Complications
Osteoporosis secondary to prolonged corticosteroid use should be prevented with regular calcium, vitamin D, and bisphosphonates.[56]
Renal involvement in PAN is not secondary to glomerulonephritis but rather is related to microaneurysms and infarcts secondary to uncontrolled vasculitis.[56] Accelerated hypertension can occur as a result of activation of the renin-angiotensin system, with up to one fifth of patients in one series developing end-stage renal failure.[105]
Prevention should be through immunosuppression for the vasculitis, regular monitoring, and input from renal physicians.
Uncontrolled vasculitis can result in mesenteric ischemia, bowel infarction, and necrosis.[109] GI involvement is an independent risk factor for poor prognosis.[19] Other abdominal organs can also be affected, resulting in, for example, cholecystitis or pancreatitis. Hepatitis B virus (HBV)-related PAN has a higher rate of GI involvement than non HBV-related PAN.[20]
Early diagnosis and prompt institution of appropriate medical therapy, as well as the use of appropriate surgical therapy, can improve the prognosis of patients who present with an acute abdomen.[35]
Mononeuritis multiplex is seen in around 80% of patients with HBV-related PAN during the course of their disease.[20] More rarely, in less than 10% of patients, there is central nervous system involvement, with strokes or encephalopathy.[20]
Treatment is as for the underlying vasculitis, but intensive occupational and physical therapy are both important for recovery of function.
The treatment of HBV-related PAN is adapted to the twin goals of control of the vasculitis and seroconversion of the hepatitis. It has been proposed that, in roughly 50% of patients who seroconvert, cure is attainable.[20] Those who do not seroconvert have an increased risk of chronic liver failure and hepatocellular carcinoma.[78][79][80]
Long-term follow-up of patients with PAN demonstrates that infection is the cause of death in 12.9% of patients.[56] Infection is the second major cause of early death (death within the first year), accounting for 26% of deaths.[54]
Treatment with cyclophosphamide should be accompanied by prophylaxis against Pneumocystis jiroveci and fungal infections, and tuberculosis should be excluded before treatment starts.[60] Immunizations against Pneumococcus and influenza should also be routine.[113]
In long-term follow-up of patients with non HBV-related PAN and Churg-Strauss syndrome, cardiac disease results in 9.4% of overall deaths.[56] Control of vasculitis is essential, but attention to other risk factors for cardiovascular disease, such as smoking, hypercholesterolemia, and hypertension, is also important.[60]
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