This is from a medical textbook published in 2007.  This is what our future MD’s are learning:

 BASICS

A multisystem infection caused by the spirochete Borrelia burgdorferi, which is transmitted primarily by Ixodid ticks.

  • Stage 1, early localized Lyme disease, includes a characteristic expanding skin rash (erythema migrans) and constitutional flulike symptoms
  • Stage 2, early disseminated Lyme disease, may present with involvement of 1 or more organ systems. Neurologic (15%) and cardiac (8%) disease are most common.
  • Stage 3, chronic Lyme disease involves arthritis (50%) and chronic neurological syndromes.
  • System(s) Affected: Hemic/Lymphatic/Immunologic; Musculoskeletal; Skin/Exocrine
  • Synonym(s): Lyme arthritis
  • The drug of choice in pediatrics is amoxicillin.
  • Tetracyclines are contraindicated.
  • Because B. burgdorferi can cross the placenta, pregnant patients with active disease should receive parenteral antibiotics.
  • Doxycycline should not be used in pregnancy.
  • Awareness of the disease, protective clothing, and careful skin inspection with timely removal of ticks may reduce the incidence of disease.
  • A 3-dose vaccine, LYMErix, is no longer available.
  • Prophylactic treatment with one dose of 200 mg of doxycycline within 72 hours of a tick bite in endemic areas has been suggested.
  • Predominant age: Can occur in all ages, but most common in children ages 5–14 and in the 50–59-year age group.
  • Predominant sex: Male > Female

Overall incidence: 8.2/100,000

Cases have been reported in all states except Hawaii, Montana, and Oklahoma. Most prevalent in the northeastern, middle Atlantic, and north central states (1 ).

  • Exposure to tick-infested area; most common in May to September
  • Ixodid ticks are commonly found on deer. Hunters may be at an increased risk.

HLA: Haplotype DR4 or DR2 may be more susceptible to prolonged arthritis

Infection with spirochete B. burgdorferi, transmitted by the bite of Ixodid ticks.

DIAGNOSIS

  • Stage 1
    • Erythema migrans (60–80%)
    • Fever
    • Headache
    • Myalgias
    • Arthralgias
    • Some patients may be asymptomatic.
  • Stage 2 (Involvement of 1 or more organ systems)
    • Multiple erythema migrans
    • Facial palsies or other cranial neuropathies
    • Aseptic meningitis
    • Heart block
    • Pericarditis
    • Orchitis, hepatitis, or iritis
    • Arthritis (usually large joint monarthritis)
  • Stage 3
    • Recurrent synovitis
    • Recurrent tendinitis and bursitis
    • Controversial: Neuropsychiatric symptoms may include psychotic behavior, memory loss, dementia, depression, sleep disorders
    • Encephalopathic symptoms: Headache, decreased memory, difficulty concentrating, confusion, fatigue (clinical overlap with fibromyalgia)
    • Symptoms mimicking other CNS diseases: Multiple sclerosis-like syndromes, stroke-like symptoms, vestibular neuronitis, transverse myelitis, parkinsonian symptoms
    • Peripheral neuropathic symptoms: Carpal tunnel syndrome, motor, sensory, or autonomic neuropathies
    • Ophthalmic manifestations: Iritis, keratitis, retinal vasculitis, optic neuritis
  • In Europe, borrelia lymphocytoma and acrodermatitis chronica are manifestations of Lyme borreliosis, but are rarely seen in the US.
  • Transmission does not occur if tick attachment is <48 hours, and only ∼25% transmission for attachments of <72 hours.
  • Infection is preceded by a tick bite, although patient may be unaware of tick attachment.
  • History of a tick bite followed by illness with erythema migrans is the key to diagnosis. (2 )[C]
  • Testing and treatment not indicated if tick attachment is <48 hours.
  • Diagnosis is based mainly on clinical findings in endemic areas.
  • ELISA for IgM and IgG B. burgdorferi antibodies (usually detectable 4–6 weeks after the initial infection), followed by a Western blot test if positive or equivocal (3 )[A]
  • Culture of CSF for B. burgdorferi
  • Drugs that may alter lab results: Late-stage disease with negative serology may be seen in patients who received early antibiotic treatment.
  • Disorders that may alter lab results: False-positive response has been seen with Rocky Mountain spotted fever, syphilis, systemic lupus erythematosus, and rheumatoid arthritis.
  • Diagnosis is based on clinical features with exposure to a tick bite in an endemic area.
  • Lumbar puncture when neurologic findings are present, with ELISA of CSF for B. burgdorferi antibodies

Culture of B. burgdorferi from blood or skin biopsy specimens has a very low yield.

