{"operator":"Indus Intellect LLC","notice":"Every case is a Draft - not clinically validated, pending Dr. Carlo Raj clinical sign-off. Educational simulation content only; not medical advice. No doses are published. No CME.","access":"teaser","case":{"id":"renal_hyperkalemia_01","title":"Weakness on spironolactone — hyperkalaemia","draft_flag":"Draft - pending Dr. Carlo Raj clinical sign-off","validated":false,"objectives":["Treat the ECG, not only the number","Order the three steps: stabilise, shift, remove, then monitor glucose and potassium for rebound","Identify drugs that raise potassium"],"foundation_concept":"The resting membrane potential is set mainly by the potassium gradient; raising extracellular K depolarises cells and inactivates sodium channels","presentation":{"age_sex":"60s M","chief_complaint":"Generalised weakness for a day","history_clue":"Chronic kidney disease; spironolactone recently added; also takes an ACE inhibitor","exam_localising":"Symmetric proximal weakness; no focal deficit. The danger localises to the cardiac membrane (ECG), not the muscles"},"vitals":{},"history_items":["Reviews medicines: spironolactone, ACE inhibitor, NSAIDs, potassium supplements","Asks about urine output"],"exam_items":[],"orders":["12-lead ECG immediately","Repeat potassium on a non-haemolysed sample","Serial glucose monitoring for at least 6 hours after insulin/glucose","Serial potassium and repeat ECG to check response and rebound after shift therapy"],"results":{"potassium":"Elevated (value pending source); haemolysis excluded","ecg":"Peaked T waves (reviewer may add wide QRS)","creatinine":"Raised from baseline (value pending source)"},"interventions":["IV calcium to stabilise the cardiac membrane","IV insulin with glucose to shift potassium into cells","Escalates for persistent or rebound hyperkalaemia (repeat shift therapy, renal/dialysis referral)","Stops spironolactone and the ACE inhibitor","Removes potassium from the body (binder, diuretic or dialysis by severity)"],"differential":["Hyperkalaemia (working diagnosis)","Pseudohyperkalaemia (haemolysed sample, normal ECG)","Hypocalcaemia (prolonged QT, tetany)"],"critical_actions":["ECG obtained","Membrane stabilised with IV calcium once the ECG is abnormal","Potassium shifted into cells","Causative drugs stopped","Glucose monitored serially after insulin/glucose","Potassium and ECG reassessed after shift therapy (response and rebound)"],"harmful_actions":["Insulin without glucose (hypoglycaemia)"],"mechanism":{"prompt":"Why does calcium help when it does not lower potassium?","steps":["High extracellular K makes the resting potential less negative","Partly depolarised cells inactivate sodium channels and conduction slows","Calcium raises the threshold potential and restores excitability without changing K"],"question":{"text":"IV calcium protects the heart in hyperkalaemia by:","options":[{"id":"OPT1","text":"Stabilising the cardiac membrane (threshold potential)"},{"id":"OPT2","text":"Moving potassium into cells"},{"id":"OPT3","text":"Increasing renal potassium excretion"},{"id":"OPT4","text":"Binding potassium in the gut"}],"answer":"OPT1"}},"disposition":"Admit with cardiac monitoring","notes":[]}}