Tutorial

Tutorial

باطنية
د. علي عبدالرحمن

عدد الاوراق (3)

11/9/2012

Monoarthritis

“inflammation of a single joint”
Acute: develop in < 6 weeks
Chronic: 6 weeks or more

Causes of acute monoarthritis

Inflammatory
bacterial arthritis( nongonococcal, gonococcal)
Gout, pseudogout
Juvinile idiopathic arthritis
Spondyloarthropathies
RA
SLE
Non-inflammatory
Trauma ,Internal derangements
Osteoarthritis
Amyloidosis
osteonecrosis
Neuropathic arthropathy


Initial clinical evaluation
History
Course and duration of symptoms
Morning stiffness
History of previous episodes crystalline or palindromic arthritis
Antecedent joint disease or surgery infection
Joint prosthesis loosening of the implant
Rash, diarrhea ,urethritis ,conjunctivitis reactive arthritis
Migratory polyarthralgia, dermatitis gonococcal arthritis
Weight loss malignancy , other serious systemic diseases
Trauma fracture, internal derangement .
can precipitate acute gout
can introduce infection
Fever ,chills, tick bites ,sexual risk factors, travel outside, and intravenous drug use clues to infectious causes
Recent prolonged course of steroid-infection ,avascular necrosis
Diuretic usage, alcohol binges, history of renal stones, tophi gout
Occupation
Concurrent illnesses and medications
Coagulopathy ,use of anticoagulants hemarthrosis
Family history


Physical examination
Distinguish arthritis from problems in the periarticular tissues
In arthritis swelling and tenderness tend to surround the joint , tenderness and swelling on only one side of the joint suggest a periarticular problem.
Painful limitation of passive motion of the joint in all plane s usually indicates joint involvement, pain limited to one movement suggest a periarticular problem
Intraarticular problems cause restriction of active and passive range of motion, while periarticular problems restrict active more than passive range of motion
Maximum pain at the limit of joint motion is characteristic of true arthritis
In tendonitis joint movement against resistance elicit pain
Look for extra-articular signs that might provide clues to specific causes
Mouth ulcers- behcets disease, reactive arthritis, SLE
Psoriatic patches
Keratodermia blennorrhagicum- reactive arthritis
Erythema nodosum- sarcoidosis, IBD
Skin ulceration source of infection



Laboratory evaluation

Arthrocentesis should be performed in almost every patient with monoarthritis, and it is obligatory if infection is suspected
Synovial fluid should be sent for culture, WBC count, gram stain ,and examined for crystals by polarized light microscopy
Determining wether the synovial fluid is inflammatory, noninflammatory, or bloody guides the initial differential diagnosis
Polarized light microscopy is a sensitive test for urate crystals
Calcium pyrophosphate dihydrate crystals are somewhat more difficult to visualize
Gram staining for bacteria is relatively insensitive( false negative rate 25%-50%for nongonococcal septic arthritis
Culture of synovial fluid is positive in up to 90% of cases for septic arthritis, and only in 20-50% of cases of gonococcal arthritis.


Notes
Absence of crystals is strong argument against microcrystalline disease
A negative gram stain doesnt exclude infection
The finding of crystals in synovial fluid doesnt exclude infection (infection and crystal disease may coexist)
In gonococcal arthritis the diagnosis depend on identifying N. Gonorrhoea on culture from pharynx, urethra, cervix, or rectum( positive in 80-90%)
Routine laboratory tests (CBC ,ESR, CRP, serum electrolytes and creatinine, and urinalysis) can provide helpful ancillary information
Blood cultures should be obtained if septic arthritis is suspected
Others-ANF, RF, HIV serology

Radiographs

Radiographic findings are typically unremarkable in most patients with acute monoarthritis
It can help exclude some causes
May show fractures ,tumors, or signs of antecedent chronic disease
Chondrocalcinosis in the involved joint suggest that the arthritis is caused by CPPD crystals


Differential diagnosis

Inflammatory
Differentiation between infectious and crystal arthritis can be difficult without synovial fluid analysis and culture
Patients with septic arthritis may be afebrile and may not manifest peripheral leukocytosis
Patients with crystal arthritis can have fever and elevated peripheral WBC count
An elevated serum uric acid level doesnt establish a diagnosis of gout
When the synovial fluid is highly inflammatory(WBC count more than 50000/μL but the gram stain and the polarized light microscopy findings are negatives , empiric treatment with antibiotic is prudent until the result of cultures are known
Empiric antibiotic coverage may be indicated for unexplained acute inflammatory monoarthritis with synovial fluid WBC count < 50,000/μL
Nongonococcal septic arthritis often generate very high synovial WBC count(more than 100,000/μL)
Septic arthritis can present with synovial fluid WBC count as low as 3000/μL
The synovial fluid WBC count in gonococcal arthritis is generally lower the in nongonococcal septic arthritis
Diseases that are typically oligoarticular or polyarticular, occasionally begin as an inflammatory monoarthritis


Non-inflammatory
Internal derangement (torn meniscus of the knee)
OA of a single joint may occasionally present acutely
Neuropathic arthropathy, amyloidosis , and osteonecrosis usually cause chronic noninflammatory arthritis of one or several joints, but acute symptoms are sometimes present
hemarthrosis
Frank blood can be indicative of a fracture or other joint trauma
May also occur in patient receiving anticoagulant therapy or who have a clotting factor deficiency
Bloody synovial fluid can be seen in pigmented villonodular synovitis











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