Polyarteritis Nodosa (PAN)

Exam Cram

• Polyarteritis nodosa is a medium/ small less vasculitis

• Presentation: weight loss, post prandial abdo pain,,

• Signs: livedo reticularis, mononeuritis, haemoproteinuria, 

• Diagnosis: 3/10 features

Outline

Background

• Pathophysiology: small to medium arterial vasculitis causing necrosis

• Prevalence 1/100,000

• First described in 1886 as a necrosis in arterial walls

Assessment

History

• 40M

• Subacute weeks to months: weight loss, fevers

• Myalgia or muscle weakness

Examination

• Livedo reticularis

• Mono/ polyneuropathy

• Hypertension

Investigations

• Elevated creatinine/ urea (without cause)

• Hepatitis B +ve 

• Arteriogram: visceral artery aneurysm or occlusion

• Biopsy: small/ medium artery- granulocytes

Diagnosis & Classification

Diagnostic Criteria: ACR 1990 (American Rheumatology)- 3/10 features

• Weight loss > 4kg since beginning of illness

• Livedo reticularis

• Testicular pain/ tenderness

• Myalgia or muscle weakness

• Mono/ polyneuropathy

• Hypertension

• Elevated creatinine/ urea (without cause)

• Hepatitis B +ve 

• Arteriogram: visceral artery aneurysm or occlusion

• Biopsy: small/ medium artery- granulocytes

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Differential Diagnosis: Cryoglobulinemia from HCV

Classification

• Primary: idiopathic

• Secondary to infection: HBV , HIV 

Management

Features of presentation

• Cutaneous vasculitis

• Nephritis

• Mononeuritis

• Mesenteric ischaemia

Occurs in increased rates in patients with:

• HBV

• HCV

Med Reg Notes

Secondary causes

There is debate around whether HCV can cause PAN and it can be difficult to distinguish cryoglobulinemia from PAN. 

Resources and References

1. https://www.hopkinsvasculitis.org/types-vasculitis/polyarteritis-nodosa/

2. Amini S, Ahmed Z, Basra T, Victor D, Gaber L, Kodali S. Polyarteritis Nodosa Associated With Hepatitis C Virus Infection. Cureus. 2023 Aug 25;15(8):e44129. doi: 10.7759/cureus.44129. PMID: 37753027; PMCID: PMC10518241.

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Written 2025