Large Animal Sx - Diagnosis, Treatment & Prevention of Septic Arthritis in Horses

drraythe's version from 2015-11-24 20:08

intro and Prevention of Joint Sepsis "Joint Injections"

Question Answer
***Septic Arthritis-->Routes of Infections (3)(1) HEMATOGENOUS (2) EXTENSION OF INFECTION (3) DIRECT PENETRATION (wounds OR iatorgenic)
two iatrogenic causes of direct penetration leading to possible septic arthritis?Intraarticular injections, arthroscopy
Bacteria commonly isolated from septic joints after surgery or injection?Staph aureus, Staph epidermidus (<--these 2 in 50% of the horses), Βeta hemolytic and non-beta hemolytic streptococci, Enterobacteriaceae, Pseudomonus, Anaerobes
the good news about anaerobic infections in horses?most are sensitive to penicillin (including clostridium tetanii)
Clinical Importance of septic arthritis?Expense of treatment, Loss of use of horse, Debilitating lameness, Euthanasia, Loss of clients and client good will
prognosis of septic arthritis?Historically carried a guarded prognosis (survival about 75%, return to function a little lower)
what are the joint capsules which communicate in the stifle?femoropatella communicate with medial femoral tibial.
(said in class) what is a horse's mediasteinum like?incomplete/perforated
Parameters Suggesting Sepsis--> total protein above..>35 g/L
Parameters Suggesting Sepsis--> nucleated cell count above? (adults and foals)ADULT: >20 x 10^9cells/L. FOAL: >10 x 10^9cells/L foals
Parameters Suggesting Sepsis--> Differential cell count Neutrophils?>90 %
if you suspect a horse has sepsis in a joint, but you're not sure, what should you do?TREAT ANYWAY. not worth the risk of waiting.
what kinda drugs would you want to give a horse if you're treating sepsis?IV abx: Amikacin and potassium penicillin. Also give Omeprazole (gastric ulcer protection- proton pump inhibitor)
If you are trying to treat a joint for sepsis through arthroscopy, what techniques and drugs do you wanna do?LAVAGE the joint, and then do inta-articular amikacin (Also can give mepivicaine, bc it is painful)
what pathogen is a problem in foal farms in the southern US?rhodococcus equi
***Which drug has been associated with arthropathies in young dogs and disruption of equine chondrocyte function “in vitro?”Enrofloxacin (so...try to avoid in foals if you can)
If you have a horse with septic arthritis in one leg, why might the OPPOSITE leg hurt?compensation- not putting weight on the bad leg means putting double weight on the good leg, leading to strain
what is regional limb perfusion?tourniquet above hock and carpus, stick a needle in vein and keeps conc higher in that limb. (can keep on for 30min) (can do 100 times over MC, cant do that with anything systemic)
5 Complications of joint blocksFailure to enter joint, Hemarthrosis, Broken needles, Makes primary problem worse (NO BLOCK IN FX JOINT), SEPSIS
how common are iatrogenic joint infections in horses?technically the incidence is low, but joint injections are done so frequently that its a fairly common diagnosis
most common infective bacteria causing problems in joints?Staphyloccocus sp
3 main sources of contamination resulting in joint sepsis?(1) Veterinarian (2) Horses skin (Superficial contamination on surface of skin or on hair, Microoganism in hair follicles, ducts, glands or hair roots) (3) Contaminated medication or needles
can you sterilize skin?NO! even properly cleaned skin cut with a scalpel--can culture stuff on the scalpel after
