The "sick cell syndrome" is characterized by-
Sick cell syndrome is a medical condition characterised by reduced functioning of the cellular Na+/K+ pump, which is responsible for maintaining the internal ion homeostasis. The clinical result is a rise in blood K+ level and drop of blood Na+ levels Hyponatraemia Hyponatraemia is defined as a serum Na <135 mmol/L. It is a common electrolyte abnormality with many potential underlying causes, as summarised in Box 14.10. Pathophysiology In all cases, hyponatraemia is caused by greater retention of water relative to sodium. The causes are best categorised according to associated changes in the ECF volume (Box 14.10). Hyponatraemia with hypovolaemia In this situation there is depletion of sodium and water but the sodium deficit exceeds the water deficit, causing hypovolaemia and hyponatraemia (see Box 14.3). The cause of sodium loss is usually apparent and common examples are shown in Box 14.10. Hyponatraemia with euvolaemia In this situation there are no major disturbances of body sodium content and the patient is clinically euvolaemic. Excess body water may be the result of abnormally high intake, either orally (primary polydipsia) or as a result of medically infused fluids (as intravenous dextrose solutions, or by absorption of sodium-free bladder irrigation fluid after prostatectomy). Water retention also occurs in the syndrome of inappropriate secretion of antidiuretic hormone, or vasopressin (SIADH). In this condition, an endogenous source of vasopressin (either cerebral or tumour-derived) promotes water retention by the kidney in the absence of an appropriate physiological stimulus (Box 14.11). The clinical diagnosis requires the patient to be euvolaemic, with no evidence of cardiac, renal or hepatic disease potentially associated with hyponatraemia. Other non-osmotic stimuli that cause release of vasopressin (pain, stress, nausea) should also be excluded. Suppoive laboratory findings are shown in Box 14.11. Ref Davidson 23rd edition pg 357
Hyponatremia
Hypernatremia
Hypokalemia
Hyperkalemia
Fluid and electrolytes