eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease
Lyme Disease
Updated: Apr 17, 2009
Introduction
Background
Lyme disease is the most common tick-borne illness in the United States. Although erythema migrans (EM), the characteristic rash associated with Lyme disease, was initially described in 1921, Lyme disease was first formally described in the medical literature in 1976 following an outbreak of arthritis in Lyme, Connecticut. Since then, the number of reported cases has increased dramatically, likely as a result of increased awareness of clinicians and patients in endemic areas.
Pathophysiology
Lyme disease is caused by the spirochete Borrelia burgdorferi,1 which is transmitted by Ixodid tick species, mostly Ixodes scapularis (the common deer tick).
The Ixodes scapularis tick is considerably smaller than the Dermacentor tick. The former is the vector for Lyme disease, granulocytic ehrlichiosis, and babesiosis. The latter is the vector for Rocky Mountain spotted fever. This photo displays an adult I scapularis tick (on the right) next to an adult Dermacentor variabilis; both are next to a common match displayed for scale. Photo by Darlyne Murawski; reproduced with permission.
In general, Ixodes scapularis must be attached for 24-48 hours to transmit the spirochete to the host mammal. Prophylactic antibiotics are more likely to be helpful if feeding is longer. This photo shows 2 I scapularis nymphs. The one on the right is unfed; the other has been feeding for 48 hours. Note its larger size and the fact that the midgut diverticula (delicate brown linear areas on the body) are blurred. Photo by Darlyne Murawski; reproduced with permission.
The life cycle of Ixodid ticks occurs over 2 years. The adult lays eggs in the spring, and the larvae emerge in the summer. The larvae feed on a wide variety of small animals (eg, the white-footed mouse) that serve as important reservoirs for B burgdorferi. The following spring, the larvae emerge as nymphs that likewise mainly feed on small animals. The nymphs molt into adults the following fall and spend the winter feeding on larger animals, most notably the white-tailed deer. Ticks can acquire B burgdorferi during any of the 3 life-cycle stages. Lyme disease is passed to humans mostly by nymphs because (1) nymphs are more abundant than adult ticks during the months of greatest human outdoor activity and (2) nymphs are more difficult to detect because of their smaller size.
The risk of transmission of B burgdorferi from an infected tick to a human depends on the length of exposure. It takes hours for the tick to attach fully, and experimental studies have indicated that nymphs must feed 36-48 hours and adults 48-72 hours to transmit B burgdorferi. After B burgdorferi is introduced into the skin, it spreads locally. The local spread leads to EM, a rash that is found in approximately two thirds of cases.
Over days to months, the spirochete may invade the blood stream, leading to disseminated disease. Dissemination to the skin can manifest as multiple EM. B burgdorferi can spread to any tissue but commonly affects the skin, eye, muscle, heart, and central nervous system. Arthritis is a characteristic manifestation of late disease and is caused by the persistence of organisms in the synovium. Some patients, particularly adults, appear to have persistent symptoms after adequate antimicrobial treatment, suggesting an autoimmune component to chronic symptoms.
Frequency
United States
The number of reported cases has increased 101% from 9908 cases in 1992 to 19,931 cases in 2006. Incidence is highest in children aged 5-14 years. The 3 distinct regions in the United States are (1) the Northeast (from Massachusetts to Maryland), (2) the upper Midwest (especially Minnesota and Wisconsin), and (3) the West Coast (especially northern California).
Based on the life cycle of the tick in the United States, onset of illness is between May and October, with most cases presenting in June and July.
International
Lyme disease occurs throughout the world. In Europe, most Lyme disease is reported by Scandinavian countries, Germany, Austria, and Slovenia. In Europe, Lyme disease is primarily caused by Borellia afzelii and Borellia garinii, whose clinical manifestations differ somewhat from those of B burgdorferi. B garinii tends to disseminate less widely than B burgdorferi but is especially neurotropic and may cause encephalomyelitis. B afzelii often infects the skin only but may persist in that site, causing various cutaneous manifestations including acrodermatitis chronica atrophicans.
B burgdorferi infection has also been reported in Asian countries, including China, Korea, Japan, Indonesia, Nepal, and eastern Turkey.
Mortality/Morbidity
The prognosis for Lyme disease is generally excellent when patients are treated early with appropriate antibiotic regimens. For patients with chronic symptoms postinfection, randomized controlled trials of extended antibiotic regimens have not shown any efficacy.
