An unusual case of pediatric granulomatosis with polyangiitis complicated by splenic infarction presenting as inflammatory bowel disease

Abstract

We describe a case of granulomatosis with polyangiitis (GPA) in a 7‐year‐old‐male who initially presented with symptoms concerning for Inflammatory bowel disease. GPA is a rare, multisystemic necrotizing vasculitis involving small arteries and veins. The clinical presentation can be variable given its multisystemic involvement but more commonly involves the upper and lower airways and kidneys. This case highlights rare gastrointestinal symptoms of GPA, further complicated by an additional unique finding of splenic infarction. We hope to raise awareness for this rare illness to assist in diagnosis and treatment, as timely induction of remission can reduce significant morbidity and mortality in the pediatric population.

1. INTRODUCTION

We report a 7‐year‐old male who presented with gastrointestinal (GI) symptoms initially suspicious for inflammatory bowel disease (IBD) with extraintestinal manifestations, who completed a complex multidisciplinary evaluation leading to a rare diagnosis of granulomatosis with polyangiitis (GPA), with GI and splenic involvement. GPA is a clinically complex and potentially lethal disease in the pediatric population. It is a systemic necrotizing vasculitis involving small vessels, classically involving the upper and lower airways and kidneys. ¹

2. CASE REPORT

A previously healthy 7‐year‐old male presented to the emergency department with a 4‐month history of 20 pounds of unintentional weight loss, fatigue, decreased appetite, generalized abdominal pain, and diarrhea. He complained of oral ulcers, arthralgias and 3 months of nosebleeds with cough. Family history was notable for rheumatoid arthritis and multiple sclerosis. Physical exam was significant for fatigued appearance and epigastric and left‐sided tenderness without peritoneal signs. Initial evaluation was significant for a hemoglobin of 10.9 g/dL (normal 11.2–14.5 g/dL) and iron studies consistent with both iron deficiency and chronic inflammation. He had thrombocytosis with platelets of 737 × 10⁹/L (normal 150–400 × 10⁹L), elevated C‐reactive protein 187 mg/L (normal 0–10 mg/L), erythrocyte sedimentation rate 105 mm/h (normal 0–15 mm/h), and fecal calprotectin 199 mg/kg (normal 0–49.9 mg/kg). Helicobacter pylori stool antigen, celiac screening, and stool infectious panel were normal.

He was hospitalized for further evaluation and pediatric gastroenterology was consulted due to concern for IBD. Abdominal ultrasound demonstrated abnormal spleen with heterogeneous appearance and irregular regions of hypoechogenicity, with no comment on intestinal findings. Computed tomography (CT) abdomen/pelvis with intravenous contrast demonstrated a heterogenous spleen with diffuse hypoattenuation and septation (Figure 1), fluid‐filled colon, and appendix with a locule of gas without obstruction and no other intestinal findings. The broad differential for the unusual morphology included: abscess, peliosis, infarct with partial reperfusion, neoplasm, hemangioma, and splenic vascular lesion. Hematology/oncology and infectious disease were consulted.

Figure 1.

(A) CT abdomen/pelvis demonstrating heterogeneous spleen with regions of hypoattenuation with peripheral and capsular enhancement, and several interdigitating regions of enhancement. (B) CT chest 2 months later demonstrating considerably smaller spleen, with persistent areas of irregular low attenuation centrally with peripheral sparing, consistent with large infarction. CT, computed tomography.

Oncology evaluation was unrevealing. Lymphoma was considered an unusual culprit as there was no lymphadenopathy, mediastinal mass, hepatomegaly, or cytopenia. Parasitic infection was less likely as there was no peripheral eosinophilia and negative blood parasite smear. Evaluation for Epstein‐Barr virus, Human immunodeficiency virus, and tuberculosis were unremarkable. There was ultimately low suspicion for infection.

