Clinical Manifestations Of Hypothyroidism: Cretinism, Myxedema, Hoffman’s Syndrome And Pendred’s Syndrome
Clinical Presentations Of Hypothyroidism
Insufficient synthesis and release of thyroid hormones give rise to hypothyroidism. Congenital hypothyroidism leads to developmental abnormalities resulting in cretinism. When hypothyroidism occurs in juveniles or adults, a characteristic clinical picture develops in which there is accumulation of hydrophilic mucopolysaccharides in the ground substance of the derms and several other tissues resulting in induration and coursing of the skin and enlargement of organs like the tongue. Women are affected more. Myxedema is associated with other auto-immune disorders like diabetes, rheumatoid arthritis and pernicious anemia.
Primary hypothyroidism- the thyroid gland is primary af fault.
Non-goitrous: a. Spontaneous atrophy (autoimmune)
c. surgical or I131 treatment.
Goitrous: a. Dyshormonogenesis
b. Dietary iodine deficiency
c. Antithyroid drugs given to the mother during pregnancy
d. Drug induced: PAS, iodides, phenylbutazone and lithium carbonate
e. Hashinomoto’s disease
Secondary hypothyroidism- In this condition, the thyroid is normal but the regulating system is abnormal.
- Hypopituitarism and
- Abnormalities of the hypothalamus
Clinical features of hypothyroidism depend on the age of onset of the disorder and the type.
Clinical Presentation In Cretinism
This results from hypofunction of the thyroid from birth. This may result from iodine deficiency occurring in endemic goiter belts. Babies born to hypothyroid women or those taking antithyroid drugs during pregnancy may develop cretinism. Though the abnormality is present at birth in many babies, symptoms manifest only after several months and therefore, the condition may remain undetected in the newborn. The infant is dull and lethargic. Growth is retarded. Other features include large protruding tongue, broad flat nose, widely set eyes, sparse hair, dry skin, protuberant abdomen, and umbilical hernia. Abnormal persistence of physiological jaundice, croaky voice, constipation, somnolence and problems in feeding should raise the possibility on cretinism in the newborn. As the baby becomes older, retardation of growth and milestones become evident. Neurological abnormalities are prominent in some cases. These include deafness, spastic limbs and at times, coma. Mental development is severely retarded. The appearance and ossification of several epiphyseal centers are delayed. Delay in the appearance of epiphyseal centers for carpal bones and delya in the eruption of teeth are useful diagnostic features.
Primary hypothyroidism occurring in juveniles and adults leads to myxedema. Though it is not common in secondary hypothyroidism, rarely it can manifest in seconday hypothyroidism as well. Hypothyroidism is one of the common endocrine disorders seen in India. Clinical features depend upon the degree of impairment of thyroid function and its duration. The onset is insidious and often unnoticed by the patient or her relatives. Early manifestations include slowing of activities, lethargy, somnolence, constipation and generalized disinterestedness. Due to lowering or metabolism and accumulation of fluid and adipose tissue, considerable weight gain occurs. Sensitivity to cold is increased and the patient prefers to sit in the sun or near the fire. The hair is coarse, dry, and sparse. The scalp and eyebrows may become bald. The skin is lusterless, thick and dry with scanty hair. This is a diagnostic feature in a well developed case. The voice is husky. Generalised non-pitting edema is common. Many show periorbital edema and macroglossia. Neurological features predominate in many cases. There are slowness of mental and physical activity, slowed speech, muscle cramps, muscle hypertrophy, paresthesiae and entrapment neuropathies. Carpal tunnel syndrome is common. The tendon reflexes are altered. The relaxation phase is delayed. This abnormality is best seen in the ankle jerk. Nerve conduction velocity is reduced. Psychiatric disturbances (myxedema madness) are common.
Cardiovascular manifestations include cardiomegaly, pericardial effusion, angina pectoris, mild or moderate hypertension and predisposition to ischemic heart disease. Cardiac failure is not uncommon. Impotence occurs in men, Women may develop menorrhagia and girls may attain precocious puberty.
In secondary hypothyroidism, the heart is not enlarged. The skin is thin and shiny. Unless treated early, severe cases go into somnolence, stupor and coma. Coma is precipitated by exposure to cold, infections, trauma or sedatives. Hypothermia and respiratory depression may develop. Myxedema coma carries a high mortality rate.
Hoffman’s And Pendred’s Syndromes
Hoffman’s syndrome: Muscle dysfunction is common in hypothyroidism. Hypertrophy of muscles associated with pseudomyotonia (slowness of contraction and relaxation) are features diagnostic of Hoffman’s syndrome.
Pendred’s Syndrome: In this condition, which is congenital, there is permanent deafness or deaf-mutism in addition to goitrous hypothyroidism. The defect is a block in the synthesis of thyroid hormone.
Hypothyroidism manifests in several forms due to where its pathology hits the most. Cretinism and myxedema being general manifestations while Hoffman’s syndrome (targeted at muscles) and Pendred’s syndrome (deafness) are specific or particular to some organs.
© 2014 Funom Theophilus Makama