Flashcards in 3. Chronic inflammation - diseases Deck (21)
What are the possible complications of chronic inflammation?
2. impaired function (often secondary to fibrosis)
3. increased function - rare
5. stimulation of immune response (macrophage - lymphocyte interaction)
Give an example of chronic inflammation associated with increased function.
Thyrotoxicosis - overproduction of thyroxine - in Graves' disease (autoantibodies against TSH receptors)
Give an example of chronic inflammation leading to tissue atrophy.
Pernicious anaemia: gastric autoimmune disease (antibodies to parietal cells and intrinsic factor)... causes destruction of gastric mucosa.
what is chronic cholecystitis and how is it caused
- chronic inflammation of gallbladder common bile duct
- due to repeated obstruction by gallstones
- causing fibrosis of gallbladder wall
what is chronic gastritis and how is it caused
chronic inflammation of gastric mucosa caused by infection with Helicobacter pylori
how does H. pylori cause chronic gastritis
1. directly damages epithelial cells
2. stimulates production of pro-inflammatory cytokines
3. increases acid secretion
describe the microscopic features of chronic gastritis
1. presence of H. pylori organisms
2. mucosa chronic inflammation: in superficial epithelium and lamina propria
3. lamina propria fibrosis
4. mucosal atrophy
5. intestinal metaplasia
which malignancies are associated with H. pylori gastritis
1- gastric adenocarcinoma
2- MALT lymphoma
which cell type does Mtb initially infect and how does it survive
i) Mtb enters macrophages by endocytosis... replicates within phagosome - blocks phagolysosome fusion.
ii) proliferates in pulmonary alveolar macrophages and airspaces... bacteraemia... seeding of multiple sites (asymptomatic or mild flu-like illness)
describe the immune response against Mtb infection
i) 3 wks after infection: T helper cell response against Mtb is mounted - produce IFNy... activates macrophages to become bactericidal... produce TNF.
ii) recruits monocytes with differentiate into epithelioid histiocytes... granuloma formaiton - contains illness in many.
iii) in some, infection progresses - immune response results in tissue destruction due to caseation and cavitation.
what is the main microscopic feature of TB
tuberculous granuloma consisting of central caseous necrosis and Langhans giant cells
what is the main macroscopic feature of TB
- GHON FOCUS (calcified tuberculous granuloma in lung)
- contained in a GHON COMPLEX (ghon focus + granulomas in hilar lymph node)
what is a ranke complex
seen in healed primary TB - comprises a ghon focus and ipsilateral calcified hilar node
what is miliary tuberculosis
disseminated TB throughout body (e.g. lungs, liver and spleen) resulting in small lesions esp. seen on chest x-ray
what is Pott's disease
TB in vertebrae
what is scrofula
TB in cervical region
what is sarcoidosis
autoimmune condition causing granuloma formation in various organs, esp. lungs and skin
how is TB differentiated from sarcoidosis
- caseous granuloma
- langhans giant cells
- X-ray to show Ghon lesions
- Acid-fast stain shows acid-fact bacilli
- non-caseating granuloma
- Langhans giant cells
- blood tests show high Ca2+ and high ACE levels
what is liver cirrhosis
chronic liver inflammation associated with fibrosis... architecture disorganisation and attempted regeneration... cirrhosis and impaired function
what are the common causes of liver cirrhosis
2- HBV or HCV infection
4- fatty liver disease
5- drugs and toxins