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phase 2 endo > Parathyroid > Flashcards

Parathyroid Flashcards

1
Q

where is the parathyroid gland located?

A

• Location: 4 glands behind upper and lower poles of thyroid

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2
Q

what are the cells of the parthyroid gland and what do they produce

A

• Cells: Chief (PTH) + Oxyphil (non-functional)

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3
Q

what is the function of parathyroid gland

A

maintenance of calcium and phosphate

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4
Q

what is the embryological oryin of parathyroid gland

A

o 3rd pouch→ inferior parathyroid g. (A→ thymus)

o 4th pouch → superior parathyroid g (A→ thyroid)

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5
Q

what causes DIGeorge syndrome

A

o Failure of 3rd and 4th pouch differentiation

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6
Q

what does cathc22 stand for

A

o CATHC22 – Cardiac defects, Abnormal facies (facial expression), Thymic aplasia, Cleft palate, Hypocalcaemia, deletion on chromosome 22

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7
Q

What stimulates release of PTH

A

↓ serum Ca

o Note: may be supressed by ↓Mg

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8
Q

what is the effect of PTH

A

o ↑ osteoclast activity to release ↑Ca2+ & ↓PO43– from bone
o ↑Ca2+ & ↓PO43– reabsorption in kidney DCT
o ↑ renal production of 1,25-dihydroxy-vitamin d3

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9
Q

How is vit D produced

A

o First hydroxylation: liver → 25-hydroxy vitamin D

o Second hydroxylation: kidney → 1,25-hydroxy vitamin D (calcitriol)

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10
Q

what stimulates vit D production

A

low Ca and phosphate AND PTH

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11
Q

what is the effect of vit D

A

o ↑Ca2+ and ↑PO43– absorption from the gut;
o Inhibition of PTH release;
o Enhanced bone turnover;
o ↑Ca2+ and ↑PO43– reabsorption in the kidney.

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12
Q

what is the normal range of PTH

A

0.8-8.5pmol/L

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13
Q

what is the normal range of calcium

A

Normal range of calcium: 2.2 – 2.6mmol/L

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14
Q

what are the ranges for mild, moderate and sever hypercalcaemia

A

Mild hypercalcaemia = 2.7 – 2.9 mmol/L
Moderate hypercalcaemia = 3.0 – 3.4 mmol/L
Severe hypercalcaemia = greater than 3.4 mmol/L - medical emergency

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15
Q

what presentation is expected in someone with hyperparathyroidism

A
  • Stones: Renal, Polyuria and polydipsia, Nephrocalcinosis
  • Bones: Bone pain. Pathological fractures
  • Moans: depression
  • Groans: Abdo pain, n/v and constipation, Pancreatitis, PUD (↑gastrin secretion)
  • Other:↑ BP (check Ca2+ in all with HTN)
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16
Q

Define hyperparathyroidism

A

Excessive secretion of PTH from parathyroid gland

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17
Q

what are the causes of primary hyperthyroidism and proportional distribution

A
  • Single parathyroid gland adenoma: 75-85%
  • Multi-gland adenoma/hyperplasia 14%
  • Parathyroid carcinoma 1%
  • Familial → MEN 1 and 2
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18
Q

what blood results can be expected in primary hyperthyroidism

A

↑Ca2+ + ↑/- PTH, ↑ALP, ↓PO4

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19
Q

what investigations other than blood may be useful in primary hyperparathyroidisem and what are the results expected to be

A
  • X-ray: osteitis fibrosa cystica e.g. phalangeal erosions
  • DEXA: osteoporosis
  • Biopsy
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20
Q

what can be expected on a bone x-ray of someone with primary hyperparathyroidism

A

o Subperiosteal resorption of distal phalanges
o Tapering of distal clavicles
o Salt and pepper appearance of the skull
o Brown tumours of long bones

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21
Q

what are the possible differentials for p. hyperparathyroidism

A
  • Drugs – thiazide, lithium
  • Endocrine Disorders – thyrotoxicosis, Addison’s
  • Autoimmune – sarcoidosis
  • Tertiary hyperparathyroidism
  • Malignancy – myeloma, lymphoma, squamous cell lung cancer
  • Familial – MEN 1 or 2
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22
Q

how can patients with mild asymptomathic P hyoperparathyroid.

A 
o	Surveillance 
	Check serum and calcium 6 monthly 
	3 site DEXA scan annually 
	Monitor for signs 
o	Avoid
	Dehydration and thiazide diuretics 
	High calcium and Vitamin D intake
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23
Q

what is the more complex management for p hyperparathyroid

A

• Surgical: excision of adenoma; problems:
o Hypoparathyroidism
o Recurrent laryngeal N. palsy
• Medical: bisphosphonates, VitD

24
Q

define secondary hyperparathyroidism

A

Increased PTH secretion in response to ↓Ca as a result of failing kidney, liver or GI

25
Q

what are the principle causes and symptoms of primary hyperparathyroidsm

A
  • Vitamin D deficiency: rickets, osteomalacia, ↓growth, resp symptoms
  • Chronic renal failure: oedema, renal osteodystrophy
26
Q

what is the difference between CKD and vit D secondary hhyperparathyroidism

A

↑PO4 in renal and ↓in vit D↓

27
Q

what blood results can be expected for someone with secondary hyperparathyroidsm

A

↑PTH, ↓Ca, , ↑ALP, ↓vit D

28
Q

what is the management of secondary hyperparathyroidism

A

• Correct causes
• Phosphate binders
o With Ca: calcichew
o W/o Ca: sevelamer, lanthanum
• Vit D: calcitriol (active), cholecalciferol (innactive)
• Cinacalcet: ↑ parathyroid Ca-sensitivity

