A 1½-year old exclusively breast-fed male child belonging to lower socio-economical status (SES) presented with regression of milestones since 3 months and abnormal movements since 7 days. He was managed as status epilepticus with multiple antiepileptic drugs (AEDs) in a local hospital for 2 days, and in view of no improvement in abnormal movements, he was referred to us. Examination revealed a chubby child with pallor; pigmentation of dorsum of hands, feet, and knuckles; sparse, lusterless, and depigmented hair; lack of interest in the surroundings; poor interaction with mother and examiner; apathy; and bleating cry. Coarse, jerky, generalized, low-amplitude tremors were noted involving all the limbs, face, and lips which were continuous throughout the day, disappeared during sleep, and got aggravated while crying [Video 1]. His level of consciousness, muscle tone, and deep tendon reflexes were normal. The diagnosis of infantile tremor syndrome (ITS) was made based on clinical features.
Investigations revealed hemoglobin 8 g/dL, total leukocyte count 13,500/mm 3 (neutrophils 70%, lymphocytes 30%), platelets 1,56,000/mm 3, mean corpuscular volume108 fL (normal 80–96 fL), mean corpuscular hemoglobin 25 pg (normal 27–32 pg), mean corpuscular hemoglobin concentration 28% (normal 30%–36%), and red cell distribution width 12% (normal 12%–14%). Liver and renal function tests were normal. Serum magnesium was 1.4 mg/dL (normal 1.8–3.6 mg/dL). Serum vitamin B12 level was 156 pg/mL (normal: 200–900 pg/mL) and folate was 10 ng/mL (normal 2–20 ng/mL).
He was started on nutritional rehabilitation along with supplements (vitamin B12, vitamin B6, calcium, iron, zinc, and magnesium). The AEDs were stopped. There was improvement in pallor, psychomotor functions, and tremors in the next 3 weeks.
ITS is commonly reported from India in exclusively breast-fed infants and toddlers belonging to lower SES and characterized by subacute onset of psychomotor regression, pallor, pigmentary changes of skin and hair, and tremors., Probable etiologies include malnutrition and vitamin B12 deficiency., Tremors are the most distinctive features and tend to be coarse and jerky with usually focal onset and rapid progression to generalized involvement. There may be involvement of facial, lingual, labial, and laryngeal musculature (leading to peculiar tremulous cry like bleating of a goat). Tremors are intermittent to begin with and later become constant throughout the day and disappear during sleep, but may persist during sleep in severe cases. Tremors are often misdiagnosed as status epilepticus by inexperienced clinicians and treated with multiple AEDs., Most of the children eventually recover with nutritional rehabilitation, but some may be left with long-term cognitive and language related neurological deficits.
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