Parathyroid Flashcards
What are the two causes of primary hyperparathyroidism?
Adenoma – single gland involved (weighing 0.5g-5g).
Ð Other glands atrophic.
Ð Microscopically resembles normal parathyroid
Ð May see fibrous connective tissue capsule with adjacent rim of compressed parathyroid tissue
Hyperplasia – typically involves all glands
Ð Collectively weight rarely >1.0g
(PTH raised and Ca raised)
What is the cause of secondary hyperparathyroidism?
Chronic hypocalcaemia causes compensatory over activity of the parathyroid glands
¥ Renal failure, Low Ca intake, Vitamin D deficiency
Parathyroid tissue is hyperplastic
(PTH raised and Calcium is low)
What is the cause of tertiary hyperparathroidism?
Ð Parathyroid activity becomes autonomous
Ð Associated with hypercalcaemia
(PTH raised and Calcium raised)
What are the clinical features of hyperparathyroidism?
Bone disease
Ð Pain, fracture, osteoporosis or osteitis fibrosa cystica
Nephrolithiasis
Ð Renal stones and complications
GI complications
Ð Constipation, nausea, peptic ulcer disease, pancreatitis, gall stones
CNS
Ð Depression, lethargy, seizures
Neuro-muscular
Ð Weakness and fatigue
CVS
Ð Calcification of aortic and mitral valves
Hypoparathyroid:
is this common?
causes?
treatment?
¥ Very rare
¥ Usually post operatively
¥ Rarely congenital absence – Di George syndrome (22q11.2)
¥ Familial – assoc with primary adrenal insufficiency and mucocutaneous candidiasis – autoimmune basis
Treatment: ¥ Calcium supplement : > 1-2 g per day ¥ Vitamin D Tablets: 1alpha calcidol 0.5-1 mcg Depot injection: Cholecalciferol 300,000 units - 6 monthly
What are the clinical features of hypoparathyroidism?
Tetany
Ð Neuromuscular irritability
Ð Chvostek’s sign, Trousseau’s sign
Altered mental state
Ð Emotional lability, anxiety, depression, confusion, psychosis
Basal ganglia calcification, Parkinsonian, Raised ICP, Papilloedema
Calcification of lens and cataract formation
Prolong QT interval in ECG
Dental abnormalities – if hypocalcaemia during development
What is the management of primary hyperparathyroidism?
¥ Surgery BUT not always required
¥ Diet and Drugs NO proven benefit
¥ (Cinacalcet)Tertiary hyperparathyroidism
Parathyroid carcinoma
What are the indications for parathyroidectomy?
End Organ Damage: o Bone disease (Osteitis Fibosa et cystica; brown tumours/ pepper pot skull) o Gastric ulcers o Renal stones o Osteoporosis
Very high Calcium (>2.85mmol/l)
Under age 50
eGFR < 60 mL/min
What is pseudohypoparathyroidism?
GENETIC Defect (dysfunction of G protein (Gs alpha subunit)- Gene= GNAS 1 ¥ Low calcium, but PTH concentrations are elevated ¥ Due to PTH resistance ¥ Bone abnormalities (McCune Albright) ¥ Obesity ¥ Subcutaenous calcification ¥ Mental retardation ¥ Brachdactyly (4th metacarpal)
What is pseudo-pseudo hypoparathyroidism?
¥ pseudo, but with normal calcium
¥ Patients can change from pseudo to pseudo-pseudo!!