Clinical
History
Most patients with Lyme disease do not recall a tick bite. The presenting signs and symptoms depend on the stage at which the disease is recognized, as follows:
- Early disease - Usually 7-14 days after a tick bite
- Erythema migrans (EM): Two thirds of patients with Lyme disease present with the typical rash, EM.2 The rash may be a confluent patch of erythema or may have central clearing. The rash typically expands over days and is not evanescent. EM is a clinical diagnosis, and serologic testing for children with a single EM lesion is generally not recommended because patients may be seronegative early in the course of illness.
- During early disease, with or without the rash, patients may complain of a flulike illness characterized by fever, chills, myalgias, arthralgias, headache, and malaise. In the area of the tick bite, tender adenopathy may be noted.
- Early disseminated disease - Usually develops 3-10 weeks after inoculation
- Approximately 25% of individuals infected with B burgdorferi have signs and symptoms of disseminated disease at presentation.
- Multiple EM lesions are relatively small erythematous macules (1-5 cm) and are often oval. Unlike primary single EMs, these lesions can be evanescent and do not show the typical expansion over days.
- Patients with early disseminated disease may complain of fever, myalgias, arthralgias, malaise, and headache. Persistent headache alone is a rare presentation of Lyme disease but should be considered in patients in endemic areas during summertime.
- Aseptic meningitis may develop at this stage.
- Cranioneuropathies, especially peripheral seventh nerve (Bell palsy), are common (3% of Lyme disease). In endemic areas, Lyme disease is the most commonly identified cause of acquired facial palsy, especially in children.3 Headache, absence of previous herpetic lesions, and meningeal symptoms are noted in most patients.
- Encephalitis is rare.
- Carditis may present as complete heart block.
- Late disease - Weeks to months after inoculation
- Arthritis is the hallmark of late disease. It tends to involve large joints (knee involved in 90% of cases). Arthritis needs to be differentiated from arthralgia, which is common in early disease.
- Most patients presenting with late disease do not have a history of EM because the rash typically leads to earlier treatment and, therefore, prevention of late disease.
Physical
- Early disease
- EM rash
- Confluent or central clearing
- Expands over days
- Not evanescent
- More common on head or neck in young children and on extremities in older children
- Characteristic round or oval shape, which may be more difficult to recognize on the face, neck, or axilla
- Fever
- Myalgias
- Malaise
- Arthralgia
- Patient appears in discomfort due to headache or myalgias
- Tender adenopathy (local, not diffuse)
- EM rash
- Early disseminated disease
- Multiple EMs
- Twenty-five percent of patients with Lyme disease present with multiple EM.
- Eighty-nine percent of patients with disseminated Lyme disease present with at least one EM lesion.
- Headache
- Fever
- Tender adenopathy (regional or generalized)
- Conjunctivitis (uncommon, never prominent)
- Carditis (usually manifests as heart block)
- Meningismus as a sign of aseptic meningitis
- Cranioneuropathy, especially cranial nerve VII and Bell palsy (peripheral seventh nerve palsy with decreased unilateral function, including the forehead)
- Multiple EMs
- Late disease
- Arthritis is located mostly in large joints, especially the knee.
- Warmth, swelling from effusion, and limited range of motion help distinguish arthritis from simple arthralgia.
Causes
- Lyme disease is caused by the spirochete B burgdorferi, which is transmitted by Ixodid species of tick, mostly I scapularis (the common deer tick).
More on Lyme Disease |
 Overview: Lyme Disease |
| Differential Diagnoses & Workup: Lyme Disease |
| Treatment & Medication: Lyme Disease |
| Follow-up: Lyme Disease |
| Multimedia: Lyme Disease |
| References |
| Further Reading |
| Next Page » |
References
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Halperin JJ. Nervous system lyme disease: diagnosis and treatment. Rev Neurol Dis. Winter 2009;6(1):4-12. [Medline].
Nigrovic LE, Thompson AD, Fine AM, Kimia A. Clinical predictors of Lyme disease among children with a peripheral facial palsy at an emergency department in a Lyme disease-endemic area. Pediatrics. Nov 2008;122(5):e1080-5. [Medline].
Halperin JJ, Shapiro ED, Logigian E, Belman AL, Dotevall L, Wormser GP. Practice parameter: treatment of nervous system Lyme disease (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. Jul 3 2007;69(1):91-102. [Medline].
