Battling Influenza in Elderly Patients: A Case of Severe Influenza A With Complications in a High-Risk Patient

Influenza is a significant cause of morbidity and mortality in the elderly, particularly in those with chronic comorbidities and age-related immunosenescence. This case report details an 80-year-old male with a history of hyperlipidemia, diabetes mellitus, and dementia who developed a severe influenza A infection complicated by sepsis and hypoxic respiratory failure. Upon admission, the patient presented with fever, cough, and weakness, and was initially treated for viral pneumonia. Despite negative blood and urine cultures, influenza A was confirmed via reverse transcription polymerase chain reaction (RT-PCR). The patient developed hypotension, was unresponsive to fluid resuscitation, and was transferred to the ICU for pressor support with norepinephrine and albumin. During his intensive care unit (ICU) stay, septic shock was managed with norepinephrine, with a target mean arterial pressure (MAP) of >65 mmHg. The patient also received respiratory support, initially on a 10L high-flow nasal cannula, and was later downgraded to a 4L nasal cannula. A sacral pressure ulcer and MRSA colonization further complicated his hospital course. Antibiotic therapy included ceftriaxone, azithromycin, and vancomycin, and the patient's condition gradually improved, allowing for transfer to the intermediate care unit (IMCU) after seven days. This case underscores the importance of early antiviral therapy, the need for vigilant monitoring for secondary infections, and timely intervention to manage complications such as sepsis in elderly patients. Enhanced vaccination coverage and preventive measures are critical for reducing the incidence of severe influenza and associated complications in at-risk populations.