OVERVIEW

What is polyarteritis nodosa?

Polyarteritis nodosa (PAN) is a systemic necrotizing vasculitis that typically affects medium-sized muscular arteries. Unlike other forms of systemic vasculitis, it does not involve veins.

Distinct from microscopic polyangiitis (MPA), polyarteritis nodosa is not associated with the presence of antineutrophil cytoplasmic antibodies (ANCA).

SYMPTOMS

What are the manifestations of polyarteritis nodosa?

Patients often experience systemic symptoms such as fatigue, weight loss, weakness, fever, and joint pain, as well as multi-system involvement, including skin lesions, hypertension, renal insufficiency, neurological dysfunction, and abdominal pain.

What is the mortality rate of polyarteritis nodosa?

Without treatment, the mortality rate of polyarteritis nodosa is very high.

With treatment, survival rates improve significantly, with a 5-year survival rate of approximately 80%. However, patients with hepatitis infection have lower survival rates than those without, and those with fewer organ involvements have higher survival rates.

What diseases can polyarteritis nodosa cause?

The disease has many complications, depending on which organ arteries are affected. Involvement of coronary, pulmonary, or abdominal arteries can be life-threatening in severe cases.

Does polyarteritis nodosa affect fertility?

The disease itself rarely affects fertility. However, glucocorticoids used in treatment may have a significant impact. Fertility usually recovers after discontinuing medication.

Does hepatitis B in polyarteritis nodosa patients affect treatment or disease progression?

Hepatitis B increases the risk of developing polyarteritis nodosa.

Since treatment for polyarteritis nodosa involves glucocorticoids and immunosuppressants, which may activate hepatitis B virus replication and cause harm, hepatitis B must be managed to avoid risks such as fulminant hepatitis.

CAUSES

What causes polyarteritis nodosa?

The exact cause of polyarteritis nodosa remains poorly understood.

Most cases are idiopathic, with no identifiable cause.

However, hepatitis B virus infection, hepatitis C virus infection, and certain types of leukemia play a significant role in some cases, which are referred to as secondary polyarteritis nodosa.

Is polyarteritis nodosa hereditary?

There is currently no evidence suggesting a genetic predisposition for this disease.

Can polyarteritis nodosa occur in children/young adults?

Polyarteritis nodosa can affect children and young adults. In fact, unlike many other vasculitides, it tends to occur at a relatively younger age.

Who is most commonly affected by polyarteritis nodosa?

Middle-aged and elderly individuals are more susceptible, with incidence increasing with age and peaking in patients aged 50–59.

DIAGNOSIS

What tests are needed for polyarteritis nodosa?

Routine examinations include:

• Physical examination: Look for skin manifestations, motor weakness (such as foot drop or wrist drop), or sensory loss. A thorough physical examination helps determine the extent of vascular lesions, the distribution of affected organs, and the presence of other diseases.
• Ancillary tests: Serum creatinine, muscle enzyme concentrations, liver function tests, hepatitis (HBV and HCV) serology, immunologic tests, erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), antineutrophil cytoplasmic antibodies (ANCA), urinalysis, etc. Additionally, a chest X-ray is used to rule out other diseases, particularly other types of vasculitis that commonly affect the lungs. Even in the absence of cardiac symptoms, a baseline electrocardiogram may be performed. Blood cultures are done to exclude bloodstream infections. Basic laboratory tests help identify the extent of organ involvement and their severity.
• Biopsy: Due to the relative rarity of this disease and the potential for severe adverse effects from treatment, a biopsy should be performed whenever possible to confirm the diagnosis.

Which diseases can polyarteritis nodosa be easily confused with?

The differential diagnosis for polyarteritis nodosa is broad and includes:

• Infectious diseases such as infective endocarditis, HBV or HCV infection, and HIV infection;
• Non-infectious diseases, particularly those that may cause widespread arterial embolism, thrombosis, or vasospasm, such as atherosclerosis, left atrial myxoma, malignant hypertension, certain developmental disorders, or intoxications. These conditions are not suitable for immunosuppressive therapy, so special attention should be paid to their differentiation.
• Other systemic vasculitides, such as granulomatosis with polyangiitis (Wegener's granulomatosis), microscopic polyangiitis (MPA), Henoch-Schönlein purpura (IgA vasculitis), drug-induced vasculitis, and vasculitis secondary to connective tissue diseases (e.g., systemic lupus erythematosus, rheumatoid arthritis).

TREATMENT

Which department should I visit for polyarteritis nodosa?

Rheumatology and Immunology.

