Abstract
Purpose
Our aim was to evaluate the evolution of 20 patients with H1N1 pneumonia, focusing our attention on patients with severe clinical and radiological findings who developed post-acute respiratory distress syndrome (post-ARDS) pulmonary fibrosis.
Materials and methods
Twenty adult patients (nine women and 11 men; mean age 43.5±16.4 years) with a diagnosis of H1N1 infection confirmed by pharyngeal swab came to our attention from September to November 2009 and were followed up until September 2010. All patients were hospitalised in consideration of the severity of clinical findings, and all underwent chest X-ray. Twelve of them underwent at least one computed tomography (CT) scan of the chest.
Results
In 75% of cases (15/20), there was complete resolution of the clinical and radiological findings. Twenty-five percent of patients (5/20) developed acute respiratory distress syndrome (ARDS), which progressed to predominantly peripheral pulmonary fibrosis in 10% (2/20; one died and one had late-onset pulmonary fibrosis, documented on day 68). Moreover, in one patient with a CT diagnosis of pulmonary fibrosis, we observed progressive regression of radiological findings over 4 months of follow-up.
Conclusions
In patients with H1N1 pneumonia, post-ARDS pulmonary fibrosis is not a rare complication. Therefore, a CT scan should be performed in all patients with severe clinical findings. Our study demonstrated that in these patients, fibrosis could present a different spatial distribution and a different temporal trend, with delayed late onset; moreover, in one case, the signs of interstitial lung disease partially regressed over time. Therefore, CT should be considered not only in the diagnostic stage, but also during the follow-up.
Keywords: ARDS, Fibrosis, CT, H1N1 pneumonia
Riassunto
Obiettivo
Scopo del presente lavoro è quello di effettuare una valutazione evolutiva in 20 pazienti con polmonite da H1N1, focalizzando l’attenzione sui casi con severo decorso clinico-radiologico e sulle sequele polmonari post-acute respiratory distress syndrome (ARDS).
Materiali e metodi
Venti pazienti adulti, di cui 9 donne e 11 uomini, con età media di 43,5±16,4 anni e con diagnosi di influenza suina H1N1 confermata mediante tampone faringeo sono giunti alla nostra osservazione tra settembre e novembre 2009 e sono stati valutati evolutivamente fino a settembre 2010. Tutti i pazienti, in considerazione della severità del quadro clinico, sono stati sottoposti a regime di ricovero ed hanno eseguito almeno una radiografia del torace; 12 di essi hanno eseguito inoltre almeno una tomografia computerizzata (TC) del torace.
Risultati
Nel 75% dei casi (15/20) la sintomatologia e le alterazioni a carico del parenchima polmonare sono regredite dopo terapia in assenza di significativi esiti parenchimali. Nel restante 25% (5/20), il ricovero è stato gravato da complicanze respiratorie fino ad un quadro conclamato di ARDS, con evoluzione in interstiziopatia prevalentemente periferica in 2 pazienti, di cui uno poi deceduto ed uno con sviluppo tardivo di fibrosi polmonare documentata in 68a giornata. Si segnala infine un caso in cui si è verificata comparsa di segni compatibili con interstiziopatia polmonare che sono andati incontro a graduale regressione nei controlli a quattro mesi.
Conclusioni
Poiché l’evoluzione in interstiziopatia polmonare dell’ARDS da H1N1 rappresenta una complicanza di non rara osservazione, il monitoraggio evolutivo dei pazienti con presentazioni cliniche particolarmente severe non può esimersi dall’impiego dell’indagine TC. Il nostro studio ha documentato che la interstiziopatia conseguente alla polmonite virale con ARDS può presentare non solo una distribuzione spaziale peculiare, ma anche un inconsueto andamento temporale, con insorgenza tardiva; inoltre, in un singolo caso si è documentata una parziale e graduale riduzione nel tempo dei segni di interstiziopatia. Questa osservazione può giustificare ulteriormente, l’impiego della TC non solo in acuto ma soprattutto nel monitoraggio tardivo di questi pazienti.
