Parathyroid Disorders Flashcards
What is hypocalcaemia
Low calcium levels in the blood serum
Causes of hypocalcaemia
Chronic kidney disease
(Pseudo)hypoparathyroidism
Autoimmune
Hypomagnesaemia
Symptoms of hypocalcaemia
Paraesthesia of the fingers and toes
Muscle cramps and weakness
Fatigue
Fits
Bronchospasm or laryngospasm
Clinical signs of hypocalcaemia
Chovesteks sign
Trousseau sign
QT prolongation on ECG
What is chovesteks sign
Gentle tapping over the facial nerve causes twitching of the ipsilateral facial muscles
What is trousseau sign
Inflation of the BP cuff above systolic pressure for 3 mins induces tetanic spasm of the fingers and wrist
Investigation of hypocalcaemia
Low serum calcium
Management of acute severe hypocalcaemia
IV calcium gluconate
Calcium infusion
Long term management of hypocalcaemia
Supplement
Vitamin D
What is hypomagnesemia
Low magnesium levels in the blood serum
Causes of hypomagnesemia
Alcohol, drugs, GI illness with diarrhoea, pancreatitis, malabsorption
Name some drugs which can cause hypomagnesemia
Thiazide, PPIs
Symptoms of hypomagnesemia
Anorexia
N+V
muscle weakness, lethargy
Fits
Clinical signs of hypomagnesemia
Cardiac arrhythmia
Positive chovestek sign + trousseau sign indicate secondary hypocalcaemia
Investigations for hypomagnesemia
Low serum magnesium
*measure other electrolytes: K+, Ca2+
Management of hypomagnesemia
Magnesium supplementation
+ calcium supplements if needed
What is the main complication of hypomagnesemia
Secondary hypocalcaemia
What is hypoparathyroidism
Condition where the parathyroid glands produce too little parathyroid hormone
Causes of hypoparathyroidism
DiGeorge syndrome
Destruction of gland
Autoimmune: Addisons, pernicious anaemia
Hypomagnesemia
What is the result of too little parathyroid hormone being produced
Causes blood calcium levels to fall and blood phosphorus levels to rise
Which cells produce parathyroid hormone
Chief cells
Clinical presentation of hypoparathyroidism
Paraesthesia in fingers, toes and lips
Twitching facial muscles
Tiredness, mood changes
Dry, rough cough
Coarse hair and fingernails that break easily
Biochemistry of hypoparathyroidism
Low PTH
low calcium
High phosphorus
Management of hypoparathyroidism
Calcium supplement + vit D
What is pseudohypoparathyroidism
Condition associated primarily with resistance to PTH
Genetic defect associated with pseudohypoparathyroidism
Dysfunction of Gs alpha subunit (GNAS1 gene)
Pathophysiology of pseudohypoparathyroidism
End organ resistance to PTH due to mutation of Gsa protein which is coupled to the PTH receptor
Clinical presentation of pseudohypoparathyroidism
Bone abnormalities
Obesity
Subcutaneous calcification
Learning disability
Brachydactyly
What is brachydactyly
Shortened fingers and toes
Blood results in pseudohypoparathyroidism
Low calcium
Elevated PTH due to resistance
What is pseudo-pseudohypoparathyroidism
Patient has the features of pseudohypoparathyroidism but normal blood calcium and phosphate levels
What is hyperparathyroidism
Overactivity if the parathyroid glands with high levels of PTH
What causes primary hyperparathyroidism
Tumour of the parathyroid gland
Management of primary hyperparathyroidism
Removal of the tumour
What causes secondary hyperparathyroidism
Low vitamin D or chronic kidney disease
What causes tertiary hyperparathyroidism
Occurs when secondary continues for a long time leading to hyperplasia of the glands
Blood results in primary hyperparathyroidism
High PTH
high calcium
Bloods in secondary hyperparathyroidism
High PTH
low or normal calcium
Bloods in tertiary hyperparathyroidism
High PTH
High calcium
Roles of PTH (4)
Activates osteoclasts
Increases reabsorption of calcium by renal tubules
Increases urinary phosphate excretion
Increased synthesis of active forms of vit D
How is PTH production usually regulated
It’s functions increase serum calcium which inhibits PTH secretion
What is a complication of unchecked hyperparathyroidism
Fibrosa cystica
Clinical features of fibrosa cystica
Osteoporosis
Brown tumours
Osteitis
How can brown tumours present on investigation
Lytic lesion on x-ray
Management of secondary hyperparathyroidism
Correcting vitamin D deficiency
Renal transplant to treat failure
Management of tertiary hyperparathyroidism
Surgical removal of the part of the parathyroid tissue
Indications for parathyroidectomy
End organ damage
Very high calcium
Under the age of 50
What is hypercalcaemia
High calcium levels in the blood serum
Name some causes of hypercalcaemia
Primary or tertiary hyperparathyroidism
Malignancy
Genetic syndromes
Drugs
Granulomatous disease
Name some genetic syndromes which can cause hypercalcaemia
MEN1 + 2
Familial isolated hyperparathyroidism
Familial hypocalciuric hypercalcaemia
What is Familial hypocalciuric hypercalcaemia
Autosomal dominant deactivating mutation in the calcium sensing receptor which decreases the sensitivity
Name some drugs which can cause hypercalcaemia
Vit D, thiazide
Clinical presentation of hypercalcaemia
Stones, bones, groans and psychiatric moans
symptoms of acute hypercalcaemia
Thirst, dehydration, polyuria
Confusion
What is polyuria
Excessive production of urine
Symptoms of chronic hypercalcaemia
Myopathy
Fractures
Osteopenia
Depression
Hypertension
Biochemistry of hypercalcaemia
Raised calcium
Serum ALP raised in malignancy
Serum PTH raised in hyperparathyroidism
Investigations of Familial hypocalciuric hypercalcaemia
Bloods: mild hypercalcaemia, reduced urine calcium excretion, PTH may be marginally elevated
Genetic screen
Management of acute severe hypercalcaemia
Rehydrate with 0.9% saline
Consider loop diuretics once rehydrated
Bisphosphonates
