Arthritis

SYSTEMIC FEATURES OF ARTHROPATHIES

System	Disease	Manifestation
Skin	Psoriatic arthritis	Psoriasis
	Reiter syndrome	Keratoderma blennorrhagica
	Septic arthritis (esp Neisseria gonorrhoeae)	Rash
	Lyme arthritis	Erythema chronicum migrans
	SLE	Butterfly rash, photosensitivity
Nasopharynx and ear	Reiter syndrome	Stomatitis
	Gout	Tophi
Eye	Reiter syndrome	Conjunctivitis
	Juvenile rheumatoid arthritis	Iridocyolitis
Gastrointestinal tract	Crohn disease	Diarrhea
	Whipple disease	Diarrhea
	Ulcerative colitis	Diarrhea
Heart	Lyme arthritis	Enlarged heart, arrhythmias
	Ankylosing spondylitis	Aortic insufficiency
	SLE	Pericarditis
Nervous system	Lyme arthritis	Stiff neck, headache
Genitourinary system	SLE	Nephritis
	Gout	Kidney disease

ARTHROCENTESIS (JOINT ASPIRATION)

Joint aspiration is performed to diagnose certain conditions, including gout, various types of arthritis, and joint infection (septic arthritis). It is also used to remove excess fluid from a joint, which can cause pain and decreased ROM. Following aspiration, local anesthetic or cortisone may be injected to help with pain and inflammation.

Technique

Prep the site with antiseptic solution. Local anesthetic may be injected superficial to the aspiration site or just proximal to the site to decrease the pain from the large gauge needle (18 to 22 gauge) that will be used for aspiration.

The ankle can be approached medially, just medial to the extensor hallucis longus tendon, or laterally, just distal to the fibula. For smaller digital joints, enter the joint dorsally, just medial or lateral to the extensor tendons.

SYNOVIAL JOINT FLUID ANALYSIS

Test	Normal	Noninflammatory Arthritis	Inflammatory Arthritis	Septic
Clarity	Transparent	Transparent	Translucent	Opaque
Color	Colorless	Straw	Yellow	Variable (white)
Crystals	None	None	Possibly (gout, pseudogout)	None
Cultures	Negative	Negative	Negative	Positive
Glucose (as compared with FBS)	Equal to blood	Equal to blood	Less than 50 mg/dL lower than blood	Greater than 50 mg/dL lower than blood
Mucin clot	Firm	Firm	Friable	Friable
PMN (%)	<25	<25	>50	>75
WBC	<200	200-2,000	2,000-75,000	>100,000
Viscosity	High	High	Low	Variable

DDX of Synovial Joint Fluid Analysis

Noninflammatory	Inflammatory	Sepsis
DJD	RA	Bacterial infection
Trauma	Scleroderma
Osteochondritis dissecans	Gout
Neuropathic arthropathies	Pseudogout
Pigmented villonodular synovitis	Reiter syndrome
SLE	Ankylosis spondylitis
Scleroderma	SLE
	Psoriatic arthritis
	Ulcerative colitis

RHEUMATOID ARTHRITIS

Description

Rheumatoid arthritis begins as a chronic symmetrical peripheral polysynovitis with insidious aching and morning stiffness. RA is caused by an autoimmune response that progresses to destruction of articular and periarticular structures.

Signs and Symptoms

Symmetrical inflammatory polyarthritis (≥3 joints)

Pain and swelling worse in the morning, and after rest, pain gets better with motion.

Gel phenomenon—stiffness develops after long periods of sitting or rest, and joints become painful to move.

Female to male ratio (3:1)

Onset is 20 to 50 years of age.

Affects small joints in hands and feet (MPJs, wrists, MCJs, and PIPJ)

Possible low-grade fever, fatigue, weight loss, and malaise

Rheumatoid nodules—benign subcutaneous painless masses found at sites usually subject to trauma

Boutonnière deformity—flexion of the PIPJ of the finger with hyperextension of the DIPJ

Swan neck deformity—hyperextension of the PIPJ of the finger with flexion of the DIPJ

Baker’s cyst (popliteal cyst)—a synovial fluid-filled cyst, which develops in the popliteal fossa. When ruptured, symptoms mimic a DVT.

Felty syndrome—rheumatoid arthritis with associated splenomegalia and neutropenia. Patients may present with pigmented spots on the lower extremity, and may have nonhealing leg ulcers.

Pannus transformation—the synovium develops into a vasculature granulation tissue that produces inflammatory agents and immunoglobulin-producing lymphoreticular-like elements that destroy the articular cartilage.

JUVENILE RHEUMATOID ARTHRITIS

Juvenile rheumatoid arthritis (JRA) is also called juvenile idiopathic arthritis (JIA). JRA is a type of arthritis that causes joint pain in children. Onset is usually before age 16. It is thought to be an autoimmune disorder. Females are affected more than males (4:1), and caution should be used during anesthesia (intubation) due to possible cervical spine problems (atlantoaxial subluxation).

Three Subtypes

1. Polyarticular (40%) involves many joints. This form may turn into rheumatoid arthritis. It may involve five or more large and small joints of the legs and arms, as well as the jaw and neck.

2. Pauciarticular (40%) involves four or less joints, most often the wrist or knees. It is also associated with eye problems (iridocyclitis).

3. Systemic (Still disease) (20%) involves joint swelling or pain,
fever, and rash. It is also associated with systemic manifestations (splenomegaly, generalized adenopathy).

OSTEOARTHRITIS (DEGENERATIVE JOINT DISEASE)

Description

Osteoarthritis is the most common arthritis and occurs as a result of wear and tear on joints. The cartilage that cushions the impact on the joint gradually deteriorates. As the cartilage wears down, subchondral bone is exposed, which becomes sclerotic and polished in a process called eburnation. Cysts may appear in the subchondral bone. Over time, the ends of the bones are also affected, with bone growing along the sides producing osteophytes. There is usually a predisposing factor such as trauma or prior inflammatory arthritis.