[Hashimoto encephalopathy. Analysis of four case reports]

Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT): Characteristics, treatment and outcome in 251 cases from the literature

BACKGROUND

Steroid-responsive encephalopathy and associated autoimmune thyroiditis (SREAT) is characterized by encephalopathy and the presence of antithyroid antibodies. We describe the clinical presentation, outcome and treatments for SREAT by a systematic review of the literature.

METHODS

MEDLINE via PubMed, Web of Science and the Cochrane Library were searched for articles published until 2015. Inclusion criteria were unexplained encephalopathy with antithyroid antibodies.

RESULTS

We found reports of 251 patients (median age 52years [range 18-86], 73% females, 80 [32%] with preexisting thyroiditis). Patients presented encephalitis signs with convulsions (n=117; 47%), confusion (n=115, 46%), speech disorder (n=91, 37%), memory impairment (n=107, 43%), gait disturbance (n=67, 27%) and persecutory delusions (n=61, 25%). Twenty-eight patients (11%) presented progressive memory impairment and 26 (10%) isolated psychiatric disorders. In serum, 34% of patients were positive for anti-thyroid peroxidase (TPO) antibodies, 7% for anti-thyroglobulin (TG) antibodies, and 69% both. Thyroid-stimulating hormone levels were usually normal, at 2 UI/ml [0.001-205]. Cerebrospinal fluid from 10/53 patients (19%) was positive for anti-TPO antibodies, 2/53 (4%) anti-TG antibodies and 28 (53%) both. Electroencephalography findings were abnormal for 82% of patients, showing diffuse slowing consistent with encephalopathy (70%) or epileptic activity (14%). The first-line treatment was steroids in 193 patients and other immunosuppressive drugs in 10 cases. At a median follow-up of 12months [range 0.2-110], 91% of patients showed complete or partial neurological response, with anti-TPO and -TG antibody titers at 347 UI/ml [0-825,000] and 110 UI/ml [0-50,892], respectively. During follow-up, 40 patients (16%) experienced at least one relapse. Relapse was more frequent in patients with initial coma (26% vs 13%, p=0.08).

CONCLUSION

The diagnosis of SREAT should be suspected in case of encephalopathy without obvious cause, to quickly start corticosteroid treatment. The exact modalities of treatment must be defined.

Hashimoto's encephalopathy: A rare proteiform disorder

Hashimoto's encephalopathy (HE) is a rare not well understood, progressive and relapsing multiform disease, characterized by seizures, movement disorders, subacute cognitive dysfunction, psychiatric symptoms and responsiveness to steroid therapy. The disorder is generally associated with thyroid diseases and the most common feature is the presence of anti-thyroperoxidase antibodies (TPOAb). Patients are usually euthyroid or mildly hypothyroid at presentation. All age groups can be affected. The pathophysiology is still unclear, especially the link between elevated serum TPOAb and the encephalopathy. Most reported cases occurred in women and girls. Unspecific symptoms, non-pathognomonic laboratory neurophysiology and neuroimaging features make its diagnosis a real challenge for clinicians. The case of a 16 year old boy, with a clinical picture of HE associated with hypothyroidism, demonstrating an excellent response to high dose steroids is presented together with a systematic review of the literature.

Steroid-responsive encephalopathy: an under recognised aspect of Hashimoto's thyroiditis

We present a case of a patient who was diagnosed with Hashimoto's encephalopathy based on the presence of subacute behavioural changes, negative work up for infection and immunological serology except for high serum titres of thyroid autoantibodies. Thyroid function tests (TFTs) and MRI of the brain were normal. EEG showed low amplitude, slow waves and θ waves at both frontal areas. His condition improved dramatically after treated with high-dose glucocorticoid. After 2 years of a relapsing-remitting course, a new episode occurred. There was an abrupt change of TFTs within 5 days: free thyroxine (fT4) from 1.52 to 1.53 ng/mL, free triiodothyronine (fT3) from 3.25 to >30 pg/mL and thyroid-stimulating hormone (TSH) from 5.08 to 0.78 mIU/L. On the following day found fT4 2.58, fT3 14.67 and TSH 0.042. The patient was diagnosed with Hashitoxicosis. High-dose glucocorticoid and β-blockers were initiated. The symptoms gradually improved and TFTs normalised within 2 weeks.

Hashimoto's encephalopathy in the intensive care unit

BACKGROUND

Since the first description of Hashimoto's Encephalitis (HE) in 1966 by Lord Brain, the number of reported cases has continued to increase. In addition, cases of status epilepticus have been reported, suggesting a role for intensive care unit (ICU) practitioners in taking care of patients with HE.

METHODS

A retrospective cohort study in ICU patients with HE was performed at the University Hospital of Tours, France.

