Calcium Homeostasis and disorders of calcium metabolism 2 Flashcards
What are some symptoms and signs of hypocalcaemia
Paraesthesia - fingers, toes , perioral Muscle cramps Muscle weakness Fatigue Bronchospasm or laryngospasm Fits Chovsteks sign (tapping over facial nerve) Trousseau sign (carpopedal spasm) ECG: QT prolongation
What are some of the causes of hypocalcaemia
Hypoparathyroidism Vitamin D deficiency (osteomalacia, rickets Chronic Renal Failure Pancreatitis Hyperventilation Osteoblastic bone metastases Rhabdomylolysis
What should be give in acute Hypocalcaemia
a) emergency
b) over time
IV calcium gluconate 10ml 10% over 10 mins
Infusion (10ml 10% in 100ml infusate)
Hypoparathyroidism
Congenital absence Destruction Autoimmune Hypomagnesaemia Idiopathic
What is the long term management for hypoparathyroidism
Calcium supplement (1-2g per day) Vitamin D (tablets or depot injection monthly)
Why is hypomagnesaemia important?
Calcium release from cells is dependent on magnesium
What happens to the intracellular calcium in magnesium deficiency
It becomes high
What happens to PTH in hypomagesaemia
Its release is inhibited
Skeletal and muscle receptors are less sensitive to PTH
What is the treatment for hypomagnesaemia
Calcium and magnesium replacement
What are the causes of hypomagnasaemia
Alcohol Drugs (thiazide, PPI) GI illness Pancreatitis Malabsorption
What type of disease is pseudohypoparathyroidism
Genetic defect in GNAS1
What are the biochemistry indications of pseudohypoparathyroidism
Low calcium
PTH concentration elevated
Why are PTH concentrations elevated in pseudohypoparathyroidism
Due to PTH resistance
What are some symptoms of pseudohypoparathyroidism
Obesity Bone abnormalities (McCune Albright) Subcutaneous calcification Learning Disability Brachdactyly (4th metacarpal)
What is pseudo-pseudohypoparathyroidism
The same as pseudohypoparathyroidism but with normal calcium levels
What are the names of two conditions in which there is a vitamin D deficiency
Rickets and Osteomalacia
Why might a patient be vitamin D deficient
Dietary deficiency Malaborsption: gastric surgery, coeliac disease, liver disease, pancreatic failure Chronic liver failure Lack of sunlight Drugs e.g. anticonvulsants
What are the features of osteomalacia
Low calcium Muscle wasting (proximal myopathy) Dental defects (caries, enamel) Bone tenderness, fractures, rib deformity, limb deformity pseudofractures UV exposure
If a patient has had a lot of UV exposure and presents with bone tenderness, what should be high on your differential list
Osteomalacia
What are some biochemical markers that would be present in osteomalacia
Low calcium low phosphate high alkaline phosphatase Low vitamin D High PTH
What are some of the long term consequences of Vitamin D deficiency
Demineralisation/ fractures osteomalacia/ rickets malignancy (especially colon) heart disease diabetes
