Abstract
Background: Influenza infection subtypes have emerged as a serious, fatal, but curable disease in many parts of the world for over a decade. Though classically it involves the respiratory tract, there also can be extrapulmonary involvement of multiple organ systems in Influenza that can lead to death. Case Report: We report a 79-year-old male diagnosed with an H3N2 lung infection and treated with 5 days course of Oseltamivir. He later developed CNS complications. The possible causes of encephalopathy were ruled out after a thorough evaluation. Appropriate antibiotics and antiviral drugs were started, but the patient’s condition did not improve. Studies suggest various central nervous system complications, including encephalopathy, can occur secondary to Influenza virus infection.
Influenza virus has been detected in CSF PCR, but the sensitivity is very low. The second course of Oseltamivir was started based on clinical judgement, after which the patient’s condition gradually improved. Oseltamivir was continued for 14 days. Conclusion: It is sometimes difficult to detect the causative organism in cases of CNS infection that can delay treatment. In such cases, empirical treatment with antibiotics and acyclovir or with antitubercular drugs is the usual treatment regime applied in most small hospital setups, after which the patient may or may not improve. The clinicians should not miss any history of a prior or recent attack of Influenza respiratory infection. CNS complications secondary to Influenza infections should be considered if found. In such cases, it is imperative to add Oseltamivir to the treatment. The inclusion of an extended course of Oseltamivir can save lives in resource-limited setups.

Key words: H3N2, Influenza, encephalopathy, CNS, Oseltamivir, extended course