Infectious Joint Pathologies Flashcards
Is septic arthritis inflammatory?
Infectious and inflammatory
What patients are most likely to present with septic arthritis?
Immunocompromised children
By which methods do microorganisms get into a joint in the case of septic arthritis?
- Hematogenous (pneumonia, soft tissue infection moves into synovium)
- Direct (bone into joint)
What are some etiologies of septic arthritis?
- S. aureus (most common)
- H. influenza
- Gonococcal infection in sexually active young adults
- E. coli
How is septic arthritis differentiated from gout?
Gout has hyperuricemia and takes 7 years to see destruction
Septic arthritis develops within ten days (in extremities)
(need labs)
aspiration of septic arthritis will have pus (not crystals)
What are some common locations for septic arthritis?
- Knee and hip (most common)
- Hand (often due to human bite)
What is the cause of soft tissue swelling in septic arthritis?
Joint effusion distorts fat folds
What is the first confirmatory radiographic finding for septic arthritis?
Loss of subchondral white line
A patient comes in with soft tissue swelling around the knee, seemingly filled with pus. Upon radiographs of the knee, there is a loss of joint space, bone destruction, and a loss of subchondral white line. You ask your patient if they’ve had any recent infections and they report they had a staph infection about a week ago.
What is the likely diagnosis?
Septic arthritis
A patient comes in with an acutely red and swollen proximal interphalangeal joint of the second toe with pus exuding from it. The patient reports that this appeared within a matter of days and is aggravated when they step onto that foot. Upon history, they are a sexually active young adult who has contracted gonococcal infection recently.
What is the likely diagnosis?
Septic arthritis
Septic arthritis involves rapid loss of joint space and aggressive bone destruction.
What can happen to bones in a later stage of septic arthritis?
Bone ankylosis (fusion)
What are the ESR and CRP levels in a patient with septic arthritis?
Both increased
What are the alkaline phosphatase levels in a patient with septic arthritis?
Normal
Is someone with septic arthritis positive or negative for HLA-B27?
For RF?
Both negative
What may be found in a synovial biopsy of a joint affected by septic arthritis?
- Normal uric acid (differentiates gout)
- Pus
Along with antibiotics, what are some treatments for septic arthritis?
- Aspiration to decompress the joint
- Irrigation of the joint
- Decrease motion and weight bearing
- Joint ankylosis may mean joint replacement surgery
Is fungal arthritis inflammatory?
Infectious and inflammatory
How common is fungal arthritis?
Rare
Fungal arthritis is often a complication of ___
neoplastic disease or severely immunocompromised patients (ie HIV/AIDS)
Fungal arthritis is frequently associated with involvement of which other organs?
Lungs
What is one fungus that may cause fungal arthritis?
Candida species (yeast)
Fungal arthritis in the spine presents similarly to ___
Pott’s disease (spinal tuberculosis)
Fungal arthritis is ___ destructive
highly
How is fungal arthritis treated?
Difficult: anti-fungal drugs are toxic to other tissues, especially the liver
How is fungal arthritis diagnosed?
Diagnosis by biopsy
(cannot differentially diagnose radiographically from bacterial/septic arthritis)
Is Lyme disease inflammatory?
Yes, it’s a parasitic infection that exhibits a chronic inflammatory response
Lyme disease is an infection by what bacterium?
Spirochetes: borrelia burgdorferi
Spirochete, borrelia burgdorferi, infection causes Lyme disease
What organism transmits this bacterium to humans?
Ixodes tick (in nymph stage) during May-July
How common is Lyme disease?
15,000-20,000 cases annually in the US
What ages are affected by Lyme disease?
Any age
At what stage of Lyme disease are antibiotics most effective?
Stage 1
Erythema chronicum migrans is a sensitive, non-specific indicator for which infectious joint pathology?
Bullseye rash: occurs 3-35 days after tick bite, indicates Lyme disease
The following are symptoms of which stage of Lyme disease?
- Fever
- Fatigue
- Malaise
- Headache
- Arthralgias
- Lymphadenopathy
- Cough
- Meningeal irritation
- Migratory myalgia
- Testicular swelling
- Brain fog
Stage 1 of Lyme disease
The following are symptoms of which stage of Lyme disease?
- Migratory musculoskeletal pain
- Cardiac and neurologic abnormalities
- Joint pain is migratory and transient
Stage 2 of Lyme disease
The following are symptoms of which stage of Lyme disease?
- Arthralgia
- Severe arthritis
- Swollen joints (especially the knee)
- Skin abnormalities
- Neurological abnormalities (paresthesia, encephalomyelitis, dementia)
Stage 3 of Lyme disease
A patient is in stage 1 of Lyme disease
Which cells are involved in the chronic inflammatory response that is taking place?
Lymphocytes and plasma cells
When does stage 2 of Lyme disease typically begin?
Weeks to months following lesion
When does stage 3 of Lyme disease typically begin?
Months to year post-infection
Over 50% of patients with Lyme disease have which two symptoms?
Arthralgia and severe arthritis
What is the histology of stage 3 Lyme disease?
Affected joints are like rheumatoid arthritis:
Synovial membrane undergoes villous hypertrophy with mononuclear infiltrate
At what point is Lyme disease permanent?
Stage 3 when neurologic effects begin (tingling/paresthesia, encephalomyelitis, dementia)
If Lyme is suspected, what is used for diagnosis?
Antibody titers (IgM and IgG)
Early treatment of Lyme disease uses higher doses of ___
tetracycline or erythromycin
Later stages of Lyme disease require long-term, high doses of ___
antibiotic treatment
If a patient tells you that they have recently been prescribed tetracycline or erythromycin in a high dose, what should you suspect?
Early stage of Lyme disease