Parole chiave: ARDS, Fibrosi, TC, Polmonite H1N1
References/Bibliografia
- 1.Hui D.S., Lee N., Chan P.K. Clinical management of pandemic 2009 influenza A (H1N1) infection. Chest. 2010;137:916–925. doi: 10.1378/chest.09-2344. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Writing committee of the WHO Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection. N Engl J Med. 2010;362:1708–1719. doi: 10.1056/NEJMra1000449. [DOI] [PubMed] [Google Scholar]
- 3.Mukhopadhyay S., Philip A.T., Stoppacher R. Pathologic findings in novel influenza A (H1N1) virus (“swine flu”) infection. Contrasting clinical manifestations and lung pathology in two fatal cases. Am J Clin Pathol. 2010;133:380–387. doi: 10.1309/AJCPXY17SULQKSWK. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Ministero della Salute (2010) Comunicato Stampa numero 22; Gennaio 2010
- 5.Fabbri M. Malattie dell’apparato respiratorio. Bologna: Clueb; 2003. [Google Scholar]
- 6.Mollura D.J., Morens D.M., Taubenberger J.K., et al. The role of radiology in influenza: novel H1N1 and lessons learned from the 1918 pandemic. J Am Coll Radiol. 2010;7:690–697. doi: 10.1016/j.jacr.2010.01.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.McEwen R.E., Scriven J.E., Green C.A., et al. Chest radiography findings in adults with pandemic H1N1 2009 influenza. BJR. 2010;83:499–504. doi: 10.1259/bjr/24252450. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 8.Muller R.R., Markewitz B.A., Rolfs R.T., et al. Clinical findings and demographic factors associated with ICU admission in Utah due to novel 2009 influenza A(H1N1) infection. Chest. 2010;137:752–758. doi: 10.1378/chest.09-2517. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Homsi S., Milojkovic N., Homsi Y. Clinical Pathological characteristics and management of acute respiratory distress syndrome resulting from influenza A (H1N1) virus. South Med J. 2010;103:786–790. doi: 10.1097/SMJ.0b013e3181e6ca0c. [DOI] [PubMed] [Google Scholar]
- 10.Tomashefski J.F., Jr Pulmonary pathology of the adult respiratory distress syndrome. Clin Chest Med. 1990;11:593–619. [PubMed] [Google Scholar]
- 11.Morgan P.W., Goodman L.R. Pulmonary edema and adult respiratory distress syndrome. Radiol Clin North Am. 1991;29:943–963. [PubMed] [Google Scholar]
- 12.Bernard G.R., Artigas A., Brigham K.L., et al. The American-European consensus conference on ARDS: Definitions, mechanisms, relevant outcomes and clinical trial coordination. Am J Respir Crit Care Med. 1994;149:818–824. doi: 10.1164/ajrccm.149.3.7509706. [DOI] [PubMed] [Google Scholar]
- 13.Ware L.B., Matthay M.A. The Acute Respiratory Distress Syndrome. N Engl J Med. 2000;342:1334–1349. doi: 10.1056/NEJM200005043421806. [DOI] [PubMed] [Google Scholar]
- 14.Gattinoni L., Caironi P., Pelosi P., Goodman L.R. What has computed tomography taught us about the acute respiratory distress syndrome? Am J Respir Crit Care Med. 2001;164:1701–1711. doi: 10.1164/ajrccm.164.9.2103121. [DOI] [PubMed] [Google Scholar]
- 15.Gattinoni L., Caironi P., Valenza F., et al. The role of CT scan studies for the diagnosis and therapy of acute respiratory distress syndrome. Clin Chest Med. 2006;27:559–570. doi: 10.1016/j.ccm.2006.06.002. [DOI] [PubMed] [Google Scholar]
- 16.Prokop M. Tomografia computerizzata spirale e multistrato. Milano: Elsevier-Masson; 2006. [Google Scholar]
