Dr Ira Shah,Dr.
MD, DCH (Gold Medalist), FCPS, DNB

Dr C.T.Deshmukh, Late Dr B. A. Bharucha

A 9 month old male child presented with tremors since 15 days for which he was treated with 2mg of Injection Vitamin B12 but there was no improvement. Tremors initially started in the left hand followed by twitching of the face and then subsequently involving all 4 limbs. Tremors used to disappear in sleep. There was loss of previously attained milestones during this episode. He had sparse blond hair, pallor and was hypotonic. Parents were exclusively vegetarian in diet and child was exclusively breast-fed. He had a dull apathetic look on the face. There were no skin changes. In view of the clinical symptoms a diagnosis of Infantile Tremor syndrome was considered.

A complete blood count showed Hemoglobin of 4.9 gm/dl with peripheral smear suggestive of hypo-micro-macro-polychromasia. Serum Vitamin B12 level was 2275 pg/ml [Normal=200-950pg/ml] but the patient had already received Vitamin B12. His S. folic acid was 41.3 ng/ml [Normal=3-17ng/ml]. Due to high suspicion of Vitamin B12 deficiency, his mother's serum vitamin B12 levels were done which was 183.3 pg/ml [Normal=200-950 pg/ml]. This was suggestive of primary B12 deficiency in the mother due to dietary deficiency with lack of Vitamin B12 in the breast milk.

EEG was suggestive of slow background activity with random sharp potentials on both sides, CT scan brain showed severe cerebral cortical atrophy. Patient was started on vitamin B12 [1mg IM daily] and folic acid [5m daily] and his mother was also started on B12 supplementation. His tremors decreased within 10 days of therapy. On follow up after six weeks he had regained his previously lost milestones. He was continued on vitamin B12 and folic acid for 6 weeks.

Infantile tremor syndrome (ITS) is a clinical disorder characterized by coarse tremors, anemia and regression of motor and mental milestones in children around 1 Year of age. It has been primarily reported from India and south East Asia.

Etiology- Vitamin B12 deficiency has been found to be associated with ITS. However iron deficiency, magnesium deficiency and zinc deficiency have also been postulated. It is seen in children who are on prolonged exclusive breast-feeding with mothers who are predominantly vegetarians.

Clinical Features- A classical picture of ITS is a plump looking infant between 6 months to 18 months with presence of malnutrition. These children are listless, apathetic and disinterested in surroundings. Scalp hair is sparse and light colored. Dark pigmentation is present over dorsal aspects of hands, nail folds, feet, knees, ankles, buttocks and axillae.

There is regression of milestones in the recent past. Tremors have an acute onset following an acute infection or stress. Initially they are intermittent but become continuous in a few days. They are more prominent in distal parts of limbs, head, face and tongue. These tremors disappear during sleep.

Hypotonia with flabbiness of muscles is common. There is presence of anemia, which may be macrocytic, microcytic or even normocytic.

Diagnosis - It is essentially a clinical diagnosis with peripheral smear suggestive of anemia. Vitamin B12 levels may be low. Vitamin B12 levels in the mother may also be low suggesting low levels in the breast milk.

Treatment consists of therapy for anemia and nutritional deficiency. Vitamin B12 in high doses may be required if B12 levels are low. Zinc and magnesium supplements may also be necessary. If the tremors are severe, phenobarbitone (3-5 mg/kg/day) may be required to decrease the intensity. The tremors subside slowly. Initially there is gradual reduction in the amplitude and severity then the tremors become intermittent and finally stop. Pigmentary changes in skin and hair take months to clear. Mental dullness and sluggishness takes years to come back to normal.