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Parathyroids

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Parathyroids

  1. 1. PARATHYROIDS <ul><li>Anatomy </li></ul>
  2. 2. Physiology <ul><li>Secretes parathyroid hormone (PTH) </li></ul><ul><li>PTH produced by the chief cells </li></ul><ul><li>PTH secretion is controlled by a complex feed back mechanism dependent on serum Ca levels </li></ul><ul><li>PTH or its fragments can be measured by radio immunoassay </li></ul>
  3. 3. Actions of PTH <ul><li>Stimulation of osteoclastic activity  bone resorption and mobilization of Ca &Phosphate </li></ul><ul><li> Absorption Ca from the gut </li></ul><ul><li> Reduces the urinary Ca by increasing the reabsorption Ca by renal tubules </li></ul><ul><li> Reduces the renal tubular absorption of PO4  Phosphaturia </li></ul>
  4. 4. Calcitonin <ul><li>Secreted by C cells of thyroid </li></ul><ul><li>Opposite action of PTH </li></ul><ul><li> Serum Ca </li></ul><ul><li> Ca storage in the bones </li></ul>
  5. 5. HYPERPARATHYROIDISM <ul><li> Secretion of PTH </li></ul><ul><li>One of the most common causes of hypercalcaemia </li></ul><ul><li>Large no. of patients are asymptomatic </li></ul><ul><li>In India a high proportion of patients presents with skeletal and renal disease </li></ul>
  6. 6. Classification <ul><li>Primary Hyperparathyroidism(PHPT) – inappropriately  secretion of PTH </li></ul><ul><li>Secondary hyper parathyroidism – chronic hypocalcaemia  reactive hyperplasia of all four glands </li></ul><ul><li>Tertiary hyper parathyroidism – reactive hyperplasia, the glands become autonomous e.g, chronic renal failure pt. After transplantation </li></ul>
  7. 7. Pathology <ul><li>Parathyroid adenoma </li></ul><ul><li>Usually single,5% multiple </li></ul><ul><li>Whole gland is enlarged, darker in color more vascular than usual </li></ul><ul><li>A rim of compressed normal tissues seen surrounding the adenoma </li></ul><ul><li>Predominance of chief or clear cells </li></ul>
  8. 8. Pathology(contd.) <ul><li>Parathyroid hyperplasia – hyperplasia of all the glands </li></ul><ul><li>Parathyroid carcinoma – rare (<1%) – palpable swelling , very large swelling infiltrating to the thyroid or adjacent structures – distant metastasis & recurrence have been reported </li></ul>
  9. 9. Multiple Endocrine Neoplasia (MEN) Syndrome <ul><li>Autosomal dominant disorder </li></ul><ul><li>APUD cells are involved </li></ul><ul><li>MEN Type I (Werner syndrome)  Hyperparathyroidism,pancreatic islet cell tumors,pituitary tumor </li></ul>
  10. 10. MEN Type II <ul><li>MEN Type IIA(Sipple syndrome ) </li></ul><ul><li>MedullaryCa.thyroid,Phaeochromacytoma,Hyperparathyroidism </li></ul><ul><li>MEN TypeIIB(MEN TypeIII) </li></ul><ul><li>Medullary Ca ,Phaechromocytoma ,and mucosal neuromas </li></ul>
  11. 11. Clinical presentation (contd.) <ul><li>Skeletal - mild to crippling bone disease </li></ul><ul><li>Osteitis fibrosa cystica, Brown tumors , single or multiple bone cysts, pseudomotor & pathological fractures . Vague pain in the bone and joints </li></ul><ul><li>Renal stones, nephrocalcinosis </li></ul>
  12. 12. Clinical Presentation <ul><li>Age  20 – 45 </li></ul><ul><li>Females :Males = 2:1 </li></ul><ul><li>Most common presentation in the western world  Asymptomatic hypercalcemia </li></ul><ul><li>Classical manifestations in the 3 rd world ,viz. “Bones,stones,abdominal groans & psychic moans” </li></ul>
  13. 13. Clinical presentation (contd.) <ul><li>Gastro intestinal - nausea, vomiting,anorexia and weight loss, peptic ulceration, pancreatitis. </li></ul><ul><li>Nervous system – lethargy, listlessness,personality changes,irrational behavour and memory loss. Hyper calcemia  depression of nervous system  coma </li></ul>
  14. 14. Laboratory findings <ul><li>Serum Ca -  most common finding PHPT. Normocalcemic PHPT not uncommon in India. Serum Ca level to be corrected with respect to serum albumin </li></ul><ul><li>Urinary Ca –24 hrs  </li></ul><ul><li>Serum alk. Phosphatase  in bone disease </li></ul><ul><li>Serum PTH – Normal – 65 pg/ml </li></ul>
  15. 15. Clinical presentation (contd.) <ul><li>Other complications: Corneal calcification ,Itching </li></ul><ul><li>Hypertension is seen in many pts. Reason not clear </li></ul>
  16. 16. Common causes of hypercalcemia <ul><li>a.Bony metastasis – breast, bronchus, prostate,kidney, thyroid </li></ul><ul><li>b.PTH secreting solid tumors </li></ul><ul><li>c.Haematological malignancies –multiple myeloma </li></ul><ul><li>d.Vit D intoxication </li></ul><ul><li>e.Sarcoidosis </li></ul><ul><li>f.Immobilisation,medications like lithium, thiazide etc </li></ul>
  17. 17. Imaging investigations <ul><li>Radiology  Useful for skeletal lesions </li></ul><ul><li>Ultrasound  Adenoma or multiple enlarged glands may be detected </li></ul><ul><li>CT Scan  Lesions in the chest </li></ul><ul><li>Thallium Technetium subtraction scan </li></ul><ul><li>99 Tc Sestambi scan </li></ul><ul><li>Selective angiography & venous sampling </li></ul>
  18. 18. Treatment <ul><li>Surgery is the treatment of choice </li></ul><ul><li>Parathyroid adenoma  Excision of the adenoma </li></ul><ul><li>Parathyroid hyperplasia  If more than one gland is involved,3 ½ gland can be removed or total parathyroidectomy with auto transplantation </li></ul><ul><li>Parathyroid Ca  Hemithyroidectomy + involved gland </li></ul>

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