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Approach to Acute Monoarthritis of the Knee. Henry Averns Assistant Professor Rheumatology Division Queens University. Aims of Workshop. To consider the differential diagnosis of acute and chronic knee monoarthritis
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Approach to Acute Monoarthritis of the Knee Henry Averns Assistant Professor Rheumatology Division Queens University
Aims of Workshop • To consider the differential diagnosis of acute and chronic knee monoarthritis • I.e. provide a systematic approach to the investigation and differential diagnosis of patients presenting with monoarticular pain. • To briefly review examination of the knee • To discuss indications for aspiration and injection of the knee • To practice knee injection on model knees
APPROACH TO MONOARTHRITIS OF THE KNEE MONOARTHRITIS POLYARTHRITIS Acute or Chronic? Is it inflammatory? Extra- articular features? Systemic or local problem? ARTICULAR EXTRA-ARTICULAR
History I • Age, time profile • Features of inflammation • stiffness, redness, pain, swelling, warmth • Preceding illness • GU or GI infection • history of trauma, portal of entry for infection • Associated symptoms • red eye, rash, balanitis
History 2 • Associated medical complaints • psoriasis, IBD, Ankylosing spondylitis • bleeding disorders • predisposition to infection • Drug history • immunosuppressants, aspirin, diuretics • Family history • of gout, psoriasis, IBD, AS
Differential diagnosis I • Acute monoarthritis • Septic arthritis (staph aureus) • Reactive arthritis • GI infection - campylobacter, salmonella, shigella, yersinia • GU infection - chlamydia • Crystal arthritis • Gout (uric acid) • Pseudogout/chondrocalcinosis/calcium pyrophosphate deposition disease (CPPD) • Haemarthrosis
Septic Arthritis • Risk factors • prosthetic hip or knee joint, • skin infection, • joint surgery, • rheumatoid arthritis, • age greater than 80 years, • diabetes mellitus. • Intravenous drug use and large-vein catheterization are predisposing factors for sepsis in unusual joints (e.g., sternoclavicular joint).
Examination of the Knee • Demonstration • Module
ARTHROCENTESIS / INJECTION • Indications • Diagnostic • Synovial fluid analysis • Therapeutic • Inflammatory arthritis • Gout • Osteoarthritis
ARTHROCENTESIS The things you need;
ARTHROCENTESIS • Contraindications • Infection locally OR elsewhere • Abnormal skin (relative CI) • Warfarin therapy is not a contraindication • No touch technique adequate • Local anaesthesia difficult to achieve…is it worth it? Probably not • Have appropriate tubes ready
Extra-articular features which suggest seronegative spondyloarthritis • nails (pitting, ridging, hyperkeratosis) • enthesitis, dactylitis and tenosynovitis • nodules (elbows/ears) • skin (local infection, psoriasis, keratoderma blenorrhagicum, balanitis) • eyes (conjunctivitis, uveitis) • mouth ulcers
Investigations I • Haematology - CBC, ESR, clotting • Biochemistry - U&E, LFTs, urate, CRP • Immunology • Microbiology • blood/urine/stool/urethral/sputum cultures • serology
Investigations II • Synovial fluid • volume/viscosity/cellularity • polarised light microscopy (crystals) • gram stain/culture • Imaging • plain films • loss of joint space, osteophytes, subchondral cysts, osteosclerosis, erosions, chondrocalcinosis • MRI, bone scan
Septic Arthritis • Staph aureus—most common • Strep (splenic dysfunction) • Neisseria gonorrhea (young, sexually active) • Gram negatives (immunocompromised, GI infection) • Mycobacteria (immunocompromised) • Fungus (immunocompromised) • Lyme disease