Auburn Research Day 2022

William Kenan, OMS III (1); Abby Kabo, OMS III (2); Hanna Sahhar, MD, FAAP, FACOP (1) Edward Via College of Osteopathic Medicine- Auburn Campus; (2) Edward Via College of Osteopathic Medicine- Carolinas Campus; Spartanburg Regional Medical Center Spartanburg, SC Cl i n i ca l Case Repor t | Med i ca l St udent Human Metapneumovirus Induced Syndrome of Inappropriate Antidiuretic Hormone Secretion in an Infant 62

Context: This case is the first documented case of syndrome of inappropriate antidiuretic hormone (SIADH) secretion caused by Human metapneumovirus (hMPV) leading to seizure activity in an infant. Report of Case: A 7-week-old female presented to the emergency department (ED) with fever and nasal congestion for 5 days. Her symptoms progressed to upper respiratory involvement including cough and difficulty breathing. Shortly after, she had decreased oral intake, vomiting, and possible seizure activity which was recorded and described as rhythmic eye twitching, up rolling eyeballs, and face grimacing that lasted greater than 15 seconds which prompted hospital admission. On admission, vitals showed temperature of 101.2 degrees Fahrenheit, heart rate of 150 beats/ minute, blood pressure of 101/67 mmHg, and oxygen saturation of 90% on room air. Physical examination revealed a well hydrated infant with mild respiratory distress. Laboratory investigations utilizing a Filmarray respiratory panel showed positive results for hMPV and rhinovirus/enterovirus which was repeated in few days and only showed positivity for hMPV. Management was conservative with intravenous fluids consisting of dextrose 5%, 0.45% sodium chloride with KCl 20 mEq/L) given as full maintenance since admission. Four days later, due to persistent poor oral intake, a complete metabolic panel was ordered and showed serum sodium of 108 mmol/L (normal 131-143), Glucose of 102 mg/dL (normal 60-100), blood urea nitrogen of 4 mmol/L (normal 5-27), calculated serum osmolality 217 mOsm/ kg (normal 270-350), chloride 82 mmol/L (normal 99-116), pH of 7.41 (normal 7.25-7.45), bicarbonate of 23.5 mmol/L (normal 23-28, and anion gap of 4 mg/dL (normal 6-12). The severe hyponatremia was corrected slowly over 48 hours first utilizing hypertonic saline (3% Sodium chloride) and then normal saline for an additional two days. The electrolyte derangement was corrected, and the patient’s condition improved back to baseline. The severe hyponatremia in the light of euvolemic state, lack of excessive sodium waste, and continuous supplement of sodium in the intravenous fluids, the cause of it was attributed to SIADH secretion, a condition never before observed in patients with hMPV infection.

Comments: HMPV is a negative-sense RNA virus. The FilmArray Respiratory Panel is a rapid PCR diagnostic tool testing 20 different respiratory pathogens which was used to diagnose the patient with hMPV. SIADH secretion is a cause of euvolemic hyponatremia. This complication has been seen in a similar virus called Respiratory Syncytial Virus (RSV). RSV has been linked to cases of seizures induced by SIADH secretion. With this case, we now see that SIADH induced seizures can also be associated with hMPV. Diagnosis: Based on the amount of fluids given and the fact that the patient had a decreased anion gap, decreased BUN/creatinine ratio, and bicarbonate close to normal range makes hyponatremia caused by dehydration highly unlikely. This led us to the conclusion that the hyponatremia was caused by SIADH secretion in the patient.

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