ENDOCRINAL AND METABOLIC DISORDERS

ENDOCRINAL AND METABOLIC DISORDERS

Hypothyroidism

  Thyroid hormone is essential for normal somatic growth and neurological development in infants and children.

 It is necessary for normal skeletal growth in growing children.

Deficiency of thyroid hormone :

in the first 2 years of life result in physical and psychomotor retardation. So the clinical manifestations differ in infants and older children or adolescents.

      * thyroid hormone plays a major role in metabolism and heat production In children and adults .Causes clinical manifestations differ than that in  infants (juvenile hypothyroidism).

Congenital hypothyroidism

It affects males and females equally.

Etiology

- Developmental thyroid defects (thyroid agenesis or dysgenesis): these are the primary causes of congenital hypothyroidism.

- Defective biosynthesis of thyroid hormone: it frequently results in goiter and may cause hypothyroidism.

- Transient congenital hypothyroidism: it may occur as a result of transplacental passage of maternally ingested goitrogens (e.g. iodide expectorants, antithyroid drugs or maternal antithyroid antibodies).Clinical features

Neonatal period

· Congental hypothyroidism is twice as common in girls as in boys.

· Birth weight and length are normal, but head size may be slightly increased because of myxedema of the brain.

· Prolongation of physiologic icterus due to inadequate bilirubin conjugation may be the earliest sign.

· Feeding difficulties e.g. slugishnees, lack of interest, somnolence and chocking spells during nursing.

Respiratory difficulties due to large tongue including apneic episodes, noisy respirations, and   nasal obstruction.

Infants and children

· Physical and mental retardation which increases with age.

· Affected infants cry little, sleep much, have poor appetite, and are generally sluggish.

· Hoarseness of voice.

· There may be constipation that does not usually respond to treatment.  The abdomen is large, and an umbilical hernia is usually present.

· The temperature is subnormal and the skin is cold and mottled.

·

The pulse is slow, heart mumurs and cardiomegaly are common.

· The child's growth is stunted, and the extremities are short.

· Broad hands and short fingers.

· Normal or even increased head size, the anterior and posterior fontanels are open widely.

· Coarse, brittle scanty hairs and the hairline reach far down on the forehead.

· Wrinkled forehead especially when the infants cry.

· The eyes appear for apart, with narrow palpebral fissures and swollen eyelids.

· Depressed nasal bridge.

· Open mouth, thick protruded broad tongue due to myxedema and delayed dentition.

Radiologic examination

  · Retardation of osseous development: for example:

    - Absent distal femoral epiphysis and upper tibial epiphysis that are normally present at birth.

  · Epiphyseal dysgenesis i.e. the epiphysis has multiple foci of ossification.

  · Peaking of the 12th thoracic, first or second lumbar vertebrae is common.

Treatment

* Oral L-thyroxin is the treatment of choice for life. The dose is about 10-15 μg/kg/24hr in neonates,

*In children, 4 μg/kg/24hr 

* Adults only 2 μg/kg/ 24hr.

*Thyroxin tablets should not be mixed with soy protein formula or iron, because these can inhibit its absorption. Levels of both T4 and TSH should be monitored and maintained in the normal range. If toxicity occurs, the dose is reduced.