How is polyarteritis nodosa treated? How long does treatment last?

Treatment begins with an assessment of the condition.

• Mild disease refers to cases with systemic symptoms, arthritis, anemia, and skin lesions but normal kidney function, no significant cardiac, neurological, or gastrointestinal manifestations, and no hepatitis. Initial treatment involves oral glucocorticoids for 4 weeks. If symptoms resolve without new disease manifestations or progression of arterial lesions, the dose can be gradually tapered. Glucocorticoids are usually discontinued after about 6–8 months.

• Moderate to severe disease involves kidney dysfunction, new or worsening hypertension due to vasculitis, symptomatic arterial stenosis, aneurysms, or any ischemic conditions (e.g., limb, cardiac, gastrointestinal, or central nervous system ischemia). Initial treatment includes intravenous glucocorticoids followed by oral prednisone. Cyclophosphamide pulse therapy is also used for at least 4 months, up to 12 months, until stable remission is achieved.

• Refractory disease occurs in rare cases where patients respond poorly to glucocorticoids and cyclophosphamide. For moderate to severe cases with persistent or worsening symptoms after 2–3 months of treatment, glucocorticoid pulse therapy is administered, followed by oral prednisone and switching cyclophosphamide to other immunosuppressants.

• Coinfection with hepatitis B or C: Mild cases are treated with antiviral drugs without immunosuppressants. Moderate to severe cases require antiviral therapy alongside glucocorticoids and immunosuppressants.

What medications do polyarteritis nodosa patients need? What are the common side effects?

Mainly glucocorticoids and immunosuppressants (e.g., cyclophosphamide).

Glucocorticoids:

• Thinning skin and purpura; avascular necrosis of the femoral head;
• Cushingoid features (redistribution of body fat, central obesity, buffalo hump, moon face, weight gain);
• Eye abnormalities;
• Increased risk of ischemic heart disease and heart failure;
• Impaired glucose regulation (affects insulin function);
• Dyslipidemia;
• Gastrointestinal issues like gastritis, ulcers, and bleeding;
• Fluid retention, increasing fluid burden in patients with heart or kidney disease;
• Elevated blood pressure;
• Menstrual irregularities in women, reduced fertility in both sexes;
• Increased risk of developmental abnormalities in offspring if taken during pregnancy;
• May trigger psychiatric and cognitive symptoms; increased infection risk.

Cyclophosphamide:

• May cause hemorrhagic myocardial necrosis;
• Pulmonary fibrosis; urinary system damage due to metabolite acrolein;
• Moderate to severe immunosuppression; hepatotoxicity and liver damage;
• Bone marrow suppression (severity depends on dosage);
• Skin reactions like pigmentation, mucosal ulcers, hives, hair loss, drug-induced dermatitis.

Do polyarteritis nodosa patients need follow-ups? How often?

During the initial treatment phase, follow-ups should occur at least monthly. Within the first two years, follow-ups should be at least every 3 months.

Follow-ups include physical exams, monitoring for drug toxicity, serum creatinine tests, and urinalysis to assess kidney function. Immediate medical attention is required for new symptoms.

How likely is polyarteritis nodosa to relapse?

Polyarteritis nodosa has a relatively low relapse rate. However, long-term treatment is still needed to control the condition.

DIET & LIFESTYLE

What should be noted in daily life for polyarteritis nodosa?

There are no special precautions for polyarteritis nodosa. Just maintain a healthy lifestyle like everyone else.

Dietary recommendations:

• Eat more fruits and vegetables;
• Balance meat and vegetables. If vegetarian, consume more soy products for protein. If dairy is acceptable, ensure 300 mL of milk daily to prevent calcium deficiency;
• Avoid relying solely on refined grains; replace some staples with legumes, potatoes, pumpkin, etc.;
• Use less salt and high-sodium seasonings when cooking;
• Limit pickled foods and meats; avoid alcohol as much as possible.

Beyond diet, also pay attention to:

• Engage in about 30 minutes of daily exercise, combining aerobic and strength training at a moderate intensity;
• Ensure sufficient sleep each day;
• Learn to manage stress and emotional tension.

Does polyarteritis nodosa affect fertility?

The disease itself does not affect fertility, but medications used to control polyarteritis nodosa may impact fertility or the fetus.

If pregnancy is planned, consult a doctor in advance. Control the condition with fertility-safe medications before conceiving.

PREVENTION

How to prevent polyarteritis nodosa?

Currently, the exact cause cannot be identified for most cases of polyarteritis nodosa, which may be related to immune system disorders, making it difficult to prevent.