Abstract Introduction Recurrent respiratory infections in young adults without a known cause warrant evaluation for primary or secondary immunodeficiency. This case describes a 24-year-old male who presented with acute hypoxic respiratory failure, severe neutropenia, and sepsis due to multifocal pneumonia, ultimately diagnosed with agammaglobulinemia likely secondary to common variable immunodeficiency (CVID). The case underscores the value of an integrative, multidisciplinary approach to uncovering underlying immunologic disorders in complex presentations. Description of Case A previously healthy 24-year-old male presented with acute dyspnea, fever, and cough. Initial evaluation revealed multifocal pneumonia with acute hypoxic respiratory failure and severe neutropenia. Broad-spectrum antibiotics (cefepime and azithromycin) were initiated.Pulmonology performed bronchoscopy with bronchoalveolar lavage (BAL) and endobronchial ultrasound-guided lymph node biopsy. BAL analysis showed 80% neutrophils, 15% lymphocytes, and 5% macrophages with no malignant cells. Lymph node biopsy demonstrated reactive hyperplasia without granulomas. Infectious disease workup was negative for bacterial, fungal, and mycobacterial organisms; procalcitonin was elevated (5.4 ng/mL). Hematology/Oncology evaluation, including bone marrow biopsy, ruled out lymphoma and chronic myelomonocytic leukemia (CMML). Peripheral smear revealed toxic granulations and Döhle bodies consistent with inflammation. Cardiology identified stress-induced cardiomyopathy with an LVEF of 42% and elevated BNP (560 pg/mL), managed with metoprolol succinate.Allergy/Immunology identified severe hypogammaglobulinemia (IgG 200 mg/dL, IgA 7 mg/dL, IgM 10 mg/dL), non-protective vaccine titers, and a normal B-cell count, supporting CVID rather than X-linked agammaglobulinemia. The patient received IVIG 45 g, resulting in improved IgG levels (650 mg/dL) and clinical recovery. He was discharged on oral antibiotics and beta-blocker therapy with outpatient immunology follow-up. Discussion This case represents a diagnostic and therapeutic challenge involving overlapping infectious, hematologic, cardiac, and immunologic findings. The patient’s presentation of multifocal pneumonia, neutropenia, and cardiomyopathy prompted broad multidisciplinary involvement. CVID was identified as the underlying etiology after exclusion of malignancy and secondary causes. Learning Point: Primary immunodeficiency, including CVID, should be considered in adults presenting with recurrent or severe respiratory infections, particularly when standard infectious and hematologic workups are unrevealing. Early recognition and initiation of IVIG therapy can significantly reduce morbidity and prevent long-term complications. This case highlights the importance of cross-specialty collaboration in identifying systemic immune dysfunction presenting through pulmonary manifestations. This abstract is funded by: none
Saedy et al. (2026) studied this question.