Endocrine Disorders

Pituitary Gland

Thyroid Gland

Parathyroid Gland

Adrenal Gland

Diseases of the Adenohypophysis (Anterior)

1. Pituitary Adenomas; benign but may be life-threatening due to position/excess hormone secretion

- Non-functioning (or silent) Adenomas; progressively growing expanding > compressing optic chiasm & destroying functioning adenohypophysis (E.g. Hashimoto-like symptoms)

Panhypopituitarism = reduced A.P hormone output (in children = pituitary dwarfism; adults = average stature)

- Functioning Adenomas; predominately produce prolactin, GH or ACTH. Presents with EXCESS hormone production (E.g. Acromegaly = elevated GH production AFTER epiphyseal fusion; Gigantism = elevated GH production BEFORE epiphyseal fusion)

Disease of the Neurohypophysis

Presents with reduced ADH/oxytocin production. Due to hypothalamic damage by tumours, infarction, surgery, inflammatory lesions (E.g. Diabetes Insipidus)

Grave's Disease

Excessive secretion of thyroid hormones = Hyperthyroidism

Autoimmune thyroidism > HLA-DR3 antigen vs TSH receptor

Symptoms; goitre, exophthalmos, pretibial myxoedema (skin thickening), finger clubbing.

Clinical features of thyrotoxicosis.

Pathological changes of decrease subcutaneous fat, skeletal muscle & cardiomyopathy

Hashimoto's Disease

Type of autoimmune thryroiditis > hypothyroidism. Associated with HLA-DR5/HLA-B8 antigens > cellular & humeral immune reactions

Clinical features; symmetrically enlarged, firm & white surface

Myxoedema; secondary to hypothyroidism, increased lethargy, cold sensitivity, puffy face, dry skin, deepening/hoarseness of voice & course hair

Thyroid Gland Tumours

Thyroid adenoma; benign, colloid/follicular pattern

Papillary carcinoma (derived from follicle cells); most common malignancy, young adults, well-differentiated, excellent prognosis

Follicular carcinoma (derived from follicle cells); malignant, middle-aged, good prognosis

Anaplastic carcinoma (derived from follicle cells); malignant, poor prognosis

Medullary carcinoma (derived from parafollicular cells); malignant, middle-aged/elderly, good prognosis

Hyperparathyroidism

1. Parathyroid Adenoma (primary aetiology); benign, solitary small tumour,

S/S; hypercalcaemia, depression, constipation, polyuria, calcification of BVs, corneal calcification, osteoporosis, "Stones, moans, groans & bad bones"

Detected by; elevated PTH. calcium & lowered phosphate

2. Parathyroid Gland Hyperplasia (secondary/tertiary aetiology); due to renal failure > urinary excretion

Elevated PTH > hyperparathroidism (osteoclast stimulation > bone mobilisation)

Hypoparathyroidism

Removal of PT glands > hypocalcaemia

S/S; lowered PTH secretion & calcium levels, elevated phosphate, neuromuscular irritability, cardiac arrhythmias/seizures, chvostek's (ear twitching)/trouseau's signs (wrist reflex/spasm) (+Ve)

Addison's Disease

Chronic adrenal cortical insufficiency > lack of glucocorticoids & mineralocorticoids

Aetiology; autoimmune adrenalitis (E.g. Hashimoto's, autoimmune gastritis), tuberculosis, fungal infections, adrenal tumour

S/s; dehydration, orthostatic hypotension, lethargy, weakness, vomiting, loss of appetite, brown skin pigmentation (melanocyte)

Diagnosis; lower sodium, high potassium, metabolic acidosis, hypoglycaemia

Cushing's Syndrome

Excessive glucorticoids, due to pituitary adenoma, adrenal cortical adenoma, carcinoma, ectopic ACTH secretion

S/S; 'moon faced', osteoporosis, trunk obesity & striae, skin fragility, poor wound healing, diabetes, hypokalemia, psychiatric disturbances (hippocampal)

Diangosis; elevated cortisol levels, dexamethasone suppression test, MRI & CT scans, blood ACTH levels

Conn's Syndrome

Elevated aldosterone, due to elevated renin levels (secondary)

S/S; sodium/water retention (-> HT), increased urinary potassium loss

Diangosis; blood electrolyte estimations, elevated aldosterone levels, CT/MRI scans, chvostek's/trousseau's sign (+ve)

Tumours of Adrenal Medulla

Pheochromocytoma; benign, derived from chromaffin cells, secretes adrenaline/noradrenaline,

Diangosis; elevated vanillylmandelic acid (VMA) & homovanillic acid (HVA)

S/s; HT - due to elevated amine levels, severe headaches, ideopathic cardiac failure

Neuroblastomal; malignant, derived from primitive neuroblasts, common in children <3 y/o, elevated catcholamines > elevated VMA, HVA & dopamine in urine

Prognosis; 2 yr survival rate of neonates = 70%; <1 y/o = 30%; 1-2 y/o = 20%; >2 y/o = 5%