[Myoclonus in children]

The article includes data on terminology, an etiology, mechanism and clinical presentation of myoclonus in children. The clinical classification, scheme of diagnostic search and feature of the differential diagnosis of different types of myoclonus is presented.

Presentation and clinical course of Wolfram (DIDMOAD) syndrome from North India

AIMS

Wolfram syndrome, also known as DIDMOAD, is a relatively rare inherited neurodegenerative disorder, first evident in childhood as an association of juvenile-onset diabetes mellitus and optic atrophy, followed by diabetes insipidus and deafness. The aim of the study was to examine the clinical profile of patients with DIDMOAD syndrome presenting to a tertiary care hospital in north India.

METHODS

Clinical presentation of juvenile-onset diabetes mellitus fulfilling the diagnosis of Wolfram syndrome was studied using a prepared standardized form.

RESULTS

Subjects with juvenile-onset non-autoimmune diabetes mellitus attending the diabetic clinic at a tertiary care centre in north India were followed for 10 years and a diagnosis of fully developed Wolfram syndrome was confirmed in seven individuals. The series consisted of five male and two female patients with a mean age of 17.5 ±7.34 years. Two subjects had consanguinity and none had any other family member affected. Optic atrophy was present in all, sensorineural hearing loss in 4/7, central diabetes insipidus in 4/7 and nephrogenic diabetes insipidus in 2/7 subjects. The new associations found were: spastic myoclonus, short stature with pancreatic malabsorption, nephrogenic diabetes insipidus, cyanotic heart disease and choledocholithiasis with cholangitis. Genetic analysis revealed mutation in exon 8 of the WFS1 gene in all the cases studied.

CONCLUSIONS

The present clinical series of Wolfram syndrome reveals a varied clinical presentation of the syndrome and some new associations.

Spinal segmental myoclonus during postural maintenance in a patient with cervical spondylosis: a case report

Spinal segmental myoclonus is defined as a rare involuntary movement characterized by myoclonic jerks of spinal origin. We describe the case of a 62-year-old woman who developed spinal segmental myoclonus 4 months after undergoing cervical laminoplasty for ossification of the posterior longitudinal ligament. Myoclonic jerks were observed in the upper trapezius innervated by C3-4, which corresponded to the level of myelomalacia. These jerks were elicited and aggravated in the sitting and standing positions but were completely suppressed in the supine position. The myoclonus was refractory to medication but improved with the use of a soft neck brace.

Adenylosuccinate lyase deficiency in a Malaysian patient, with novel adenylosuccinate lyase gene mutations

Most cases of adenylosuccinate lyase (ADSL OMIM 103050) deficiency reported to date are confined to the various European ethnic groups. We report on the first Malaysian case of ADSL deficiency, which appears also to be the first reported Asian case. The case was diagnosed among a cohort of 450 patients with clinical features of psychomotor retardation, global developmental delay, seizures, microcephaly and/or autistic behaviour. The patient presented with frequent convulsions and severe myoclonic jerk within the first few days of life and severe psychomotor retardation. The high performance liquid chromatography (HPLC) profile of the urine revealed the characteristic biochemical markers of succinyladenosine (S-Ado) and succinyl-aminoimidazole carboximide riboside (SAICAr). The urinary S-Ado/SAICAr ratio was found to be 1.02 (type I ADSL deficiency). The patient was compound heterozygous for two novel mutations, c.445C > G (p.R149G) and c.774_778insG (p.A260GfsX24).

A descriptive analysis of neck myoclonus during routine polysomnography

STUDY OBJECTIVES

Although episodes of neck myoclonus (head jerks) in REM sleep have a characteristic appearance, they have so far not been described systematically in video-polysomnography. This study assesses the occurrence, frequency, and characteristics of neck myoclonus in REM sleep in a prospective sleep disorder cohort, and investigates clinical correlates and associations with medication.

SETTING

University hospital sleep disorders center.

PARTICIPANTS

Two-hundred twenty-eight mixed sleep disorder patients.

INTERVENTIONS

Not applicable.

