Fever/Immune Flashcards
what is the difference between fever and hyperthermia?
fever: raised thermoregulatory set point
hyperthermia: no alteration in thermoregulatory set point
what are the broad categories of disease that cause fever?
Neoplasia
Infection
Immune-mediated disease
Inflammation
NIII
what is a fever of unknown origin?
- fever persists long enough that many common or self-limiting causes are ruled out
- initial diagnostics do not reveal fever (hx, PE, CBC/chem/UA, imaging)
what are the steps to the initial approach for fevers?
- clinical signs: usually non-specific
- history + signalment
- PE: may help you localize
- diagnostics: look for focus of disease
autoimmune diseases are mostly mediated by what cells? why is this important to know?
Th2 cells and/or autoantibodies
- autoantibody prod by lymphocytes
- opsonized cells (marked for clearance)
- inflammatory cytokines/chemokines
these are the treatment targets
what is the difference between primary and secondary autoimmune diseases?
primary: no underlying cause ID, dx of exclusion
secondary: underlying cause ID
what is systemic lupus erythematosus (SLE)?
multi-systemic autoimmune disorder, constituents of the cell nucleus, damage via opsonization, interference with cellular physiology, immune complexes
causes a wide range of presentations
what signalments are systemic lupus erythematosus (SLE) most common in?
middle-aged dogs (3-7 yrs)
GSD, Nova Scotia duck tollers, sheltie, collie, old English sheepdog, afghan hound, beagle, poodle, Irish setter
what are the most common presentations of SLE?
- fever
- lameness or joint swelling
- proteinuria
- cutaneous
- lymphadenopathy
- blood dycrasias
how do you dx SLE?
diagnosis of exclusion! rule out all other ddx first
Antinuclear Antibody Test (ANA)
- measures autoantibodies against DNA, RNA, histones in nucleus
- patients must have compatible signs!
- ELISA, FAT
- limitations
Lupid erythematosus (LE) cells
- neutrophils containing phagocytized nucleus
- not sensitive, but specific
- joint, pericardial, pleural, blister, peritoneal, CSF fluid
to diagnose, you need 2+ C/S and a +ANA, or 3+ C/S and a -ANA
what is the treatment for SLE?
- immunosuppressive therapy
- supportive care
- adjunct therapy (based on cell lines/tissues involved)
what is the prognosis of SLE?
variable, relapse possible
what are the 4 types of non-inflammatory joint disease?
developmental joint disease, degenerative, trauma, tumor
what is inflammatory joint disease?
neutrophilic inflammation in the joints
can be septic or sterile
what are the two types of inflammatory joint disease?
infectious and immune-mediated
how do you tell the difference between an infectious or immune-mediated inflammatory joint disease based on clinical signs and presentation?
is this definitive?
septic more likely:
- single swollen/painful joint
- hx of sx or trauma of/near joint
- previous/current infection (hematogenous spread)
sterile more likely:
- multiple joints affected (often smaller/distal joints)
- hx of recent Abx or vaccination
NO NOT DEFINITIVE
how can you tell FOR SURE whether an inflammatory joint disease is immune-mediated vs infectious?
sample those joints!!!
when should you do joint fluid analysis?
- solitary joint disease w/ signs of local inflammation or systemic illness
- evidence of polyarthritis (pain, effusion, warmth)
- fever of unknown origin
tell me what normal joint fluid looks like
clear, colourless, viscous
cytology: low cellularity, mixture of mononuclear cells (macrophages, lymphocytes), <10% neutrophils
tell me what abnormal joint fluid looks like
turbid/cloudy, discoloured, thin
cytology: high cellularity, >20% neutrophils, ± bacteria
you have a cytology of joint fluid that you know came from an inflammatory joint diseased joint. how can you tell if it’s normal, sterile inflammatory, septic, or degenerative/traumatic?
normal: mostly mononuclear cells, occasional neutrophils <10%, low cellularity
sterile: mostly non-degen neutrophils, high cellularity
septic: degen neutrophils ± bac t, high cellularity
degen or trauma: mostly mononuclear cells, low or slightly increased cellularity
what is the difference b/t erosive and non-erosive polyarthritis?
erosive has sub-chondral bone destruction
what are the two categories of immune-mediated inflammatory joint disease?
erosive and non-erosive
which is more common, erosive or non-erosive immune-mediated inflammatory joint disease?
non-erosive
which is more common, primary or secondary non-erosive immune-mediated inflammatory joint disease?
primary
what does IMPA stand for?
non-erosive immune-mediated polyarthritis
what is non-erosive immune-mediated polyarthritis?
IMPA
immune-complex deposition in synovium (type 3 hypersensitivity)
what are some causes of IMPA?
idiopathic (most common), SLE, reactive (secondary), other (breed-assoc, vaccine-assoc)
who typically gets primary/idiopathic IMPA?
middle aged dogs
no sex or breed predilections
what are the 4 types of secondary/reactive IMPA?
- infectious (anywhere in body, but not in joint)
- medications (Abx, vaccines)
- neoplasia
- dietary elements (uncommon)
what are the IMPA C/S?
joint specific:
- lameness –> stiff gait or “walking on eggshells
- joint pain or swelling
- reluctance to move
nonspecific signs
polysystemic signs (derm, pallor/bleeding, ulcers)
less than 50% may be lame or have palpable joint effusion and are presented for vague signs of systemic illness
how do you diagnose IMPA?
- arthrocentesis: neutrophilic inflammation in multiple joints (non-degenerative), negative culture (always culture!!! urine or blood)
- look for secondary or concurrent disease!! (PE, CBC/chem/UA, etc)
- joint radiographs ±
- SNAP 4Dx Plus or Accuplex (anaplasma, Borrelia, Erlichia, heartworm)