- 17.Busi Rizzi E., Schininà V., Ferraro F., et al. Radiological findings of pneumonia in patients with swineorigin influenza A virus (H1N1) Radiol Med. 2010;115:507–515. doi: 10.1007/s11547-010-0553-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Ajlan A.M., Quiney B., Nicolaou S., Müller N.L. Swine-origine influenza A (H1N1) viral infection: radiographic and CT findings. AJR Am J Roentgenol. 2009;193:1494–1499. doi: 10.2214/AJR.09.3625. [DOI] [PubMed] [Google Scholar]
- 19.Marchiori E., Zanetti G., Hochhegger B., et al. High-resolution computed tomography findings from adult patients with influenza A (H1N1) virusassociated pneumonia. Eur J Radiol. 2010;74:93–98. doi: 10.1016/j.ejrad.2009.11.005. [DOI] [PubMed] [Google Scholar]
- 20.Marchiori E, Zanetti G, Fontes CA et al (2010) Influenza A (H1N1) virusassociated pneumonia: high-resolution computed tomography-pathologic correlation. Eur J Radiol, in press [DOI] [PubMed]
- 21.Agarwall P.P., Cinti S., Kazerooni E.A. Chest radiographic and CT findings in novel swine-origin influenza A (H1N1) virus (S-OIV) infection. AJR Am J Roentgenol. 2009;193:1488–1493. doi: 10.2214/AJR.09.3599. [DOI] [PubMed] [Google Scholar]
- 22.Marchiori E., Zanetti G., Mano C.M. Swine-origin influenza A (H1N1) viral infection: small airways disease. AJR Am J Roentgenol. 2010;195:W317. doi: 10.2214/AJR.10.4651. [DOI] [PubMed] [Google Scholar]
- 23.Marchiori E., Zanetti G., Mano C.M., et al. Follow-up aspects of influenza A (H1N1) virus-associated pneumonia: the role of high-resolution computed tomography in the evaluation of the recovery phase. Korean J Radiol. 2010;11:587. doi: 10.3348/kjr.2010.11.5.587. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24.Lee C.W., Seo J.B., Song J.W., et al. Pulmonary complication of novel influenza A (H1N1) infection: imaging features in two patients. Korean J Radiol. 2009;10:531–534. doi: 10.3348/kjr.2009.10.6.531. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 25.Henzler T., Meyer M., Kalenka A., et al. Image findings of patients with H1N1 virus pneumonia and acute respiratory failure. Acad Radiol. 2010;17:681–685. doi: 10.1016/j.acra.2010.03.013. [DOI] [PubMed] [Google Scholar]
- 26.Mollura D.J., Asnis D.S., Crupi R.S., et al. Imaging findings in a fatal case of pandemic swine-origin influenza A (H1N1) AJR Am J Roentgenol. 2009;193:1500–1503. doi: 10.2214/AJR.09.3365. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Harms P.W., Schmidt L.A., Smith L.B., et al. Autopsy findings in eight patients with fatal H1N1 influenza. Am J Clin Pathol. 2010;134:27–35. doi: 10.1309/AJCP35KOZSAVNQZW. [DOI] [PubMed] [Google Scholar]
- 28.Guo H.H., Sweeney R.T., Regula D., Leung A.N. Fatal 2009 influenza A (H1N1) infection, complicated by acute respiratory distress syndrome and pulmonary interstitial emphysema. Radiographics. 2010;30:327–333. doi: 10.1148/rg.302095213. [DOI] [PubMed] [Google Scholar]
- 29.Gill J.R., Sheng Z.M., Ely S.F., et al. Pulmonary pathologic findings of fatal 2009 pandemic influenza A/H1N1 viral infections. Arch Pathol Lab Med. 2010;134:235–243. doi: 10.5858/134.2.235. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Zompatori M., Sverzellati N. La polmonite interstiziale non specifica (NSIP) Radiol Med. 2010;115(Suppl):S139–S143. [Google Scholar]
- 31.Screaton N., Hiorns M., Lee K., et al. Serial HRTC in NSIP. Prognostic value of initial pattern. Clin Radiol. 2005;60:96–104. doi: 10.1016/j.crad.2004.06.029. [DOI] [PubMed] [Google Scholar]