Case in the Spotlight 15 - answers
The case: An older man with rheumatoid arthritis on presents with acute confusion.
He has not been seen for two days, a family member checked on him today after he did not answer the phone.
Past medical history. Rheumatoid arthritis. Hypertension. GORD.
Medications. Prednisolone 20mg daily. Methotrexate weekly. Pantoprazole 40mg nocte. Prazosin nocte.
Physical signs HR 120 RR 30 BP 110/70
Blood gas is performed on room air
Ph 7.16 mmHg
pCO2 28 mmHg
pO2 100 mmHg
Describe the acid base disturbance and put it into the clinical context – outline the key management priorities.
• The acid base disturbance is metabolic acidosis, essentially acidosis plus low HCO3
• ** The anion gap is 120+7 – (100+14) = 14 so not elevated
• You expect the CO2 to be 8 + (1.4 x 14) = 29 so appropriate respiratory compensation
• There is a low sodium and high potassium + low BP, so acute adrenal crisis due so sudden cessation of steroids should be considered
What is the likely diagnosis
Differential diagnoses for NAGMA
• Renal Failure
Other management issues –
on floor for 2 days, check CK and temperature
Look for causes of this, eg sepsis and stroke, and for consequences of a fall, such as fractured ribs, hip, pelvis, don’t forget the cervical spine.