Fever/Immune Flashcards
what is the difference between a fever and hyperthermia?
fever is a raised thermoregulatory set point, set by the anterior hypothalamus and the presence of pyrogens
with hyperthermia there is no alteration of the thermoregulatory set point, can be caused by exercise, seizures, stress, etc
what are the things that cause fever?
the knights who say NIII
neoplasia, infection, immune mediated, inflammation
what is a FUO?
fever of unknown origin: when fever persists long enough to where the common self limiting causes are ruled out and initial diagnostics do not reveal a cause for a fever
a dog presents for fever. what history questions will you ask the owner?
- travel history?
- any recent medications?
- recent history of fighting or trauma?
- recent heat? (pyo)
- any animals or humans in close contact showing signs?
what sorts of things might you be looking for on PE with a pet with a fever?
heart murmur, joint effusion, back pain, bone pain, bite wounds, renal pain, organ enlargement, rectal exam, masses, URI, lung auscultation, enlarged LNs, abdominal or chest effusion, oral exam, ocular exam, derm lesions?
what are some first line diagnostic tools you can use for working up a fever?
CBC/blood smear, biochemistry, urinalysis, urine culture, FeLV, FIV in cats, imaging
others: ultrasound, echocardiogram, joint taps, FNAs, biopsies, etc
autoimmune diseases are most mediated by ___ cells and ______
Th2 cells and autoantibodies
what are 3 characteristics of immune mediated diseases and therefore 3 treatment targets?
-autoantibody production by lymphocytes
-opsonized cells cleared by marcophages or complement
- inflammatory cytokines
what is the difference between primary and secondary autoimmune disease
primary is idiopathic and is a diagnosis of exclusion
secondary has an underlying cause you can identify
immune mediated diseases require complete workups to:
look for an underlying cause and rule out infectious etiology BEFORE you suppress the immune system
what us SLE?
systemic lupus erythematosus
a multisystemic autoimmune disorder where there are antibodies against many tissues, including the nucleus of cells. opsonization happens as well as the formation of immune complexes.
common in dogs, GSDs and duck tollers, usually middle aged
a 6 yo duck toller presents for fever and joint swelling. upon further examination you notice skin lesions on the muzzle and in the oral cavity. The LNs are enlarged. differential? what diagnostics tests do you want?
systemic lupus erythematosus
hard to diagnose with 100% certainty
first, rule out underlying disorders. consider a urinalysis to check for proteinuria which could be indicative of glomerulonephritis
ideally do a ANA test (antinuclear antibody test) or a LE test
what is the ANA test?
autonuclear antibody test for SLE. tests for antibodies agaisnt DNA, RNA, and hostones. false positives and false negatives possible.
usually an ELISA test
what is an LE test?
for SLE diagnosois
looking for lupus erythematosus cells: neutrohpils containing phagovytized nucleus. not sensitive, but very specific.
the 6yo duck toller tests positive for the ANA test and the LE test. how will you treat and what is the prognosis?
immunosuppressive therapy
adjunct therapy for secondary issues like IMHA or PLN
supportive care
prognosis is variable and relapse is very possible
what causes non inflammatory joint disease?
developmental joint disease (like OCD)
degenerative (like arthritis)
trauma
tumors
what can cause inflammatory joint disease?
either septic or sterile, will see neutrophils in the joint
septic: bacterial infection
immune complexes: type III hypersensitivity reaction, complexes depositied in joints, activating complement and inflammation
sterile: inflammation within the joint itself
how do you differentiate between an infectious joint disease and an immune mediated joint disease?
septic: more likely a single swollen joint, history or surgery or trauma, or a previous infection
immune: multiple joints, often smaller more distal joints, history of antibiotic or vaccination
how do you differentiate between septic and sterile joints?
sample the synovial fluid
when should you consider doing a joint tap?
if you have solitary joint disease with signs of inflammation or systemic illness, evidence of polyarthritis, or if you have a FUO
ALWAYS CULTURE A JOINT TAP
what does normal joint fluid look like?
clear, colorless, viscous, with low cellularity, mononulcear cells and very few neutrophils
what does abnormal joint fluid look like?
turbid, cloudy, discolored (pink or yellow), very thin, high cellularity with many neutrophils and maybe some bacteria
describe synovial fluids results for a :
sterile inflammatory joint
a septic joint
degenerative or traumatic joint
sterile: thin, turbid, discolored, cellularity between 3000-150,000 cells/uL, non degenerative neutrophils
septic joint: thin, turbid, discolored, cellularity more than 150,000/uL, degenerative neutrophils, maybe bacteria
degenerative: clear,colorless, could be blood with trauma, low or slightly elevated cellularity, mononuclear cells
what is erosive polyarthritis ?
subchondral bone is destroyed, usually carpal bones, happens in small middle aged dogs. very UNCOMMON
