Severe hypernatremia in a dog following activated charcoal treatment for chocolate ingestion

A 7-year-old spayed female Corgi dog was presented for care 1.5 h after ingestion of chocolate brownies (theobromine dosage: 88.3 mg/kg, BW). Physical examination revealed mild tachycardia and hyperthermia. Vomiting was induced, and the dog was treated with maropitant and activated charcoal with sorbitol (1.9 g/kg, BW, PO) prior to ER transfer. Tremors and seizures were noted 4.5 h following ingestion. Despite rehydration, treatment with activated charcoal containing no sorbitol (0.9 g/kg, BW, PO) resulted in the dog's serum sodium concentration quickly elevating [Na: 174 mmol/L; reference range (RR): 144 to 160 mmol/L]. The dog developed neurologic signs and azotemia. Treatment included customized fluid therapy, anticonvulsant medications, positive pressure ventilation, and administration of emergency drugs related to a near-arrest event. With continued care, the dog was discharged 57 h following admission. One month following discharge, the dog had mild vestibular signs remaining that resolved 10 mo after discharge. To the authors' knowledge, this is the first reported case that documents a dog developing severe hypernatremia following activated charcoal therapy related to chocolate toxicosis. The case details may be helpful to clinicians treating similar complex toxicity, those interested in potential neurologic recovery following severe hypernatremia, and those who are seeking insights into risk factors for developing hypernatremia with activated charcoal therapy. Key clinical message: A case of chocolate toxicity and severe hypernatremia following activated charcoal therapy highlights that patients which have ingested an osmotically active toxin, such as chocolate, especially those at risk of dehydration, may be at increased risk for hypernatremia following activated charcoal therapy. If activated charcoal is used in such complex cases, frequent monitoring of patient's electrolytes and neurologic status is recommended to minimize the risk of development of life-threatening hypernatremia.