Pathology Flashcards
What is secondary vasculitis?
when vessels become inflamed as they are in proximity to inflam eg vessels beside the appendix which get inflamed during appendicitis
What is infection vasculitis?
when there is direct invasion of the vessel by pathogens and therefore inflammation of the vessel wall eg syphilis
What causes immune mediated vasculitis?
immune compex deposition and speciif antibodies (anti-endothelial)
What does ANCA stand for?
anti-neutrophil cytoplasmic antibodies
What is the difference between pANCA and cANCA?
p stnads for perinculear and just binds around nucleus whereas c stands for cytoplasmic and antibodies are diffuse throughout the cytoplasm
How is vasculitis classified?
by the size of vessels affected- large, medium or small
What is an example of large vessel vascultiis?
giant cell arteritis
What is seen on biopsy of giant cell arteritis?
granulomas in the media of the vessel with the elastic fibres almost completely obliterated- segmental with skip lesions
What is the signifance of skip lesions in biopsies?
a negative biopsy doesnt rule out as might hve biopsied okay area
What are the symptoms of giant cell arteritis?
affects temporal artery- temporal headache jaw claudication, scalp tenderness, blindness
What is the treatment for giant cell arteritis?
steroids
Why dont you get rashes with large vessel vasculitis?
big vessels arent near the skin
What type of vasculitis of polyarteritis nodosa?
medium vessel
Why is PAN thought to be caused by circulating immune complexes?
1/3rd of pts have hepB positivity with circulating immune compexes and antibodies
What is seen on biopsy of PAN?
transmural necrotising inflam- fibrinoid necrosis of vessel
What organs are affected in PAN?
kidneys- spares lungs (unusual)
What are the small vessel vasculitis?
Wegeners-granulomatosis with polyangiitis
Churg Strauss-eosinophilic granulomatosis
Henoch Schonlein Purpura
Cryoglobulinaemia
Goodpastures
What is crystal arthropathy?
gout
What is the cause of gout?
build up of urate and uric acid - end products of purine synthesis (adenine and guanine are purine based) so urate is formed in DNA replication etc.
What are the 2 pathways that can cause hyperuricaemia?
making too much or etting rid of too little
What can cause making too much urate?
usually idiopathic (unkown enzyme defect) known genetic defect increased cell turnover- cancer; psoriasis; tumour lyssi with chemo
What is the most common cause of gout?
under-excretion
What is a common drug that reducing urate excretion?
thiazide diuretics
Why does uric acid end up joints?
moves around and then crystallises in joints due to the lower temperatures there
What happens when uric acid is depostied in joints?
crystals stimulate an inflammatory response which causes damage
What does uric acid cause in the kidney?
stones and direct deposition in the tubules
What do the uric acid crystals look like?
needle-shaped crystals; show negative birefringence
What does negative birefringence mean?
crystals bend the light twice at a negative angel
What causes pseudo gout or chondrocalcinosis?
calcium pyrophosphate
what can cause psuedogout?
usually idiopathic but- hypercalcaemia (inc. hyperparathyroidism); haemachromatosis; hypomagnesia
What is the difference between the crystals in gout and pseudogout?
gout- negative bifringence whereas pseudogout-weak positive birefringence, crystals are thicker and bigger, rhomboid shape
What is Paget’s disease?
abnormality of bone turnover
What causes Paget’s?
increase osteoclastic activity which causes more bone but not normally structured
What causes Paget’s?
genetics, viral infections
What is the difference pathologically between Paget’s and normal bone?
normal bone is v. organised- looks like rings in trees whereas in Paget’s there is thick excess bone with abnormal mosaic pattern
What causes pain in Pagets
microfractures and nerve compression
What bones does Paget’s mainly affect?
axial bones
What does increased metabolism mean in terms of presentations?
heat, warm skin, AV shunt and high output HF
What secondary malignancy can Pagets cause?
osteosarcoma
What causes osteomalacia?
abnormal vitamin D metabolism (adult version of rickets) due to reduced sun exposure