should you clip/shave hair if you are going to do a joint injection?no need- Presence of hair does not inhibit ability of antiseptics to “effectively” reduce bacterial flora to an acceptable level on surface of healthy skin
Do you want to do an injection if the horse has dermatits?nope...just gonna be pushing all that into the joint. Also avoid if wounds in limb you want to inject.
what is the "superior" skin disinfectant?Chlorhexidine Gluconate solutions removed with saline may be a superior skin disinfectant for humans and horses
can the wells of drugs be contaminated by the needles?yes! can find hairs and tissue cores in them....try to use a NEW vial for joint injections
how many times can you use a needle for a joint injection?DO NOT REUSE!! ONE TIME STICK ONLY
can you accomplish effective disinfection of skin and hair?yes, but you cannot disinfect the deep layers of the skin.
when should you remove hair for joint injection?remove LONG hair if using Terumo or Kendall Monoject 20 gauge spinal needles
**three drugs most likely to cause an inc risk of septic arthritis when intra-articularly injected?Polysulfated glycosaminoglycans** (aka PSGAG) , Hyaluronan, Methylprednisolone
how can Polysulfated glycosaminoglycans have a negative effect on the joints...why?make staph MORE infectious. Increase the minimum inhibitory concentration of Amikacin ( 32 X) and Gentamicin ( 160X) for Staph aureus.
how can you try to dec the horrible risks of Polysulfated glycosaminoglycans (aka PSGAGs) cause with septic arthritis?Addition of 125 mg Amikacin to the PSGAG eliminated all experimental infections
what do a lot of vets do to preemptively avoid joint sepsis when performing injections?can add antimicrobial INTO the injection. Amikacin most often used (125-250 mg/joint)
Indications for addition of antimicrobial drugs to medications instilled in joints? (4)(1) Intra-articular PSGAG administration (risks of this drug in other cards) (2) immune compromised horses (SCID, foals with no colostrum, old horses with cushings) (3) Injecting multiple joints in the same horse (4) Multiple injections into the same joint on the same day
what are some risks associated with IA injections of corticosteroids and sepsis?Clinical experience suggests very low risk, put possible inc risk of sepsis. Big thing is that Can delay onset of the clinical signs of sepsis for 9-10 days
which type of drugs should you NEVER use in joints??Compounded drugs
can LAs inc risk of joint infection?No apparent increased risk of infection from use of the drug
which LA is less irritating and chondrotoxic?Mepivicaine hydrochloride
communicating joints in the tarsustarsocrural, proximal intertarsal. ( the bottom 2 can sometimes communicate- which we also can fuse. tarsocentral (distal intertarsal) and tarsometatarsal)
**which drug(s) has a weird special stipulation for storage, and what is that?local anesthetics- DO NOT REFRIGERATE-- it inhibits the preservative inside
which drugs are a green light to use intraarticularly? which is a caution? which is a red light?GREEN: Corticosteroids, Hyaluronan, Local Anesthetics. CAUTION: Polysulfated glycosaminoglycans. RED: compounded drugs
which vials should you avoid for intraarticular injections, and why? what should you do instead?Multidose Vials, because Often contaminated with bacteria, rubber particles, metallic particles, and skin fragments or blood. DO use SINGLE DOSE VIALS--- or use a brand new multidose vial
how often you should change your needle when injecting mult doses/drugs/ structures?EVERY PUNCTURE of EVERY SITE requires a new needle

