Case 23 - 33 yo F with knee pain

Question 1

Physical examination

Answer 1

Mouth exam
Musculoskeletal exam (inspection and palpation of both knees, including range of motion, examined other joints, including shoulders, elbows, wrists, hands, fingers, hips and ankles)
Hair and skin exam
CV exam
Pulmonary exam
Abdominal exam

Question 2

Closure

Answer 2

Mentioned need for pelvic exam (“sometimes infections from the pelvis can spread to other parts of the body, such as the knee”)
Discussed safe sex practices
Do you have any questions for me?

Question 3

Differential diagnosis

Answer 3

Gout
Rheumatoid arthritis
Systemic lupus erythematosus

Question 4

Differential diagnosis

Answer 4

Gout (monoarticular joint pain and tenderness, h/o swollen toe, alcohol use, swelling at L knee)
Rheumatoid arthritis (morning joint stiffness, FHx of RA, anorexia, weight loss, fatigue, low-grade fever)
Systemic lupus erythematosus (anorexia, weight loss, fatigue, oral ulcers, spontaneous abortions, Raynaud's phenomenon)

Question 5

Diagnostic work-up

Answer 5

CBC with differential
ANA titer, anti-dsDNA, RF, anti-CCP
Knee aspiration with Gram stain, culture and inspection for crystals
XR - L knee and both hands
Pelvic exam and cervical cultures (for gonococcal septic arthritis)

Question 6

The diagnosis of SLE requires at least four of the following 11 criteria

Answer 6

Malar ("butterfly") rash
Discoid rash
Symmetric arthritis
Photosensitivity
Oral ulcers
Serositis
Renal disease
CNS involvement
Immunologic abnormalities (such as antiphospholipid antibodies)
Hematologic abnormalities (such as anemia)
ANA positivity

Question 7

Tests for SLE

Answer 7

ANA
anti-dsDNA Ab
anti-Smith Ab
anticardiolipin Ab
lupus anticoagulant

Question 8

Tests for RA

Answer 8

Rheumatoid factor (RF)
Anti-cyclic citrullinated peptide (anti-CCP) Ab