy, which highlights the need to continue therapy beyond simply the appearance of improvement. …
An autoimmunological basis for psychiatric disturbances such as schizophrenia and depression has been theorized for decades.55,56 The characterization of multiple encephalopathies as autoimmune in nature provides a foothold for a greater under-standing of how antibody-mediated syndromes can manifest with behavioral changes. Paraneoplastic limbic encephalitis, nonparaneoplastic limbic encephalitis, and encephalitis that involves glutamate receptors represent a heterogeneous group of disorders with common pathogenic mechanisms.
The diverse cognitive and behavioral symptoms in these disorders emphasize the need for psychiatrists to consider such syndromes in their differential diagnosis for patients with atypical behavioral changes. Moreover, given the potential for a significant role in recognition of these neurologically complex disorders, psychiatrists should become familiar with diagnostic criteria and appropriate therapeutic options.”