Appeal type: Medical necessity
Decision: Upheld

Diagnosis: Influenza A
Treatment: Inpatient hospital stay
The insurer denied the inpatient hospital stay.
The health plan's determination is upheld.

The patient is a male with a medical history significant for non-verbal autism and food aversion that was taken to the emergency department (ED) with undocumented fever, poor appetite, and no stool for two days. There was no history of vomiting, cough, runny nose, or irritability. His vital signs included temperature 36.7, heart rate 122, respiratory rate 26, and his peripheral capillary oxygen saturation (SpO2) was 98 percent (%) on room air. The examination was significant for no acute distress, non-toxic appearance, underweight, posterior oropharyngeal erythema, benign abdomen with possible palpable stool in the left lower quadrant, poor skin turgor on the abdomen, and non-focal neurologic examination.

The laboratory studies (labs) were significant for hypernatremia with a sodium of 156, metabolic acidosis with a carbon dioxide (CO2) of 12, hyperkalemia with a potassium of 6.2, blood urea nitrogen (BUN) 64.0, creatinine 1.09, glucose 67, and his white blood cell (WBC) count was 2.25. The rapid viral testing was positive for influenza A. An abdominal x-ray was obtained revealing constipation without evidence of bowel obstruction. He was initially treated with Normal Saline but was transitioned to Lactated Ringers because of hypernatremia. He was subsequently admitted for ongoing management of hypernatremic dehydration and he was determined to be 10% dehydrated. The admission orders included calculated fluid repletion, serial labs, Tamiflu, and MiraLAX. The repeat labs indicated persistent hypernatremia with sodium 158, metabolic acidosis with CO2 13, BUN 56.0, and his creatinine was 0.83. Serial labs demonstrated slow improvement in metabolic acidosis, hypernatremia, and prerenal azotemia. He was deemed stable for discharge with a sodium of 151, CO2 19, BUN 22.0 and to complete a course of Tamiflu.
 
Influenza viral infection is a common viral respiratory illness caused by strains of influenza A or B with a broad clinical presentation for which immunization is recommended annually. Onset is typically acute, and associated with systemic symptoms such as fever, malaise, headache, myalgia, and decreased appetite. Sore throat and cough may be present from the beginning or may develop over the course of the illness. Gastrointestinal complaints may also be present, including nausea, vomiting, diarrhea, and abdominal pain. The most common complications include otitis media and pneumonia. Pneumonia may be viral or the result of secondary bacterial infection with Staphylococcus aureus. Less common complications include myocarditis, encephalitis, myelitis, and Guillain Barre syndrome. Reye syndrome may occur with concomitant administration of Aspirin-containing compounds. Prematurity is a risk factor for influenza-related complications, along with neurological disorders, sickle cell disease, immunosuppression, diabetes, and age under two years. Antiviral agents are available, and if administered early in the course of illness (within 48 hours), decreased duration of symptoms and likelihood of complications. Additional treatment is supportive or related to concomitant complications or bacterial infection. Annual administration of influenza vaccine for prevention is encouraged.

This patient with autism and feeding issues presented with fever and dehydration secondary to influenza A infection. Laboratory data supported a diagnosis of hypernatremic dehydration (serum sodium greater than 155). He was treated with intravenous (IV) fluids to slowly correct the dehydration and the hypernatremia. He had no issues of vomiting and was able to tolerate his diet. While it was medically necessary to monitor the patient in the hospital while correcting laboratory abnormalities, he was overall hemodynamically stable with no new neurologic deficits.