Addison's Disease (Adreno-cortical deficiency) CAUSE Reduced gluco-corticoid and mineralo-corticoid due to : 1. Primary disease 2. Secondary: bilateral adrenalectomy, steroid therapy, auto-immune, severe sepsis Loss of body hair and pigmentation of exposed areas is charcteristic. PROBLEMS • Nausea, vomiting, diarrhoea, hypovolaemia, hypotension, weight loss • Small heart, and· heart failure with minor fluid overload • Hypoglycaemia, hyponatraemia, hyperkalaemia, uraemia • Associated pernicious anaemia and myasthenia gravis Steroid cover : Hydrocortisone 25mg i. v. at induction and 200mg/day Adrenal crisis : precipitated by stress and mimics hypovolaemic and septic shock. Low BP, Na, BS. high K, temperature. Management : Resuscitation with fluids and inotropes. Hydrocortisone 200mg/day
Phaeochromocytoma SIGNS Related to excess noradrenaline and adrenaline Paroxysmal hypertension, headache, sweating, palpitations, dysrhythmia , cardiac enlargement, hyperglycaemia PROBLEMS : Hypertension during intubation, tumour handling, and extubation Hypotension after devascularisation of the tumour PRE-OPERATIVE AWS 1. Reduce the BP and prevent paroxysmal hypertensive crises 2. Increase the intravascular volume 3. Improve myocardial function DRUG THERAPY Alpha antagonists: Phenoxybenzarnine oral, doxazocin oral, phentolamine i.v. Beta antagonists : propranalol, esmolol, labetalol after block with alpha antagonists. Consider calcium blockers, ACE inhibitors, labetalol for control of hypertension. ANAESTHESIA Control of blood pressure Epidural analgesia (to minimize stress response and for analgesia) with GA MgS04 very useful to control BP and heart rate throughout anaesthesia and surgery. At induction 40 mg/kg i.v. over 20 minutes to obtund the intubation response. Infusion of 0.5-2g/h titrated to BP control for adrenergic surges during tumour handling, and discontinue with ligation of adrenal vein. Also titrate phentolamine, labetalol, GTN or sodium nitroprusside when needed. Induction with propofol or etomidate Intubation with vecuronium or rocuronium (avoid suxamethonium). Maintenance with isoflurane and Np I oxygen with fentanyl I alfentanyl. A void atropine, halothane, and histamine releasing drugs. Control sudden decrease in BP following ligature with colloids (CVP> 1 Omm Hg), nor adrenaline and adrenaline. Hypoglycaemia may occur at this stage and blood sugar should be monitored. Monitoring: Intra arterial BP, CVP, ETC02, Sp02, temperature, UOP and BS. Post-operatively expect drowsiness due to sudden reduction of stimulation. BP and catecholamine levels do not normalise for several days and need treatment.
Steroid Cover Steroid cover should be given with caution to provide adequate cover to ensure a constant blood level throughout the day, avoiding complications leading to a poor outcome. Indications for steroid cover 1. Established corticosteroid deficiency 2. Hypothyroidism as it is often combined with steroid deficiency 3. History of steroid therapy within 3 months Stopped steroid therapy 3 months prior : No supplements needed Stopped steroid therapy < 3 months prior : Need steroids according to dose Prednisolone < lOmg I day : No supplements are needed Prednisolone > lOmg I day: Daily steroid+ hydrocortisone 25mg i.v. at induction and 6 hourly for major surgery till oral drugs can be re-commenced. (Prednisolone lOmg = prednisone lOmg, hydrocortisone 40mg, methyl prednisolone 8mg, dexa or betamethasone l .5mg). Complications of steroid therapy • CVS : hypertension • CNS : depression, euphoria, psychoses, insomnia • Endocrine: obesity, low K, insulin resistance (dangerous in DM) • Renal : polyuria, nocturia • GIT : peptic ulcer, bleeding, pancreatitis • Immune suppression : increased susceptibility to infection, delayed wound healing • Other: cataracts, proximal myopathy, wasting, osteoporosis, skin fragile, bruised Cushings Syndrome CAUSES High dose long trem steroid therapy Adrenal hyperplasia ( adenoma, carcinoma or ectopic) ACTH secreting pituitary tumour PROBLEMS Airway CVS : Truncal obesity, OSA, buffalo hump, moon face, reflux : Hypertension, CCF, ECG changes mimic IHD Endocrine : Hyperglycaemia, hypematraemia, hypokalaemia, pancreatitis Positioning: Osteoporosis, proximal myopathy, thin fragile skin, easy bruising Wound healing poor
Conn's Syndrome (Hyper-aldosteronism) CAUSE: Benign adenoma of adrenal cortex (75%) or bilateral hyperplasia (25%) PROBLEMS High BP and BS, low Kand metabolic alkalosis (treated with spironolactone) Renal tubular damage and nephrogenic diabetes insipidus CVS instability during tumour removal. Steroid replacement needed.