RESULTS

Eight HE cases were admitted to the ICU between 1/1/2000 and 1/1/2012. Herein, we describe the characteristics of the patients, with an emphasis on ICU disease management and its outcome.

CONCLUSION

ICU practitioners should be aware of this disease, since it can include life-threatening presentations.

Hashimoto's encephalopathy cases: Chinese experience

Background

Hashimoto’s encephalopathy is a poorly understood syndrome consisting of heterogeneous neurological symptoms and high serum antithyroid antibody titers, typically responding to steroids. More clinical series studies are required to characterize the clinical, laboratory and imaging features, and outcomes, especially in the Chinese population.

Methods

We analyzed the clinical, laboratory, and imaging features and outcomes of thirteen consecutive patients with Hashimoto’s encephalopathy diagnosed in Xuan Wu Hospital, Beijing from 2005 to 2010 retrospectively.

Results

Cognitive impairment (84.6%) and psychiatric symptoms (38.5%) were the most frequent symptoms. Seizures (30.8%) and myoclonus (7.7%) were less common than previously described. Three (23.1%) patients showed abnormal signals in hippocampus or temporal lobe, which were believed related to their memory disorders or seizures. MRI changes showed resolution paralleling clinical improvement in one patient. Among eight patients who received steroid therapy, five patients recovered, one patient improved with residual deficits, and two patients relapsed or had no effect. Among five non-steroid treated patients, three patients experienced stable remission with antiepileptic drugs or general neurotrophic therapy, and two patients experienced continuous deterioration.

Conclusions

Most patients with Hashimoto’s encephalopathy showed good response to steroids. Some patients improved without steroid therapy. Considering its reversible course, we recommend that Hashimoto’s encephalopathy should always be in the differential diagnosis while evaluating disorders of the central nervous system.

Clinical manifestations, diagnostic criteria and therapy of Hashimoto's encephalopathy: report of two cases

Hashimoto's encephalopathy (HE) is a rare, still not well understood, autoimmune disease with neurological and psychiatric manifestations. and elevated titers of antithyroid antibodies in serum and cerebrospinal fluid (CSF) as a hallmark of the disease. Patients are mostly women. Current diagnostic criteria include corticosteroide responsiveness, but it is the case in only 50% of patients with HE. In steroid non-responders other immunomodulatory therapies or plasmapheresis could be applied. Disease course can be acute, subacute, chronic or relapsing-remitting. Two distinct forms emerged from the reported cases: a vasculitic type characterized by multiple relapsing-remitting stroke-like episodes and mild cognitive impairment and a diffuse progressive type characterized by dementia and psychiatric symptoms. Both forms may be accompanied by depressed level of consciousness (stupor or coma), tremor, seizures, or myoclonus. We present two patients with two distinct forms of HE who had different clinical manifestations and response to therapy.

Hashimoto's encephalopathy

Hashimoto's encephalopathy (HE) is a controversial neurological disorder that comprises a heterogenous group of neurological symptoms that manifest in patients with high titers of antithyroid antibodies. Clinical manifestations of HE may include encephalopathic features such as seizures, behavioral and psychiatric manifestations, movement disorders, and coma. Although it has been linked to cases of Hashimoto's thyroiditis or thyroid dysfunction, the most common immunological feature of HE is the presence of high titers of antithyroglobulin or anti-TPO (antimicrosomal) antibodies. At present, it is unclear whether antithyroid antibodies represent an immune epiphenomenon in a subset of patients with encephalopathic processes or they are really associated with pathogenic mechanisms of the disorder. The significance of classifying encephalopathies under the term HE will be determined in the future once the relevance of the role of antithyroid antibodies is demonstrated or dismissed by more detailed experimental and immunopathological studies. The responsiveness of HE to steroids or other therapies such as plasmapheresis supports the hypothesis that this is a disorder that involves immune pathogenic mechanisms. Further controlled studies of the use of steroids, plasmapheresis, or immunosuppressant medications are needed in the future to prove the concept of the pathogenic role of antithyroid antibodies in HE.

Epilepsy and dementia in the elderly

Epilepsy is a frequent condition in the elderly; however, it remains a relatively understudied condition in older adults with dementia. The diagnosis of a seizure is particularly difficult and is most often based on questions to the caregiver. Epilepsy in dementia has significant consequences on the prognosis of the underlying dementia: it can result in a worsening of cognitive performance, particularly in language, as well as a reduction in autonomy, a greater risk of injury and a higher mortality rate. In this review, management strategies are recommended for the clinician. The presence of pre-existing Alzheimer's disease does not exempt the clinician from ruling out other symptomatic causes of seizures. Anti-epileptic drugs (AED) should be started only after the diagnosis has been clearly established, when the risk of recurrence is high, and with monotherapy whenever possible. Although few data are available, the more recent AED offer significant advantages over the older medications in this context.

