MON-260 Simple Febrile Seizure vs Hypocalcemic Seizure: Complicated Case of an 11-Month-Old

Background Hypocalcemia in young children can be an incidental finding, however, it may also present as spasms or seizures. Simple febrile seizures (SFS) are common benign convulsive events in children younger than 5 years. We present a case of an infant who presented with fever, seizures, and unresponsiveness and was found to have low calcium and Vitamin D levels. Case This 11-month-old African American female, born full term, was found unresponsive by parents at home after 2 days of URI symptoms and fever. She had upward eye rolling and stiffening of upper extremities and parents started CPR. On EMS arrival, the patient was responsive but weak. In the ER, she was febrile (103F), tachycardic, and alert. Physical examination was unremarkable except for nasal congestion. No frontal bossing, widening of wrist joint or long bone deformities were noted. On dietary history, patient was exclusively breastfed until 6 months of age. Upon presentation, she was on stage 1 food and expressed breast milk, but no other dairy products or vitamin supplements. Laboratory workup showed a normal CBC, serum calcium 4.8 mg/dl (9-11 mg/dl), ionized calcium 2.9 mg/dl (4.9-5.5mg/dl), phosphorus 3.6 mg/dl (4-6.5 mg/dl), 25 hydroxy-vitamin D <3.4 ng/ml (20-100 ng/ml), Vitamin D 1,25 (OH)(2) 25.8 pg/ml (16 - 65 pg/ml), alkaline phosphatase 625U/l (150-420 U/l) and PTH 281 pg/ml (15-65 pg/ml). Distal fraying at radial and ulnar physis were seen on X-ray. EKG showed prolonged QT interval of 466ms (370 - 440ms). After receiving an IV calcium bolus in the ER, she was admitted to the PICU for cardiac monitoring and IV calcium infusions. High dose oral Vitamin D (5000 IU daily) was given. She had no further seizure episodes. She was discharged home on oral calcium and Vitamin D after her calcium levels and QT interval had normalized. All her laboratory parameters improved on outpatient follow up. Conclusion Nutritional rickets in infants can be missed due to its non-specific clinical manifestations and recommendations that do not include chemistry panels on routine health visits. Our patient was initially assessed as SFS with her classic clinical presentation. Even though the AAP suggests no benefit of routine blood studies in SFS(1), in our patient, it was vital in identifying and treating the underlying hypocalcemia, which could have contributed to the seizure. With this case we want to highlight the morbidity associated with undiagnosed infantile rickets. Nutritional rickets needs to be considered in young children presenting with seizures, especially in those who are exclusively breastfed and are coming from high-risk populations. 1. Febrile Seizures: Guideline for the Neurodiagnostic Evaluation of the Child With a Simple Febrile Seizure. Pediatrics Feb 2011, 127 (2) 389-394