MEASUREMENTS AND RESULTS

REM sleep was screened visually for short "stripe-shaped" movement-induced artifacts visible vertically over the EEG leads in polysomnographic registration. If such artifact was present, the synchronized video was inspected for the presence of neck myoclonus. Out of 205 patients, 54.6% (n = 112) had neck myoclonus during REM sleep. The mean neck myoclonus index was 1.0 +/- 2.7/h REM sleep. Younger patients had a higher neck myoclonus index than older patients (< 45 years versus 45-60 years versus > 60 years: 1.8 +/- 4.2 versus 0.6 +/- 1.1 versus 0.5 +/- 1.1; P = 0.004). Ninety-five percent of subjects < 45 years had a neck myoclonus index between 0 and 9.4/h; 95% of subjects > 45 years had a neck myoclonus index between 0 and 2.7/h. Patients on benzodiazepine treatment had no neck myoclonus (0/112 vs. 13/93; P < 0.001). In 23 patients, additional surface neck EMG was performed. EMG activation associated with neck myoclonus had a mean duration of 0.6 +/- 0.4 sec. Correlation between duration of neck EMG activation and movement-induced EEG artifact duration was very high (rho = 0.96; P < 0.001).

CONCLUSIONS

Neck myoclonus is common during REM sleep and more frequent in younger individuals. This could indicate that neck myoclonus during REM sleep is a physiological phenomenon. If there is a cut-off distinguishing normal from excessive has to be investigated in further studies.

[Does Jeavons syndrome exist? A report of a series of 10 cases]

INTRODUCTION

Jeavons syndrome (JS) or eyelid myoclonia (EM) with or without absences is an epileptic syndrome characterised by EM on closing the eyes, in bright environments, which coincides on the electroencephalogram with brief generalised polyspike and polyspike-wave discharges at 3-6 Hz. Photoparoxysmal response is associated in photostimulation. The ILAE recognises EM as a special type of myoclonic seizures, yet it still does not include JS as a separate condition in its classification of epileptic syndromes.

AIM

The aim of this article is to report on a series of 10 cases, with special attention given to their clinical-electro-encephalo-graphic description. We believe it is a condition that is not infrequent, but one which is underdiagnosed. Moreover, we also want to highlight the pros and cons determining the fact that today there is still controversy about whether or not it should be recognised as an independent epileptic syndrome.

PATIENTS AND METHODS

We conducted a retrospective study of 10 cases collected over the period between 2002 and 2009 in our adult Epilepsy Unit.

RESULTS

All our patients fulfilled JS criteria. There is a predominance of females (n = 8), with the existence of cases of idiopathic generalised epilepsy in the family (n = 5), which are associated with clonic-tonic generalised seizures in nearly all of them (n = 9) and are well controlled with treatment in monotherapy, although the EM persist in three cases. The results of a neurological exploration and neuroimaging are normal in all cases.

CONCLUSIONS

JS is a photosensitive epilepsy that is not easily confused with other conditions; nevertheless, there can be an overlap with other idiopathic generalised epilepsy syndromes that lead to their being underdiagnosed. Genetics and functional neuroimaging will determine whether it is an independent condition or not.

[Myoclonia in an oldest old woman: a frequent and reversible etiology]

A 98-year-old woman was referred to our hospital because of myoclonia. The concentration of calcium and vitamin D in the serum was low. In this context, we concluded of neuromuscular irritability secondary to hypocalcaemia. The symptoms disappeared after a treatment of intravenous calcium. This case shows how important it is to investigate electrolytes in case of neuromuscular irritability symptoms in elderly people.

[Non epileptic paroxysmal movements disorders in infant]

Paroxysmal non-epileptic disorders may cause episodic and paroxysmal symptoms that mimic true epileptic seizures and they must be considered in the differential diagnosis. Paroxysmal movement disorders are not uncommon in infants, but are probably under-recognised. These phenomena represent various clinical situations, characterised by intermitted and episodic disturbances of movement. Clinical experience and a detailed history and careful observation with video recording are often helpful to establish the correct diagnosis. In the large majority of the cases, paroxysmal movement disorders are benign situation. Most of the time, no treatment will be required, and the families will be informed of the good prognosis. These disorders in infants are discussed in the present review.

