Characteristics - On exam include decreased ROM and crepitus. The knee is the most common joint affected. Treatment begins with supportive measures (activity modification, cane, etc.) and includes NSAIDs and a variety of surgical procedures ranging from arthroscopy to arthroplasty.
Neuropathic Arthropathy (Charcot Joint)
An extreme form of osteoarthritis caused by a disturbance in the sensory innervation of a joint. Causes include diabetes (foot), tabes dorsalis (lower extremity), syringomyelia (upper extremity), Hansen’s disease, myelomeningocele.
Acute Rheumatic Fever Group A B-hemolytic strep infections.
OchronosisDegenerative arthritis resulting from alkaptonuria, a rare inborn defect of the homogentisic acid oxidase enzyme system (tyrosine and phenylalanine catabolism).
Etiology - Unclear, but probably related to cell mediated immune response (T cell) that incites an inflammatory response initially against soft tissues and later against cartilage (chondrolysis) and bone (periarticular bone resorption). Hallmark is synovitis.
Characteristics - Usually an insidious onset of morning stiffness and polyarthritis. Synovium and soft tissues are first affected, elevated ESR and a positive RF (IgM). Radiographs demonstrate periarticular erosions and osteopenia.
Treatment - Control of synovitis and pain, maintenance of joint function, and prevention of deformities are the goals of therapy.
Systemic Lupus Erythematosus.Polymyalgia RheumaticaJuvenile Rheumatoid Arthritis - Three major types are recognised.
Spondyolarthropathies - Enthesopathies (occur at ligament insertion into bone) characterised by positive HLA-B27 (sixth chromosome, D).
Ankylosing spondylitis - Bilateral sacroilitis - acute anterior uveitis in a HLA-B27 - positive male is diagnostic of this disease.
Reiter’s Syndrome - Classic presentation is a young male with a triad of urethritis, conjunctivitis, and oligoarticular arthritis.
Psoriatic Arthropathy - Affects about 7% of patients with psoriasis. Many different HLA loci may be involved.
Enteropathic Arthritis - About 10-20% of Crohn’s disease and ulcerative colitis patients can develop peripheral joint arthritis.
Crystal Deposition Disease
Gout - A disorder of nucleic acid metabolism causes hyperuricemia, which leads to mono-sodium urate crystal deposition in joints. Recurrent attacks of arthritis, especially in males 40-60 yo (usually in the lower extremity - especially the great toe, crystal deposition in tophi (ear helix, eyelid olecranon, Achilles; usually seen in chronic form), and renal disease/stones (2% Ca2+ vs. normal 0.2%) are characteristic.
Chondrocalcinosis - Caused by several disorders, including calcium pyrophosphate deposition disease (CPPD), ochronosis, hyperparathyroidism, hypothyroidism, and hemochromatosis, which lead to increased calcium -+ pyrophosphate crystal deposition.
Calcium Hydroxyapatite Crystal Deposition DiseaseInfectious ArthritidesCommon Characteristics - Aspirates of acute, red, hot, effusions usually show opaque fluid with >80,000 WBCs (75 + % PMNs), low glucose (>25 mg/dl less than serum values), and positive Gram’s stains/cultures.
Pyogenic Arthritis - Occurs from haematogenous spread or by extension of osteomyelitis. Commonly occurs in children. Occurs more commonly in adults who are at risk, including IV drug abusers (esp. SC and sacroiliac joints), sexually active young adults (gonococcal, especially if seen with skin papules), diabetics (feet and lower extremities), rheumatoids, and following trauma (fight bites, open injuries) and surgery (iatrogenic).
Tuberculous Arthritis - The chronic granulomatous infection caused by Mycobacterium tuberculosis usually involves joints by haematogenous spread. Spine and lower extremities are most often involved, typically in Mexicans and Asians. Radiographically, both sides of the joint. Diagnosis is helped with positive PPD, demonstration of acid-fast bacilli and rice bodies (fibrin globules) in joint fluid, positive cultures (may take several weeks), and characteristic x-rays (subchondral osteoporosis, cystic changes, notch-like bony destruction of the edge of the joint, and joint space.
Fungal Arthritis - More common in neonates, AIDS victims, and drug users.
Lyme DiseaseHaemorrhagic Effusions.Can be the result of haemophilia, sickle cell disease, pigmented villonodular synovitis, or other causes discussed elsewhere.
Haemophilic Arthropathy - X-linked recessive factor VIII deficiency (haemophilia A -classic or factor IX deficiency; haemophilia B-Christmas disease) associated with repeated hemarthrosis from minor trauma leading to synovitis, cartilage destruction (enzymatic processes).
Sickle Cell Disease 
