Master CPS - Musculoskeletal
for MSRA
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Core Concepts
Key musculoskeletal pathologies for MSRA:
- Degenerative: Osteoarthritis (OA) – "wear and tear."
- Inflammatory:
- Rheumatoid Arthritis (RA) – autoimmune, symmetrical polyarthritis.
- Gout/Pseudogout – crystal deposition.
- Septic Arthritis – joint infection (MEDICAL EMERGENCY).
- Traumatic: Fractures, sprains/strains.
- Spinal: Non-specific back pain, sciatica, Cauda Equina Syndrome (SURGICAL EMERGENCY).
- Metabolic: Osteoporosis – fragile bones.
Clinical Presentation
- Osteoarthritis (OA):
- Gradual, activity-related pain.
- Morning stiffness <30 min, crepitus.
- Asymmetrical, weight-bearing joints (knees, hips, spine, hands).
- Rheumatoid Arthritis (RA):
- Symmetrical polyarthritis (small joints: MCPs, PIPs).
- Morning stiffness >30 min, fatigue, systemic symptoms.
- Swelling, warmth, tenderness, rheumatoid nodules.
- Gout:
- Acute, severe monoarthritis (often big toe).
- Rapid onset of pain, redness, swelling, warmth.
- Septic Arthritis:
- Acute, hot, swollen, exquisitely painful monoarthritis.
- Fever, chills, inability to move joint (passive or active).
- Fractures:
- Trauma, sudden pain, swelling, deformity, loss of function.
- Hip fracture: shortened, externally rotated leg.
- Back Pain:
- Non-specific: Mechanical, no red flags.
- Sciatica: Radicular leg pain, neurological deficit (dermatome/myotome).
- Cauda Equina Syndrome: Saddle anaesthesia, bilateral leg weakness, new bladder/bowel dysfunction.
Diagnosis (Gold Standard)
- OA: Clinical + X-ray (joint space narrowing, osteophytes).
- RA: Clinical (ACR/EULAR) + Bloods (RF, anti-CCP, ESR, CRP) + X-ray (erosions).
- Gout/Pseudogout: Joint aspiration for synovial fluid microscopy (Gout: neg. birefringent urate; Pseudogout: pos. birefringent CPPD).
- Septic Arthritis: Joint aspiration for Gram stain, MCS. Bloods (FBC, CRP, ESR).
- Fractures: Plain X-ray. CT for complex/occult.
- Back Pain:
- Non-specific/Sciatica: Clinical. MRI for red flags or persistent symptoms.
- Cauda Equina: Urgent MRI spine.
Management (First Line)
- OA: Physiotherapy, weight loss. Paracetamol, NSAIDs (oral/topical). Intra-articular steroids for flares.
- RA: Prompt DMARDs (e.g., Methotrexate). NSAIDs for symptoms, oral steroids for flares.
- Gout: Acute: NSAIDs, Colchicine, oral steroids. Prophylaxis: Allopurinol (after acute resolves).
- Septic Arthritis: Urgent IV antibiotics + surgical washout/drainage.
- Fractures: Analgesia, immobilisation, reduction (closed/open), fixation (internal/external). Urgent surgery for open, neurovascular compromise, or unstable fractures (e.g., hip).
- Back Pain:
- Non-specific/Sciatica: Analgesia, stay active, physiotherapy.
- Cauda Equina: Immediate neurosurgical referral + urgent decompression surgery.
Exam Red Flags
- Septic Arthritis: Hot, swollen, very painful monoarthritis + fever + inability to move joint.
- Cauda Equina Syndrome: New/worsening bilateral leg weakness, saddle anaesthesia, new bladder/bowel dysfunction, reduced anal tone.
- Neurovascular Compromise: Pallor, pulselessness, paraesthesia, paralysis, pain distal to injury. Compartment syndrome.
- Open Fracture: Skin breach over fracture.
- Back Pain Malignancy/Infection: Unexplained weight loss, night pain, fever, history of cancer, IVDU, new onset >50 or <20, unremitting pain.
- Non-Accidental Injury (NAI) in Children: Inconsistent history, multiple fractures, spiral fractures in non-ambulatory.
Sample Practice Questions
A 60-year-old female complains of gradual onset left shoulder pain over the past 3 months. She struggles to lift her arm above shoulder height and finds it difficult to reach behind her back. Passive range of movement is also significantly limited and painful. She denies any specific injury. What is the most likely diagnosis?
A 32-year-old male presents to the emergency department after twisting his ankle during a football match. He reports immediate pain and swelling and is unable to bear weight on the affected foot. On examination, there is tenderness over the posterior edge of the lateral malleolus and the base of the fifth metatarsal. According to the Ottawa Ankle Rules, what is the most appropriate initial investigation?
A 22-year-old male presents to the emergency department after sustaining a twisting injury to his right knee during a football match. He describes hearing a 'pop' and immediately felt severe pain, followed by rapid swelling of the knee. He reports feeling as though his knee 'gives way' when trying to bear weight. On examination, there is a moderate effusion, and Lachman's test is positive. What is the most likely diagnosis?
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