Acute ANCA Vasculitis and Asymptomatic COVID-19

Case

A 12-year-old girl with progressive respiratory failure was transferred to a tertiary children’s hospital from a community hospital for further diagnostic evaluation and management. Two weeks before transfer, she had onset of mild, productive cough with blood streaked sputum without any respiratory distress, fevers, rash, bruising, or joint pain. On physical examination by her primary care physician, she had crackles at the left lung base. Community-acquired pneumonia was diagnosed, and amoxicillin was prescribed. Because of high prevalence of COVID-19 in the community (community testing rate of 25%–30% positive results in the week of illness onset), nasopharyngeal swab polymerase chain reaction (PCR) testing for COVID-19 was performed, and the result was negative. Four days later, she had acute onset of bilateral leg and feet pain that led to progressive difficulty with ambulation, prompting admission to a community hospital. On admission, she was afebrile and had a normal respiratory rate, normal oxygen saturations, and a normal heart rate. A physical examination revealed mild swelling of the right knee and left ankle without erythema or warmth and crackles in the left lung base. A chest radiograph revealed left lower lobe consolidation consistent with a previous diagnosis of pneumonia, and the result of repeat nasopharyngeal swab COVID-19 PCR testing was negative. Amoxicillin was discontinued, and ceftriaxone, clindamycin, and azithromycin were started. Laboratory findings were notable for the following: white blood cell count of 15.5 × 10³/mL, hematocrit value of 30.7%, platelet count of 565 × 10³/mL, C-reactive protein level of 10.9 mg/dL, and erythrocyte sedimentation rate of 54 mm/hour. Her knee and ankle pain resolved with acetaminophen, but she had new onset of dyspnea, which resulted in progression over 3 days from room air to requiring low-flow nasal cannula oxygen to requiring 10 L/minute of high-flow nasal cannula supplemental oxygen. A chest computed tomography scan was obtained and revealed dense consolidation in the left lower lobe and patchy infiltrate in the right middle and upper lobes without ground-glass opacities (Fig 1). Because of her worsening respiratory status, she was transferred to a tertiary children’s hospital ICU.

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FIGURE 1

Chest computed tomography image revealing left lower lobe consolidation and patchy infiltrate in other lung fields.

On admission to the ICU, she was placed on bilevel positive airway pressure at 22/10 cm H₂O, which resulted in improvement in dyspnea. A physical examination revealed nonblanching, violaceous macules on her right foot, diminished breath sounds in the left lung base and crackles in all lung fields, normal mentation, erythematous oropharynx, normal conjunctiva, and normal neurologic functioning. Because of ongoing community spread of COVID-19, she was placed in airborne isolation precautions. Laboratory findings at the time of transfer were notable for the following: white blood cell count of 13.9 × 10³/mL, hematocrit value of 25.7%, platelet count of 530 × 10³/mL, C-reactive protein level of 16.4 mg/dL, erythrocyte sedimentation rate of 117 mm/hour, and urinalysis results of 1+ leukocyte esterase, negative nitrites, 3+ microscopic hematuria, and a urine protein/creatinine ratio of 0.25. Repeat nasopharyngeal swabs and induced sputum samples were negative for COVID-19 by PCR testing. Antibody testing was positive for COVID-19 immunoglobulin G (IgG) antibodies. Rheumatology, infectious disease, nephrology, and pulmonology were consulted. Ceftriaxone and clindamycin were discontinued, azithromycin was continued, and vancomycin, cefepime, and fluconazole were initiated. Antibody testing revealed a positive myeloperoxidase antibody (anti-MPO) result as well as a positive ANCA result, with a titer of 1:640 and a perinuclear pattern. Results of Antinuclear antibody, double-stranded DNA antibody, and extractable nuclear antigen panels were negative. C3 and C4 complement levels were normal. Given these results, suspicion for systemic lupus erythematosus was low. Antiphospholipid antibody testing was not performed given low suspicion, but testing could be considered in future cases. Bronchoalveolar lavage was used to diagnose diffuse alveolar hemorrhage consistent with possible vasculitis. Bronchoalveolar lavage fluid was negative for COVID-19 by PCR testing. A renal biopsy specimen revealed a pauci-immune necrotizing and crescentic glomerulonephritis, confirming the diagnosis of anti-MPO ANCA vasculitis with pulmonary and renal involvement. She was initiated on methylprednisolone, rituximab, and cyclophosphamide, which resulted in improvement in her clinical status.