Diagnosis

The most important aspect with respect to the diagnosis of this condition is to be aware of the possibility of polyarteritis. Often the diagnosis is based solely on clinical grounds. Histology may provide proof but often the lesion does not affect a vessel wall continuously and so the lesion may be missed on biopsy. Arteriography, especially of the splanchnic vessels, can be useful, but is of low sensitivity.

Lab values:

• ESR - may be raised
• FBC - normochromic, normocytic anaemia (9-11g/dl); a neutrophil leucocytosis is usually found (this may be as high as 40 x 10 power 9 /l). An eosinophilia is found in 10-20%
• RF - not specific
• hypocomplimentaemia - not a feature of microscopic polyarteritis