Hypomagnesaemia

Low magnesium (many many causes)

Too little in (distal small bowel absorption)

Too much out (renal tubular reabsorption problems)

• Low calcium accompanies it (but cause is by organ resistance to PTH)
• Can get from acute pancreatitis (magnesium soaps get formed in the areas of fat necrosis) and liver cirrhosis
• Is caused by loop and thiazide diuretics (also acute tubular necrosis along with Bartter's and Gitelman's syndromes)
• Usually no symptoms - can get neuromuscular irratibility
• ECG features can look like like potassium (small T, large U), also long QT and ventricular arrhythmias can follow