MOD Flashcards
List the 5 macroscopic features of acute inflammation
Calor - heat Rubor - red Tumor - swollen Dolor - pain Loss of function
List some common causes of acute inflammation
Microbial infections Hypersensitivity reactions Physical agents Chemicals Tissue necrosis
What is the purpose of acute inflammation?
To limit tissue damage
What are the steps in acute inflammation?
Vasodilation, gaps in endothelium form, exudation, margination (neutrophils adhere to endothelium) and emigration (neutrophils migrate through membrane). Neutrophils move there by chemotaxis. Macrophages and lymphocytes behave similarly to neutrophils
List some chemical mediators and what they do
Histamine and prostaglandins - increase vascular permeability and vasodilation
Leukotrienes - emigration of leukocyte
What do neutrophils do in acute inflammation?
Phagocytise microorganisms then fuse the phagosomes with lysosomes to destroy them. They can also release metabolites/enzymes which causes damage to tissue
What are some symptoms of acute inflammation?
Decreased appetite, raised heart rate, altered sleep pattern, fever and shock
What are the possible outcomes to acute inflammation?
Resolution
Continued acute inflammation and chronic inflammation
Chronic inflammation
Death
How might resolution of acute inflammation be achieved?
The chemical mediators all have short half lives so may degrade or inactivate or be diluted. This means the changes are reversed (neutrophils stop marginating, vessels return to normal, exudate drains and fibrin degrades) and damaged tissue regenerates
What are some potential complications of acute inflammation?
Swelling could block tubes - in GI
Exudate could compress organs - cardiac tamponade
Excessive fluid could be lost
Pain/loss of function
Give some examples of acute inflammation
Skin blister, abscess and pericarditis
Give some inherited disorders of acute inflammation
Alpha 1 anti trypsin deficiency
Hereditary angio-oedema
Chronic granulomatous disease
Defect in neutrophil function/number
Explain Hereditary angio-oedema and how it is treated
The C1 inhibitor is deficient. As well as C1, C1 inhibitor also inhibits bradykinin, a peptide which increases permeability and therefore causes a build up of fluid and oedema. Treat with a C1 inhibitor infusion or fresh frozen plasma
Explain alpha 1 anti trypsin deficiency
Alpha 1 antitrypsin inhibits trypsin. Trypsin activates elastase which will break down lung and liver tissue causing emphysema and liver sclerosis
Explain chronic granulomatous disease
A recessive sex linked condition which stops the body from making ROS so certain bacteria can’t be killed and therefore they are contained in granulomatous
What is an abscess?
In solid tissues. Exudate forces tissue apart. Liquefaction necrosis in the centre. Can cause high pressure and therefore pain. Can damage nearby tissue
How can chronic inflammation arise?
Take over from acute inflammation if the damage is severe
Arise de novo - autoimmune, certain infections, chronic low level irritation
Alongside acute inflammation
What are the effects of chronic inflammation?
Fibrosis
Impaired function
Atrophy
Stimulation of immune response
List the cells involved in chronic inflammation
Macrophages, lymphocytes, eosinophils, fibroblasts, myofibroblasts, and giant cells formed by fused macrophages such as langerhans, foreign body type and touton giant cells
What to macrophages do in chronic inflammation?
Phagocytosis, processing and presentation of antigen, synthesis and release of cytokines, complement components, clotting factors and proteases
What do lymphocytes do in chronic inflammation?
B - differentiation into plasma cells to produce antibodies
T - involved in control and cytotoxic function
When will eosinophils appear in chronic inflammation?
Allergic reactions, parasitic infection and certain tumours
Give two clinical examples of chronic inflammation with fibrosis
Chronic cholecystitis
Gastric ulceration
(Liver cirrhosis)
Give 2 clinical examples of chronic inflammation with impaired function
Ulcerative colitis
Crohn’s disease
(Liver cirrhosis)
Explain chronic cholecystitis and how it is treated
Repeated obstruction of the gall bladder by gallstones causes repeated acute inflammation which will lead to chronic inflammation and fibrosis of the gall bladder wall. Treat by removing gall bladder
What is gastric ulceration, what are possible causes and how is it treated?
Acute gastritis - due to alcohol/drugs
Chronic gastritis - due to helicobacter pylori
Ulceration occurs due to an imbalance between acid production and mucosal defences
Treat helicobacter pylori with proton pump inhibitors (omeprazole) and 2 antibiotics (amoxicillin/clarithromycin)
What is liver cirrhosis, some possible causes and how is it treated?
Chronic inflammation of the liver with fibrosis. This leads to disorganisation of architecture and attempted regeneration.
Causes: alcohol, hep b/c, immunological, drugs, toxins and fatty liver disease
Treatment: modify lifestyle to prevent further damage or liver transplant
What are granulomas?
