Lyme disease as a cause of childhood arthritis is something we see frequently at HSS.
Lyme disease is very familiar to those living in the northeastern United States. The ticks that carry the disease are found in this area, and up to 90% of cases occur here. However, Lyme disease is not caused by ticks; rather it is caused by a small spiral shaped organism called Borrelia burgdorferi that lives for part of its life cycle inside some species of ticks.
When a tick bites to feed, the Lyme-causing organism can be transferred to the blood stream of the animal, usually a deer or a mouse. If the infected tick then feeds on a child, Lyme disease may result.
Lyme disease presents in 3 stages – local disease (in a specific area), followed by disseminated (or widespread) disease, and ultimately chronic / late disease.
Classic Lyme disease presents with a rash occurring at the site of the tick bite. This rash may be completely red, but usually develops a pale area in the center that makes it look like a bull’s eye; this is known as a ‘target lesion.’ Symptoms of early disease occur within days or weeks of the tick bite and resemble the flu. In fact, early disease is dismissed often as a viral infection in children and therefore is not treated.
If the Lyme disease is not recognized or remains untreated, children commonly progress to ‘late disease,’ often many months later. This can involve the heart, nervous system, and, very commonly, the joints. Up to 70% of untreated patients develop arthritis, and Lyme arthritis can affect any joint. Arthritis often involves one large joint, like the knee, which rapidly becomes markedly swollen and painful, but symptoms may be more subtle.
While not everyone that is bitten by a tick gets Lyme disease, and not everyone that gets Lyme disease gets arthritis, in an endemic area, children displaying symptoms should be tested and treated appropriately.
The question often arises of what to do for a child who has been found with an embedded tick, but has displayed no symptoms. In these cases, a Lyme test should be performed, and it is considered appropriate to begin medication, which can be stopped if repeat Lyme testing is negative.
The blood test for Lyme involves a two step process. First, a screening test is performed which is very sensitive and detects any Borrelia organisms including those causing Lyme disease, but also many others that occur normally. The second phase of the Lyme test, known as a Western blot, is done on all patients with positive results; this tests very specifically for Borrelia Burgdorferi.
Treatment is with antibiotics; the type used depends on the age and medical allergies of the child.
The duration of treatment differs based on the stage of disease. A longer course is given if patients have late symptoms. Sometimes fluid can be removed from a swollen, painful joint to give symptomatic relief; and anti-inflammatories can be given to help patients feel better.
A small proportion of children continue to have some symptoms despite extensive antibiotic treatment. It is thought that this does not represent persistence of the Borrelia organism in the body, but rather persistent stimulation of the inflammatory system, and as such is best treated with the battery of medications that we use for inflammation.
In an endemic area, awareness is essential. Check children for ticks, particularly during the summer months. Any suspicious rashes should be evaluated by a physician. Finally, don’t ignore unexplained joint complaints.
If you have any queries about Lyme arthritis in children, the Pediatrics department at Hospital for Special Surgery would be happy to help you.