PULMONARY ALVEOLAR PROTEINOSIS PRESENTING AS INTRACEREBRAL NOCARDIOSIS

Abstract

SESSION TITLE: Diffuse Lung Disease SESSION TYPE: Med Student/Res Case Report PRESENTED ON: 10/09/2018 07:30 am - 08:30 am INTRODUCTION: Pulmonary alveolar proteinosis (PAP) is a rare disorder with an incidence of 0.5 / million people [1]. PAP is caused by the accumulation of surfactant in the alveoli, leading to hypoxemic respiratory failure and increased risk of opportunistic infections [2]. First-line therapy after infection eradication is whole-lung lavage. Treatment with exogenous granulocyte macrophage colony stimulating factor (GM-CSF) is under investigation. PAP can be a diagnostic challenge due to its low prevalence and nonspecific presentation. Here we describe a unique presentation that was diagnosed as PAP. CASE PRESENTATION: A 56 year old male farmer, never smoker, with no past medical history presented with right-sided weakness, two months of dyspnea, and dry cough. Brain MRI demonstrated multiple cerebral rim-enhancing abscesses (Fig 1A). He underwent a craniotomy and evacuation of cerebral abscesses with acid fast cultures positive for Nocardia farcinica. Chest CT showed a "crazy paving" pattern consistent with PAP (Fig 1B, C). Serum anti GM-CSF antibody was positive. Bronchoscopy showed opaque fluid on bronchoalveolar lavage, with negative cultures, and clumps of amorphous proteinaceous material consistent with PAP. Disseminated Nocardia was treated with ciprofloxacin for 1 year and sulfamethoxazole/ trimethoprim for 6 months. He underwent a whole lung lavage with resolution of symptoms. DISCUSSION: PAP is caused by surfactant accumulation due to incomplete removal by alveolar macrophages. Autoimmune PAP (primary PAP) accounts for the majority of cases [1]. Autoimmune PAP is caused by anti GM-CSF antibodies that disrupt macrophage activation, antigen presentation, and phagocytosis [2]. Secondary PAP is thought due to a relative deficiency of GM-CSF usually in the setting of hematologic diseases or dust exposures. The ensuing macrophage dysfunction leads to increased infection risk. Opportunistic infections including Nocardia, Mycobacterium, and fungi in otherwise immunocompetent patients with PAP have been previously reported [2]. In a report of 7 patients with disseminated Nocardiosis without PAP, 5 patients were found to have anti GM-CSF antibodies; two of these patients were also found to have radiographic characteristics of PAP [3]. CONCLUSIONS: Primary PAP is a rare autoimmune disorder that confers an immunocompromised state due to impaired alveolar macrophage activation. Opportunistic infections such as Nocardiosis are frequently seen with PAP. Eradication of the opportunistic infections, and targeted whole lung lavage are effective at relieving hypoxia in PAP. A high diagnostic suspicion is essential in the work-up of PAP. Reference #1: Clinics in Chest Medicine. 2016;37(3):431-440. https://doi.org/10.1016/j.ccm.2016.04.006 Reference #2: Journal of Infectio. 2012;65(2):173-179. https://doi.org/10.1016/j.jinf.2012.03.020 Reference #3: Clinical Infectious Disease. 2014;60(7):1017-1025. https://doi.org/10.1093/cid/ciu968 DISCLOSURES: No relevant relationships by David Dennis, source=Web Response No relevant relationships by Ulysses Magalang, source=Web Response No relevant relationships by Virgil Secasanu, source=Web Response