Organizing Pneumonia Seco...

BACKGROUND :

Organizing Pneumonia (aka BOOP), it is a diffuse parenchymal lung disease which affects alveolar ducts, alveolar walls and distal bronchioles. Lower Respiratory infections mainly of bacterial or viral origin are known to be associated with secondary form of Organizing Pneumonia (OP) with less predilections to fungal Infections. Here, we report a case of Organizing Pneumonia (OP) associated with Pneumocystis Carinii Pneumonia (PCP) in a Post-Covid 19 patient was on long term steroid therapy. Patient had a new lung parenchymal lesion (Ground Glass Haze) toward the end of TMP-SMX therapy for PCP. Spontaneous clinical and radiological resolution of the lesion was seen when treated with steroids.

Case Study :

A 27 years old male, presented with dyspnea on exertion of 5 days duration along with dry cough and generalised weakness since 8-10 days. His dyspnea on exertion was progressive; cough was non-progressive and non-productive. He had no history of fever, chest pain, Hemoptysis or weight loss. He had recovered from Covid-19 infection 6 months back with history of steroidal medications for longer duration. He had no other comorbidities. He was on Methylprednisolone for approximately 1 month (on tapering doses) for persistent oxygen requirement and to prevent lung fibrosis. He denied smoking or any other drug abuse/addiction.

On examination, he was afebrile, hemodynamically stable and had a respiratory rate of 26/min with saturation of 92% on room air. Otherwise general examination was normal. Auscultation was suggestive of bilateral inspiratory crackles with normal cardiovascular examination. The examination of other systems was unremarkable. His laboratory parameter were: Hb-16.2 g/dl; TLC-9000/microlitre  (Neutrophils-47%, lymphocytes-45%); PLT-120k. Serum IgE-719.8. Renal function test & Hepatic function tests were unremarkable. Arterial Blood Gas (ABG) was suggestive of Mild hypoxia(PaO2-64mm Hg). Viral Markers were not significant. Chest X-ray was suggestive of bilateral diffuse alveolar infiltrates. HRCT Chest revealed bilateral extensive patchy ground glass haze and interlobular steal thickening (relatively more severe on left side). No Pleural or mediastinal abnormality detected. So the differentials were Pnemocystis Carinii Pneumonia (PCP), Cytomegalovirus (CMV) Pneumonia and atypical bacterial pneumonia. Sputum induction was unsuccessful, so Flexible Bronchoscopy and Bronchoalveolar Lavage (BAL) was done. BAL Genexpert & AFB smear was negative. Also CMV inclusion bodies, fungal hyphae were not detected. BAL PCP by IFA was positive, though Grocott’s Methenamine Silver stain for PCP was negative.

After completion of 21 days of TMP/SMX therapy, patient was still dyspneic on exertion along with occasional dry cough so TMP/SMX therapy was extended for another 2 weeks. Post-therapy PFT was suggestive of Moderate Restriction with reduced DLCO. Repeat Chest X-ray revealed left lung infiltrates along with few in right lung also. Repeat HRCT Chest revealed bilateral extensive patchy ground glass haze, relatively more severe in left lower lobe. Repeat BAL fluid analysis for AFB, Fungus and PCP was negative. BAL cytology revealed non-specific inflammation. So Transbronchial lung biopsy was taken from left lower lobe showed alveoli filled with inflammatory debris consisting of granulation tissue and interstitial inflammation with areas of intra-alveolar fibrin deposition. Quantitative PCR for CMV DNA was negative. PCP by IFA was also negative. So diagnosis of Organizing Pneumonia was made. And Methylprednisolone was started at 40 mg twice daily for the first 5 days which was later tapered slowly over a period of 2 months. Patient started improving clinically and radiologically. The Organizing Pneumonia was attributed to be associated with PCP which was due to Covid/steroid related immunosuppression. The patient remains stable on follow up at 6 months without any relapse.

DISCUSSION :

This article reports a 27 years old male patient of Organizing Pneumonia associated with PCP. The association between the two diseases is less common and has never been reviewed before. OP being a parenchymal disease which may be Cryptogenic or associated with any inciting event. If OP related to infection, it occurs as a part of non resolving pneumonia of the primary causative agent or as an exaggerated inflammatory reaction triggered by that agent after resolution of the primary cause. Fungal infection are less commonly associated with OP which includes Cryptococcus neoformans, Pneumocystis Carinii, Penicillium janthinellum. The association of PCP with OP was previously reported in HIV positive individuals and in organ transplant recipients.

CONCLUSION :

Organizing Pneumonia can complicate the course of PCP  or may develop after resolution of the infection. The treatment strategy for OP includes treatment of the inciting factor and the use of immunosuppressant in refractory cases (glucocorticoids and cytotoxic therapy).

REFERENCE: Fernández-Codina A, Caralt-Ramisa B, Masclans JR, Farré M, Bravo C, Rello J. An unusual case of organizing pneumonia and infection by P.jirovecii. Med Intensiva. 2013;37:299–300.