Week 4 - Case 2

Question 0

What is the common differential for Acute Monoarticular Arthritis?

Answer 0

1. Gout
2. Pseudogout
3. Reactive arthritis
4. Septic arthritis

Question 1

What is acute monoarticular arthritis?

Answer 1

An acute joint inflammation that occurs days or less before seeking attention - (mono = one joint)

Question 2

What causes gout?

Answer 2

Uric acid crystals precipitate in the joint

Question 3

Describe gout and how it is diagnosed.

Answer 3

Very acute onset, low grade fever, most common site is great toe, uncommon in shoulders

Diagnosis: joint aspiration, polarized light demonstrates negatively birefringent crystals

Question 4

What causes pseudogout?

Answer 4

Calcium pyrophosphate crystal deposition

Question 5

What are the symptoms of pseudogout and how do you diagnose?

Answer 5

Looks the same as gout - can involve the same joints (feet, knee, wrist, ankle) plus shoulder and hips

Diagnosis - joint aspiration, positive birefringent crystals

Question 6

What is reactive arthritis?

Answer 6

Acute, symmetric arthritis following urethritis (chlamydia) or gastroenteritis

• usually happens 6 weeks after infection
• Affects joints, mostly commonly knees

Question 7

What are some complications of Reactive Arthritis?

Answer 7

Patients may also get conjunctivitis and urethritis - Reiter’s syndrome

Question 8

What organisms cause septic arthritis?

Answer 8

1. Staph aureus - most common overall, patients usually have pre-existing joint problem or are IV drug users
2. Neisseria gonorrhoeae - most common organism under age 30

Question 9

How do you know a condition is septic arthritis caused by staph. aureus or Neisseria gonorrheae?

Answer 9

Joint aspiration - and look at the cells under microscope

Question 10

What are the two muscoskeletal syndromes caused by disseminated GC (Gonococcal arthritis)?

Answer 10

Arthritis-dermatitis syndrome & Localized septic arthritis

Question 11

What symptoms are associated with Arthritis-dermatitis syndrome (GC Arthritis)?

Answer 11

Arthralgias, Skin lesions, Inflammation of tendons (these three are what the patient usually comes into the office with) - Patient doesn’t usually come in with an inflamed joint.

Septic arthritis is rarely found at same time as bacteremia.

Question 12

What joint is commonly affected in localized septic arthritis? What is septic arthritis usually not found with?

Answer 12

Knee - Septic arthritis and bacteremia are rarely found at the same time

Question 13

What influences dissemination/spread of Gonococcal arthritis?

Answer 13

• Phenotypes of GC that are expressed during menstruation are more likely to disseminate - one week after start of period
• GC in homosexual men are less likely to disseminate
• Disseminating strains are less potent inflamm. response stimulators = less likely to cause urethral symptoms

Question 14

How do you diagnose GC arthritis?

Answer 14

History & Physical, Lab work, Gram stain & Culture

Question 15

What will the labs show for a GC infection?

Answer 15

WBC high (above 10,000)
Blood cultures positive
Joint aspiration shows WBC count over 100,000 (not specific though - can also be seen in gout)

Question 16

What is the primary diagnostic test for GC arthritis?

Answer 16

Gram stain & culture of joint aspiration

Question 17

What does the gram stain for GC arthritis look like?

Answer 17

Many, large white blood cells with cocci shown in enlarged cells

Question 18

How do you treat for GC arthritis?

Answer 18

3rd generation cephalosporin = ceftriaxone
Azithromycin = Oral macrolide antibiotic (also used for chlamydia treatment)

Prognosis is usually very good with rapid resolution of signs and symptoms

Question 19

What frequently causes septic arthritis?

Answer 19

Staph. aureus

Question 20

How can gout be diagnosed?

Answer 20

White count in joint aspirate

Question 21

Urethritis, conjunctivitis and monoarthritis is called. . .

Answer 21

Reiter’s syndrome

Question 22

What are symptoms associated with mono and GC arthritis (septic joint)?

Answer 22

• right knee pain
• sore throat
• fever
• diffuse aches
• nausea
• great pain
• right knee swollen & very tender
• Lymphadenopathy
• Tonsils enlarged

Question 23

What is septic arthritis/joint?

Answer 23

Intensely painful infection of the joint