Introduction to Wegener’s Granulomatosis
Wegener’s granulomatosis, also known as granulomatosis with polyangiitis, is a type of small-vessel vasculitis. It is a rare disease with a prevalence of 3 cases per 100 000 people (1). It affects males and females equally and occurs most frequently in Caucasian population (1). Although the disease can be observed at any age, the average age of onset is 40 years (1). Wegener’s granulomatosis typically involve a triad of features: systemic small-vessel vasculitis, inflammation of respiratory tract, and necrotizing glomerulonepritis (2). For the purpose of classification, a patient must possess 2 of the following 4 criteria below. The sensitivity of this criteria is 88% and its specificity is 92% (3)
- Inflammation in nose or oral cavity: development of oral ulcers, purulent or bloody nasal discharge (3)
- Abnormal chest x-ray: nodules, infiltrates, or cavities (3)
- Urirnary sediment: microhematuria (3)
- Biopsy indicating granulomatous inflammation: histologic changes indicating granulomatous inflammation within wall of a blood vessel (3)
To differentiate Wegener’s granulomatosis from other types of small vessel vasculitis, clinicians need to examine the patient’s clinical presentation, biopsy pattern, and presence of certain laboratory markers. A simplified diagnostic table is shown below in Table 1.
Table 1. Differential diagnosis of small vessel vasculitis, adapted from (2).
- Inflammation in nose or oral cavity: development of oral ulcers, purulent or bloody nasal discharge (3)
- Abnormal chest x-ray: nodules, infiltrates, or cavities (3)
- Urirnary sediment: microhematuria (3)
- Biopsy indicating granulomatous inflammation: histologic changes indicating granulomatous inflammation within wall of a blood vessel (3)
To differentiate Wegener’s granulomatosis from other types of small vessel vasculitis, clinicians need to examine the patient’s clinical presentation, biopsy pattern, and presence of certain laboratory markers. A simplified diagnostic table is shown below in Table 1.
Table 1. Differential diagnosis of small vessel vasculitis, adapted from (2).
References
1. Langford CA, Fauci AS. Chapter 326. The Vasculitis Syndromes. In: Fauci AS, Kasper DL, Jameson JL, Longo DL, Hauser SL, eds. Harrison's Principles of Internal Medicine. 18th ed. New York: McGraw-Hill; 2012. http://www.accesspharmacy.com.proxy.lib.uwaterloo.ca/content.aspx?aID=9138083. Accessed April 1, 2013
2. Jennete JC, Falk RJ. Medical progress: small vessel vasculitis. NEJM 1997 Nov;337:1512-1523. 3. Papadopoulos, PJ. Wegener’s granulomatosis [Internet]. [Place unknown]: Medscape references; 2012 [ updated 2012 May]. Accessed on April 1, 2012. Available from: http://emedicine.medscape.com/article/332622-overview#aw2aab6b2b2aa
1. Langford CA, Fauci AS. Chapter 326. The Vasculitis Syndromes. In: Fauci AS, Kasper DL, Jameson JL, Longo DL, Hauser SL, eds. Harrison's Principles of Internal Medicine. 18th ed. New York: McGraw-Hill; 2012. http://www.accesspharmacy.com.proxy.lib.uwaterloo.ca/content.aspx?aID=9138083. Accessed April 1, 2013
2. Jennete JC, Falk RJ. Medical progress: small vessel vasculitis. NEJM 1997 Nov;337:1512-1523. 3. Papadopoulos, PJ. Wegener’s granulomatosis [Internet]. [Place unknown]: Medscape references; 2012 [ updated 2012 May]. Accessed on April 1, 2012. Available from: http://emedicine.medscape.com/article/332622-overview#aw2aab6b2b2aa