Polyarteritis Nodosa

Vasculitis all details click here.

Polyarteritis nodosa (PAN) is a necrotising vasculitis invol￾ving small and medium-sized muscular arteries of multiple organs and tissues. ‘Polyarteritis’ is the preferred

nomenclature over ‘periarteritis’ because inflammatory involvement occurs in all the layers of the vessel wall. The disease occurs more commonly in adult males than

females. Most commonly affected organs, in descending order of frequency of involvement, are the kidneys, heart liver, gastrointestinal tract, muscle, pancreas, testes, nervous system and skin. The syndrome of PAN presents with varied

symptoms pertaining to different organs. However, some usual clinical features are fever, malaise, weakness, weight loss, renal manifestations (albuminuria, haematuria and renal failure), vascular lesions in the alimentary tract (abdominal pain and melaena), peripheral neuritis and hypertension. The  condition is believed to result from deposition of immune complexes and tumour-related antigens.

-> Typically involve renal & viseral vessels but sparing the pulmonary circulation .

-> 30% of patients patient with PAN have chronic Hepatitis B & deposit containing HBsAg - HBsAb complex in affected vessels. 

-> Inflammation of multiple arteries leading to formed nodes.

-> Common in young adults.

-> Involve in renal & visceral vessels not pulmonary circulation.

-> Transmural inflammation in all the 3 layers of medium vessels ( tunica adventitia, tunica media, tunica intima ).

• At the site of inflammation -Aneurysm formation and Fibrinoid necrosis ( hall mark of immune complex disease ).

-> About 30% patients with PAN have HbBsAg present but not associated with ANCA.

-> Aneurysm & thrombosis -> dincrease blood supply -> ischemia degeneration of tissues -> ulcer( due to sloughing of necrotic tissue ) ->  infaction -> Hemorrhage.

Symptoms-:

• Ischemic degeneration.

• Ulcer.

• Infraction.

• Hemorrhage.

 Clinical features-:

i) Systematic effect-

• Due to cytokines -> fever , malaise, weight loss, anorexia. 

• Cytokines also activate liver tk secret Acute phase Reaction -> increase ESR & C-reactive protein.

ii) Local effect-

• Abdominal pain.

• Gangrene.

• Ischemia in kidney.

• HTN Hypertension in patients.

• Mononeuritis multiplea.

Treatment -::

i) Immunosuppressive (90% patients recovered).

Eg - Cydophosphamide 

ii) fatal PAN is untreated.