Endocrinology OSCE

Question 1

Addisonian Crisis

Answer 1

Low BP, high HR, decreased GCSLow Na, High K, metabolic acidosis, AKILow serum osmolalityCauses:Primary - autoimmune, haemorrhage, malignancy, TB, exogenous steroid useSecondary - Pituitary failureMx - ABCDE, IV fluids, IV hydrocortisone, plan SST

Question 2

DKA

Answer 2

Joint British Diabetes Society Guidelines
Dx - Ket > 3, Gluc > 11, Bic < 15 or pH <7.3
- Fluids - Saline with added K
- 1/2/2/4/4/6 hrly bags
- Insulin
- VRII
- Electrolytes
- Targets - ketones < 0.5/hr, glucose < 3/hr, Bic > 3/hr, K 4-5.5
-Severe DKA - Ket > 6, Bic < 5, pH < 7, low K, GCS < 12, BP < 90, AG > 16
Complications - High or low K, Low glucose, cerebral oedema, pulm oedema
Caution in - young, elderly, pregnant, CCF/CKD
Resolution - pH > 7.3, Bic >15, Ket < 0.6

Question 3

Sodium

Answer 3

Major extracellular cation - gradient maintained by Na/K ATPase pump
Total body sodium under hormone control via renal excretion - ADH, renin-angio-aldo system and BNP/ANP
Normal plasma osmol = 285-295

Hypovol low Na - water and Na both low but disproportionate
-Urinary Na < 20 - extra renal loss (diarrhoea, vomiting, burns)
-Urinary Na > 20 - diuretics, cerebral salt wasting (Na > 40)

Euvol low Na
-Urinary Na < 20 - low Na intake, psychogenic polydipsia
-Urinary Na > 20 - SIADH, Hypothyroidism, adrenal insufficiency

Hypervol low Na
-Urinary Na < 20 - CCF, nephrotic syndrome, cirrhosis
-Urinary Na > 20 - renal failure

Mx:If symptomatic (seizure, confusion, coma) - give 3% NS to reverse cerebral oedema Aim to rise by 8-10mmol in 24hrs

Question 4

SIADH

Answer 4

Causes:
1 - Drugs - diabetic meds, antipsychotics
2 - Malignancy - lung, brain, pancreas
3 - CNS - infection, trauma, stroke, haemorrhage
4 - Resp - pneumonia, resp failure
Mx:fluid restrictDemeclocycline/Tolvaptan

Question 5

CSWS

Answer 5

Renal sodium loss due to brain injury - unknown mechanism but likely to involve ANP and BNP.
Low serum Na
High serum osmol (dehydrated)
Urine osmol normal or high
Urine Na > 40