According to a recent article, a new study shows that granulomatosis with polyangiitis (GPA) and tuberculosis might have shared features, making diagnosis more difficult.
Granulomatosis with Polyangiitis (GPA)
Granulomatosis with polyangiitis (GPA), formerly known as Wegener’s granulomatosis, is a rare blood vessel disease that is potentially serious when not promptly diagnosed. GPA is characterized by the abnormal inflammation of the small and medium-sized blood vessels throughout the body, which does not allow blood to flow properly and prevents cells from getting the oxygen that they need.
Most commonly, GPA affects the sinuses, lungs, and kidneys, but can also affect the eyes, ears, skin, nerves, and joints. Symptoms of GPA can develop over days to months, usually beginning in the respiratory tract. These early symptoms include:
- Nasal congestion
- Frequent nosebleeds
- Shortness of breath
- Bloody cough
In addition, other early symptoms can include joint pain, decreased hearing, skin rashes, fatigue, fever, night sweats, and numbness. More seriously, ongoing inflammation in the blood vessels or organs can cause organ failure.
GPA is caused by tissue injury when cells do not get the oxygen they need due to blood vessel inflammation. However, the exact cause of this inflammation is still largely unknown, though some speculate that it may develop after an infection or other inflammation-causing trigger.
There is not one set test for diagnosing GPA, so a physical examination, alongside laboratory and imaging testing all play a role in the diagnosis.
Besides an MRI, urine tests, and CT scans, a doctor may order an antibody test called ANCA to check for this associated antibody in the bloodstream. If the results from this test come back positive, a tissue biopsy will be needed to confirm a diagnosis.
Tuberculosis (TB) is a potentially serious infectious disease that mainly affects the lungs. The bacteria that cause tuberculosis are spread from person to person through tiny droplets released into the air via coughs and sneezes.
Although your body can harbor the bacteria that cause tuberculosis, your immune system usually can prevent you from becoming sick. For this reason, doctors make a distinction between:
- Latent TB: You have a TB infection, but the bacteria in your body are inactive and cause no symptoms. Latent TB, also called inactive TB or TB infection, isn’t contagious. Latent TB can turn into active TB, so treatment is important.
- Active TB: Also called TB disease, this condition makes you sick and, in most cases, spreads to others. It can occur weeks or years after infection with the TB
Signs and symptoms of active TB include:
- Coughing for three or more weeks
- Coughing up blood or mucus
- Chest pain, or pain with breathing or coughing
- Unintentional weight loss
- Night sweats
- Loss of appetite
Tuberculosis can also affect other parts of your body, including the kidneys, spine or brain. When TB occurs outside your lungs, signs and symptoms vary according to the organs involved. For example, tuberculosis of the spine might cause back pain, and tuberculosis in your kidneys might cause blood in your urine.
Case Study: The Diagnosis
The case study involved looking at the diagnosis of a 66-year-old man. The patient visited the Shifa International Hospital in Pakistan where he presented with a low fever, anorexia, night sweats, discomfort, and significant weight loss in a short amount of time. He had no underlying conditions and was previously a smoker.
The patient underwent a CT scan where he was found to have a mass in his mediastinum, the area of the body between the lungs. After obtaining a biopsy of the mass, doctors discovered there was some inflammation caused by immune cells clumping together. This type of inflammation is often seen after an infection and is usually caused by mycobacterium tuberculosis.
Doctors started the patient on an anti-tuberculosis therapy (ATT), but this led to the patient having liver inflammation. Therefore, he was switched to a different regimen of ATT.
The patient’s molecular analysis of the biopsy resulted in the mass being negative for mycobacterium tuberculosis. However, the patient remained on his ATT regimen.
One year after starting his treatment, the patient’s symptoms had improved, he had gained a good amount of weight, and the mass had gone away. In spite of all of this, doctors were still concerned since his blood tests came back with markers of inflammation such as creatinine. He was referred to a doctor in the nephrology department, but he never made an appointment. Two years later, the patient returned for a check-up with symptoms similar to the ones he had before and was again referred to a nephrologist.
The patient once again underwent a CT scan, which showed he had a mass in his left lung with mediastinal widening. This discovery led his doctor’s to believe he had granulomatosis with polyangiitis (GPA), which is a form of ANCA-associated vasculitis. He was therein referred to a rheumatologist, and blood analysis revealed the patient had anti-neutrophilic cytoplasmic antibodies (ANCA).
While doctors recommended the patient be treated with immunosuppressive medicine cyclophosphamide inserted directly into his veins, the patient refused, citing his worry for its possible side effects. As a result, he was treated with pulse steroids. The steroids were inserted through the vein in high doses over a short period of time. In addition to these steroids, the patient was also treated with an immunosuppressant called CellCept.
The patient was monitored by both his rheumatologist and nephrologist. His treatment proved to be successful, with the mass disappearing, his symptoms lessening, and his creatinine levels stabilizing.
This case study emphasizes the difficulties that come with determining whether a patient has tuberculosis or GPA. The two diseases share some common symptoms, making differentiating them difficult at times. While some doctors may jump to the typical choice, researchers are urging them to still consider the possibility of the disease being GPA.