Source: Manual of Ambulatory Pediatrics 2010
SOAP Note – Lyme Disease
A tick-borne illness associated with widespread immune-complex disease. It has three stages, each with multiple clinical features, not all of which are apparent in each patient. It can affect the dermatologic, cardiac, neurologic, and musculoskeletal systems. The hallmark of the disease is erythema chronicum migrans, an annular expanding skin lesion.
This protocol deals primarily with the identification and treatment of stage 1 because recognition of the clinical picture and treatment at stage 1 prevent the subsequent manifestations of stages 2 and 3.
I. Etiology
A. A spirochete, Borrelia burgdorferi, which is transmitted by Ixodes dammini, a tiny deer tick. The cycle of transmission depends on the interaction of immature deer ticks and the white-footed mouse, their primary hosts.
B. Studies indicate that the infected tick must feed for 36 to 48 hours to transmit B. burgdorferi.
II. Incidence
A. Primarily occurs in northeast, midwest, and western United States
B. Onset of illness is generally between May and November, with most cases seen in June and July.
C. All ages and both sexes are affected.
D. Incidence is highest among children 5 to 10 years of age.
E. It is endemic in areas where the adult female deer tick can feed on deer, virtually the sole blood source for the adult tick. The larval ticks subsequently feed on infected mice. After feeding for 2 days, which is when infection by Borrelia is suspected to occur, they lie dormant over winter. They molt to the nymph stage in the spring. This is the stage when the ticks tend to bite humans.
F. The risk of developing Lyme disease after a tick bite in an endemic area is low, approximately 5%.
III. Incubation period: 3 to 32 days, with a median of 11 days
IV. Subjective data
A. History of tick bite may not be reported because of the tiny size of the tick (no larger than a pinhead). Child or parent may not realize child has been bitten. Only 50%–60% of patients recall a tick bite.
B. First stage: Generally 7 to 10 days after inoculation
1. Rash
a. Round, red rash that enlarges
b. Clear in center
c. May have one or several lesions
d. Nonpruritic, nonpainful
2. Associated symptoms
a. Chills, fever
b. Headache, backache
c. Malaise
d. Fatigue, often severe and incapacitating
e. Conjunctivitis
f. Arthralgia
C. Second stage: 2 weeks to months after bite
1. Heart palpitations, chest pain
2. Dizziness
3. Shortness of breath, dyspnea
4. Generalized swollen glands
5. Neurologic complications: Meningitis, cranial neuritis, peripheral neuropathy, encephalitis
D. Third stage: Weeks to years after onset if untreated (generally 2 to 6 months after vector bite)
1. Joint pains, particularly knees
2. Less commonly, memory loss, mood swings, inability to concentrate
V. Objective data
A. Characteristic rash: Erythema chronicum migrans (ECM)
1. Most often seen at site of tick bite 3 to 30 days after inoculation
2. Occurs most commonly on thighs, groin, and axillae
3. Occurs in 80% to 90% of cases
4. An annular, expanding lesion of at least 6 cm to as many as 60 cm
5. As lesion expands, it looks like a red ring and generally has central clearing.
6. Center may be intensely erythematous and indurated in early lesions.
B. Secondary and migratory annular lesions
1. Smaller
2. Centers not indurated
3. May occur anywhere on body but generally spare palms, soles, and mucous membranes
C. Regional lymphadenopathy
D. Neck pain and stiffness
E. Hepatosplenomegaly
F. Malar flush
G. Urticaria
H. Bell’s palsy
I. Except for ECM and Bell’s palsy, physical examination is of limited value.
VI. Assessment: Diagnosis
A. Clinical diagnosis is most readily made by evaluation of ECM—the hallmark of Lyme disease—by history of associated flu-like symptoms, by epidemiologic data, and by serologic testing.
B. Lyme titer: Not accurate until 3 weeks after exposure. Indirect fluorescent antibody (IFA) and an ELISA test are available, but tests are not standardized. ELISA has slightly greater specificity and sensitivity. Both false-positives and false-negatives occur. Diagnostic help is most needed during stage 2 or 3 when patient has attained a peak antibody rise. (IgM titer usually peaks between 3 and 6 weeks after infection; specific IgG antibody titers rise slowly and are generally highest weeks to months later.) Because antibodies remain elevated for years, missing the diagnostic rise in stage 1 can be problematic in making an association between positive titer and symptoms in stages 2 and 3.
VII. Plan
A. Prophylactic antimicrobial therapy is not routinely indicated after a tick bite in endemic areas. In most cases, experts advise judiciously waiting for symptoms of Lyme disease or the appearance of erythema migrans unless patient is immunocompromised. However, if local rate of infection is 20% or above, for children over 8 years of age:
1. Doxycycline—one dose if tick has been attached at least 36 hours and if treatment can begin within 72 hours after tick removal.