These form when the immune system can’t eliminate something and therefore act to wall it off
What are some possible causes of granulomatous diseases?
Mycobacterium - TB, leprosy Syphilis Some fungi Sarcoidosis Crohn's disease
Explain tuberculosis
The mycobacterium causing TB don’t actually do any damage to the cells themselves but as they can’t be removed the persistent induction of cell mediated immunity (granulomas) causes the damage.
Define haemostasis
The body’s response to stop bleeding and the loss of blood
What is required for successful haemostasis?
Vessels - constrict to limit blood loss
Platelets - adhere to walls and each other to form a platelet plug
Coagulation system - clotting cascade
Fibrinolytic mechanisms - break down fibrin after
How does fibrinolysis occur and what drugs can be given to do so?
Plasminogen is activated and becomes plasmin which breaks down the fibrin.
Streptokinase
Define thrombosis
The formation of a solid mass of blood within the circulatory system
What makes thrombi more likely to form?
Virchow’s triad:
Change in blood flow - stagnant/turbulent blood
Change in vessel wall - atheroma, injury or inflammation
Change in blood components - smokers or pregnancy
What are the differences between arterial and venous thrombi?
Arterial/Venous Pale/deep red Granular/soft Lines of Zahn/gelatinous Lower cell content/higher cell content
What are the potential outcomes to a thrombus and briefly explain each one?
Lysis - complete dissolution of thrombus
Propagation - thrombus moves along blood stream
Organisation - in growth of fibroblasts and capillaries
Recanalisation - incomplete blood flow reestablishment by channels forming in thrombus
Embolism - thrombus breaks off, moves through blood stream and lodges elsewhere
What are the differences between the effects of arterial and venous thrombi?
Arterial - ischaemia and infarction
Venous - ischaemia, infarction, oedema and congestion
Define embolism
The blockage of a blood vessel by a solid liquid or gas at a site distant from its origin
What are some types of embolism?
Thrombo-emboli (90%), air, nitrogen (the bends), amniotic fluid, medical equipment and tumour cells
Where would the following embolisms end up if they formed in: systemic veins?
Heart?
Carotid arteries?
Abdominal aorta?
Lungs
Arteries
Brain
Legs
Outline the differences in the severity of pulmonary embolisms including symptoms
Massive - if over 60% blood flow blocked it is rapidly fatal
Major - shortness of breath, cough and blood in sputum
Minor - asymptomatic or shortness of breath
Recurrent - pulmonary hypertension
What makes a deep vein thrombus more likely to form?
Immobility, post operation, post partum, oral contraceptive, burns and cardiac failure
How do you treat deep vein thrombosis?
Intravenous Heparin
Oral Warfarin
How might the following emboli form: Fat? Cerebral? Iatrogenic? Nitrogen?
Long bone fracture breaks up adipose tissue
Atrial fibrillation
Medical equipment (air injection)
Nitrogen - bubbles form from decompression
What is Disseminated Intravascular Coagulation?
Lots of small clots form in the body which uses up the clotting factors so can cause haemorrhaging
Explain haemophilia
X linked recessive from a nonsense mutation
Two types - A: factor VIII deficient B: factor IV deficient
Causes haemorrhaging
What is thrombocytopenia?
Low platelet count due to: low rate of production, high rate of destruction or they’re being sequestered. Usually an accompanying bone marrow dysfunction
What are some causes of cell injury?
Trauma, chemicals, drugs, electrical, heat, immunological, hypoxia, radiation, cold, toxins and microorganisms
What are the reversible changes of hypoxia and how do they occur?
Lack of oxygen means oxidative phosphorylation can’t take place. This means anaerobic respiration takes place so there’s a build up of lactic acid and pH decreases. The lack of ATP means that Na pumps don’t work so no Na gradient can be made and therefore Na builds up in the cell, bringing water in as well causing swelling. Ribosomes detach
What are the different types of hypoxia?
Hypoxaemic - e.g. High altitude
Anaemic - e.g. CO poisoning, iron deficiency anaemia
Ischaemic - e.g. Ischaemia
Histiocytic - e.g. Cyanide
What are the irreversible changes in hypoxia?
Cytosolic calcium concentration massively increases because the sodium calcium exchanger is reversed. Enzymes are activated
Define hypoxia
Hypoxia is reduced O2
What are the reversible, microscopic structural changes in cell death?
Swelling, chromatin clumping, autophagy, ribosome dispersal and blebs
What are the irreversible, structural changes in cell death?
Pyknosis (nucleus shrinks), karryohexis (nucleus fragments), karryolysis (nucleus dissolves), membrane defects, lysosomes rupture and ER lysis
Define apoptosis?
Controlled cell death that is energy dependent
Define necrosis?
The morphological changes after cell death
What is oncosis?
The changes in a cell prior to cell death