Category Archives: Endocrinology.

Other endocrine disorders

DISEASES OF MANY GLANDS Multiple gland failure This is caused by autoimmune disease as detailed. Commonest are the associations of primary hypothyroidism and type 1 diabetes, and either of these with Addison’s disease or pernicious anaemia. Multiple endocrine neoplasia This is the name given to the simultaneous or metachronous recurrence of tumours involving a number of endocrine glands. They are inherite

Endocrinology of Blood Pressure Control

The control of blood pressure (BP) is complex involving neural, cardiac, hormonal and many other mechanisms. BP is dependent upon cardiac output and peripheral resistance. Although cardiac output can be increased in endocrine disease (e.g. thyrotoxicosis), the main role of hormonal mechanisms is control of peripheral resistance  and of circulating blood volume. The oral contraceptive pill is a common endocri

The Thirst Axis

Thirst and water regulation is largely controlled by ADH (vasopressin), which is synthesized in the hypothalamus, and then migrates in neurosecretory granules along axonal pathways to the posterior pituitary. Pituitary damage alone without hypothalamic involvement does not therefore lead to ADH deficiency as the hormone can still ‘leak’ from the damaged end of the intact axon. Changes in plasma o

Congenital adrenal hyperplasia (CAH)

PATHOPHYSIOLOGY This condition, comprising six major types, results from an autosomal recessive deficiency of an enzyme in the cortisol synthetic pathways, most commonly 21- hydroxylase which occurs in about 1 in 15000 births. The 21-hydroxylase deficiency has been shown to be due to defects on chromosome 6 near the HLA-region affecting a cytochrome P450 enzyme (P450C21)’ As a result, cortisol secretion

Secondary Hypoadrenalism

This may arise from hypothalamic-pituitary disease or from long-term steroid therapy leading to hypothalamicpituitary- adrenal suppression. Most patients with the former have panhypopituitarism and need T4 replacement as well as cortisol; in this case hydrocortisone must be started before T4. The commonest cause of hypoadrenalism is long-term corticosteroid medication for non-endocrine disease. The hypothala

The Glucocorticoid Axis

ADRENAL ANATOMY AND FUNCTION The human adrenals, weighing only 8-10 g together, comprise an outer cortex with three zones (reticularis, fasciculata and glomerulosa) producing steroids and an inner medulla that synthesizes, stores and secretes catecholamines (see Adrenal medulla). The adrenal steroids are grouped into three classes based on their predominant physiological effects: GLUC0CORTICOIDS. These are na


Thyrotoxicosis is often clinically obvious but treatment should never be instituted without biochemical confirmation. Differentiation of the mild case from anxiety states may be difficult; useful positive clinical markers are eye signs, proximal myopathy and wasting. The hyperdynamic circulation with warm peripheries seen with thyrotoxicosis can be compared with the clammy hands of anxiety. The signs of hypert


Goitre is more common in women than in men and may be either physiological or pathological. CLINICAL FEATURES Most commonly a goitre is noticed as a cosmetic defect by the patient or by friends or relatives. The majority are painless but pain or discomfort can occur in acute varieties. Goitres can produce dysphagia and difficulty in breathing, implying oesophageal or tracheal compression. Clinical examination


Hypothyroidism may produce many symptoms. The classical picture of the slow, dry-haired, thick-skinned, deep-voiced patient with weight gain, cold intolerance, bradycardia and constipation makes the diagnosis easy; the term ‘myxoedema’ refers to the accumulation of mucopolysaccharide in subcutaneous tissues. Milder symptoms are, however, more common. Special difficulties in diagnosis may arise: C

The thyroid axis

The metabolic rate of many tissues is controlled by the thyroid hormones, and overactivity and underactivity of the gland pose the commonest of all endocrine problems. Anatomy The gland consists of two lateral lobes connected by an isthmus. It is closely attached to the thyroid cartilages and to the upper end of the trachea, and thus moves on swallowing. It is often palpable in normal women. Embryologically