B. Antimicrobial treatment at stage 1 shortens stage 1 and aborts stages 2 and 3. Regardless of treatment, signs and symptoms disappear in 3 to 4 weeks. However, dermatologic manifestations often recur. Duration
of treatment depends on clinical response. All patients with Bell’s palsy or early arthritis should be treated for the maximum duration.
C. Children through age 9
1. Amoxicillin 250 mg every 8 hours for 14 to 21 days (30–50 mg/kg/d in divided doses, maximum 2 g/d) or
2. Cefuroxime axetil (Ceftin): 30 mg/kg/d in 2 divided doses for 14 to 21 days (maximum 500 mg/d for children under 13 years). Give with food.
or
3. Erythromycin: 30 mg/kg/d in 4 divided doses; >20 kg, 250 mg every 6 hours for 21 to 30 days
D. Ages 9 and up
1. Doxycycline 100 mg PO every 12 hours for 14 to 21 days or
2. Amoxicillin 500 mg PO every 8 hours for 14 to 21 days
E. Stages 2 and 3 should be treated with antibiotics as indicated above. Persistent arthritis, carditis, meningitis, or encephalitis require IV or IM antibiotics and hospitalization.
VIII. Education
A. Prompt removal of ticks is the best method of prevention. A minimum of 24 hours of attachment and feeding is necessary for transmission to occur.
B. Examine children’s bodies after playing outside, hiking, and so forth.
C. Shower or bathe after expected exposure.
D. Scalp, axillae, and groin are often preferred sites for tick attachment.
E. Avoid tick-infested areas.
F. Areas of risk must be suitable for both mice and ticks to live in— generally wooded areas and overhanging brush, although they have been found in grass.
G. Dress for protection.
1. Light-colored clothing so that ticks can be easily spotted.
2. Long-sleeved shirts
3. Tuck cuffs of pants into socks or boots.
4. Check clothes for ticks.
H. Wash and dry clothing in high temperatures.
I. Use tick repellent containing diethyltoluamide (DEET) or Permethrin.
J. Use DEET sparingly in young children because seizures have been reported coincident with its use.
1. Use products with no more than 10% DEET, such as Off! Skintastic for Kids (5% DEET), Skedaddle for Children with sunscreen (6.5% DEET), Repel Camp Lotion for Kids (10% DEET), Banana Boat Bite Block Sunblock for Children (9% DEET SPF15 Lotion), DEET Free Bull Frog Sunblock with Insect Repellant.
2. Do not apply to children’s hands, near eyes, or on lips.
3. Wash DEET preparations off skin once child is indoors.
K. Permethrin should not be applied directly to skin but sprayed on clothing, tents, sleeping bags, and so forth. Cutter Outdoorsman Gear Guard contains 0.5% permethrin.
L. Identify tick.
1. I. dammini: Pinhead-sized
2. Oval body with no apparent segmentation and no antennae
3. Body covered with leathery, granulated cuticle
4. Deer ticks have a scutum, or hard shield, on their backs
5. Stages
a. Larvae: Less than 2 to 3 mm long with 6 legs
b. Nymphs: 4 to 8 mm long with 8 legs (stage at which they generally infect humans).
6. Unfed ticks are flat; ticks that have recently fed are engorged.
M.T ick removal
1. Do not handle tick with bare hands; infectious agents may enter through breaks in the skin.
2. Use blunt tweezers.
3. Grasp tick close to skin and pull with steady, even pressure.
4. Do not squeeze, crush, or puncture tick. (Body fluids may contain infected particles.)
5. Disinfect bite site.
6. Flush tick down toilet or submerse in alcohol.
N. Rash
1. ECM and secondary lesions generally disappear within days once treatment is started.
2. If untreated, lesion may persist for months and recur for up to one year after onset.
3. Pets may bring ticks into the house but pets do not transmit disease to humans.
IX. Follow-up
A. Recheck in 24 to 48 hours by telephone.
B. Call immediately if symptoms exacerbate.
C. Recheck Lyme titer if nonresponsive to medication.
D. Convalescent titers may be done to monitor progress of disease.
X. Complications
A. Cardiac complications: Seen 4 to 83 days (median 21 days after onset of ECM) in approximately 8% of untreated cases
B. Lyme arthritis
C. Neurologic: Bell’s palsy, Guillain-Barré, polyradiculitis
D. Cognitive defects such as impaired memory.
XI. Consultation/referral: Stages 2 and 3