He developed worsening epistaxis, purpura (Figure 2), and respiratory distress requiring transfer to the pediatric intensive care unit. Endoscopic evaluation was deferred due to respiratory status and increased suspicion for rheumatologic disorder given microscopic hematuria, elevated proteinase 3 (PR3) antibody, and c‐antineutrophil cytoplasmic antibody (ANCA). Laryngobronchoscopy demonstrated nasal polyposis and severe subglottic stenosis. Nasal and tracheal biopsies demonstrated destructive lymphocytic angiitis and granulomas (Figure 3) which solidified the GPA diagnosis. Pediatric criteria for diagnosis are adopted from adult criteria. At least three criteria must be present: positive ANCA serology, necrotizing vasculitis on histology, or upper airway, laryngotracheobronchial, pulmonary, or renal involvement. ² He was treated with high‐dose steroids and Rituximab with improvement.

Figure 2.

Evolving upper extremity purpura consistent with cutaneous vasculitis.

Figure 3.

Histopathology of nasal biopsy demonstrates destructive lymphocytic angiitis and poorly formed granulomas surrounding by palisading histiocytes consistent with granulomatosis with polyangiitis at (A) ×100 and (B) ×200 magnification.

One month later, his abdominal pain and diarrhea resolved, with improved appetite and weight gain. However, he developed diffuse alveolar hemorrhage, requiring escalation to plasmapheresis, cyclophosphamide, and pulse steroids. On CT chest with IV contrast for further evaluation, there was the demonstration of large splenic infarction (Figure 1).

3. DISCUSSION

GPA is a rare, potentially life‐threatening diagnosis in the pediatric population. ¹ The estimated annual incidence is 1:100,000 in adults and 0.1:100,000 in children. ³ In children, it is the most common ANCA‐associated vasculitis with only 3.3% of cases presenting before 20 years of age. ¹ It is a systemic necrotizing vasculitis involving small vessels, commonly involving the upper airway, lungs, and kidneys. The true frequency of GI involvement in GPA is unknown, and there are sparse reports of presentation with GI symptoms, especially in children. ¹ , ⁴ In the few cases described, symptoms are similar to IBD including weight loss, abdominal pain, diarrhea, and hematochezia. ⁵ In adults, GI involvement may occur in 5%–20% of cases with abdominal pain, ileocolitis, cholecystitis, hemorrhage, and bowel perforation. ¹ Cases are associated with PR3 positivity, a marker also shown in primary sclerosing cholangitis, though less likely in this case given the lack of hepatitis and cholestasis. ⁶

Splenic involvement including infarction, hemorrhage, and capsular adhesions is underdiagnosed, and associated with younger age, ear, nose, and throat involvement, and PR3 positivity. Splenic involvement is more often noted on autopsy. Infarction can be secondary to occlusion of the distal branches of the splenic artery. ⁷ It is typically asymptomatic, though rarely may be associated with nonspecific or left‐sided abdominal pain. ⁷ , ⁸ The frequency of splenic involvement is unclear due to subclinical symptoms. This patient's splenic findings with a broad constellation of symptoms led to a wide differential diagnosis, including the exceedingly rare possibility of IBD‐associated splenic abscess. ⁹ However, advanced imaging was consistent with splenic infarction, supportive of GPA.

In this case, the splenic and GI involvement likely contributed to abdominal pain. The mild elevation in fecal calprotectin was originally thought to be secondary to IBD, however was likely secondary to vasculitis. ⁴

The diagnosis of a rare, multisystemic disease such as GPA is challenging due to nonspecific symptoms mimicking more common conditions, such as IBD. Prompt recognition is crucial as induction immunosuppression is essential for remission and decreasing mortality. ¹⁰ Estimated mortality reaches 90% 1 year from diagnosis if untreated. ³ Pediatric gastroenterologists must maintain a high index of suspicion and broad differential of weight loss and abdominal pain to avoid delays in diagnosis and therapy for this life‐threatening illness.

CONFLICT OF INTEREST STATEMENT

The authors declare no conflict of interest.

ETHICS STATEMENT

Consent was obtained from the patient's mother to use the information provided for this report.

Pathania S, Rehman R, Ward M, et al. An unusual case of pediatric granulomatosis with polyangiitis complicated by splenic infarction presenting as inflammatory bowel disease. JPGN Rep. 2024;5:398‐401. 10.1002/jpr3.12099