Aim: The aim of the study was to highlight the systemic life-threatening manifestations of anorexia nervosa (AN). Background: AN is a psychiatric disorder commonly seen among young females with significant systemic manifestations and the highest mortality among psychiatric disorders. Description: We present the case of an athletic adolescent girl (after obtaining written consent for publication from her father) presenting to the emergency department in shock with cardiac failure. She also had hypoalbuminemia and multiple electrolyte disturbances like hyponatremia, hypokalemia, hypocalcemia, and hypophosphatemia. She underwent extensive evaluation including coronary angiogram and other appropriate tests to rule out malabsorption syndrome. In the absence of organic causes, and as she gave a history of deliberate food restriction, she underwent a psychiatric evaluation. She was found to be a perfectionist with obsessive personality traits. She started to restrict her diet due to fear of gaining weight as she got bullied by her peers in the new school. There was a significant weight loss of almost 14 kg over a period of 6 months. Additionally, she had depressive symptoms like decreased mood, anhedonia, and lack of energy and initiative, concentration difficulties, and an apparent academic decline. Conclusion: She met the criteria for the diagnosis of AN—restrictive type severe, comorbid with major depressive disorder, and was started on combined psychotherapy and pharmacotherapy with fluoxetine leading to a dramatic clinical improvement. Clinical significance: The case highlights the life-threatening complications of AN and the role of timely psychiatric interventions in managing these patients.