Infantile Tremor Syndrome: Causes, Clinical Features, Diagnosis & Treatment

Introduction

Infantile tremor syndrome is a self-limiting clinical disorder that causes tremors, skin pigmentation, pallor, nutritional tremor syndrome, and anemia. It is also known as infantile meningoencephalitis. It is usually found in infants and young children between two and six months of life. It affects male children more than female children and is prevalent in one to two percent of the pediatric population. Infantile tremor syndrome is commonly seen in young children of low socioeconomic status. The peak incidence of the disease is during the summer season. The low level of vitamin B12 is the primary causative factor. Therefore, the treatment plan focuses on treating anemia and nutritional therapy.

What Is Infantile Tremor Syndrome?

Infantile tremor syndrome is a rare disorder characterized by the tetrad of pallor, skin pigmentation, scanty brownish scalp with coarse hair, and developmental delay in milestones. It causes coarse tremors, anemia, and regression in mental and motor development in children around one year of age. In addition, involuntary tremors are present with significant illness and long-term cognitive neuro defects.

What Are the Causes of Infantile Tremor Syndrome?

The primary cause of infantile tremor syndrome is vitamin B12 deficiency. Vitamin B12 is crucial for the neurological development of the child. Vitamin B12 deficiency is commonly seen in children breastfed for a prolonged duration or by strictly vegetarian mothers. Following are the etiological factors of infantile tremor syndrome.

• Decreased level of vitamin B12 and transport transcobalamin two protein.

• Exclusively breastfeeding the child for prolonged periods.

• Children whose mothers are vegetarians.

• Absence of initiation of the weaning due to the need for more appropriate guidance.

• Dietary deficiency.

• Lack of iron, magnesium, and zinc in the diet.

• Malnutrition due to lack of care.

• Khan's nutritional recovery syndrome.

• Infections like meningoencephalitis.

• Transient tyrosine metabolism defect.

• Degenerative atrophic changes.

What Are the Clinical Features of the Infantile Tremor Syndrome?

Clinically the child appears plump between the age of six to eighteen months. The child is lethargic and distressed and has a regression in developmental milestones. There is the presence of tremors in acute infection, and the onset of the tremor is acute. Macrocytic, microcytic, or normocytic anemia (reduced hemoglobin levels in the blood) in children is seen, the muscles appear flabby, and long-term cognitive and language imbalances are seen in children. Tremors are initially seen in hands and gradually spread to feet. The tremor also develops in the tongue, and a tremulous cry is also seen. Tremors subside during sleep and resolve eventually after a few days. Following are the various phases of infantile tremor syndrome:

• Pre-tremor Phase

  • This phase starts in the second week and lasts up to two months.

  • The child appears chubby despite malnutrition.

  • There is a regression in developmental milestones.

  • The child has a vacant expressionless face.

  • The neurological and motor growth of the child is slow.

  • The child is unable to recognize the mother.

  • Does not show any interest in the surrounding environment.

  • The child appears lethargic.

  • There needs to be a better response to bright and colorful objects.

  • Tremors are absent in this stage.

  • The hair is sparse and light-colored.

  • There is the presence of brownish pigmentation on the surface of the hand, feet, knees, ankles, and medial surface of the thigh and lower abdomen. The pigmentation is a reticular pattern, also known as honeycomb pigmentation.

  • There is the presence of a fever.

  • Mild to moderate pallor is seen.

  • The child can also have upper respiratory tract infections, edema, diarrhea, and hepatomegaly.

• Tremor Phase

  • It is also known as the classical phase.

  • Tremors usually last for about two to five weeks.

  • Tremors originate from the cortical neurons and resemble Parkinson's disease.

  • Tremors are coarse and of low amplitude.

  • The frequency of tremors is six to twelve cycles per second.

  • Initially, tremor is intermittent. In later stages, it becomes continuous.

  • Tremors are seen during crying and feeding.

  • It involves the finger, face, and tongue of the child.

  • Tremors are generalized and more prominent in the distal part of the upper limbs.

  • The child tends to assume a typical bird with wings spread posture.

  • The child produces a crying sound like a lamb, known as a tremulous cry.

  • Impairment of motor development.

• Post-tremor Phase

  • It is also known as the recovery phase.

  • This phase lasts for about one to six months.

  • This phase may be prolonged due to associated infections.

  • In this phase, there is a regression of tremors.

  • The mental dullness of the child persists.

How is Infantile Tremor Syndrome Diagnosed?

Infantile tremor syndrome is diagnosed with a peripheral smear examination showing anemia. The diagnosis of infantile tremor syndrome depends on the medical history, clinical features, and vitamin B12 deficiency. Following are the various investigations indicated for the diagnosis of infantile tremor syndrome.

• Hemoglobin is between six to nine milligrams per deciliter.

• There is variable morphology of red blood cells.

• Normoblastic megaloblastic and dimorphic changes are seen in the bone marrow.

• There is the presence of variable total leukocyte count due to infections.

• Deficiency of vitamin B12, iron, magnesium, and zinc.

• Mild inflammatory changes are seen in the cortical biopsy.

• Cortical atrophy is seen in pneumoencephalography (evaluation of brain and spinal cord structures).

• Magnetic resonance imaging (MRI) shows delayed myelination and diffuse atrophy.

• Electroencephalogram (EEG) shows epileptic activities.

What Are the Treatment Plans for Infantile Tremor Syndrome?

The management of infantile tremor syndrome involves nutrition and diet therapy. A high dose of vitamin B12 is indicated with zinc and magnesium supplements. In addition, medications like Phenobarbitone in a dose of three milligrams are given for severe tremors. It helps in reducing the intensity of the tremor. Skin pigmentation and hair texture improve after a few months of treatment.

Conclusion

Infant tremor syndrome is a clinical condition caused by vitamin B12 deficiency. It is characterized by amnesia, regression of motor development, and delayed milestone development in children. The parents are responsible for observing the developmental milestones in the child's life. Nutritional deficiency requires proper management. In addition, parents should incorporate righteous feeding practices for the child's growth. It is also essential to recognize and treat infantile tremor syndrome at an early stage. Diagnosing infantile tremor syndrome can be challenging as no specific diagnostic findings exist.