J09-J18: Influenza and pneumonia
J11: Influenza, virus not identified
Influenza, often referred to as the flu, is a group of illnesses caused by various strains of influenza viruses that have not been specifically identified. This common infectious condition is mostly transmitted through the air by coughs or sneezes, and can also spread through close contact with an infected person or touching surfaces contaminated with the virus. Common symptoms include fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headaches, fatigue and sometimes vomiting and diarrhea. The disease generally starts suddenly, and while most people recover within a week or two, some may develop serious complications like pneumonia. The influenza virus affects primarily the respiratory system, weakening it and making it more vulnerable to other infections.
Patient Disclaimer
The information provided on this page is for general educational purposes only. It is not intended for self-diagnosis and does not replace professional medical advice. Always consult your doctor or a qualified healthcare provider with any questions or concerns about your health.
If you see an ICD diagnosis code (e.g., on a medical report), be aware that doctors may also include additional indicators to express diagnostic certainty. Only a healthcare professional can interpret these codes accurately in the context of your individual case.
For a complete understanding of your condition and what the diagnosis means for you, please speak directly with your doctor.