Begin AKI with bladder scan and urinalysis before broad testing. Severe renal failure with anaemia, thrombocytopenia, schistocytes, hypertension, and proteinuria should trigger urgent concern for thrombotic microangiopathy, while dialysis decisions still follow AEIOU indications rather than the creatinine alone.

A sepsis-like collapse with cytopenias, liver failure and diarrhoea becomes much more useful when ferritin, triglycerides and fibrinogen move up the list. Open this for a sharp reminder that HLH is not the end of the diagnosis, and that chronic thrombocytopenia with hepatosplenomegaly deserves a storage-disorder work-up.

A missed dialysis session and a high potassium result can look calmer than they are. Open this for the treatment sequence: monitor early, give calcium promptly, run shift-and-elimination measures in parallel, and do not let a normal ECG or well appearance slow dialysis planning.