Viral respiratory infections (VRI’s) are generally thought of as benign, self-limited syndromes. However, VRI’s can have severe complications, even in immunocompetent hosts. This report describes the case of an 18 year old male who suffered prolonged critical illness after parainfluenza infection.
An 18 year-old man was transfered to the intensive care unit (ICU) for respiratory failure. He had no past medical history, and had felt well until ten days before admission. He initially reported nonspecific symptoms of dry cough, fever, and malaise. On the day of admission he reported worsening dyspnea, and was brought to the emergency department. There, he was found to have severe hypoxemia and respiratory failure, as well as fevers and hypotension. He was intubated and received mechanical ventilation and fluid resuscitation. Direct fluorescent antigen testing was positive for parainfluenza virus, and sputum cultures grew methcillin-resistant staphylococcus aureus (MRSA). Over the next two days, the patient developed bilateral pneumothoraces, and chest tubes were placed. The right chest-tube had a persistent air leak. After twenty-one days the patient was liberated from mechanical ventilation. He was alert and talking with his family. Two days later he suddenly developed hypoxemia, and was found rigid with frothy secretions in his mouth. He was emergently intubated. Computerized tomography (CT) of the brain showed multiple non-specific areas of low attenuation confined to the bilateral white matter. Magnetic resonance imaging (MRI) of the brain demonstrated multifocal T2/FLAIR signal abnormalities involving the white matter, along with associated petechial hemorrhages, and no evidence of ischemia or contrast enhancement. Samples of cerebrospinal fluid (CSF) showed normal cell counts, protein, and glucose levels; stains for organisms were negative, as were cultures and other microbiologic tests for viruses. These findings supported a diagnosis of acute disseminated enchephalomyelitis (ADEM). The patient was treated with anticonvulsants and high-dose corticosteroids, and was extubated after two days. His mental status improved, and although he was weak from prolonged critical illness, he was communicative and interacting normally with his family.
While VRI’s are often self-limited, this case reports a young man who developed prolonged critical illness after parainfleunza infection. This case provides an unfortunate reminder that viral respiratory infections can have uncommon but potentially devastating consequences, including bacterial pneumonia (leading to ARDS, sepsis, and bronchopleural fistula), and seizures resulting from a diffuse demyelinating lesion of the central nervous system (CNS). The relationship between respiratory viruses and co-infecting bacterial pathogens is unclear, but likely involves pathogen- and host-related variables. ADEM probably results from an auto-immune process, although direct involvement on the CNS by the virus may be possible.
Critical care physicians and pulmonologists should be alert to the potential complications of VRI’s, including bacterial pneumonia and acute disseminated encephalomyelitis. Furthermore, important variables related to viral pathogenicity and the host response to VRI remain to be elucidated.
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