[Steroid responsive encephalopathy associated with auto-immune thyroiditis]

Since the first description of encephalopathy associated with Hashimoto's thyroiditis in 1966, more than 100 cases of this entity called Hashimoto's encephalopathy or SREAT [steroid-responsive encephalopathy associated with auto-immune thyroiditis] have been reported. The two cases reported here illustrate different diagnostic criteria and offer the opportunity to discuss the many pathophysiological hypotheses based on particularly pertinent biological data, especially the activity of anti-TPO and anti-TG antibodies present in serum and cerebrospinal fluid and the recent discovery of anti-alpha-enolase antibody. Different treatment options are also discussed, in particular corticosteroid therapy.

[Potentially reversible dementia]

Reversible dementia is rare and accounts for approximately 1.5% of all dementias. Systematic ancillary investigations aimed at detecting an infectious disease, an endocrine aetiology or a vitamin deficiency are rarely contributive, but remain relevant since reversible dementia may, very rarely, mimic Alzheimer-type dementia. Aetiological investigations are much better selected and contributory when they rely on a precise analysis of the clinical picture (past medical history, age of the patient, cognitive, psychiatric and behavioural symptoms, type of onset, and associated signs) and of cerebral imaging. Discovering a reversible cause of dementia does not always mean that the patient will completely recover; thus it is more appropriate to use the term "potentially reversible dementia". Finally, when the patient does not recover from dementia, systematic ancillary investigations can identify and treat concomitant reversible conditions, which in nearly 25% of dementia cases contribute to worsening the condition.

Clinical and diagnostic aspects of encephalopathy associated with autoimmune thyroid disease (or Hashimoto's encephalopathy)

Encephalopathy associated with autoimmune thyroid disease, currently known as Hashimoto's encephalopathy, but also defined as corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis, is a relatively rare condition observed in a small percentage of patients presenting with autoimmune thyroid disease. It consists of a subacute, relapsing-remitting, steroid-responsive encephalopathy characterised by protean neurologic and neuropsychiatric symptoms, diffuse electroencephalographic abnormalities and increased titres of antithyroid antibodies in serum and/or in cerebrospinal fluid. Most of the cases presenting this neurologic complication are affected by Hashimoto's thyroiditis or, less frequently, by other autoimmune thyroid diseases, chiefly Graves' disease. The pathogenesis of this encephalopathy is still unknown and largely debated, because of extremely varied clinical presentation, possibly referable to different aetiologic and pathophysiologic mechanisms, as confirmed by the two clinical cases we report in this paper. Autoimmune aetiology is, however, very likely in view of the well established favourable response to corticosteroid administration. Both vasculitis and autoimmunity directed against common brain-thyroid antigens represent the most probable aetiologic pathways. Clinical manifestations include consciousness changes, neurologic diffuse or focal signs, headache, and altered cognitive function. Although unspecific, cerebral oedema has also been described. Cerebrospinal fluid examination often discloses an inflammatory process, with a mild increase in protein content and occasionally in lymphocyte count. In this review, clinical criteria for the diagnosis of defined, probable, or possible encephalopathy associated with autoimmune thyroid disease are suggested. Corticosteroid therapy currently allows us to obtain rapid remission of disease symptoms, but adverse outcomes as well as spontaneous remissions have also been reported.

Hashimoto Encephalopathy (Autoimmune Encephalitis)

Patients with Hashimoto thyroiditis may have neurologic manifestations that have been described in the literature for some decades now; these include psychiatric disorders, abnormal movements, and simulation of cerebrovascular events. Nuclear magnetic resonance (MRI) studies have revealed diffuse leukoencephalopathy in most cases. We describe a case having clinical manifestations simulating cerebrovascular events, together with cognitive alterations (a presentation already described in other patients). Among the 2 main forms of neurologic manifestations, the cognitive type, which is probably associated with endocrinologic alteration, may improve with hormone supplement. Those alterations simulating cerebrovascular events are most probably related to autoimmune vasculitis. The latter may improve with the administration of corticosteroids, which are proposed as treatment of this disorder.

Progressive dementia caused by Hashimoto's encephalopathy - report of two cases

Dementia induced by Hashimoto's encephalopathy (HE) seems to be a rare condition. We report on two patients, who revealed a syndrome consisting of a rapid progressive dementia with myocloni. In both patients, the detection of antithyroid antibodies enabled the diagnosis of HE. The symptoms receded completely during a high-dose glucocorticoid therapy. In patients with rapidly progressive dementia or with dementia of unknown origin, HE should be considered.