The ILADS Working Group. Evidence-based guidelines for the management of Lyme disease. Expert Rev Anti Infect Ther. 2004;2(1 Suppl):S1-13.
Wormser GP, Dattwyler RJ, Shapiro ED, et al. The clinical assessment, treatment, and prevention of lyme disease, human granulocytic anaplasmosis, and babesiosis: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. Nov 1 2006;43(9):1089-134. [Medline].
Afzelius A. Erythema chronicum migrans. Acta Derm Venereol. 1921;2:120-125.
Avery RA, Frank G, Glutting JJ, Eppes SC. Prediction of Lyme meningitis in children from a Lyme disease-endemic region: a logistic-regression model using history, physical, and laboratory findings. Pediatrics. Jan 2006;117(1):e1-7. [Medline].
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Cook SP, Macartney KK, Rose CD, Hunt PG, Eppes SC, Reilly JS. Lyme disease and seventh nerve paralysis in children. Am J Otolaryngol. Sep-Oct 1997;18(5):320-3. [Medline].
Edlow JA. Lyme disease and related tick-borne illnesses. Ann Emerg Med. Jun 1999;33(6):680-93. [Medline].
Gerber MA, Zemel LS, Shapiro ED. Lyme arthritis in children: clinical epidemiology and long-term outcomes. Pediatrics. Oct 1998;102(4 Pt 1):905-8. [Medline].
Halsey NA, Abramson JS, Chesney PJ. American Academy of Pediatrics. Committee on Infecious Diseases. Prevention of Lyme disease. Pediatrics. Jan 2000;105(1 Pt 1):142-7. [Medline].
Kaplan RF, Trevino RP, Johnson GM, et al. Cognitive function in post-treatment Lyme disease: do additional antibiotics help?. Neurology. Jun 24 2003;60(12):1916-22. [Medline].
Krupp LB, Hyman LG, Grimson R, et al. Study and treatment of post Lyme disease (STOP-LD): a randomized double masked clinical trial. Neurology. Jun 24 2003;60(12):1923-30. [Medline].
Masuzawa T. Terrestrial distribution of the Lyme borreliosis agent Borrelia burgdorferi sensu lato in East Asia. Jpn J Infect Dis. Dec 2004;57(6):229-35. [Medline].
Moses JM, Riseberg RS, Mansbach JM. Lyme disease presenting with persistent headache. Pediatrics. Dec 2003;112(6 Pt 1):e477-9. [Medline].
Nadelman RB, Nowakowski J, Fish D, et al. Prophylaxis with single-dose doxycycline for the prevention of Lyme disease after an Ixodes scapularis tick bite. N Engl J Med. Jul 12 2001;345(2):79-84. [Medline].
Seltzer EG, Shapiro ED, Gerber MA. Long-term outcomes of lyme disease. JAMA. Jun 21 2000;283(23):3068-9. [Medline].
Shapiro ED. Lyme disease. Pediatr Rev. May 1998;19(5):147-54. [Medline].
Steere AC. Lyme borreliosis in 2005, 30 years after initial observations in Lyme Connecticut. Wien Klin Wochenschr. Nov 2006;118(21-22):625-33. [Medline].
Steere AC. Lyme disease. N Engl J Med. Jul 12 2001;345(2):115-25. [Medline].
Vázquez M, Sparrow SS, Shapiro ED. Long-term neuropsychologic and health outcomes of children with facial nerve palsy attributable to Lyme disease. Pediatrics. Aug 2003;112(2):e93-7. [Medline].
Further Reading
- Practice parameter: treatment of nervous system Lyme disease (an evidence-based review). Report of the Quality Standards Subcommittee of the American Academy of Neurology
- Evidence-based guidelines for the management of Lyme disease
- Infectious Diseases Society of America practice guidelines for clinical assessment, treatment and prevention of Lyme disease, human granulocytic anaplasmosis, and babesiosis
Keywords
lyme borreliosis, Borrelia burgdorferi, B burgdorferi, Ixodes scapularis, deer tick, tickbite, tick bite, tick-borne illness, Lyme arthritis, Lyme disease, Lyme meningitis, Ixodid ticks, erythema migrans, EM, aseptic meningitis, cranioneuropathies, Bell palsy, encephalitis, carditis, rash, treatment, diagnosis, skin rash, meningismus
