A 35 year old with likely post op knee infection presents withThe blood tests show:
hypochloraemic
hypokalaemic
metabolic alkalosis
appropriate respiratory compensation
classically seen in severe vomiting (and gastric outlet obstruction) with fluid depletion (dehydration). Young man unlikely to have endocrine cause.
Anion gap = low normal – no additional metabolic component
He requires Potassium replacement, fluid, symptom management and referral for his knee infection