Monitoring

The objectives of monitoring are to prevent adverse-effects and disease relapse.

During the remission phase

		Practise sequential monitoring of ESR, C-reactive protein and ANCA levels at monthly intervals for the first year, then less frequently.
		Both ESR and CRP are influenced by other factors than vasculitis and rising levels have low predictive value for relapse but are usually elevated at the time of relapse.
		Persistent ANCA positivity, the conversion of ANCA from negative to positive, or a rising ANCA level during remission has predictive value for relapse of 50-75%. The median interval between a rise in ANCA and clinical relapse is seven weeks.
		Sequential assessment of organ function and localised vasculitic activity -- eg, serum creatinine and urine red cell count -- should be included.
		Relapse usually, but not always, is manifested in a similar distribution to the presenting disease.
		Relapse not threatening vital organ function may be treated by an increase in the oral steroid dose; major relapse needs return to cyclophosphamide.

Adverse-effects

Side-effects of treatment contribute to death in 10% of cases and mobidity in 100%. Permanent damage and incapacity caused by treatment occurs in over 50%. So, current regimens and recommendations focus on minimising this burden of drug toxicity.

Cyclophosphamide-induced neutropaenia and steroid dose appear to be the major contributors to infection, which is more common in the elderly and those with renal failure.

		Neutropaenia should be avoided by frequent white cell counts and reduction or withdrawal of cyclophosphamide for a falling count.
		Haemorrhagic cystitis occurs in 2-5% of those receiving daily oral cyclophosphamide but is less common with pulse administration. MESNA may be used but this is not universal.
		The incidence of bladder cancer rises eleven-fold after one year of daily oral cyclophosphamide.
		Infertility, in both man and women, is an important risk with prolonged administration.

Prophylactic recommendations include

		Treat Pneumocystis carinii pneumonia with low dose sulfamethoxazole-trimethoprim for the duration of cyclophosphamide therapy.
		Give therapy against fungal infection for the first six weeks.
		Give gastric prophylaxis with a protein pump inhibitor or histamine 2 antagonist.
		For steroid-induced bone disease, give either calcium and vitamin D and monitor bone density or biphosphonate with or without bone densitometry.

Cardiovascular events (stroke and myocardial infarction) occur frequently in vasculitis patients, but have not yet been studied in detail. Previous vasculitis, vasculitis treatment and renal impairment contribute to vascular disease. Cholesterol lowering with statins and/or aspirin may be beneficial.