H1N1 (Swine Flu) Affected Organ Systems: Comprehensive Overview

The 2009 H1N1 pandemic virus caused multi-system involvement:

Primary Target: Respiratory

• Trachea, bronchi, bronchioles, alveoli
• Viral pneumonia, ARDS, bacterial superinfection

Extra-Pulmonary Manifestations

• Neurological: Encephalopathy, encephalitis, seizures, Reye-like syndrome, Guillain-Barré.
• Cardiovascular: Myocarditis, pericarditis, MI exacerbation, cardiomyopathy.
• Musculoskeletal: Myositis, rhabdomyolysis (elevated CK).
• Gastrointestinal: Nausea, vomiting, diarrhea (more common than seasonal flu).
• Renal: AKI (rhabdo, sepsis, dehydration).
• Hematologic: Leukopenia, thrombocytopenia.
• Cutaneous: Rash, urticaria.
• Ocular: Conjunctivitis.

Severe Complications

• Multi-organ failure
• Septic shock
• Secondary bacterial pneumonia (S. aureus, S. pneumoniae)

High-Risk Groups

• Pregnancy, obesity, asthma/COPD, diabetes, immunocompromise, children <5, elderly.

Annual vaccination remains primary prevention.