A Case of Multifactorial Severe Hypophosphatemia

Introduction: Hypophosphatemia is defined as serum phosphate < 2.5 mg/dL. It is induced by internal redistribution, decreased intestinal absorption, or urinary wasting. We present a case of multifactorial severe hypophosphatemia in the setting of chronic alcoholism and presumed refeeding syndrome. Case Description: A 69 year old male with a history of alcohol use disorder presented to the ED with generalized muscle weakness, recurrent falls and confusion. He reported consuming 2 bottles of wine daily for several years, with his last drink 24 hours prior to presentation. He reported a history of caloric restriction with intentional weight loss followed by a recent increase in caloric intake in the preceding week. His initial presentation was consistent with sepsis from contained sigmoid perforation due to foreign body ingestion, likely a chicken bone. Labs revealed phosphorus < 1, potassium 2.0, magnesium 1.4, lactate 8.5, WBC 6.1 with 34% band neutrophils, mild alkalosis (venous pH 7.43), pCO2 42, HCO3 24. He was admitted to the ICU and received volume resuscitation, IV antibiotics, management of alcohol withdrawal, intravenous phosphate, potassium and magnesium. Repeat labs showed improved phosphorus to 1.9, however serum corrected calcium decreased from 9.5 to 7.5 mg/dL. He continued to receive further repletion of electrolytes with eventual normalization. Discussion: The etiology of this patient’s severe hypophosphatemia was multifactorial from chronic alcoholism and refeeding syndrome. Refeeding syndrome was likely present in this case given the patient’s malnutrition and weight loss with recent significantly increased caloric intake resulting in severe hypophosphatemia, hypokalemia and hypomagnesemia. His generalized muscle weakness can be explained by alcoholism and severe electrolyte derangements. Fortunately, he did not develop respiratory failure which is a complication of severe hypophosphatemia as a result of decreased intracellular ATP. For patients with severe hypophosphatemia (< 1 mg/dL), IV phosphate repletion is recommended with level monitoring every six hours. This patient developed hypocalcemia in the setting of phosphate repletion, which is a known complication and should be monitored closely.