Diseases of endocrine system affects the endocrine organs – pituitary, thyroid, parathyroid, adrenal glands, pancreatic islet cells and gonads.
Metabolic disorders are condition which can be attributed to biochemical abnormality, enzyme defect and abnormal receptor mechanism.
Hyperlipidaemia is an example of metabolic disorders.
Both these groups of diseases often present as a constellation of otherwise non-specific symptoms.
There are a number of symptom complexes that particularly suggest an endocrine disease or metabolic cause.
Thirst and Polyuria
Excessive thirst and increased urine output are the most important presenting symptoms of diabetes mellitus. This occurs due to increased water loss associated with sugar loss.
Deficiency or failure of antidiuretic hormone, or increased fluid intake are other causes of these symptoms
Loss of weight can be due to decreased food intake or increased metabolic rate or both. Malignancy, hyperthyroidism, amenorrhoea and insulin dependent diabetes are common causes of weight loss.
Primary hypothyroidism is major endocrinal cause of weight gain.
It can occur in thyrotoxicosis, Cushing’s syndrome and vitamin deficiency.
Metabolic mypoathy such as in vitamin D deficiency causes symmetrical proximal weakness.
The weakness may be subclinical and needs to be demonstrated in physical examination..
Polymyositis and polymyalgia rheumatica, spinal root or plexus disease need to be differentiated.
An out of proportion abnormal sensation may indicate underlying hypothyroidism whereas thyrotoxicosis may be associated with heat intolerance
Excessive sweating can be a constitutional abnormality and often familial.
A recent increase in sweat secretion may indicate thyroid overactivity.
Paroxysmal sweating is a common feature of anxiety.
Other causes are increased catecholamine secretion from a pheochromocytoma, autonomic dysfunction and increased levels of growth which probably causes hypertrophy of sweat glands
A fine resting tremor may occur in thyrotoxicosis.
Tremors of anxiety are coarser and more irregular tremor.
Other diseases causing tremor are parkinson’s disease, cerebellar intention tremor.
Palpitations refer to sensation of increased heart rate or contraction. Anxiety is common cause.
Paroxysmal tachyarrhythmias and thyrotoxicosis are other causes.
Missed beat is the sensation of intermittent forceful cardiac contraction, often due to the compensatory pause following an ectopic beatis usually a normal phenomenon.
Dizziness or a sensation of faintness on standing may occur with reduced blood volume. Adrenal insufficiency, autonomic neuropathy, hypertensive the drug therapy are other causes of postural hypotension. The cause is generally the change in blood pressure with posture.
Decreased visual acuity/ partial loss of visual fields may occur from space-occupying lesions compressing the optic nerve. Diabetes and thyrotoxicosis may also cause visual disturbances.
Symptoms on Fasting
Tachycardia, sweating and tremor, occurring intermittently, especially when fasting, are suggestive of hypoglycaemia. Spontaneous or fasting hypoglycaemia can be due to insulinoma, glucocorticoid deficiency, primary adrenal failure, hypopituitarism, inappropriate insulin administration, excessive sulphonylurea drug administration, hepatic failure and rapidly growing malignant lesions.
Cramps and Pins and Needles
Intermittent cramp and ‘pins and needles’, especially if bilateral, can be due to a decreased circulating ionize calcium or level. This occurs in hypoparathyroidism hyperventilatory states and hypokalemia or decreased potassium levels.
Neurological causes of pins and needles should be differentiated.
This is a rare symptom of endocrine disease. Adrenal insufficiency and thyrotoxicosis may cause this symptom
Difficulty in swallowing is an unusual manifestation of endocrine disease but may be the presenting feature of multinodular thyroid enlargement with retrosternal extension.
Neck Pain and Swelling
Superficial discomfort in the neck may lead to the incidental finding of thyroid enlargement in goiter or thyroiditis.
Decreased erectile potency may be a consequence of primary abnormalities, such as:
- Atherosclerosis [decreased blood supply]
- Neural dysfunction [autonomic neuropathy as in diabetes]
- Testosterone deficiency [in hypopituitarism and primary testicular failure]
- Drug therapy [certain antihypertensives]
Apart from physiological delay as a cause, pituitary dysfunction, ovarian failure, thyroid dysfunction; and defects in lower genital tract development are important causes.
It refers to inappropriate milk secretion from breast. Prolactin-secreting or lactotropin disinhibiting tumors of the pituitary gland can cause glactorrhoea. Dopamine antagonist drugs are also known to cause increase in prolactin levels and thus glactorrhoea.
Idiopathic glactorrhoea also occurs in hyperprolactinaemia due to lesions if the hypothalamic-pituitary region.
Excess Hair Growth
Also caused hirsutism, excess hair growth is caused by polycystic ovary syndrome, congenital adrenal hyperplasia and androgen secreting ovarian or adrenal tumours.
Various endocrine and metabolic disorders can cause skin changes.
- Pallor – Primary testicular failure and in pan-hypopituitarism.
- Excessive pigmentation- Cushing syndrome, with increased sebum production causing greasy skin and acne on the face and shoulders.
