A client is admitted with anorexia nervosa. Which finding is the highest priority for the nurse to monitor?

ANOREXIA NERVOSA — PHYSIOLOGICAL PRIORITY: While the psychological aspects (body image distortion, control issues) are central to the disorder, the IMMEDIATE LIFE THREAT is physiological. CARDIAC AND ELECTROLYTE COMPLICATIONS are the leading cause of death: Hypokalemia (low potassium) → fatal cardiac dysrhythmias; bradycardia and hypotension; cardiac muscle wasting; prolonged QT interval; REFEEDING SYNDROME: A dangerous complication when nutrition is reintroduced too quickly — rapid shifts in phosphate, potassium, and magnesium can cause cardiac failure; refeeding must be SLOW and monitored; MONITORING PRIORITIES: Cardiac rhythm, electrolytes (K+, phosphate, magnesium), vital signs, weight; OTHER COMPLICATIONS: Amenorrhea, osteoporosis, lanugo, electrolyte imbalances from purging; TREATMENT: Multidisciplinary — medical stabilization first, then nutritional rehabilitation, then psychotherapy (CBT, family therapy); ABCs/physiological needs take priority (Maslow) — address life-threatening cardiac/electrolyte issues before psychological interventions; nursing role: monitor cardiac/electrolyte status, implement refeeding protocol safely, address psychological needs.