The borderland of epilepsy: clinical and molecular features of phenomena that mimic epileptic seizures

Paroxysmal losses of consciousness and other episodic neurological symptoms have many causes. Distinguishing epileptic from non-epileptic disorders is fundamental to diagnosis, but even this basic dichotomy is often challenging and is certainly not new. In 1907, the British neurologist William Richard Gowers published his book The Border-land of Epilepsy in which he discussed paroxysmal conditions "in the border-land of epilepsy-near it, but not of it" and their clinical differentiation from epilepsy itself. Now, a century later, we revisit the epilepsy borderland, focusing on syncope, migraine, vertigo, parasomnias, and some rarer paroxysmal disorders. For each condition, we review the clinical distinction from epileptic seizures. We then integrate current understanding of the molecular pathophysiology of these disorders into this clinical framework. This analysis shows that, although the clinical manifestations of paroxysmal disorders are highly heterogeneous, striking similarities in molecular pathophysiology are seen among many epileptic and non-epileptic paroxysmal phenomena.

Parkinsonism & related disorders. Myoclonus

Myoclonus has now been recognized to have many possible etiologies, anatomical sources, and pathophysiologic features. Classification schemes may be based on clinical syndromes and etiology, neurophysiology properties, or exam findings. In recent years, many myoclonus case reports and short series have been published. However, this article will group new developments into three areas: (1) Myoclonus in parkinsonian disorders, (2) Concepts in myoclonus generation, and (3) Treatment. Current findings do not allow one to conclude whether or how parkinsonism contributes to the myoclonus mechanism in parkinsonian disorders. Therefore, it seems unlikely that the myoclonus in Lewy body disorders is mostly caused by abnormal basal ganglia input to motor areas of the neocortex. The exact source of cortical myoclonus generation is controversial. Increased corticomuscular coherence represents a robust phenomenon that will need to be explained by any model that offers a putative explanation for cortical myoclonus generation. Myoclonus treatment is still limited, and more research on basic mechanisms before truly effective treatment will be available. The best approach for myoclonus is based on the physiological classification of the myoclonus.

Post-hypoxic myoclonic status: the prognosis is not always hopeless

A 67-year-old woman abruptly developed acute pulmonary oedema, severe bradycardia and then cardiac arrest while in hospital 6 days after an elective hernia repair. She was resuscitated, intubated and transferred to the intensive care unit. Within 24 hours, she began to display repetitive, generalised myoclonic jerks that failed to respond to therapy with conventional anticonvulsants; an electroencephalogram confirmed myoclonic status. After administration of levetiracetam was begun on Day 3, myoclonic jerks reduced, and there was gradual clinical improvement. By Day 6 after the arrest, the patient was alert and oriented (Glasgow Coma Score, 15/15). Although she died on Day 11 after massive haemoptysis and cardiac arrest, this patient demonstrates the possibility of reasonable neurological recovery despite early onset of myoclonic status.

[Differential diagnosis of status epilepticus]

The diagnosis of status epilepticus can be retained, wrongly, in several circumstances. Nonepileptic pseudoseizures from a psychiatric origin and some movement disorders can mimic convulsive status epilepticus. Encephalopathy of various causes (post-anoxic, metabolic, toxic, Creutzfeldt-Jakob disease) can be wrongly taken for non-convulsive status epilepticus, mainly due to inadequate interpretation of the electroencephalogram (EEG). In these encephalopathies, the existence of (non-epileptic) myoclonus and the abolition of the EEG abnormalities with the use of a benzodiazepine (without correction of the clinical symptoms) are additional confounding factors, leading to false diagnosis. Nevertheless, in general, the diagnosis of status epilepticus can be confirmed or rejected base on a combined analysis of the clinical data and the EEG.

[Objective tinnitus and essential palatal tremor in children: report of a case]

Palatal tremor is a rare neurotological disorder responsible for objective tinnitus in children. Palatal tremor may be symptomatic of an underlying neurological disease or essential when a cause cannot be identified. We report a case of an essential palatal tremor in a 10-year-old girl complaining of clicking tinnitus. No treatment was undergone as she was not obviously bothered by the ear-clicking sound. Different treatment modalities have been used for distressing tinnitus related to palatal myoclonus. Recently several publications reported satisfactory results with botulinum toxin injection, which seems to be the treatment of choice.