What is Polyarteritis Nodosa?
Polyarteritis Nodosa (PAN) is a rare, necrotising vasculitis that selectively affects medium-sized muscular arteries, causing ischaemic damage to the organs they supply — most commonly the kidneys, skin, peripheral nerves, and gastrointestinal tract. Crucially, PAN does not affect the small vessels (capillaries, venules, arterioles) and does not cause glomerulonephritis, which distinguishes it from the small-vessel ANCA vasculitides.
PAN can be idiopathic (cause unknown) or associated with Hepatitis B virus infection — a relationship that was much more common in the past before widespread Hepatitis B vaccination. In Hepatitis B-associated PAN, treatment focuses on antiviral therapy in addition to immunosuppression.
Livedo racemosa and skin ulceration from medium vessel vasculitis in PAN.
Symptoms: Ischaemia of Multiple Organs
The clinical presentation of PAN reflects the ischaemic damage caused to the organs supplied by the involved arteries:
- Constitutional symptoms: Fever, weight loss (often dramatic, 5-10 kg), profound fatigue, and myalgias are nearly universal.
- Peripheral Neuropathy (mononeuritis multiplex): The most common neurological feature — asymmetric weakness and sensory loss affecting individual named nerves (e.g., foot drop from common peroneal nerve involvement). Characteristically affects multiple distinct nerves.
- Skin involvement: Livedo racemosa (a widespread, irregular, non-blanchable skin mottling), subcutaneous nodules along the course of arteries, skin ulcers, and digital gangrene.
- Renal involvement: Renovascular hypertension from renal artery stenosis, and renal infarction — but notably no glomerulonephritis (absence of haematuria and proteinuria helps distinguish PAN from ANCA vasculitis).
- Gastrointestinal: Abdominal angina (pain after eating), bowel infarction, appendicitis, and liver involvement.
- Testicular pain: Testicular artery involvement causing orchitis is a characteristic and relatively specific feature of PAN in men.
Mesenteric angiography showing the pathognomonic "microaneurysms" — small arterial aneurysms that are characteristic of PAN.
🔬 Diagnosis: Biopsy and Angiography
PAN is diagnosed by demonstrating necrotising arteritis in medium-sized vessels on tissue biopsy (sural nerve biopsy for neuropathy, skin biopsy for skin lesions) or by the finding of characteristic microaneurysms on visceral angiography (coeliac, renal, or mesenteric). ANCA antibodies are typically negative in PAN — a key differentiating point.
Dr. Prateek's Approach to Polyarteritis Nodosa
PAN is a serious vasculitis that can be life-threatening without aggressive treatment. Dr. Prateek Deo provides expert diagnosis and management, ensuring the most appropriate immunosuppressive regimen is selected based on disease severity and Hepatitis B status.
Five-Factor Score (FFS)
We use the validated Five-Factor Score to stratify PAN severity and guide immunosuppressive therapy intensity — matching treatment aggressiveness to disease severity.
HBV Testing and Treatment
All PAN patients are tested for Hepatitis B. HBV-associated PAN requires antiviral therapy (e.g., Tenofovir) alongside a shorter course of immunosuppression to control initial inflammation.
Nerve and Vessel Monitoring
Regular neurological assessments to track peripheral neuropathy recovery, and imaging to monitor vascular disease progression and aneurysm size.
Cyclophosphamide Expertise
For severe, life-threatening PAN, we have extensive experience with pulse intravenous Cyclophosphamide — the most effective induction therapy.