MD Musculoskeletal and Connective Tissue 5 — Questions and Answers
Question 1: A 55-year-old man presents with pain and stiffness in his shoulders and hips that is worse in the morning, elevated ESR, and normal muscle enzymes. He responds dramatically to low-dose prednisone. What is the diagnosis?
- Polymyalgia rheumatica (Correct answer)
- Polymyositis
- Giant cell arteritis
- Fibromyalgia
Correct answer: Polymyalgia rheumatica
Polymyalgia rheumatica presents with proximal girdle stiffness, markedly elevated ESR/CRP, normal CK, and a dramatic response to low-dose corticosteroids.
Question 2: A 30-year-old woman with SLE develops new hematuria and proteinuria. Renal biopsy shows diffuse proliferative glomerulonephritis with 'wire-loop' lesions. What class of lupus nephritis is this?
- Class IV (diffuse lupus nephritis) (Correct answer)
- Class II (mesangial proliferative)
- Class III (focal lupus nephritis)
- Class V (membranous lupus nephritis)
Correct answer: Class IV (diffuse lupus nephritis)
Class IV diffuse lupus nephritis is the most severe form, characterized by diffuse glomerular involvement and wire-loop lesions from subendothelial immune complex deposits.
Question 3: A 65-year-old man on aspirin therapy for cardiovascular disease develops a hot, swollen knee. Synovial fluid WBC is 85,000/mm³ with 95% neutrophils. Gram stain is negative. What is the most appropriate next step?
- Empiric intravenous antibiotics pending culture results (Correct answer)
- Intra-articular corticosteroid injection
- Oral colchicine and NSAIDs
- Aspiration alone and observation
Correct answer: Empiric intravenous antibiotics pending culture results
Synovial WBC >50,000/mm³ with high neutrophilia is presumptive septic arthritis requiring immediate empiric antibiotics while awaiting culture, given the risk of joint destruction.
Question 4: A 14-year-old boy has pain in his right knee that worsens with activity. X-ray shows fragmentation of the tibial tuberosity. What is the diagnosis?
- Osgood-Schlatter disease (Correct answer)
- Patellar fracture
- Osteosarcoma
- Legg-Calvé-Perthes disease
Correct answer: Osgood-Schlatter disease
Osgood-Schlatter disease is a traction apophysitis at the tibial tuberosity insertion of the patellar tendon, common in physically active adolescents during growth spurts.
Question 5: A 50-year-old woman with rheumatoid arthritis develops a vasculitic rash, peripheral neuropathy, and digital gangrene. Which complication of RA does she have?
- Rheumatoid vasculitis (Correct answer)
- Felty syndrome
- Caplan syndrome
- Sjögren overlap syndrome
Correct answer: Rheumatoid vasculitis
Rheumatoid vasculitis is a rare but serious extra-articular complication of severe RA characterized by inflammation of small-to-medium vessels causing neuropathy, skin ulcers, and digital ischemia.
Question 6: A 4-year-old girl has fever, rash, uveitis, and arthritis affecting fewer than 5 joints. ANA is positive. What is the greatest long-term ocular risk?
- Chronic anterior uveitis leading to band keratopathy and blindness (Correct answer)
- Acute posterior uveitis with retinal detachment
- Optic neuritis causing sudden vision loss
- Scleritis with globe perforation
Correct answer: Chronic anterior uveitis leading to band keratopathy and blindness
Oligoarticular JIA with ANA positivity carries a high risk of asymptomatic chronic anterior uveitis that can cause band keratopathy, cataracts, and blindness if not screened regularly.
Question 7: A 48-year-old woman presents with widespread musculoskeletal pain for 6 months, fatigue, and sleep disturbance. Physical examination reveals 14/18 tender points. Lab work is normal. What is the mechanism of her condition?
- Central sensitization with amplified pain processing (Correct answer)
- Autoimmune synovitis
- Crystal deposition in tendons
- Muscle fiber necrosis
Correct answer: Central sensitization with amplified pain processing
Fibromyalgia is characterized by central sensitization — amplified central pain processing — rather than peripheral inflammation, explaining normal lab results and diffuse tenderness.
MD Musculoskeletal and Connective Tissue 5
A 55-year-old man presents with pain and stiffness in his shoulders and hips that is worse in the morning, elevated ESR, and normal muscle enzymes.
He responds dramatically to low-dose prednisone.
What is the diagnosis?