There is a general slowing down of all physiological activities of the body following prolonged deficiency of thyroid hormones. The thyroid hormone deficiency leads to a reduction in cellular metabolism which subsequently brings about mental and physical sluggishness, as well as weakening of the cardiac contractility.
The decreased cardiac contractility leads to decrease in cardiac output. The body tries to compensate for this decrease in cardiac output through vasoconstriction which eventually leads to rise in diastolic blood pressure. There is usually a high level of serum cholesterol in hypothyroidism. This coupled with the elevated blood pressure leads to atherosclerotic changes in the blood vessels.
The patient suffers subnormal temperature and intolerance to cold which is due to decrease heat production following a reduction in metabolism. The reduction in metabolism also leads to decrease in energy production, and fatigue.
Constipation occurs as result of general decrease in gastrointestinal motility.
Accumulation of mucopolysaccharides in the subcutaneous tissues has the tendency to retain water leading to oedematous appearance commonly seen in myxoedema. Congestive cardiac failure may arise from the pericardial effusion that follows water retention.
Menorrhagia or amenorrhoea and loss of libido are common features in the hypothyroid women.
Megaloblastic anaemia may develop in few cases as a result of depression of the bone marrow activity following the general slowing down of the body's activities.
Mental sluggishness in form of apathy, lethargy and slowness in response also occurs. This may suddenly progress to severe impairment of consciousness and coma which is referred to as myxoedema coma. Psychosis may also be present. This manifests in form of hallucinations, delusions, disorientation and suicidal tendencies.
Signs and symptoms
i. Obesity
ii. Constipation
iii. Puffy face
iv. Enlarged tongue
v. Slow speech
vi. Sluggish movement
vii. Subnormal body temperature
viii. Husky voice
ix. Gynaecomastia in males (increase in breast size)
x. Amenorrhoea or menorrhagia in women
xi. Increased size of hands and feet
xii. Extreme fatigue
xiii. Cold intolerance
xiv. Dry and thick skin
xv. Thin hair.
Complications of myxoedema
1. Cardiac failure
2. Hypertension
3. Mental retardation
4. Megaloblastic anaemia
5. Myxoedema coma
6. Myxoedema psychosis.
Diagnosis
The total serum T4 and plasma Thyroid Stimulating Hormone (TSH) should be measured. Elevation in the level of the plasma TSH level is indicative of primary hypothyroidism.
You will only be able to make an accurate and an acceptable diagnosis after you studied the presenting signs and symptoms, and after conducting thorough laboratory investigations.
