4. Parathormone
■ 84 aminoacids
■ Secretion not dependent on pitutary gland
■ Half life- 4 minutes
■ Functions :
– Converts vitamin D into 1,25- dihydrocholecalciferol in kidney
– Absorption of calcium from gut
– Mobilises calcium from bone
– Reabsorption from renal tubules
5. Calcium metabolism
■ Normal value: 8.5-10.2 mg/dl
■ Commonest protein part of bound calcium is Albumin (80%)
■ Level controlled by
– PTH
– Calcitonin
– Vitamin D- Acts on bone, kidney and GIT
■ Functions
1. Blood coagulation
2. Neuromuscular activity
3. Cellular activity
4. Bone integrity.
8. PRIMARY HPT
■ 3rd most common endocrine disease
■ Causes hypercalcemia
■ Etiology
- Parathyroid adenoma
- Familial/ genetic causes
- MEN 1 syndrome
- Therapeutic ionizing radiations
- Lithium: parathyroid hyperplasia and HPT with no bone or renal problems
9. Clinical features of HPT
■ Clinical vignette: “Bones, stones, abdominal groans and psychic moans”
■ Middle aged women( 3:1)
■ Incidence: 1:1000
■ Asymptomatic > 50% cases
10. Clinical feature contd.
■ BONES
- Raised PTH
- Increased osteoclastic activity
- Extensive decalcification of bone
- Bone pain, subosteal erosions
- Osteitis fibrosa cystica: single/ multiple cysts/ pseudotumours in the jaw, skull or
phalanges
- Osteopenia, osteoporosis and pathological fracture
11. Clinical feature contd.
■ STONES:
- Renal stone in 25% patients
- Recurrent stones
- Calcium phosphate and oxalate type
- Metaststic calcification, nephrocalcinosis, renal failure
- Calcification in renal vessels: renal hypertension.
12. Clinical feature contd.
■ ABDOMINALGROANS
- Stimulates gastrin release: peptic ulceration
- Precipitate acute pancreatitis
- Increases gall stone disease ( calcium bilirubinate)
■ PSYCHIC MOANS:
- Behavioural and neurotic problems: depression and anxiety
13. Acute hyperparathyroidism (Crisis)
■ Causes
- Sidden increase in PTH due to rupture od parathyroid cyst or bleeding in parathyroid
tumour
- Severe dehydration precipitates crisis
- Secondaries in bone.
15. Acute hyperparathyroidism (Crisis)
■ Treatment
- Forced diuresis: 3-5 litres of saline with frusemide
- Rehydration: normal saline 300ml/hr
- Steroids: inhibit effects of vitamin D
Dose: 400/ day iv for 5 days
- Bisphosphonate:
Cloodranate sodium, pamidronate
Inhibits mobilization of calcium from bone
Dose: 4mg iv followed by 8mg
16. Investigations
Parameters Primary HPT Secondary HPT
parathormone High High
Calcium High Normal
Phosphate Dcreased Increased
• Increased serum PTH level: specific abd diagnositic, > 0.5
• Bone density assesment
• Vitamin D estimation
• Increased urinary calcium level: >250 mg/24 hours
• Raised al;kaline phosphate level
17. Investigations
■ X-ray features:
- skull: salt and pepper appearance
- Phalanges: supperiosteal bone resorption
- Jaw: osteitis fibrosa cystica
- Spine: rugger jersy spine
■ USG abdomen
■ Thallium- technetium scan: hot spotes ( diagnostic of parathyroid adenoma)
18. Treatment
■ Parthyroidectomy
■ Indications
1. Severe symptoms
2. Young age group
3. Markedly reduced bone density
4. Serum calcium > 11mg%
5. Urinary calculi
6. Urinary calcium > 400 mg/24 hours
19. Parathyoidectomy
■ Preoperative preperation:
- Vocal cords assesed
- Treatment of high calcium levels preoperatively
1. Diuresis
2. Steroids: prednisolone 20mgTDS for 5 days
3. Phosphate infusion: 100mmol infusion in 6 hours
4. Calcitonin subcutaneous injection: 200 units BD for 5 days
5. Biphosphate- Etiodronate disodium: 7-5 mg/kg slow iv infusion for 3 days
6. Mithramycin: 25 microgram/kg single dose.
20. Parathyoidectomy
■ Total parathyroidectomy
- For parathyroid hyprplasia
- All four glands removed
- 1/3 rd of one gland autotransplanted into forearm muscle (brachioradia;is) or
sternocleidomastoid with marker stitch
- Transplamted gland slice in 1mm pieces
- 18 pieces embedded
21. Parathyoidectomy
■ Adenoma in gland with normal other glands: Removal of single gland
■ Carcinoma: parathyroidectomy plus hemithyroidectomy with postoperative
radiotherapy
■ All 4 glands diseased:Transcervical thymectomy added.
23. Parathyoidectomy
■ Complications:
- Haemorrhage, RLN palsy, hypocalcaemia.
- Persistent HPT: Serum calcium does not normalise immediately after surgery.
- Recurrent HPT: Serum calcium after surgery becomes normal but again increases in 6-
12 months.
- Hypoparathyoidism with devere hypocalcaemia- whwn all glands arec removed
- Hungry bone syndrome: In patients with npreop hypethyoidism,Thyroid hormone
level drops acutely after surgery, stimulus to break down bone is removed,
Bones remove calcium from plasma rapidly
27. MEN syndrome
■ Type II A ( Sipple syndrome): chromosome 10
- Medullary carcinoma thyroid
- Pheochromocytoma
- Parathyroid hyperplaisa
■ Type II B
- Medullary carcinoma thyroid
- Pheochromocytoma
- Neuroma
