History and exam
Key diagnostic factors
common
age 40 to 60 years
Polyarteritis nodosa (PAN) can manifest itself at any age, but the majority of cases are diagnosed between the ages of 40 to 60 years.
fever
Fever is a common but non-specific symptom.
weight loss
A history of unintended weight loss is a common but non-specific symptom.
myalgia or arthralgia
Muscle or joint pain are common but non-specific symptoms.
mononeuritis multiplex
Mononeuritis multiplex is a common manifestation of PAN.
paraesthesia
Motor weakness and/or sensory loss in a peripheral nerve distribution is a common feature and is suggestive of vasculitis.
muscle tenderness
A non-specific manifestation. Areas of tenderness usually reflect areas of muscle ischaemia or infarction and provide a useful site for tissue biopsy.
abdominal pain
Abdominal pain can be caused by ischaemia or infarction of bowel or other abdominal organs.
skin manifestations
Livedo reticularis, skin ulcers, bullous or vesicular eruptions, purpura, or skin infarction may occur in PAN. However, many other diseases, including several of the vasculitides as well as infection, can cause these skin manifestations.
A skin biopsy showing vasculitis does not necessarily indicate systemic involvement.
diastolic blood pressure >90 mmHg
High diastolic blood pressure is associated with PAN.
uncommon
history of blood transfusion predating introduction of routine HBV screening
Before routine screening of blood products for hepatitis B virus (HBV), transfusion was a major mode of transmission of the virus.
previous or current intravenous drug abuse
A recognised mode of transmission of hepatitis B virus.
recent hepatitis B virus (HBV) infection
The majority of cases of HBV-related PAN occur in the first few months after acquiring the infection.
The incidence of HBV-related PAN has dramatically reduced in the past 2 decades, owing to improved screening of blood products and routine vaccination against HBV.
testicular pain
Ischaemic orchitis is a classically described but rare feature of PAN.
Other diagnostic factors
common
male sex
In most series, males seem to be over-represented. However, a prevalence estimate in Sweden in 2007 reported the opposite, with two-thirds of the patients being females.[16]
uncommon
hairy cell leukaemia
There is a weak association between a pre-existing diagnosis of hairy cell leukaemia and the development of PAN.
seizure
An unusual manifestation of PAN, caused by central nervous system involvement.
upper motor neuron weakness
Stroke is a rare manifestation of PAN.
gastrointestinal (GI) bleeding
Ischaemic bowel or ruptured aneurysm can cause GI blood loss.
peritonitis
Can be caused by ischaemic bowel or infarction of any of the abdominal organs.
monocular blindness
Ischaemic optic neuropathy and retinopathy with retinal haemorrhages have been described, but these are rare manifestations.
chest pain
Ischaemic pain and myocardial infarction are possible from involvement of the coronary arteries.
congestive cardiac failure
Ischaemic cardiomyopathy caused by PAN may present with cardiac failure.
tender breast lumps
Breast involvement is a rare manifestation of PAN.
Risk factors
strong
hepatitis B virus (HBV) infection
Polyarteritis nodosa (PAN) develops in 1% to 5% of patients with hepatitis B virus (HBV) infection, which equates to an approximately 1000-fold increase in risk compared with the background population.[13][11][26]
HBV infection is present in 7% to 38.5% of patients with PAN, and in this setting is thought to be directly related to the development of the disease. The prevalence of HBV-related PAN has reduced in recent years as a result of vaccination for HBV and improved screening of blood products.[15][23]
Evidence for the pathogenic nature of HBV and immune complexes is supported by the effectiveness of a treatment strategy to eradicate HBV with antiviral therapy and remove immune complexes by plasmapheresis without the need for long-term immunosuppression.[21][22]
age 40 to 60 years
PAN can present at any age, but the most common age at presentation is 40 to 60 years.
weak
hairy cell leukaemia
There are case reports describing the development of PAN in patients with pre-existing hairy cell leukaemia.[27][28] In 80% of these cases, the patient had undergone splenectomy before the development of PAN. HBV infection was found in some of these case reports, with other case reports predating routine testing for HBV.
Potential mechanisms for the association between hairy cell leukaemia and PAN are cross-reactivity of antibodies between the tumour cells and the endothelium, direct damage of the endothelium by tumour cells, and local production of pro-inflammatory cytokines triggering vessel wall damage.[28]
history of blood transfusion predating introduction of routine HBV screening
Before routine screening of blood products for HBV, transfusion was a major mode of transmission of the virus.
hepatitis C virus (HCV) infection
HCV infection has been associated with cutaneous PAN in one retrospective study of 16 patients, in which five of the patients were found to have HCV infection.[22] However, cutaneous PAN (a form that is limited to the skin and is chronic) is usually considered a separate clinical entity from systemic PAN and is not covered here, although the pathological findings on skin biopsy are indistinguishable between the two.[29]
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