Biochemistry Flashcards

1
Q

What are the clinical features of adrenocortical insufficiency?

A
Lethargy 
Anorexia 
Pigmentation of hands and mouth 
Abdominal pain 
Weight loss
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2
Q

How does a lack of mineralocorticoid affect the kidneys?

A

Na+ cannot be retained and is then lost from ECF

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3
Q

What does a reduced ECF volume result in?

A

Hypotension, dehydration, dizziness and lethargy

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4
Q

Excess pigmentation reflects an excess of which hormone?

A

ACTH

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5
Q

Degradation of ACTH releases which hormone?

A

Melanocyte stimulating hormone

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6
Q

Hypovolaemia and hypotension stimulate release of what?

A

Arginine vasopressin

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7
Q

Which test is definitively used to diagnose adrenal insufficiency?

A

Synacthen test

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8
Q

Describe the short synacthen test

A

ACTH analogue given IV at 250micrograms and cortisol should normally increase

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9
Q

What does a long synacthen test determine?

A

If adrenal insufficiency is primary or secondary

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10
Q

What is Addison’s disease?

A

Primary adrenal insufficiency

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11
Q

What is psuedohyponatraemia?

A

When lipoproteins and proteins have a larger volume in the blood than they should
This then gives a lower absolute amount of Na+ but overall conc is fine

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12
Q

What commonly causes secondary psuedohyponatraemia?

A

Administration of corticosteroids

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13
Q

Describe the circulating blood volume in oedema?

A

Reduced

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14
Q

What is relative adrenal insufficiency?

A

Inability to respond adequately to cortisol

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15
Q

Which test allows you to determine between central and nephrogenic diabetes insipidus?

A

Water depravation

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16
Q

Describe the water depravation test in nephrogenic diabetes insipidus?

A

ADH analogue is given but there is not response

17
Q

What does hyperkalaemia look like on an ECG?

A

Tall tented T waves

18
Q

What may result in decreased excretion of potassium?

A

Renal failure

Hypoaldosteronism

19
Q

What is the most common cause of hypoaldosteronism?

A

ACE inhibs

Sprionolactone

20
Q

What may result in the redistribution of potassium out of cells?

A

Metabolic acidosis
Release from damaged cells (rhabdomyolysis)
Insulin deficiency

21
Q

How is hyperkalaemic periodic paralysis inherited?

A

AD

22
Q

What is hyperkalaemic periodic paralysis?

A

Rare condition were paralysis occurs after exercise

23
Q

How is the risk of hyperkalaemia reduced when giving blood products?

A

Using fresh blood

“Washing” units prior to transfusion

24
Q

What is given to treat hyperkalaemia?

A

Calcium carbonate
Insulin
Dextrose

25
Q

Mineralocorticoid activity is to do with…

A

Exchange of potassium and hydrogen

26
Q

What are the 3 main causes of psuedohyperkalaemia?

A

Delay in centrifugation of the sample, or if chilled
In-vitra haemolysis
Increase in plt or WCC

27
Q

What are the symptoms of hypercalcaemia?

A

Moans, bones, groans and stones and arrhythmia

Psychiatric features
Bone pain
GI problems
Renal calculi (and thirst and polyuria)

28
Q

What most commonly causes primary hyperparathyroidism?

A

Parathyroid adenoma (which secretes PTH)

29
Q

How do some tumours cause hypercalcaemia?

A

Parathyroid hormone related peptide (acts like PTH)

30
Q

What is tertiary hyperparathyroidism?

A

When PTH secretion becomes independent to calcium feedback after long standing cause of hyperparathyroidism is removed

31
Q

What is the management of hypercalcaemia?

A

Saline (to restore GFR and promote diuresis)
Bisphosphonates
Desonumab

32
Q

How is familial benign hypercalcaemia investigated?

A

Urine calcium excretion is too low to match the serum calcium

33
Q

Where is ADH released from?

A

Posterior pituitary