Presentation

A 58-year-old woman with no significant medical history presented to the emergency department with hemoptysis, cough, and dyspnea for 1 week. She also mentioned several times of vomiting and dizziness episodes in the past year. On examination, the patient was alert and interactive. The temperature was 36.6 °C, blood pressure was 115/64 mm Hg, heart rate was 73 beats per minute, and respiratory rate was 20 breaths per minute. The oxygen saturation was 93% while she was breathing ambient air initially, but the oxygen demand of the nasal cannula was rapidly increased to 4 L per minute subsequently. Conjunctiva was pale, auscultation revealed left-sided diffuse coarse crackles, and bilateral lower leg showed grade 2 pitting edema. Laboratory tests showed a low hemoglobin count (5.7 g/dL), high serum creatinine level (7.42 mg/dL), and no leukocytosis (9.5 × 109/L). Urine analysis showed microscopic hematuria and proteinuria. Chest X-ray and subsequent chest computed tomography revealed unilateral diffuse consolidation opacities and ground-glass pattern (Fig. 1A–C). Fiberscope performed by otorhinolaryngologist for hemoptysis revealed bleeding from subglottic origin. Bronchoscopy was not performed due to the patient’s hesitation. Sputum cultures all showed negative results for pathogen isolation. A clinical diagnosis of alveolar hemorrhage was impressed, and subsequent serologic testing showed positive for p-ANCA and MPO-Ab (21.9 IU/mL, normal range < 2.0 IU/mL). Renal biopsy performed showed extensive glomerular crescent formation without evidence of granuloma formation. Immunofluorescence staining showed negative results. All findings are consistent with microscopic polyangiitis. The final diagnosis of microscopic polyangiitis with a presentation of the pulmonary renal syndrome was made. The patient received immunosuppressives and plasmapheresis. Chest X-ray showed significant improvement of left-side opacities after 4 weeks of treatment (Fig. 1D).

Fig. 1
figure 1

Chest X-ray (A) and chest computed tomography (B, C) on the same day showed unilateral left-sided diffuse lung patchy ground-glass and consolidative opacities. D The chest X-ray 4 weeks after pulse steroid and cyclophosphamide treatment showed dramatic regression of left-sided infiltrates

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Discussion

Antineutrophilic cytoplasmic antibody–associated vasculitides (AAVs) are a group of rare autoimmune disease that predominantly causes inflammation of small vessels, and most commonly affected the kidney and the respiratory tract. Previous studies reported that the incidence of pulmonary involvement in AAV varies from 52 to 77% [1, 2]. Among the respiratory tract involvement, pulmonary capillaritis–related diffuse alveolar hemorrhage (DAH) is a potentially life-threatening pulmonary manifestation of ANCA-associated vasculitis (AAV) and may cause respiratory failure if untreated. Patients with alveolar hemorrhage may present with rapid onset of dyspnea, cough, hemoptysis, anemia, and/or hypoxemia. Besides, radiographic findings usually revealed bilateral focal or diffuse parenchymal opacities in most cases.

The presentation of unilateral alveolar hemorrhage in AAV was extremely rare and was reported in only seven cases previously before our literature review. Among the seven cases, four were GPA and the other three were MPA, with female patients accounting for 71% (5 of 7) (Table S1 in Online Resource). All four cases of GPA presented with a unilateral diffuse pulmonary involvement and all three patients of MPA showed only unilateral focal lung involvement. In MPA patients, two cases of three are female and aged 59, 82, and 58 years, separately. As for clinical presentation, all three MPA patients had hemoptysis, two of them had rapidly progressive glomerulonephritis, and fever was presented in one [3,4,5]. This unique presentation of unilateral alveolar hemorrhage will make the initial diagnosis more challenging since AAV can also present with fever and malaise, which may mimic an infection episode. Furthermore, acute renal function impairment associated with fluid overload and pulmonary congestion, such as in our patient, may also mask the pulmonary hemorrhage if chest computed tomography was not performed. Since the main treatment of AAV to date is still steroid with other immunosuppressants, the wrong diagnosis may worsen the infection or delay the treatment of AAV conversely. To our knowledge, this is the first description of a complete unilateral diffuse alveolar hemorrhage due to microscopic polyangiitis.