An elderly woman was diagnosed with the granulomatosis with polyangiiti (GPA) subtype of ANCA-associated vasculitis (AAV) after being misdiagnosed with pneumonia, illustrating the challenges in diagnosing this condition, according to a case report.
All types of AAV should be in the differential diagnosis for all patients with organ involvement, particularly in people with lung and kidney conditions, the researchers recommended.
The case study, “Granulomatosis with polyangiitis (GPA) in a 76-year old woman presenting with pulmonary nodule and accelerating acute kidney injury,” was published in the Journal of Clinical Nephrology.
ANCA-associated vasculitis (AAV) is a group of diseases characterized by inflammation and damage to small blood vessels.
Subtypes of AAV are categorized according to the organs whose blood vessels have been damaged. These subtypes include granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), and eosinophilic granulomatosis with polyangiitis (EGPA).
The GPA subtype can be difficult to diagnose as symptoms are nonspecific. Some of the early symptoms, which can last for weeks or months, include fever, fatigue, weight loss, cough, hearing loss, nose bleeds, and joint pain.
GPA can also mimic diseases such as pneumonia, cancer, sarcoidosis, and viral, bacterial, or fungal infections.
While the early stages of GPA typically affect the upper respiratory tract or skin and are not considered life-threatening, GPA may progress to vital organs like the kidneys or lungs. This risk emphasizes the need for an early diagnosis, and the start of treatments to prevent disease progression.
The challenges in diagnosing GPA-AAV are illustrated in this case. The woman, 76, came to an emergency department complaining of abdominal pain that had worsened in the previous two weeks. She also reported feeling generally weak and having a dry cough.
She had a medical history of chronic abdominal pain, reflux disease, irritable bowel syndrome, asbestos exposure, and a high heart rate (tachycardia). She was taking medications for high blood pressure, anxiety, and pain.
Moderate tenderness in the right upper chest area was noted in a physical examination, and lab tests found a large amount of blood in the urine. A computerized tomography (CT) scan showed mild swelling and more stool in the colon than usual. She was negative for gallbladder inflammation and an abdominal ultrasound was negative as well.
Both a CT scan and positron emission tomography (PET) scan found a nodule (growth of abnormal tissue) in her upper right lung, suggesting a malignancy. While a biopsy did not find signs of cancer or infection, tests found evidence of pneumonia with fibrosis.
Following treatment for her constipation, her abdominal pain eased and the woman was sent home with an antibiotic to treat a presumed diagnosis of pneumonia.
However, she made another emergency visit one week later complaining about pain on her right side, weakness, swelling in her lower extremities, poor appetite, tongue soreness, a lack of urine, and a persistent cough.
An ulcer was found on her tongue in another physical examination. Lab tests showed high levels of blood urea nitrogen (BUN) and creatinine — both markers for kidney disease — and significant levels of blood cells in the urine.
Significantly, she also tested positive for cytoplasmic ANCA antibodies that were specific to proteinase 3 (PR3), a known marker for GPA, and tested negative for myeloperoxidase (MPO) specific antibodies, a marker for MPA-AAV.
After a biopsy of the left kidney, a GPA diagnosis was confirmed and the woman started on glucocorticoids and antibiotics in addition to receiving plasma exchange and blood dialysis.
“Diagnosis of granulomatosis with polyangiitis (GPA) can be challenging and the consequences detrimental when misdiagnosis occurs,” the investigators said.
“GPA is a rare disease with low physician awareness but should be kept in the differential diagnosis of those patients who presents with non-specific symptoms,” they advised.