T1 L4 & 5 Calcium homeostasis

Question 1

What can cause too much hormone to be produced?

Answer 1

Single nodule
Multiple nodules
Generalised increase in tissue (hyperplasia)

Question 2

What are the layers of the adrenal glands?

Answer 2

Zona glomerulosa
Zona fasciculata
Zona reticularis
Medulla

Question 3

What is primary hyperaldosteronism?

Answer 3

Conn’s syndrome
Excess production of hormone aldosterone from the adrenal glands which leads to low renin levels
Occurs in zona glomerulosa

Question 4

What are the adrenal causes of hypertension?

Answer 4

Primary hyperaldosteronism

Phaeochromocytoma

Question 5

What are the causes of too much aldosterone in the zona glomerulosa?

Answer 5

Adenoma
Hyperplasia
Rare genetic causes

Question 6

What hypertensive patients should be screened?

Answer 6

Hypokalaemia
Resistant hypertension
Younger people

Question 7

What tests can be used to diagnose primary hyperaldosteronism?

Answer 7

Initial screening tests: suppressed renin, normal / high aldosterone
Confirmatory tests: oral or Iv sodium suppression test

Question 8

What tests can be done to find the cause of primary hyperaldosteronism?

Answer 8

Adrenal CT scan
Adrenal venous sampling
Metomidate PET CT

Question 9

What treatment is given for unilateral adenoma?

Answer 9

Laparoscopic adrenalectomy

Medical treatment

Question 10

What treatment is given for bilateral hyperplasia?

Answer 10

Medical treatment (aldosterone antagonists)
Spironolactone
Eplerinone

Question 11

What does phaeochromocytoma cause?

Answer 11

Increased adrenaline and noradrenaline leading to raised BP

Question 12

What catecholamines does the adrenal medulla produce?

Answer 12

Dopamine
Norepinephrine
Epinephrine

Question 13

How does phaeochromocytoma present?

Answer 13

Spells of headache, sweating, pallor, palpitation, anxiety

Hypertension (permanent or intermittent)

Question 14

What genetic conditions are associated with phaeochromocytoma?

Answer 14

Neurofibromatosis type 1 (NF1)
Multiple endocrine neoplasia type 2 (MEN 2)
Von Hippel-Lindau syndrome

Question 15

What is the biochemical diagnosis for phaeochromocytoma?

Answer 15

24 hour urine: normetanephrines and metanephrines will be high. 3 methoxytyromine

Plasma: noradrenalin, adrenalin and metanephrines

Question 16

Why can’t you measure urine dopamine when diagnosing phaeochromocytoma?

Answer 16

This comes from the kidney and the nervous system and not from the adrenal medulla

Question 17

What are some other causes of raised catecholamines?

Answer 17

Obstructive sleep apnoea
Amphetamine like drugs
L-DOPA
Labetalol

Question 18

What is the management of phaemochromocytoma?

Answer 18

Alpha blockers
Beta blockers
Laparoscopic adrenalectomy

Question 19

What are the effects of noradrenaline?

Answer 19

Vasoconstriction leading to increased BP and pallor

Glycogenolysis

Question 20

What are the effects of adrenaline?

Answer 20

Vasoconstriction
Vasodilation in muscle
Increased heart rate
Sweating

Question 21

Why does hypocalcaemia destabilise neurons?

Answer 21

1) Decrease in extracellular calcium concentration
2) Increased membrane permeability to sodium
3) Sodium depolarises membrane
4) Action potential

Question 22

What are the physical signs of hypocalcaemia?

Answer 22

Carpopedal spasm

Chvostek’s sign

Question 23

What is carpopedal spasm?

Answer 23

Occlude brachial artery using BP cuff causes a carpal spasm

Question 24

What is Chvostek’s sign?

Answer 24

Abnormal reaction to stimulation of facial nerve

Tap facial nerve at angle of jaw causes facial muscles on same side to contract

Question 25

What are the acute consequences of hypercalcaemia

Answer 25

Thirst and polyuria | Abdominal pain

Question 26

What are the chronic consequences of hypercalcaemia?

Answer 26

``` Constipation Musculoskeletal aches / weakness Neurobehavioural symptoms Renal calculi Osteoporosis ```

Question 27

How much calcium is protein bound?

Answer 27

40% Albumin bound - 90% Globulin bound - 10%

Question 28

How much calcium is bound to cations?

Answer 28

10%

Question 29

How much calcium is ionised?

Answer 29

50%

Question 30

What can make the corrected calcium inaccurate?

Answer 30

Albumin concentration below 20g/l | Severe acute illness

Question 31

What are the normal levels of calcium in the blood?

Answer 31

2.15-2.55mmoles/l

Question 32

What does activation of calcium-sensing receptor cause?

Answer 32

Activation of phospholipase C leading to DAG & IP3 Inhibition of adenylate cyclase which suppresses intracellular concentration of cAMP Can activate mitogen-activated protein kinase pathway

Question 33

What is primary hyperparathyroidism?

Answer 33

Body has too much parathyroid hormone

Question 34

What are the symptoms of primary hyperparathyroidism

Answer 34

``` Fatigue Fractures Decreased height Upper abdominal pain Loss of appetite Nausea Muscle pain Depression Kidney stones ```

Question 35

What test results diagnose primary hyperparathyroidism?

Answer 35

Raised serum calcium Lowered serum phosphate Raised PTH Bone X-ray may show bone reabsorption or fractures Imaging of kidneys or ureters may show calcification or blockage

Question 36

What is the treatment for primary hyperparathyroidism?

Answer 36

Drinking more fluids to prevent kidney stones Avoiding immobilisation Avoiding thiazide-like diuretics

Question 37

What are the complications of primary hyperparathyroidism?

Answer 37

Osteoporosis | Bone cysts if severe

Question 38

What are the causes of hypoparathyroidism?

Answer 38

Iatrogenic - thyroidectomy, radical neck surgery Autoimmune Hypomagnesaemia Genetic mutations

Question 39

What are some common causes of secondary hyperparathyroidism?

Answer 39

Low / low normal serum calcium and hight PTH Low serum 25 OH vitamin D (lack of sun exposure, GI problems) Renal failure