Gram positive bacilli
Look like "tennis rackets"
Can produce tatanospasmin which can cause toxicity. Should vaccinate patients against tetanus if they haven't been.
Management of Open Wounds
Operative irrigation and debridement
Tetanus toxoid for tetanus-prone wounds
Bone Scintigraphy (Scan)
A nuclear scanning test to find certain abnormalities in bone. It is primarily used to diagnose cancer, inflammation, damage from infections, etc.
Curative vs Suppressive Treatments
Usually go for curative when joints become infected, but sometimes you may opt for a suppressive treatment.
For example, if a 90-year old man who is relatively immobile became infected, it wouldn't make sense to perform surgery to replace the joint. The risks of surgery would be too great. Instead, he may be put on antibiotics for the rest of his life to prevent spread.
Peak incidence is 15-30 years old.
Usually monoarticular (particularly knee)
Treatment is IV antibiotics for 48 hours, then oral antibiotics for 7 days.
Group A Streptococcus
Gram positive cocci
Can be aggressive
An anti-inflammatory drug
Hip vs Knee Infection
The hip is deeper and is often much harder to tell if it is infected.
CBC and Infection
Hemoglobin is often decreased during infection
WBC is often increased (but can be normal)
CRP and ESR will be elevated
Also called indium leukocyte imaging
White blood cells are removed from a patient, tagged with Indium-111 and then injected intravenously into the patient. The tagged leukocytes subsequently localize to areas of relatively new infection.
This is useful in differentiating conditions such as osteomyelitis.
Is an external coating of bacteria with protective function, made mostly of polysaccharides. Can make it very difficult for antibiotics to penetrate.
Risk Factors for MSK Infections
Patients with artificial joints
IV drug users
The Most Common Joint in Septic Arthritis
Routes of Bacterial Spread
Infected Artificial Joint
Most commonly caused by S. aureus, and most commonly affects the hip.
This is a surgical emergency.