23/07/2013 by admin | Endocrine
  1. p/c:
    1. o Circumoral tingling and paraesthesia of hands and feet, tetany, especially in muscles supplied by long nerves and seizures
    2. o Chvostek’s sign = tap facial nerve just anterior to ear causing brief facial muscle contraction
    3. o Trousseau’s sign = inflation of BP cuff (3 mins) causing carpopedal spasm
    4. o Chronic hypocalcaemia results in basal ganglia calcification and cataracts.
  2. Aetiology:
    1. o Generally rare
  3. Secondary hyperparathyroidism is most common cause of hypocalcaemia, occurring in acute or chronic renal failure
    1. o Failure of renal Vit D hydroxylation, together with phosphate retention, depress serum calcium, stimulating PTH release in an attempt to normlaize calcium. This results in osteoclast activation, cysts formation, bone marrow fibrosis (osteitis fibrosa cystica), which together with aluminium toxicity contribute to renal bone disease.
    2. o XR = classical findings in hands, skull (‘pepper pot’), spine (‘rugger jersey’)
    3. o ECG: prolonged QT interval
    4. o Diagnosis is obvious from creatinine and phosphate levels
    5. o Tx: vit D and phosphate binders. If secondary hyperparathyroidism is untreated – parathyroid gland hyperplasia leads to autonomous production of PTH = ‘tertiary hyperparathyroidism’ with frank hypercalcaemia
  4. Post thyroid/parathyroid surgery: transient hypocalcaemia may occur
  5. Idiopathic autoimmune parathyroid failure: rare, parathyroid antibodies are found, other autoimmune conditions may exist
  6. Osteomalacia: resulting from inadequate active vit D, asscoaited low calcium levels. May be compounded by dietary calcium deficiency or relate to malabsorption.
  7. Tx of hypocalcaemia:
    1. o Acute symptoms: (Ca <1.9mmol/L) = IV bolus of 10% calcium gluconate 10-20mL with ECG monitoring followed by IV infusion if necessary. Oral calcium and Vit D asap. IV magnesium sulphate may be required
  1. o Chronic disease: vit D metabolites (calcitrol or alphacalcitrol) or oral calcium. 
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