INTRODUCTION: On April 2010, novel influenza A (H1N1) virus (S-OIV) was identified in Mexico, the USA and elsewhere. Pulmonary changes commonly associated with this infection are consolidation, diffuse edema and hemorrhage. We present the case of a young H1N1 infected adult that developed uncommon pulmonary changes and represented a clinical challenge due to persistent air leak.
CASE PRESENTATION: Our patient is a 32 year old man, who was diagnosed with Influenza H1N1 virus infection and Staphylococcus aureus secondary bacterial pneumonia. He developed acute type I respiratory failure and was admitted to the ICU for mechanical ventilation and amine support. His treatment included oseltamivir, meropenem, vancomycin, amikacin and moxifloxacin.8 days after admission, chest X-rays showed a right-sided 20% pneumothorax for which a 28 Fr. chest tube was placed. Control chest X-rays proven pulmonary re-expansion. On the 13th day, X-rays showed right-sided pneumothorax recurrence and subcutaneous emphysema. Chest CT scan was performed on day 14th, which demonstrated persistence of the pneumothorax and a large right- sided cystic lesion. Pleural drainage showed persistent air leak. Due to clinical improvement, the patient was discharged on day 18 with a portable pleural drainage system and a scheduled re-hospitalization for definite management of the air leak.2 months after initial admission, the patient developed sudden right-sided chest pain and resting dyspnea. Chest CT scan showed a right-sided pneumothorax, along with persistence of the cystic lesion, bilateral lung parenchymal injury and fibrosis. A second 28 Fr. chest tube was placed and the patient's conditions markedly improved. Definite treatment was performed by means of a thoracoscopic resection of the cystic lesion and lysis of pleural adherences. Chest tubes were removed 5 days after surgery. Two days after, the patient was asymptomatic, X-rays showed pulmonary expansion and he was discharged.He was then treated as outpatient with inhaled bronchodilators and anti-inflammatory therapy, plus supplementary oxygen. He is currently a NYHA functional class I and is no longer on supplemental oxygen.
DISCUSSIONS: The clinical spectrum of the Influenza A H1N1 (S-OIV) infection is still being defined. Current available information is mainly based on large observational studies. Pathological changes associated with S-OIV infection are more often localized to the lungs; being the most common: lung consolidation, diffuse edema and variable degrees of hemorrhage.Secondary complications, such as primary viral pneumonia and secondary bacterial pneumonia may be responsible for severe illness in many patients. Staphylococcus aureus has been identified in Mexico as the most common cause of secondary bacterial pneumonia in ICU patients with H1N1 infection.The most common chest CT abnormalities in H1N1 affected patients are local patchy shadowing, bilateral or unilateral infiltrates and ground-glass opacities. The authors did not find any references of cystic lesions after H1N1 infection. As in the case presented, a pneumatocele is a cystic airspace within the lung that characteristically increases in size over a period of days to weeks. It is associated with infection, particularly staphylococcal pneumonia. This patient presented this uncommon complication, probably due to the secondary S. aureus pneumonia. Immediately after surgery, air leak ceased and the patient conditions progressively improved.
CONCLUSION: H1N1 spectrum is still being defined. It is important to be aware of uncommon complications like the one presented in this case, since they may require special therapeutic decisions that could markedly improve the patient’s outcome.
DISCLOSURE: Luis Martin-Del-Campo, No Financial Disclosure Information; No Product/Research Disclosure Information