29
Q

define tertiary hyperparathyroidism

A

Prolonged 2O HPT —> autonomous PTH secretion

30
Q

what results are expected in tertiary hyperparathyroidism

A

Prolonged 2O HPT —> autonomous PTH secretion

31
Q

what is the management of tertiary hyperparathyroidism

A
  • Subtotal parathyroidectomy

* Cinacalcet

32
Q

what are the differences in PTH, Calcium and phosphate in primary, secondary and tertiary hyperparathyroidism

A

Class PTH Calcium Phosphate
Primary ↑ ↑ ↓
Secondary ↑ ↓/- ↓ in vit D/↑CKD
Tertiary ↑ ↑ ↑

33
Q

what is the aetiology of tertiary hyperparathyroidism

A
  • ↑production after cause corrected: ↑Ca

* E.g. CKD →persistent ↑Ca post-transplant

34
Q

what does SPASMODIC stand for and in what condition

A 
hypocalcaemia 
•	Spasms (carpopedal = Trousseau’s sign)
•	Perioral paraesthesia
•	Anxious, irritable
•	Seizures
•	Muscle tone↑→ colic, wheeze, dysphagia
•	Orientation impaired (confusion)
•	Dermatitis
•	Impetigo herpetiformis (↓Ca + pustules in pregnancy)
•	Chovsteks, cardiomyopathy (↑ QTc → ↑dP)
35
Q

what are the primary and seondary causes of hypoparathyroidism

A 
Primary 
•	Autoimmune 
•	Congenital: DiGeorge
o	Cardiac abnormality: Fallot’s
o	Abnormal facies
o	Thymic aplasia
o	Cleft palate
o	Hypocalcaemia
o	Chr 22
Secondary →Iatrogenic
•	Surgery
•	Radiation
36
Q

what investigations and results are expected in hypoparathyroidism

A
  • ↓Ca, ↑PO4, ↓PTH, normal ALP
  • eGFR→ CKD
  • Renal ultrasound
37
Q

how is hypoparathyroidsm managed

A 
•	Ca + vit D supplements
•	Calcitriol
•	Severe hypocalcaemia 
o	10ml of 10% calcium gluconate IV over 30mins 
o	Repeat when necessary
38
Q

what is Pseudohypoparathyroidism

A

Failure of target organ response to PTH

39
Q

what are the symptoms of Pseudohypoparathyroidism

A
  • Symptoms of hypocalcaemia

* Short 4th and 5th metacarpals, short stature

40
Q

what are the findings in investigations for Pseudohypoparathyroidism

A

Ix: ↓Ca, ↑PTH

41
Q

what is the management of Pseudohypoparathyroidism

A

• Rx: Ca + calcitriol

42
Q

what is Pseudopseudohypoparathyroidism

A

• Normal (maternal) receptor in kidney —> normal biochem
• Abnormal (paternal) receptors in body —>
pseudohypoparathyroidsm phenotype

43
Q

what are the causes of vitamin D deficiency

A
  • CKD
  • ↓Sun exposure/housebound
  • GI malabsorption → coeliac
  • Liver disease
  • HAART, steroids, rifampicin
44
Q

what is the progression of vit D deficiency

A

↓vitD →↓Ca+PO3- → ↑PTH →↑bone mineralisation

45
Q

how common is vit D deficiency in UK

A
  • 50% of UK adults have some level of deficiency

* 16% have sever deficiency during winter

46
Q

what are the risk factors for vit d deficiency

A
  • Dark skin
  • Age: children + >65s
  • Breastfeeding (exclusively)
  • Obesity
  • Routine face and hand covering
  • Housebound
  • Sunscreen
  • Pregnancy (particularly miscarriages)
  • Alcohol
47
Q

How can vit D deficiency be prevented

A
  • Early diagnosis and treatment
  • Education
  • Use of Calciferol
48
Q

what are the complications of vit D deficiency

A
  • ↑ risk of T2DM
  • ↑ risk of several cancers, e.g. prostate
  • ↑ risk of cardiovascular disease
49
Q

what is the presentation of rickets

A

Failure to thrive, hypotonia and apathy.
Once walking: knock-kneed (genu valgum); bow-legged (genu varum); softening of the skull, chest deformity
Hypocalcaemia (severe vitamin D deficiency) — paraesthesia, tetany, cramps, seizures.

50
Q

What is the presentation osteomalacia

A

Bone pain and tenderness, Rib, hip, pelvis, thigh, and foot pain are typical
Pathological fractures (particularly femoral neck).
Proximal myopathy causing proximal weakness and possibly a waddling gait.

51
Q

What blood results can be expected in vit d deficiency

A
  • ↓vit D, ¬-Ca, ↑PTH, ↓PO3, -/↑ALP, ↑Mg,
  • Anaemia
  • eGFR: ?CKD
52
Q

What are the x-ray changes in rickets

A

o Metaphyseal cupping and flaring
o Epiphyseal irregularities
o Widening of the epiphyseal plates

53
Q

what are the x-ray changes in osteomalacia

A

osteopenia, pseudofractures, low density bands

54
Q

What scan can be used to asses bone density in vit D deficiency

A

DEXA

55
Q

what is the general management of vit D deficiency

A

o Treat the cause
o Sun exposure advice
o Dietary advice: oily fish/cod liver oil, egg yolk and milk
o Vit D and calcium tablets: AdcalD2

56
Q

what is the mangement of severe vit D deficiency

A
  • Depends on cause and level of progression

* Good if no specific treatment resistance

57
Q

what is the prognosis of vit D deficiency

A
  • Depends on cause and level of progression

* Good if no specific treatment resistance

phase 2 endo (4 decks)

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