Benign febrile myoclonus in childhood

Prognostic factors for functional recovery in children with moderate to severe acute disseminated encephalomyelitis

BACKGROUND

Acute disseminated encephalomyelitis (ADEM) is an immune-mediated encephalopathy with heterogeneous disease courses. However, clinical characteristics for a prognostication of functional recovery from acute episodes of ADEM remain limited. The study aims to characterize the clinical presentations and neuroimaging findings of children with poor functional recoveries from acute episodes of moderate to severe ADEM.

METHODS

The multicenter retrospective cohort study included children under 18 years of age who presented with moderate to severe ADEM (modified Rankin Scale [mRS] ≥ 3 at nadir) from 2002 to 2019. Children were assigned to a good recovery group (mRS ≤ 2) and a poor recovery group (mRS ≥ 3) after mean 4.3 months of follow-up. The clinical presentations and the distribution of brain lesions on magnetic resonance imaging were compared between the two groups by the t-test for numerical variables and Fisher's exact test for categorical variables. Analyses of logistic regression were conducted and significant variables in the multivariate model were examined by the receiver operating characteristic curve for the prediction of functional recovery.

RESULTS

Among the 73 children with moderate to severe ADEM, 56 (77%) had good functional recoveries and 17 (23%) showed poor functional recoveries. Children with poor recoveries had a lower rate of prodromal headache (12% vs. 39%, p = 0.04), and presented with higher proportions of dystonia (29% vs. 9%, p = 0.046), myoclonus (24% vs. 2%, p = 0.009), and cerebellar lesions on neuroimages (59% vs. 23%, p = 0.01). The multivariate analyses identified that a lack of prodromal headache (OR 0.1, 95% CI 0.005 - 0.7, p = 0.06) and the presentations of myoclonus (OR 21.6, 95% CI 1.7 - 874, p = 0.04) and cerebellar lesions (OR 4.8, 95% CI 1.3 - 19.9, p = 0.02) were associated with poor functional recoveries. These three factors could prognosticate poor outcomes in children with moderate to severe ADEM (area under the receiver operating characteristic curve 0.80, 95% CI 0.68 - 0.93, p = 0.0002).

CONCLUSION

Nearly one-fourth of children with moderate to severe ADEM had a poor functional recovery from acute episodes, who were characterized by a lack of prodromal headache, the presentation of myoclonus, and the neuroimaging finding of cerebellar lesions. The clinical variables associated with poor functional recoveries could assist in the planning of immunotherapies during hospitalization for a better outcome in moderate to severe ADEM.

Fever-Associated Seizures or Epilepsy: An Overview of Old and Recent Literature Acquisitions

In addition to central nervous system infections, seizures and fever may occur together in several neurological disorders. Formerly, based on the clinical features and prognostic evolution, the co-association of seizure and fever included classical febrile seizures (FS) divided into simple, complex, and prolonged FS (also called febrile status epilepticus). Later, this group of disorders has been progressively indicated, with a more inclusive term, as "fever-associated seizures or epilepsy" (FASE) that encompasses: (a) FS divided into simple, complex, and prolonged FS; (b) FS plus; (c) severe myoclonic epilepsy in infancy (Dravet syndrome); (d) genetic epilepsy with FS plus; and (e) febrile infection-related epilepsy syndrome (FIRES). Among the FASE disorders, simple FS, the most common and benign condition, is rarely associated with subsequent epileptic seizures. The correlation of FS with epilepsy and other neurological disorders is highly variable. The pathogenesis of FASE is unclear but immunological and genetic factors play a relevant role and the disorders belonging to the FASE group show to have an underlying common clinical, immunological, and genetic pathway. In this study, we have reviewed and analyzed the clinical data of each of the heterogeneous group of disorders belonging to FASE.

Isolated transient myoclonus in the elderly: an under-recognized condition?

BACKGROUND

Cases of transient myoclonus without other neurological manifestations in the elderly have very rarely been reported.

OBJECTIVE

To report clinical features of elderly people with isolated transient myoclonus.

METHODS

Clinical and laboratory features of 11 consecutive patients with isolated transient myoclonus (six men and five women; mean age, 75 years) were reviewed. Transient myoclonus was defined as an acute onset of tremulous myoclonus with/without asterixis in adults without other neurological symptoms.

RESULTS

Preceding infections were recorded in five patients (pneumonia, two; upper respiratory tract infection, two; and septic arthritis of the shoulder, one). Myoclonus predominantly affected the head and/or neck (n=10) and upper extremities (n=11), compared with the trunk (n=2) and lower extremities (n=6). Asterixis was observed in six patients. Laboratory testing, neuroimaging, and electroencephalograms revealed no specific abnormalities. With or without treatment using benzodiazepines, myoclonus in all patients resolved completely within 1-4 days, although five had recurrence 2-19 months after their first episodes. Among these five patients, the accompanying asterixis patterns (presence or not) in four were different in the first and subsequent episodes.

CONCLUSIONS

Isolated transient myoclonus with or without asterixis may be more common than generally believed, and it could be a clinical entity or disease spectrum. Transient myoclonus is a benign condition in the elderly, but can be under-reported or misdiagnosed. Therefore, it is important to recognize that the elderly may have this syndrome.

Febrile myoclonus

Febrile myoclonus is a poorly understood and rarely reported phenomenon. We report a case with particular characteristics that continue to help define this benign disorder.