Polyarteritis Nodosa

Polyarteritis Nodosa (PAN) is a rare vasculitis that primarily affects medium-sized muscular arteries, leading to damage and inflammation. The disease can result in organ and tissue damage due to the reduced blood flow caused by inflamed arteries. Commonly affected organs include the kidneys, skin, joints, muscles, peripheral nerves, and gastrointestinal tract.

1.0Polyarteritis Nodosa Causes

• The exact cause of polyarteritis Nodosa (PAN) is not well understood, but several factors are thought to contribute to its development:
•  It is considered an autoimmune disease in which the immune system mistakenly attacks the body's own blood vessels, leading to inflammation and necrosis.
• Hepatitis B Virus (HBV): There is a well-established association between PAN and hepatitis B infection. Approximately 30% of PAN cases are linked to chronic HBV infection. 
• There may be a genetic predisposition to developing PAN, although specific genetic markers have not been clearly identified. 
• Exposure to certain environmental triggers or toxins may contribute to the development of PAN.

2.0Who Gets Polyarteritis Nodosa

• Polyarteritis Nodosa (PAN) can affect individuals of any age, gender, or ethnicity, but certain patterns have been observed in its occurrence:
• PAN can occur at any age but is most commonly diagnosed in adults between the ages of 40 and 60 years. It is less common in children and adolescents, although pediatric cases occur.
• PAN affects both men and women, but some studies suggest it may be slightly more common in men.
• The PAN varies by region, and higher rates may be found in certain areas, potentially related to the prevalence of hepatitis B infection.

3.0Polyarteritis Nodosa Symptoms

Polyarteritis Nodosa (PAN) is characterized by a wide range of symptoms due to its systemic involvement of medium-sized arteries in various organs. 

Common symptoms include:

• Fever
• Weight Loss
• Fatigue
• Rashes
• Nodules: Painful lumps or nodules under the skin.
• Ulcers
• Myalgia: Muscle pain and tenderness.
• Muscle Weakness: Decreased muscle strength.
• Mononeuritis Multiplex: Damage to multiple separate peripheral nerves, causing severe pain and weakness.
• Hypertension: High blood pressure.
• Heart Failure: Due to long-standing hypertension or direct cardiac involvement.

4.0Polyarteritis Nodosa Complications

Polyarteritis Nodosa (PAN) can lead to various complications due to the widespread inflammation and damage to medium-sized arteries. The complications depend on which organs are affected and can range from mild to life-threatening.

• Hypertension: High blood pressure is common due to the involvement of renal arteries.
• Renal Failure: Progressive kidney damage can lead to chronic kidney disease or acute renal failure.
• Peripheral Neuropathy: Damage to the nerves can cause pain, numbness, and limb weakness.
• Abdominal Pain: Due to mesenteric artery involvement, leading to ischemia of the intestines.
• Gastrointestinal Bleeding: Ulcers and perforations can occur, causing bleeding.
• Intestinal Infarction: Severe cases can lead to bowel necrosis and perforation, which is life-threatening.
• Myocardial Infarction: Involvement of coronary arteries can lead to heart attacks.
• Skin Ulcers and Nodules: Painful skin lesions can occur, often on the lower extremities
• Myositis: Inflammation of the muscles can cause muscle pain and weakness.
• Arthritis: Joint inflammation leading to pain and swelling.
• Fever and Weight Loss: Chronic inflammation often leads to fever, fatigue, and significant weight loss.
• Malaise and Fatigue: Persistent inflammation and organ damage can cause feelings of unwellness and extreme tiredness.

5.0Polyarteritis Nodosa Treatment

• High doses of corticosteroids such as prednisone are often the first line of treatment. They help reduce inflammation quickly.
• Antiviral drugs such as lamivudine, entecavir, or tenofovir are used to control the infection if PAN is associated with HBV infection.
• Antiviral therapy is also used if PAN is associated with HCV infection.
• Blood Pressure Control: Medications to control hypertension are crucial.
• Medications for neuropathic pain, such as gabapentin or pregabalin, may be prescribed.
• Cardiac Monitoring: Regular monitoring and management of heart function.
• Medications for pain relief and inflammation, including NSAIDs, may be used cautiously.
• Calcium and vitamin D supplements 
• Regular Exercise: Helps maintain strength and mobility.

Side Effects of Treatment

Treatment for polyarteritis Nodosa (PAN), particularly with corticosteroids and immunosuppressive drugs, can lead to various side effects. 

Short-Term Side Effects:

• Increased Appetite and Weight Gain
• Mood Changes
• Insomnia
• Elevated Blood Sugar Levels
• Fluid Retention
• Gastrointestinal Issues include nausea, stomach ulcers, and indigestion.

Long-Term Side Effects

• Osteoporosis
• Hypertension
• Cataracts
• Increased Risk of Infections
• Thinning of the skin, easy bruising, and delayed wound healing.

6.0Polyarteritis Nodosa Vasculitis 

PAN is classified as a medium-sized vessel vasculitis, meaning it primarily affects medium-sized arteries. 

Vasculitis Classification:

• PAN is classified within the broader category of medium-vessel vasculitides. Other types of vasculitis include:
• Small-Vessel Vasculitides: Affecting small arteries, venules, and capillaries (e.g., microscopic polyangiitis, granulomatosis with polyangiitis).
• Large-Vessel Vasculitis: Affecting large arteries like the aorta (e.g., giant cell arteritis, Takayasu arteritis).

7.0Cutaneous Polyarteritis Nodosa

• Cutaneous polyarteritis Nodosa (PAN) is a subset of polyarteritis Nodosa (PAN) that primarily affects the skin. 
• It involves inflammation of medium-sized arteries in the skin and is characterized by specific dermatological manifestations. 

8.0Microscopic Polyarteritis Nodosa

• Microscopic polyarteritis Nodosa (PAN) is a term sometimes used to describe a variant of polyarteritis Nodosa in which the disease is more likely to present with small-vessel involvement. 
• However, it's important to note that in current medical terminology, "microscopic polyangiitis" (MPA) is a more precise term used to describe a distinct condition that differs from polyarteritis Nodosa but has some overlapping features.

9.0Is Polyarteritis Nodosa ANCA positive?

• Polyarteritis Nodosa (PAN) is typically ANCA-negative. 
• In general, PAN is not associated with anti-neutrophil cytoplasmic antibodies (ANCA), which distinguishes it from other types of vasculitis, such as microscopic polyangiitis and granulomatosis with polyangiitis (Wegener's granulomatosis), which are often ANCA-positive.

10.0ANCA and Polyarteritis Nodosa

• Polyarteritis Nodosa (PAN): PAN is usually negative for ANCA, and the presence of ANCA is not a characteristic finding.
• Other Vasculitides: Conditions like microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA) often have poWegener'sCA, specifically perinuclear ANCA (p-ANCA) with myeloperoxidase (MPO) specificity or cytoplasmic ANCA (c-ANCA) with proteinase 3 (PR3) specificity.