Polyarteritis Nodosa (PAN)

Polyarteritis Nodosa (PAN)

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Inflammatory vasculitis affecting small to medium-sized arteries, typically found at branching points and bifurcations, commonly results in weakened vessels and aneurysms. This carries a risk of rupture and hemorrhage, and small aneurysms caused by fibrotic healing are known as 'Nodosa'.


The exact cause remains unknown, but viral infections such as HIV, CMV and HBV have been linked to Polyarteritis Nodosa.


Acute multisystem disease symptoms include fever, malaise, anorexia, weight loss, myalgia and arthralgia. It can also affect the cardiovascular system (resulting in pericarditis, myocardial infarction and congestive heart failure), the nervous system (including seizures and a range of sensorimotor polyneuropathy), the gastrointestinal system (abdominal pain, nausea, vomiting and GI infarction) and the eyes (retinal vasculitis and retinal detachment). Additionally, it can cause skin rash, purpura, nodules, cutaneous infarcts and Raynaud phenomenon, and renal failure.


Some of the common signs include raised BP, fever, livedo reticularis and mononeuritis multiplex.


FBC, ESR, CRP, ANCA, viral serology and blood cultures are all assessments conducted to diagnose Polyarteritis Nodosa, while a urine dip is used to screen for infection. Imaging tests such as chest X-ray and angiography are used to look for aneurysms and stenosis, while EMG and NCS can assess for peripheral neuropathy.


The main treatments are corticosteroids, cyclophosphamide and antiviral therapy for Polyarteritis Nodosa related to hepatitis.


Potential complications include skin ulcerations, extremity gangrene, organ infarction, aneurysm rupture, stroke, heart failure, myocardial infarction, pericarditis, renal failure, peripheral neuropathy and gastrointestinal bleeding.


Patients with cutaneous Polyarteritis Nodosa and without systemic or visceral involvement have a better prognosis.

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