Infectious Joint Pathologies

Question 1

Is septic arthritis inflammatory?

Answer 1

Infectious and inflammatory

Question 2

Which patients are most likely to present with septic arthritis?

Answer 2

Immunocompromised; children and elderly

Question 3

By which methods do microorganisms get into a joint in the case of septic arthritis?

Answer 3

Hematogenous

e.g. pneumonia infects soft tissue which moves into synovium

Question 4

What are some etiologies of septic arthritis?

Answer 4

• S. aureus (most common)
• H. influenza
• Gonococcal infection in sexually active young adults

all of these have the same effect

Question 5

How is septic arthritis different from gout?

Answer 5

Gout: hyperuricemia, 7 years before destruction visible, crystal deposits
Septic arthritis: develops within ten days (in extremities), purulent exudate

need joint aspiration

Question 6

The day septic arthritis infects a joint, the joint is ___

Answer 6

destroyed

Question 7

What are some common locations for septic arthritis?

Answer 7

• Knee and hip (most common)
• Hand (often due to human bite/punch to the mouth)

Question 8

How does septic arthritis distort fat folds/stripes?

Answer 8

Effusion of fluid inside joint

Question 9

With septic arthritis, is joint space loss uniform?
How fast does it occur?

Answer 9

Uniform loss of joint space
Less than thirty days

Question 10

What is the first reliable radiographic finding for septic arthritis?

Answer 10

Loss of subchondral white line

Question 11

A patient comes in with soft tissue swelling around the knee, seemingly filled with fluid or 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?

Answer 11

Septic arthritis

Question 12

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?

Answer 12

Septic arthritis

Question 13

Septic arthritis involves rapid loss of joint space and aggressive bone destruction.
What can happen to bones in a later stage of septic arthritis?

Answer 13

Bone ankylosis (fusion)

Question 14

A patient’s x-ray shows distortion/displacement of three fat stripes all around the hip with no joint space visible. With the swelling noted by the chiropractor, the patient is sent to the ER.
What is the differential diagnosis before joint aspiration is performed?

Answer 14

• Septic arthritis
• Gout
• Rheumatoid arthritis

Question 15

What are the ESR and CRP levels in a patient with septic arthritis?

Answer 15

Both increased

Question 16

What are the alkaline phosphatase levels in a patient with septic arthritis?

Answer 16

Normal

Question 17

Is someone with septic arthritis positive or negative for HLA-B27?
For RF?

Answer 17

Both negative

Question 18

What allows for a definitive diagnosis of septic arthritis?

Answer 18

Synovial biopsy

Question 19

What may be found in a synovial biopsy of a joint affected by septic arthritis?

Answer 19

• Normal uric acid (differentiates gout)
• Pus/purulent exudate

Question 20

Along with antibiotics, what are some treatments for septic arthritis?

Answer 20

• Aspiration to decompress the joint
• Irrigation of the joint
• Decrease motion and weight bearing
• Joint ankylosis may mean joint replacement surgery

Question 21

Is fungal arthritis inflammatory?

Answer 21

Infectious and inflammatory

Question 22

How common is fungal arthritis?

Answer 22

Rare

most infections are bacterial

Question 23

Fungal arthritis is often a complication of ___

Answer 23

neoplastic disease or severely immunocompromised patients

e.g. chemotherapy patients, HIV/AIDS patients

Question 24

Fungal arthritis is frequently associated with involvement of which primary organ?

Answer 24

Lungs

Question 25

What is a common fungus that may cause fungal arthritis?

Answer 25

Candida species (yeast)

Question 26

Fungal arthritis in the spine presents similarly to ___

Answer 26

Pott's disease (spinal tuberculosis)

Question 27

Fungal arthritis is ___ destructive

Answer 27

highly

Question 28

How is fungal arthritis treated?

Answer 28

Fungi are hard to kill; anti-fungal drugs are toxic to other tissues, especially the liver May need to amputate

Question 29

How is fungal arthritis diagnosed?

Answer 29

Biopsy ## Footnote cannot differentiate from bacterial/septic arthritis radiographically

Question 30

Is Lyme disease inflammatory?

Answer 30

Yes, it's a parasitic infection that exhibits a chronic inflammatory response ## Footnote evidenced by lymphocytes and plasma cells

Question 31

Lyme disease is an infection by what bacterium?

Answer 31

Spirochetes: borrelia burgdorferi ## Footnote tick bite with a systemic effect

Question 32

Spirochete, borrelia burgdorferi, infection causes Lyme disease. What organism transmits this bacterium to humans?

Answer 32

Ixodes tick (in nymph stage) during May-July | very small tick

Question 33

How common is Lyme disease?

Answer 33

15,000-20,000 cases annually in the US

Question 34

What ages are affected by Lyme disease?

Answer 34

Any age

Question 35

At what stage of Lyme disease are antibiotics most effective?

Answer 35

Stage 1

Question 36

Erythema chronicum migrans is a sensitive, non-specific indicator for which infectious joint pathology?

Answer 36

Bullseye rash: occurs 3-35 days after tick bite, indicates **Lyme disease**

Question 37

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

Answer 37

Stage 1 of Lyme disease

Question 38

The following are symptoms of which stage of Lyme disease? * Migratory musculoskeletal pain * Cardiac and neurologic abnormalities * Joint pain is migratory and transient

Answer 38

Stage 2 of Lyme disease

Question 39

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)

Answer 39

Stage 3 of Lyme disease

Question 40

A patient is in stage 1 of Lyme disease. Which cells are involved in the chronic inflammatory response that is taking place?

Answer 40

Lymphocytes and plasma cells

Question 41

When does stage 2 of Lyme disease typically begin?

Answer 41

Weeks to months following lesion

Question 42

When does stage 3 of Lyme disease typically begin?

Answer 42

Months to years post-infection

Question 43

Over 50% of patients with Lyme disease have which two symptoms?

Answer 43

Arthralgia and severe arthritis

Question 44

With stage 3 lyme, synovial membranes undergo villous hypertrophy with mononuclear infiltrate. Which other joint pathology is this most similar to?

Answer 44

Rheumatoid arthritis

Question 45

At what point is Lyme disease permanent?

Answer 45

Stage 3 when neurologic effects begin (tingling/paresthesia, encephalomyelitis, dementia)

Question 46

If Lyme is suspected, what is used for diagnosis?

Answer 46

Antibody titers (IgM and IgG)

Question 47

Early treatment of Lyme disease uses higher doses of ___ or ___.

Answer 47

tetracycline or erythromycin

Question 48

Later stages of Lyme disease require long-term, high doses of ___

Answer 48

antibiotic treatment

Question 49

If a patient tells you that they have recently been prescribed tetracycline or erythromycin in a high dose, what should you suspect?

Answer 49

Early stage of Lyme disease