Granulomatous inflammation
- Distinctive inflammation with central area of necrosis in some types, surrounded by activated epithelioid macrophages and giant cells, with a peripheral accumulation of lymphocytes.
- Occurs in three main settings
- Persistent T-cell response to certain microbes (e.g. in TB)
- Immune mediated inflammatory diseases (e.g. Crohn's)
- Unknown etiology of Sarcoidosis
- Foreign bodies, such as splinters, forming so called foreign body granulomas
Based on this we can divide chronic inflammation into two distinct morphological patterns:
- Nongranulomatous (diffuse and nonspecific)
- Mononuclear infiltrates into interstitium of organs, results in fibrosis
- Example include chronic viral hepatitis, pyelonephritis and Glomerulonephritis
- Granulomatous inflammation
- Can be specific (e.g. TB, Syphilis, Leprosy) or nonspecific (e.g. Foreign body)
Rheumatism
- Any disease marked by inflammation and pain to joints, muscles or fibrous tissue
- Types include
- Back pain
- Tendinitis/Bursitis
- Capsulitis
- Neck pain
- Osteoarthritis
- Many are autoimmune, including
- Ankylosing spondylitis
- Systemic lupus erythematosus
- Rheumatoid arthritis
- Gout (crystal-induced, not autoimmune)
- Such autoimmune cases are a result of T-cell activation and chronic inflammation to the joints and connective tissue.
- This leads to forming of granulation tissue around the tissue (in arthritis for example, granulation tissue forms around the synovial lining)
H&E, rheumatic myocarditis: an Aschoff body (centre) between myocardial fibres, a pale focus of fibrinoid change with large Anitschkow and Aschoff cells.
Image: “Aschoff Body in Rheumatic Myocarditis” by Ed Uthman, MD, CC BY-SA 2.0, via Wikimedia Commons.
Remember: the specific lesion of rheumatic fever is the Aschoff body: a focus of fibrinoid necrosis surrounded by lymphocytes, plasma cells, Anitschkow ("caterpillar") cells and multinucleated Aschoff cells, typically in the myocardium. Rheumatic fever follows group A streptococcal pharyngitis by about 2–3 weeks.