Prevention of Joint Sepsis "Wounds/Arthroscopy", Treatment of Septic Synovitis

Question Answer
if you see a wound near a joint, you should always...make sure it didn't get into the joint!! foreign material, hair, etc can be pushed inside
4 things you can do for.. Prevention/treatment of contaminated synovial cavities?(1) Systemic Antibiotics (2) Local Antimicrobial Therapy (3) Anti-inflammatory drugs (4) ARTHROSCOPY***
if there is a puncture wound, and you want to flush it out, how do you go about this?you wan to go opposite side and flush from there so you are flushing things out, not more in
what's SSI?surgical site infection
what is a Superficial SSI (surgical site infection)only skin and subcutaneous tissue
what is a Deep SSI (surgical site infection)infection of deep soft tissues
what is a Organ /space SSI (surgical site infection)infection of organs and spaces opened during the operation that are not part of primary incision
what are the two categories of joint infections?(1) superficial (2) deep (joint cavity)
how much do perioperative abx help with surgical infections following arthroscopy postoperatively?Perioperative antibiotics have not been proven to reduce POSToperative infections in human or horses (they are good for dec risk of perioperative infections tho)
how do you admin Perioperative antibiotics? (when? route? how would you select your abx?)Give within 1 hour of start of surgery and again in immediate post-op period. Intravenous route recommended. Select antibiotics with activity against staphylococcus
how do you admin Intraoperative antibiotics? which abx? when?Intra-articular medication of Amikacin at conclusion of surgery (Dose 250 mg Amikacin in 6-10 ml of 2% mepiviciane hydrochloride)
*how do most post-operative infections occur? (examples of what might cause some of them?)Many post-operative joint infections are due to contamination of the joint after the surgery and not due to intraoperative contamination. Premature removal of bandages may predispose to postop infection. Perioperative prophylactic antibiotics will not protect against post-operative contamination
best LA for cartilage?mepivicaine
Prevention of arthroscopic surgical infections – surgical preparation--> what should you do about hair?Do not clip or shave skin prior to surgical procedure (Pustules and scratches form which increase bacterial load)
what might you need to differentiate from joint sepsis post operatively? (normal thing)We should determine if a swollen joint is due to sepsis or joint flare resulting from inflammation due to the medication or the trauma of injection (difficult to differentiate soon after onset by clinical signs alone- both have heat, swelling, pain..)
When does joint flare occur and when does joint sepsis occur?Joint flare often occurs within 24 hours, but sepsis usually has a Delay of 3-9 days in onset of clinical signs
is there lameness with joint flare? joint sepsis?joint flare will only cause very minor probs if any. But joint sepsis can cause a AAEP grade 3-4 lamenss (Consistently observable at the trot to Obvious lameness, marked nodding or hiking (lameness seen at walk) )
what does synovial fluid look like in a septic joint?Turbid, cloudy, discolored, Total WBC count > 20 X 109 cells/L, Total protein > 35 g/L, WBC differential > 90% neutrophils
what should you do if your suspected joint sepsis culture comes back negative?Cultures are often negative which does not rule out sepsis
if you arent sure if it's joint flare or early joint sepsis, what should you do?WHEN IN DOUBT TREAT THE JOINT FOR SEPSIS
which types of things should you culture for when suspecting/treating joint sepsis?Culture for aerobic & anaerobic bacteria. Fungal cultures when steroids have been injected
which Systemic Antimicrobial Drugs can you use for Treatment of sepsis in early stage of disease?Gentamicin, Amikacin, Potassium Penicillin (IV)
which NSAIDS can you use systemically for treatment of sepsis in early stage of dz?Flunixin meglumine or phenlybutazone IV
Staph aureus usually susceptible to?amikacin
Staph epidermidus usually susceptible to?amikacin
All enterobacteriaceae usually susceptible to?amikacin
Beta- hemolytic streptococcus usually suseptible to?Penicillin
anaerobes are usually suseptible to?penicillin
Amikacin is good for what three bact types?Staph aureus, Staph epidermidus, All enterobacteriaceae
Penicillin is good against what two types of bacteria?Beta- hemolytic streptococcus, Anaerobes
explain how you Joint lavage. what tools, what kinda flush? what do you do when you're done?flush Through and through with pump or pressurized bag (Large syringes if pump or bag not available). Use a Balanced electrolyte solution. Instill amikacin in the joint after flushing
how would you treat sepsis in the early stages?Intravenous regional perfusion with Amikacin (IVRP can be done simultaneously with joint lavage)
what kinda abx is amikacin?aminoglycoside
for Local antimicrobial delivery, which drug(s) do you want to use? at what kind of doses?Amikacin (aminoglycoside). Post antimicrobial effect for aminoglycoside drugs: > 8x above minimum inhibitory concentration (MIC) (so lasting antimicrobial effect are strong), Most bacteria resistant to routine levels of aminoglycosides are sensitive to high levels of aminoglycosides (so if you dose HIGH you can still be effective), and then the amikacin Penetrates biofilms and can also Penetrate poorly perfused tissues
*******Antimicrobial treatment of confirmed septic arthritis should continue for a minimum of _________(how long?)_________14 days
when would you consider (what are the indications for) arthroscopy as a tx for joint sepsis?[debride and flush with arthroscope] (1) Through and through lavage not successful due to fibrin and or severe synovitis (2) Initiation of treatment is delayed (3) Failure to respond to initial treatment in 48 hours
3 ways to admin Local antimicrobials?(1) Regional perfusion (2) intraarticular AM (antimicrobials) (3) continuous antimicrobial infusion