JOINT SWELLING
The best approach to analysis of this symptom is anatomic and
histologic (Table 43). However,
if one remembers the biochemical causes of joint disease, gout, pseudogout,
and ochronosis immediately come to mind.
Let us discuss the conditions to be considered in an anatomic and histologic
breakdown of the joint. In the skin, an abscess or hematoma is a
possibility. Subcutaneous lipoma and pretibial myxedema may involve the
joint area as may edema, particularly in phlebitis. Around all joints are
bursae that can become inflamed and swollen, especially when torn
ligaments constantly rub against them.
JOINT SWELLING
|
| V | I | N | D |
|
| Vascular | Infection | Neoplasm | Degenerative |
|
|
Skin |
|
Carbuncle |
| |
|
Subcutaneous Tissue |
|
Cellulitis |
Lipoma | |
|
Bursa |
|
Bursitis |
| |
|
Synovium |
|
Gonococcal arthritis Tuberculous arthritis Streptococcal arthritis |
Synovioma | |
|
Ligaments of Joint |
|
|
| |
|
Joint Space |
|
|
|
“Joint mice" |
|
Cartilage |
|
|
|
Degenerative osteoarthritis |
|
Bone |
Aseptic bone necrosis |
Staphylococcal osteomyelitis Tuberculous osteomyelitis |
| |
|
Blood Vessels |
Sickle cell anemia |
Phlebitis |
| |
|
JOINT SWELLING
|
| I | C | A | T | E |
|
| Intoxication | Congenital or | Allergic | Trauma | Endocrine |
|
| | Collagen | Autoimmune | | |
|
|
|
|
|
Hematoma |
| |
|
|
|
|
| |
|
|
|
|
| |
|
|
|
Lupus Rheumatoid arthritis |
Reiter disease Serum sickness |
Hemarthrosis |
| |
|
|
|
|
|
Ruptured ligament |
|
| Gout, pseudogout |
Rheumatic fever |
|
Hemarthrosis |
Intermittent hydrarthrosis |
|
|
|
Ochronosis |
|
Torn meniscus |
| |
|
|
|
|
| |
| |
|
|
|
Hemophilia |
| |
|
Next let us consider the ligaments of the joint, especially those in
the knee. Weak collateral ligaments will lead to recurrent swelling from
fluid accumulation in the knee. Ruptured anterior or posterior cruciate
ligaments will also create intermittent pain and swelling. To diagnose this
condition, bend the knee and pull the tibia and lower leg forward and
backward like opening and closing a drawer. If the meniscus is ruptured, a
distinct popping or locking of the joint will occur when the joint is flexed
and then extended under pressure, especially with internal or external
rotation of the lower leg.
The synovium is the site of most pathologic conditions of the knee.
Rheumatic fever, RA, lupus erythematosus, and Reiter disease are classic
collagen diseases affecting the synovium. The most common infectious
diseases are gonorrhea and Streptococcus organisms, but tuberculosis and brucellosis
should not be forgotten. Trauma to the synovium produces hemarthrosis, but
it does not take much to cause hemarthrosis in hemophilia and occasionally
in other coagulation disorders.
Moving on to the bone, osteomyelitis and syphilis must be considered:
Staphylococcus and tuberculosis are common offenders. Aseptic bone necrosis (e.g.,
Osgood–Schlatter disease of the knee) is another condition of the bone that
causes apparent joint swelling.
Idiopathic degeneration of the cartilage is a common cause of joint disease
in the form of osteoarthritis. Ochronosis may lead to degeneration, but
there is usually calcification of the cartilage on radiographs.
Approach to the Diagnosis
The clinical picture will often help identify the cause of the joint
swelling. If there is fever and migratory arthritis, one suspects rheumatic
fever or Lyme disease. Fever with involvement of several joints would
suggest RA, lupus erythematosus, or gonorrhea.
Fever and involvement of one joint primarily is found in septic arthritis
and tuberculosis but may be found in gonorrhea. No fever and large joint
involvement may be found in osteoarthritis, gout, and pseudogout.
Osteoarthritis customarily affects the distal phalangeal joints, whereas RA
affects the metacarpophalangeal joints. Psoriatic arthritis also affects the
distal phalangeal joints primarily. Charcot joints are usually large.
The initial workup of joint swelling includes a CBC, sedimentation rate,
urinalysis, chemistry panel, and x-rays of the involved joints. If a large
joint is involved, joint fluid can be aspirated and analyzed. A culture
should also be done.
If gonococcal arthritis is suspected, urethral or cervical smears and
cultures will be helpful, but culture of the fluid on special medium is most
important. If gout or pseudogout is suspected, it is important to examine
the joint fluid for crystals under polarized light. If RA is suspected, an
RA titer will often be positive. Lupus erythematosus can be confirmed by a
positive ANA and anti–double-stranded DNA antibodies. Rheumatic fever can
be confirmed by a positive ASO titer or streptozyme test. If the synovial
fluid has a high white count, hospitalization and initiation of parenteral
antibiotics are indicated without delay.
Other Useful Tests
-
Venereal Disease Research Laboratory (VDRL) test (Charcot joints)
-
Electrocardiogram (ECG) (rheumatic fever)
-
Tuberculin test (tuberculosis of the joint)
-
Blood cultures (septic arthritis)
-
Monospot test (infectious mononucleosis with joint involvement)
-
Lyme disease antibody titer
-
Sickle cell prep
-
Coagulation profile (hemophilia)
-
Cervical or urethral smears and cultures for gonococci
-
Febrile agglutinins (infectious arthritis)
-
MRI of joint (torn meniscus)
-
Synovial biopsy (RA)
-
Therapeutic trial of colchicine (gout)
-
Bone scan (osteomyelitis)
