Polyarteritis Nodosa 

Polyarteritis Nodosa (PAN) - is a serious disease and has a VERY high mortality unless treated with immunosuppression...usually in the form of prednisone and Cyclophosphamide.

It essentially consists of an inflammatory reaction in the wall of blood vessels - resulting in occlusion of the vessels and starvation of the tissues of blood flow and oxygen. The result is severe tissue damage. The blood vessel wall is infiltrated with neutrophil white cells.

The organs most affected in PAN are the

Skin - with ulceration.
Nerves - with neuropathy and mononeuritis and potential for paralysis.
Kidneys - with nephritis and potential for renal failure
Bowel - with abdominal pain and bowel perforations.
Abdominal viscera - including gallbladder etc..

The illness is usually characterized initially by :-

Constitutional symptoms
Weight loss
Fever and sweats: In fact a pyrexia (fever) of unknown origin - may be the only sign early on.
Malaise
Fatigue.
Arthralgia
Myalgia
Anaemia
Skin ulcers
Abdominal pain
Hypertension.
Coronary arteries may also be involved as can many othe viscera.

There is often a long delay in diagnosis, often months and it is a problem that should be considered in many multisystem diseases which are otherwise diagnostically difficult and unexplained.

The investigations show :

Anaemia
Elevated White cell count.
High ESR and CRP.
The urine examination may show protein and blood.
Nerve conduction abnormality on electrical testing of involved nerves.
Angiography : The blood vessels may be visualized on visceral Angiography (the investigation of choice), as having weakness in their walls and outpouchings - called microaneurysm's.
Tissue biopsy is desirable - skin / kidney / Muscle / rectal / abdominal fat / sural nerve being frequently chosen as biopsy sites.

Therapy MUST be aggressive.

The untreated 5 year survival is 13%.
Treated patients have a much higher survival 60-90%