Infectious Arthritis Flashcards
Someone presents with an edematous, erythematous, painful knee. What is the most likely etiologic cause (Bacteria, Virus, Fungus)?
• What from their history will help you be confident of this?
Bacteria most often cause infectious arthritis. The history helps to determine the cause because bacterial causes of infectious arthritis will be acute in onset. Fungal (other than candida) and viral infections take a more chronic corse course and progress slowly.
T or F: Infectious arthritis is a surgical emergency anytime it occurs
False, its only a surgical emergency if its bacterial
After diagnosis of actue bacterial/septic arthritis in a patient what can you tell them about the seriousness and downstream effects of this disease?
• Bacterial Arthritis is a serious condition with a high mortality rate and high post-infection morbidity as a result of joint destruction
Mark presents with a swollen, erythematous, elbow that has rapidly progressed in the past 1-2 weeks. On palpation the joint is approximately the same temperature as the skin overlaying his bicep. He is currently in intense pain.
• In what ways is this the typical presentation of bacterial arthritis?
• What symptoms are importantly absent?
• Would you ever expect fever?
People with acute infective arthritis most often present with swollen, red joints, that progress rapidly if of a bacterial etiology. These joints are typically VERY painful. Fever and malaise is typical in these patients, but HIGH fever and shaking chills would by atypical. (these symptoms are importantly absent in this scenario)
Mark presents with a swollen, erythematous, elbow that has rapidly progressed in the past 1-2 weeks. On palpation the joint is approximately the same temperature as the skin overlaying his bicep. He is currently in intense pain.
- How did the pathogen most likely get there?
- What are some other possible routes of infection?
Hematogenous spread is the most common way for bacteria to get into a joint.
Other:
• Direct Innoculation via: Percutaneous Puncture, Bites, Trauma, Surgery
• Contingous spread: Adjacent soft tissue or bone infections
Jan presents to the nursing home physician with a swollen, erythematous, ankle that has rapidly progressed in the past 1-2 weeks. On palpation the joint warm. Here blood glucose is 160 mg/dL and her serum urate is 8.0 mg/dL and she is afebrile. She is convinced that is this is a flare up of her RA and has been self-administering extra doses of methotrexate and has upped her insulin dose.
• what are her risk factors for acquiring her current condition?
• Which is the most important for anyone who gets this disease?
Risk Factors for Infective Arthritis:
- Abnormal Joint Architecture - RA, and potentially gout and osetoarthritis as well.
- Advanced Age (she’s in a nursing home)
- Diabetes Mellitus (insulin, uncontrolled BG - normal = 70-100 mg/dL)
- Immunosuppression (MTX and potential other meds for RA like TNF-alpha antagonists and upping the dose, this may explain why she’s afebrile)
****ABNORMAL JOINT ARCHITECTURE is the MOST IMPORTANT risk factor****
Jan presents to the nursing home physician with a swollen, erythematous, ankle that has rapidly progressed in the past 1-2 weeks. On palpation the joint warm. Here blood glucose is 160 mg/dL and her serum urate is 8.0 mg/dL and she is afebrile. She is convinced that is this is a flare up of her RA and has been self-administering extra doses of methotrexate and has upped her insulin dose.
• what 2 important risk factors does jan NOT have?
Risk Factors she doesn’t have:
• IVDU
• Endocarditis
Risk Factors she does have:
• Abnormal Joint architecture - based on here advanced age there is a good chance she has OSTEOARTHRITIS too
• Diabetes
• Immunosuppression
• Advanced Age
T or F: it is not uncommon for patients with acute bacterial arthritis to lack any risk factors for the development of disease.
True, up to 1/4 of patients have no prior existing risk factors
Why are synovial membranes such a common area for bacterial infections to seed?
• do patients who get septic arthritis always have positive blood cultures?
- They are very vascular and lack a basement membrane
- bacteremia causing hemotogenous spread may be overt or occult
A 65 year old man presents to the ER with an extremely swollen and painful knee that is warm. He had artificial knees put in two years ago. Blood cultures are positive and the mostly likely causative agent is ____________(a).
• what is the pathophysiology bacterial seeding of a joint?
(a) Staph Aureus - most common cause of acute bacterial arthritis
Pathophysiology:
• Organisms must first colonize the synovial membrane. They can do this because of the hypervascularity of the synovial membrane which has increased adhesion factors. The presence of extracellular matrix proteins like fibronectin, collagen, elastin and hyaluronic acid that allow for bacterial attachment.
***Note: HOST INFLAMMATORY RESPONSE WILL UPREGULATE ADHESION FACTORS THAT ARE ACTUALLY BENEFICIAL FOR BACTERIAL SEEDING****
Staphlococcus aureus is the most common cause of acute bacterial arthritis accounting for 37-65% of all cases. What comorbidities/risk factors put you at an even greater risk of SA being the etiologic agent of your bacterial arthritis?
