Granulomatosis with polyangiitis is a rare condition that causes inflammation in small blood vessels throughout the body, most often affecting the respiratory system and kidneys. This disease, once known as Wegener’s granulomatosis, can develop quietly over months or appear suddenly, making early recognition and treatment essential for preserving organ function and quality of life.

Understanding Granulomatosis with Polyangiitis

Granulomatosis with polyangiitis, commonly shortened to GPA, belongs to a family of diseases called vasculitis, which means inflammation of blood vessels. The name itself describes what happens inside the body: “polyangiitis” refers to inflammation affecting many different types of blood vessels, while “granulomatosis” describes the formation of small inflammatory masses called granulomas in blood vessels and organs.^[1]

When blood vessels become inflamed in GPA, they can swell, break, bleed, or develop scar tissue that narrows their opening. This restricts blood flow and deprives tissues of the oxygen and nutrients they need to function properly. The granulomas that form are clusters of immune cells that grow and can invade surrounding tissues, causing additional damage.^[2]

The condition has a particular preference for certain parts of the body. It most commonly affects the upper respiratory tract, including the sinuses, nose, ears, and windpipe, as well as the lungs and kidneys. However, because it targets small blood vessels that travel throughout the entire body, GPA can potentially affect almost any organ, including the eyes, skin, joints, nerves, and heart.^[4]

Epidemiology

Granulomatosis with polyangiitis is considered a rare disease. In the United States, it affects approximately three out of every 100,000 people.^[6][22] While this might seem like a small number, thousands of people live with this condition and face its daily challenges.

The disease can strike at any age, but it most commonly appears in middle-aged adults. People in their 40s through 60s are most frequently diagnosed, though it is not unusual for the condition to be discovered in someone in their 70s or even 80s. Cases in childhood do occur but are less common.^[7]

GPA affects men and women at nearly equal rates, with a slight tendency toward more cases in men. The disease does not appear to favor any particular ethnic or racial group, though most research has been conducted in populations of European descent.^[7]

Causes

The exact cause of granulomatosis with polyangiitis remains unclear to medical researchers. What is known is that GPA is an autoimmune disease, meaning the body’s immune system mistakenly attacks its own healthy tissues rather than protecting against foreign invaders like bacteria or viruses.^[2]

Most people with GPA have abnormal immune proteins in their blood called antineutrophil cytoplasmic antibodies, or ANCA for short. These antibodies attack normal human proteins in white blood cells called neutrophils. Approximately 90 percent of people with GPA have these antibodies, most commonly those that target a protein called proteinase 3. When these antibodies attach to their target protein, they trigger inflammation that contributes to the signs and symptoms of the disease.^[6]

The genetic basis of GPA is not well understood. Having a particular version of the HLA-DPB1 gene is the strongest genetic risk factor for developing this condition, though several other genes may be involved. It is likely that a combination of genetic predisposition and environmental factors leads to GPA, though the specific environmental triggers remain unknown.^[6]

Unlike infectious diseases, GPA is not contagious and cannot be passed from person to person. It is also not directly inherited, though genetic factors may increase susceptibility in some individuals.^[6]

Risk Factors

Because the exact cause of GPA remains unknown, identifying specific risk factors has been challenging. Age appears to play a role, as the disease typically develops in middle to older adulthood. However, no age group is completely immune to the condition.^[7]

Having certain genetic variations, particularly in the HLA-DPB1 gene, increases the risk of developing GPA. This suggests that some people may have a genetic susceptibility that, when combined with unknown environmental factors, leads to the disease.^[6]

There are no known lifestyle factors, such as diet, exercise, or smoking, that definitively increase the risk of developing GPA. Unlike some other autoimmune diseases, GPA does not appear to be triggered by specific infections, medications, or environmental exposures, though research in this area continues.^[4]

Symptoms

The symptoms of granulomatosis with polyangiitis vary greatly from person to person, depending on which organs are affected and how severely. Some people experience symptoms that develop slowly over many months, while others find their symptoms appear suddenly. Many people first notice vague, general symptoms that could easily be mistaken for a common illness like the flu.^[1]

Early general symptoms often include persistent tiredness that doesn’t improve with rest, fever, night sweats, unexplained weight loss, loss of appetite, and a general feeling of being unwell. Joint pain, stiffness, and muscle aches are also common. These symptoms reflect the body’s widespread inflammatory response.^[3]

Symptoms affecting the ears, nose, and throat are often the first signs that bring people to seek medical attention. Persistent nasal congestion that doesn’t respond to usual treatments is very common. The nose may produce pus-like drainage with crusting, and frequent nosebleeds occur. Some people develop sores inside the nose or mouth. Sinus infections become persistent or recurrent. Earaches, fluid draining from the ears, and hearing loss can develop. In severe cases, inflammation can cause the bridge of the nose to collapse, resulting in a saddle-shaped deformity.^[1][7]

