A 30 year old female presents to ED with a 1 week history of vomiting. According to the patient she has no diagnosed medical problems, but has been unwell for the last 6 months intermittently with fatigue, anorexia and weight loss.
- List 6 acid base abnormalities and show the necessary calculations
Metabolic acidosis pH 7.201 HCO3 16mmol/l
Compensation – expected pCO2 = 1.5 x HCO3+8 = 32mmHg – uncompensated/underlying respiratory acidosis
AG = NA – (Cl+HCO3) = 8 NAGMA (likely underlying HAGMA due to lactic acidosis)
Corrected K – for every 0.1 decrease in pH, there is a 0.5 increase in K -6.1
Severely low sodium, severely uncorrected high potassium, raised lactate and creatinine and Hb, mildly decreased BSL
- List 2 possible diagnosis in the case and reasoning for them (4 Marks)
- Addisons disease – history of fatigue and weight loss (underlying autoimmune or infiltrative disorder), NAGMA with hyperkalaemia, hyponatraemia and hypoglycaemia
- RTA – type IV – NAGMA hyperkalaemia, with mild renal dysfunction
-
GI HCO3 losses – vomiting, more likely if associated diarrhoea, sodium markedly low related to volume loss from vomiting
- Complete the following table comparing the difference presentation between primary and secondary adrenal insufficiency (12 Marks)
| Primary Adrenal Insufficiency | Secondary Adrenal Insufficiency | |
| Aldosterone Deficiency | present | absent |
| Volume status | Marked hypovolaemia and low BP | Not as severe unless crisis present |
| Serum potassium | Hyperkalaemia | Hypokalaemia |
| Serum Sodium | Hyponatraemia (d/t salt wasting) | Hypernatremia (aldosterone functioning) or hyponatraemia (d/t water retention) |
| Cushingoid | Absent | Present if long standing |
| Symptoms of other pituitary hormone deficiencies | absent | May be present depending site of hypothalamic – pituitary lesion |
- Discuss the immediate management of this patient (4 Marks)
- Fluid resuscitation – 20ml/kg in boluses to assess response – aim for MAP > 60, u/o 0.5ml/kg and normal mentation. Further maitainence fluid given over 48 hours to gradually increase Na level by around 10mmol/l per 24 hours
- Vasopressors if patient not fluid responsive after steroids given
- Hydrocortisone 200mg bolus/ dexamethasone 10mg (does not interfere in subsequent cortisol assays – if dx is not yet confirmed
- Hyperkalaemia may correct with fluids and steroid treatment, but if patient symptomatic or ECG needs urgent correction
- Treat hypoglycaemia 50ml 50% dextrose