Hypothyroidism
Hypothyroidism
Hypothyroidism
Clinical Presentation
Hypothyroidism is a clinical state in which
hyaluronic acid that alters the composition of the ground substance in the dermis and other tissues.
This material is hygroscopic, producing the
mucinous edema (non pitting edema) that is responsible for the thickened features and puffy appearance.
This condition is known as myxedema.
and tends to fall out. Hair may be lost from the temporal aspects of the eyebrows.
Cardiovascular System
The cardiac output at rest is decreased
because of reduction in both stroke volume and heart rate, reflecting loss of the inotropic and chronotropic effects of thyroid hormones.
responsible for the coolness and pallor of the skin and the sensitivity to cold.
Electrocardiographic changes
include
sinus bradycardia,
and electrocardiographic alterations, and the serum enzyme changes has been termed myxedema heart.
Hypothyroidism is consistently associated with
elevations of total and low-density lipoprotein (LDL) cholesterol, which improve with thyroxine replacement.
Treatment with thyroid hormone corrects the
hemodynamic, electrocardiographic, and serum enzyme alterations of myxedema heart and restores heart size to normal.
After
Respiratory System
Pleural effusions usually are evident only on
Chest radiograph show an enlarged heart (computed cardiothoracic ratio of 1:2), with a water-bottle configuration, and bilateral pleural effusion.
Alimentary System
Patients experience a modest gain in weight.
by retention of fluid by the hydrophilic glycoprotein deposits in the tissues, but does not exceed 10% of body weight.
with the decreased food intake, is responsible for the frequent complaint of constipation. Achlorhydria may be present in patients with primary hypothyroidism. Ascites in the absence of another cause is unusual in hypothyroidism, but it can occur.
development, including hypoplasia of cortical neurons with poor development of cellular processes, retarded myelination, and reduced vascularity.
A condition known as cretinism. If the deficiency is not corrected in early postnatal
and memory defects are common, lethargy and somnolence are prominent, and dementia in elderly patients.
may predispose to confusional attacks and syncope, which may be prolonged and lead to stupor or COMA. Myxedema coma is a life threatening emergency condition, which requires immediate treatment.
frequent; in the fingers these symptoms may be due to compression by glycosaminoglycan deposits in and around the median nerve in the carpal tunnel (carpal tunnel syndrome).
Epidemiologic studies have shown an
Muscular System
Stiffness and aching of muscles are common
jerks.
Muscle mass may be reduced or enlarged due
to interstitial myxedema.
Hoffmann syndrome - profound increase in
leads to both a delay in the development of, and an abnormal, stippled appearance of the epiphyseal centers of ossification (epiphyseal dysgenesis).
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Hematopoietic System
In response to the diminished oxygen
requirements and decreased production of erythropoietin, the red blood cell mass is decreased; this is evident in the mild normocytic, normochromic anemia that often occurs.
hyperplasia of the thyrotropes may cause the pituitary gland to be enlarged. Rarely, the pituitary enlargement compromises the function of other pituitary cells and causes pituitary insufficiency or visual field defects. May have increased serum prolactin levels, stimulated by the elevation in TRH and proportional to the level of serum TSH elevation, and galactorrhea may develop in some patients.
hypothyroidism, pituitary and adrenal function may be secondarily decreased and adrenal insufficiency may be precipitated by stress or by rapid replacement therapy with thyroid hormone.
Reproductive Function
Infantile hypothyroidism, if untreated, leads to
sexual immaturity, and juvenile hypothyroidism causes a delay in the onset of puberty followed by anovulatory cycles.
Pregnancy complications are associated with
levothyroxine treatment in pregnant women with subclinical hypothyroidism has shown that the increased incidence of preterm delivery and spontaneous abortions are reversed by treatment.
production is reflected in the low basal metabolic rate, decreased appetite, cold intolerance, and slightly low basal body temperature.
Both the synthesis and the degradation of
protein are decreased, with the result of Positive nitrogen balance , retardation of both skeletal and soft tissue growth.
expression of the insulin sensitive glucose transporter (GLUT-4), and the levels of this transporter are reduced in hypothyroidism.
There is reduction in glucose disposal to skeletal
reduced gluconeogenesis and degradation of insulin is slowed and the sensitivity to exogenous insulin may be increased.
The net effect of these influences is usually a
and the mobilization of free fatty acids in response to fasting, catecholamines, and growth hormone is impaired.
Summary
Signs and Symptoms of Hypothyroidism (Descending Order of Frequency) Symptoms Tiredness, weakness F Dry skin r Feeling cold e Hair loss q Difficulty concentrating and poor memory u Constipation e Weight gain with poor appetite n Dyspnea c Hoarse voice Menorrhagia (later oligomenorrhea or amenorrhea)y Paresthesia Impaired hearing
Signs Dry coarse skin; cool peripheral extremities Puffy face, hands, and feet (myxedema) Diffuse alopecia Bradycardia Peripheral edema Delayed tendon reflex relaxation Carpal tunnel syndrome Serous cavity effusions.
F r e q u e n c y