Lyme Arthritis

Lyme Arthritis is a feature of Lyme disease is caused by the spirochete Borrelia burgdorferi, a type of bacteria  and is transmitted by the tick Ixodes dammini (deer tick) or a related ixodid tick.

Arthritis is the presenting manifestation in the majority of cases.

The infection is endemic in certain areas of North America and has been described in 19 countries. The disease characteristically develops in the summer and autumn-periods when the ticks are very active.

Clinical Features

The arthritis is preceded in about half the cases by a characteristic rash- erythema chronicum migrans. The appearance of the rash in striking. Half of the affected children will definitely recollect being bitten by a tick.

Prodromal systemic illness in the form of low-grade fever, stiff neck, or headache is present in about 40 percent of cases.

The arthritis is pauciarticular, usually affecting one or a few large joints.

The knee is the most common site and is involved in over 95 percent of cases. Other joints that can be affected are the elbow, hip, ankle, shoulder, sternoclavicular, and interphalangeal.

The arthritis follows the skin rash or prodromal systemic symptoms usually within a few months (Range- One week to 12 months).

The synovitis manifests itself as joint swelling, increased local heat, joint tenderness, and pain on extremes of motion. When the knee, hip, or ankle is involved, the patient is able to bear weight and walk on the affected lower limb with an antalgic limp.

The typical pattern of synovitis is brief and intermittent. If untreated, however, it becomes chronic.

Other clinical features of Lyme disease are meningitis or neurologic disease in the form of nerve palsy such as Bell’s, and cardiac involvement, particularly conduction defect.

Fifty percent of untreated persons experience intermittent episodes of monarthritis or oligoarthritis involving the knee and/or other large joints. The symptoms wax and wane without treatment over months, and each year 10 to 20 percent of patients report loss of joint symptoms.

Twenty percent of untreated persons develop a pattern of waxing and waning arthralgias. Ten percent of patients develop chronic inflammatory synovitis resulting in erosive lesions and destruction of the joint.

Diagnosis

Elevated titers of I&M and I&G antibodies against Ixodes dammini will establish the diagnosis of Lyme disease.

A nonspecific finding is elevation of the erythrocyte sedimentation rate. In its initial stages Lyme disease should be differentiated from the monarticular or pauciarticular form of juvenile rheumatoid arthritis.

This may be difficult but following differences can help to delineate.

• The attacks of Lyme arthritis are usually brief and self-limited, but that of juvenile rheumatoid arthritis is unremitting for at least six weeks.
• Chronic iridocyclitis does not occur in Lyme arthritis.

It is advisable to carry out serologic tests to rule out Lyme disease when one is working on JRA.

For confirmation of Lyme disease The serological laboratory tests most widely available and employed are the Western blot and ELISA. The sensitive ELISA test is performed first, and if it is positive or equivocal, then the more specific Western blot is runPolymerase chain reaction (PCR) tests for Lyme disease have also been developed to detect the genetic material (DNA) of the Lyme disease spirochete. PCR tests are susceptible to false positive results from poor laboratory technique

Pyogenic septic arthritis is another entity to be differentiated from Lyme disease.

In pyogenic arthritis, the affected joint is acutely painful, red, and hot, and the patient is unable to bear weight on the lower limbs if the knee or hip is involved. In septic arthritis, joint fluid cultures are positive in 70 percent of cases.

Synovial fluid analysis is ordinarily not of great assistance in differentiating the two because in both conditions the leukocyte count is elevated with neutrophilia. The erythrocyte sedimentation rate is elevated in both.

In case of doubt the arthritis should be treated as if septic while serologic tests for Lyme disease are sent which should be available within one to two weeks.

Treatment of Lyme Arthritis

Joint is given rest. Antibiotics are the primary treatment

Oral administration of doxycycline is widely recommended as the first choice [ contraindicated in children younger than eight years of age and women who are pregnant or breastfeeding]. Alternatives to doxycycline are amoxycillin, cefuroxime axetil, and azithromycin.

Intravenous administration of ceftriaxone is recommended as the first choice in disseminated cases.