  • Juvenile rheumatoid arthritis
  • Viral syndromes
  • Later stages may mimic many other diseases (see “Signs and Symptoms”).

 TREATMENT

Appropriate health care

  • Stage 1: Clinical diagnosis; can be treated as an outpatient
  • Stage 2 and 3: May require more intensive treatment, based on symptoms
  • Prevention of the infection is possible by careful examination of skin for ticks after outdoor activities.
  • The prompt removal of ticks may limit transmission.
  • Clothing that covers the ankles should be worn in endemic areas, and the use of insect repellants is recommended.

Cefuroxime (Ceftin) axetil: 500 mg b.i.d. for 14–21 days (4 )[A]

  • Stage 1
    • Doxycycline (Vibramycin): 100 mg PO b.i.d. for 14–21 days (do not use in children under 12 or in pregnancy); or
    • Amoxicillin: 500 mg PO t.i.d. for 14–21 days, (pediatric dose 25–100 mg/kg/d) or
  • Stage 2
    • Normal CSF, treat for 14–21 days: Doxycycline 100 mg PO b.i.d. or Amoxicillin 500 mg PO t.i.d.
    • With abnormal CSF, treat for 14–21 days Ceftriaxone (Rocephin) 2 g IV daily
  • Stage 3
    • Oral treatment for 28 days with doxycycline 100 mg b.i.d. or amoxicillin 500 mg t.i.d.
    • If oral treatment fails, begin an IV treatment for 2–3 weeks with ceftriaxone 2 g daily; or cefotaxime 2 g q8h; or 150 mg/kg/d in 3–4 doses for children.
  • Contraindications
    • Allergy to agent
    • Doxycycline is contraindicated in children and in women who are pregnant or breast-feeding.
  • Precautions: Refer to the manufacturer’s profile of each drug.
  • Significant possible interactions
    • If the patient is taking oral anticoagulants, it may be necessary to reduce the dose.
    • Oral contraceptives may be less effective.

Cefuroxime (Ceftin): 500 mg b.i.d. for Stage 1 disease, or t.i.d. for Stage 2 or 3 of the disease.

FOLLOWUP

  • Early treatment with antibiotics can shorten the duration of the symptoms and prevent later disease.
  • Response of late-stage disease is variable.
  • Recurrent synovitis, tendonitis, bursitis
  • Chronic neurological symptoms
  • Peripheral neuropathies
  • See “Signs and Symptoms” (Stage 3)

Based on the severity of the symptoms, patients with Stage 2 or 3 of the disease require careful monitoring over a period of months to years.

MISCELLANEOUS

  • Cases of Lyme disease should be reported to the health department.
  • Ixodid ticks require white-footed mice to complete their life cycle.
  • Investigators have had some success in eradicating the ticks by providing permethrin-laced cotton in areas where the mice forage for bedding material.

FAQ

  • Q: What is the best way to diagnose Lyme disease?
    • A: It is a clinical diagnosis. The presence of erythema migrans, arthralgias, or a flu-like syndrome following a tick bite in an endemic regions warrants empiric treatment [A].
  • Q: Is there benefit from prolonged antibiotic treatment of patients with persistent symptoms?
    • A: Two controlled trials of patients with persistent symptoms and a history of Lyme disease (NEJM 2001;345:85–92) found no more benefit than placebo [A].
  • Q: What is the best way to prevent Lyme disease?
    • A: Keeping arms and legs covered when outdoors in areas where ticks may be encountered and using DEET containing insecticide on clothing.