When GPA affects the lungs and windpipe, people may experience a persistent cough, sometimes producing bloody or discolored phlegm. Shortness of breath and wheezing are common. Some people develop chest pain. A serious complication called subglottic stenosis, which is narrowing of the windpipe just below the vocal cords, can cause hoarseness and difficulty breathing. This condition may progress gradually but can become a medical emergency requiring urgent treatment.^[2][7]

Kidney involvement in GPA is particularly concerning because it often causes no pain or obvious symptoms in the early stages. People may notice blood in their urine, making it appear pink, red, or cola-colored. The urine may become foamy due to excess protein. Swelling in the face, hands, or feet can occur. If kidney damage progresses, high blood pressure and kidney failure may develop. Because kidney symptoms can be silent, regular monitoring is essential for anyone diagnosed with GPA.^[2]

Eye symptoms can range from mild to severe. Redness, burning, and pain in the eyes are common. The white part of the eye may become inflamed, a condition called scleritis. Inflammation behind the eye can cause the eye to bulge forward, called proptosis. This can put pressure on the optic nerve and potentially cause sudden vision loss. Blurred or double vision may also occur.^[2][7]

Skin manifestations of GPA include rashes, small red or purple spots called purpura, ulcers, and lumps under the skin. These occur when small blood vessels in the skin become inflamed. Joint pain and swelling can affect multiple joints, making movement uncomfortable.^[3]

Nerve involvement can cause numbness, tingling, or loss of sensation in the hands and feet. Some people experience burning pain or weakness in their limbs. This happens when inflammation damages the nerves that carry signals between the brain and the rest of the body.^[2]

Prevention

Because the exact cause of granulomatosis with polyangiitis is unknown, there are no proven strategies to prevent the disease from developing in the first place. Unlike conditions that can be prevented through lifestyle changes or vaccination, GPA appears to arise from a complex interaction of genetic susceptibility and unknown environmental factors.^[4]

However, early detection and prompt treatment can prevent serious complications and organ damage. People who have been diagnosed with GPA should maintain regular contact with their healthcare providers and report any new or returning symptoms immediately. This allows for early intervention if the disease becomes active again.^[3]

For people living with GPA, preventing infections is important because immunosuppressive medications used to treat the disease reduce the body’s ability to fight infections. Staying up to date with recommended vaccinations, practicing good hand hygiene, and avoiding close contact with people who are sick can help reduce infection risk.^[10]

Regular monitoring through blood tests, urine tests, and sometimes imaging studies helps catch any changes in disease activity before they cause serious problems. This proactive approach to monitoring is a form of secondary prevention that can preserve organ function and quality of life.^[8]

Pathophysiology

Granulomatosis with polyangiitis causes changes in normal body functions through inflammation of blood vessels and formation of granulomas. Understanding these processes helps explain why the symptoms occur and why certain organs are particularly vulnerable.

The disease primarily affects small and medium-sized blood vessels through a process called necrotizing vasculitis. This means the inflammation is severe enough to cause death of tissue in the blood vessel walls. When blood vessels become inflamed, their walls thicken and the opening through which blood flows becomes narrower. In some cases, the vessels can break and bleed. In others, they develop scar tissue that permanently restricts blood flow.^[4]

The granulomas that characterize this disease are organized clusters of immune cells, particularly white blood cells called macrophages, that gather at sites of inflammation. These granulomas start small but can grow larger over time, invading and destroying surrounding healthy tissue. They are particularly common in the respiratory tract and can cause structural damage to the nose, sinuses, and lungs.^[1]

In the kidneys, GPA causes a specific type of damage called pauci-immune glomerulonephritis. The glomeruli are tiny filtering units in the kidneys that remove waste products from the blood. In GPA, inflammation damages these delicate structures with minimal presence of antibodies or immune complexes, hence “pauci-immune” which means “few immune.” This damage allows blood and protein to leak into the urine and prevents the kidneys from properly filtering waste products.^[4]

The respiratory system is vulnerable because it has an extensive network of small blood vessels that are exposed to the environment through breathing. Inflammation in the nasal passages leads to tissue destruction that can erode through the nasal septum or cause the cartilage supporting the nose to collapse. In the lungs, inflammation can cause nodules, infiltrates, or bleeding into the air spaces, making breathing difficult and gas exchange less efficient.^[2]

The presence of ANCA antibodies contributes to the disease process. When these antibodies bind to proteins in neutrophils, they activate the white blood cells inappropriately. The activated neutrophils release toxic substances and enzymes that damage blood vessel walls and surrounding tissues, perpetuating the cycle of inflammation.^[6]