Biochemistry Flashcards
What are the clinical features of adrenocortical insufficiency?
Lethargy Anorexia Pigmentation of hands and mouth Abdominal pain Weight loss
How does a lack of mineralocorticoid affect the kidneys?
Na+ cannot be retained and is then lost from ECF
What does a reduced ECF volume result in?
Hypotension, dehydration, dizziness and lethargy
Excess pigmentation reflects an excess of which hormone?
ACTH
Degradation of ACTH releases which hormone?
Melanocyte stimulating hormone
Hypovolaemia and hypotension stimulate release of what?
Arginine vasopressin
Which test is definitively used to diagnose adrenal insufficiency?
Synacthen test
Describe the short synacthen test
ACTH analogue given IV at 250micrograms and cortisol should normally increase
What does a long synacthen test determine?
If adrenal insufficiency is primary or secondary
What is Addison’s disease?
Primary adrenal insufficiency
What is psuedohyponatraemia?
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
What commonly causes secondary psuedohyponatraemia?
Administration of corticosteroids
Describe the circulating blood volume in oedema?
Reduced
What is relative adrenal insufficiency?
Inability to respond adequately to cortisol
Which test allows you to determine between central and nephrogenic diabetes insipidus?
Water depravation
Describe the water depravation test in nephrogenic diabetes insipidus?
ADH analogue is given but there is not response
What does hyperkalaemia look like on an ECG?
Tall tented T waves
What may result in decreased excretion of potassium?
Renal failure
Hypoaldosteronism
What is the most common cause of hypoaldosteronism?
ACE inhibs
Sprionolactone
What may result in the redistribution of potassium out of cells?
Metabolic acidosis
Release from damaged cells (rhabdomyolysis)
Insulin deficiency
How is hyperkalaemic periodic paralysis inherited?
AD
What is hyperkalaemic periodic paralysis?
Rare condition were paralysis occurs after exercise
How is the risk of hyperkalaemia reduced when giving blood products?
Using fresh blood
“Washing” units prior to transfusion
What is given to treat hyperkalaemia?
Calcium carbonate
Insulin
Dextrose
