Parathyroid

Question 1

How does high calcium present acutely?

What are two most common causes? Other causes?

Answer 1

Bones, stones, psychic groans and abdominal moans

• Confusion, drowsiness, coma, muscle weakness, psychosis.
• Polyuria and polydypsia if less severe (nephrogenic diabetes insipidus).
• Anorexia, nausea and vomiting.
• Pain and constipation
• Chondrocalcinosis and ectopic calcification

Primary hyperPTH (adenoma) & malignancy e.g. Myeloma, mets(with bone tumour deposits, or rarely PTH-related peptide in lung SCC)

Other causes include:

• Thiazides, Lithium,
• Excess action of Vit D e.g. iatrogenic,
• Sarcoid, Acromegaly,
• 3y hyperPTH,
• Addison’s, MEN, Paget’s
• Milk-alkali syndrome - excessive calcium intake

Question 2

Hypercalcaemia Cont.

What Ix?

How Manage?

Answer 2

Bone profile

• raised Ca, low phosphate and normal/high PTH (during hyperCa) suggests primary hyperPTH

PTH levels

LFTs - elevated AlkP and other LFTS suggets malignancy

Isolated large rise in AlkP suggetss Paget’s

EP - paraprotein band in Myeloma

X-ray - hilar LA in Sarcoid; Frontal bossing and deformity in Paget’s (inc deafness)

High Res CT/MRI; ? USS -> if suspect parathyroid adenoma

Rehydrate, ? Loop diuretics, ? Bisphophonates, ? Steroids in malignancy or Calcitonin in Paget’s

Question 3

Indications for Parathyroid surgery? (5)

Answer 3

Renal stones or impaired rebnal function

Bone involvmenet/marked reduciton in density

unequivocal marked raised Ca

Below 50y old (uncommon)

Previou episode of severe acute hyper Ca2+

Question 4

Hypocalcaemia

Signs and symptoms?

2 Eponymous signs?

What is main cause? Pathology behind it? What is osteitis fibrosa cystica and how is it caused?

2 other causes

How treat acutely and in chronic disease?

Answer 4

Circumoral tingling, cramps, anxiety, tetany Followed by convulsions, larngeal stridor, dystonia and psychosis

Chvostek - tapping on facial nerve;

Trousseau - inflate BP cuff –> carpopedal spasm

Causes:

• Chronic renal failure,
• post thyroid/parathyroid surgery,
• acute pancreatitis,
• blood transfusion,
• vitamin D resistance,
• PTH resistance - psuedo-hypoparathyroidism
• severe low Mg2+

Acute - Calcium gluconate + ECG monitoring then ORal calcium + Vit D ASAP

Chronic - Vit D metabolites e.g. caclitriol, + calcium

Question 5

Investigations in low calcium?

treatment?

Answer 5

Serum and urine creatinine, PTH levels, parathyroid antibodies, 25-hydroxy vitamin D levels, metacarpal x-ray (psuedo-hypoPTH)

Caclium and alphacalcidol

Question 6

Secondary HyperPTH

What is main cause?

Pathology behind it?

What is osteitis fibrosa cystica and how is it caused?

Answer 6

Secondary HyperPTH in renal failure

• No -OH vit D + retained phosphate cause Ca drop, leading to PTH release.
• OC activation, bone cysts and bone marrow fibrosis (osteitis fibrosa cystica) leading to renal bone disease – pepper pot skull and hand/spine changes
• WIll develop into tertiary if untreated (with Vit D and phosphate binders)

Question 7

Common tumours in :

MEN 1

MEN 2A

MEN 2B

autosomal dominant manner, defective oncogene (2 hhypothesis)

Answer 7

PPP -> TPP -> TMP

1. Parathyroid, Pituitary - esp PRL, ACTH and GH, Pancreas (islet cell, Zolinger-elison), Adrenal (non-functional), Thyroid
   2a. Thyroid (medullary - calcitonin producing), parathyroid and adrenal (phaeochromocytoma and cushings)
   2b. SImilar to 2a but no parathyroid; Marfanoid body habitus