- Violaceous cyanosis – Carcinoid tumors of the gut or lung
- Variegate, patchy rash – porphyria
- Pallor with pigmentation of the conjunctival membrance beneath the lids, and of the inside of mouth, and axillae – Hypoadrenalism
- Pale, sallow skin, and thin hair – hypothyroidism
- Dry and hot skin – hyperthyroidism
- Pale, yellow sslightly pigmented skin – uremia. Uremic frost appears in terminal uremia.
- Vitiligo – Autoimmune disorders, a vitamin B12 definciency.
Physical Examination of Diseases of Endocrine System and Metabolic Disorders
Physical examination begins with general appearance, nutrition and with built.
Concentration of fat in the intrabdominal and interscapular regions with relative sparing of the limbs is characteristic of Cushing’s syndrome.
Patients with growth hormone hypersecretion, resulting pituitary adenomas, also demonstrate a classical facial appearance. Increased adiposity in a child who is growing poorly suggests the possibility of growth hormone deficiency or hypothyroidism.
The skeletal proportions should be noted. A longlimbed appearance may indicate delayed epiphysial fusion due to hypogonadism or the connective tissue abnormality, Marfan’s syndrome. Shortening of the limbs occurs with a variety of skeletal dysplasias.
Clubbing may be seen in thyrotoxic Graves’ disease. Palmer erythema may also be found in thyrotoxicosis, chronic liver disease or rheumatoid arthritis.
Increased pigmentation in buccal, circumoral or palmar region may indicate the increased secretion of adrenocorticotropic hormone in case of adrenal failure.
Patches of depigmentation, or vitiligo, may also be found in Addison’s disease or other organ specific autoimmune disorders.
Violet stretch marks on skin are seen in glucocorticoid excess.
Abnormal dryness of the skin and the coarseness of the hair are found in hypothyroidism. Localized thickening of the classically described as pretibial myxoedema, is rare extrathyroidal manifestations of Graves’ disease. An ulcerating skin lesion seen in diabetes mellitus.
Xanthelasmata [Subcutaneous deposits of cholesterol just medial to the eyelids] are suggestive of hypercholesterolaemia.
In females, abnormal hair distribution or hair loss in a male pattern may indicate increased circulating androgen.
The neck should be examined for evidence of thyroid enlargement on inspection. Palpation of the thyroid gland is best carried out from behind the .
Any enlargement should be examined in detail.
Particular attention should be paid to any postural drop in blood pressure.
A hyperdynamic circulation, sinus tachycardia or atrial fibrillation may be found. In thyrotoxicosis this may progress to cardiac decompensation and cardiac failure.
In male breast, any tendency to gynaecomastia should be noted.
Genital examination in the male should document testicular volume.
Testicular atrophy in the adult male indicates hypogonadism, due either to primary testicular failure, hypothalamic- pituitary dysfunction or chronic liver disease.
An enlargement of testicles may occur in testicular tumors.
Enlargement of the clitoris in female is a feature of excess androgen secretion.
Ambiguity of the external genitalia is indicative of fetal androgen excess.
The hypercalcemic patient should be carefully examined for corneal calcification. It is seen as a narrow band on the medial or lateral border of the cornea and usually indicates long-standing hypercalcemia.
Exophthlmos may be noted in cases of thyrotoxicosis. Visual acuity should be measured both with and without a pinhole to correct for any refractive error.
In the diabetic patient retinoscopy may show small hemorrhages and exudates, and areas of pallor, indicating ischaemia.
Neural examination reveals a rapid fine tremor in thyrotoxicosis. Proximal weakness the shoulder and hip girdle musculature is a typical feature of thyrotoxicosis and vitamin D deficiency.
Neural excitability may be demonstrated by gentle percussion over the proximal party of the facial nerve. It is seen in patients with low calcium.
Tendon reflexes will be abnormally brisk in thyrotoxic patients and may be slow in hypothyroidism. Entrapment syndromes particularly of the median nerve at the wrist may be seen in hypothyroidism and acromegaly.
Periphreral neuropathy, as in diabetes, may show sensory loss in a stocking distribution, exaggeration of the foot arch and metatarsal drop leading to their plantar prominence.
The aim of lab studies is to know if a specific gland is overactive or underactive. Various hormonal assays can provide this information.
Other investigations that can be done are electrolytes levels, minerals, metabolites or hormones in plasma.
Plain x-ray imaging is of limited value in the investigation of endocrine disorders. Abnormal calcification in the pituitary fossa or expansion of the fossa can be seen in intrasellar or suprasellar tumours.
Renal calcification in patients with long standing hypercalcaemia or renal tubular acidosis may be noted.
CT imaging provides better information about pituitary, adrenal gland and thorax. MRI of the pituitary offers define advantages over CT in terms of improved precision in detecting small intrasellar tumours and better definition of the lateral border of the pituitary and the cavernous sinus.
Isotopic imaging is particularly useful for demonstrating autonomous function within endocrine tumours in thyroid, adrenal cortex and the adrenal medulla.