• who do you worry about MRSA the most in?
- RA patients
- IVDU
- Eldely Pts.
- Recent surgery
***Other than ppl. that are known to be colonized with MRSA, you want to watch out for Eldery and people who have had recent surgery***
John comes in with several septic joints that grow gram positive cocci in chains.
• What are 3 risk factors John may have that put him at high risk of getting this infection?
MULTIPLE JOINTS implies Group B streptococcus as the etiologic agent, this is unique because this infection typically is only caused in one joint.
Risk Factors:
• Neonates
• Diabetics
• Maligancy
What groups/members of the strepococcus species can cause joint infections?
• How common is this?
• what other gram +’s besides staph aureus are known to cause these infections?
Stretptococcus is the 2nd most common cause of joint infections
• Group A, B, C, G and pneumoniae (less common) strep are all known to cause disease
Other Gram +’s:
• Coagulase Negative Staphlylococcus (s. epidermitus)
Jim is an 80 year old HIV positive herion addict who has experienced increasing pain at his sternoclavicular joint over the past week and is feeling extremely lathargic with a slight fever. Bacterial arthritis is suspected but cultures grow bacteria but they are not gram + cocci.
• What is likely seen on gram stain of organisms infecting Jim?
• What are his risk factors?
• what other group is also at an elevated risk to getting this type of infection?
Gram negative bacilli are seen in 5-20% of patients with septic arthritis.
Risk Factors:
• Elderly
• Immunocompromised
• IVDU
• Neonates
Jim is an 80 year old HIV positive herion addict who has experienced increasing pain at his sternoclavicular joint over the past week and is feeling extremely lathargic with a slight fever. Bacterial arthritis is suspected but cultures grow bacteria but they are not gram + cocci.
• it is determined that the infective agent is an indole +, Lactose -, gram negative bacillus. Who else gets this type of infection?
Pseudomonas aeruginosa infections are often contracted by BOTH IVDU’s and via iatrogenic causes like SURGERY or INTRA-ARTICULAR INJECTIONS.
Who typically gets joint infections by Neisseria gonorrhea or Neisseria meningitidis?
- Young Adults
- People with Late Complement Deficiency
**Note: Neisseria is a non-motile gram negative pathogen***
Who is most likely to get a joint infection from salmonella?
• what are the staining charactistics of salmonella?
- SICKLE CELL PATIENTS
- Salmonella is a gram negative and aerobic
Beth presents with a cat bite to her lower extremity and now has an infection of her ankle. What pathogen is the most likely cause?
• Gram staining characteristics?
Pasteurella multocida - often the cause of acute bacterial arthritis that results from a dog or cat bite
• Pasteruella is Gram negative
Tom is a hipster who presents to the ER because he has developed severe pain in his sacral area. The affected area is warm and erythematous. He remarks that the symptoms have progressed rapidly in the past week or two.
• What pathogen do you suspect and what are the staining characteristics?
• what are key characteristics of this presentation?
• Risk Factors
Brucella gram negative coccobacilli
Risk Factors:
• Consuming Unpasterized Dairy Products (b/c he’s a hipster he might)
Key Characteristics:
• Sacroiliac joint arthritis should definitely clue you in to Brucella (note: TB pott’s sequence also commonly affects the back as does non-infective processes like the SERONEGATIVE arthropathies)
Jannet, a 56 year old patient with rheumatoid arthritis that is well controlled with infliximab, presents with severe worsening joint pain in her hip and shoulder over the past 1 to 2 weeks. Physical exam shows limited ROM with focal joint tenderness. Blood cultures are positive to a gram positive cocci that grows in clusters.
• What are Jannet’s risk factors for multiple joint involvment?
• What other organism commonly causes polyarticular infection?
Risk Factors:
• Rheumatoid Arthritis
• Immunosuppression (infliximab)
• Prolonged Bacteremia (especially with Staph. a.)
Other Organisms for Polyarticular disease:
• Group B streptococcus
What is this guy’s risk factor for the infection shown?
IVDU - pretty much only seen in people who are IVDUers
What is probably causing this person’s recent onset arthritis?
Niessiera gonorrhea (gram negative) • Top = Dermatitis • Bottom = Tenosynovitis
What symptoms do you see in Early Infection Stage I of Lyme Disease?
• Early infection Stage II? (how long does it take to get from I to II?)
• what are some of the more severe symptoms you might see in stage II?
Early infection stage I:
• Target Rash (erythema migrans) - not 100% present, sometimes its just red
• Headache
• Regional Lymphadenopathy (not 100%)
• Fever, malaise, chills
Early infection stage II:
• After several days to weeks of onset of your target rash you’ll secondary skin lesions similar to the first but smaller. You may also get a malar rash and conjunctivitis.
• 15% - meningitis or other CNS symptoms
• 5% - CV problems, most often AV Block
