Lyme Disease

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Lyme Disease is a tick-borne disease caused by the spirochaete Borrelia Burgdorferi, though other species of Borrelia can cause the disease.

  • Also known as Borreliosis
  • Endemic areas and incidence are increasing, which may be due to changing climate patterns.


Incidence

  • Incidence = 800 cases annually (UK) - uncommon
  • Age:
  • Sex
  • Ethnicity:


Epidemiology and aetiology

The disease is contracted by being bitten by an infected tick of the genus Ixodes. The ticks themselves usually live in long grass in forested areas and feed on blood meals from Deer.

  • In the UK, the New Forest and Thetford Forest are areas known to be endemic.
  • Reports of rising incidence of Lyme Disease in other areas have been made in the past few years.

Late spring, early summer and autumn are the peak times for tick feeding, breeding and therefore infection. Risk of infection is low if a tick is removed promptly since bacteria are not usually transferred during the initial phase of feeding. Plus, most ticks are not infected with Borrelia. Not every person infected will develop symptoms.


Clinical features

Symptoms from Lyme Disease are divided into early disease, intermediate and late effects.


Early Infection

A tick may have been seen on the skin. They can be difficult to remove without leaving the head/jaws embedded in the skin, which can lead to localised infection. Usually a history of being in an endemic area needs to be sought.

  • Erythema Chronicum Migrans - a red rash originating at the site of a tick bite. Appears 3-40 days following infection. Ring-shaped and slowly enlarges. The lesion clears from the centre and may appear 'target-like'.
    • Resolves in 3-4 weeks usually
    • Up to 90% of patients will have this rash.
  • Flu-like symptoms
    • Fever
    • Lymphadenopathy
    • Headache
    • Lethargy
    • Arthralgia
    • General Malaise

These symptoms may last for weeks untreated. Early treatment is important.


Late Disease

Late complications can be serious with major morbidity.

  • Meningitis / encephalitis
  • Cranial nerve palsies, especially CN VII (Facial Nerve) palsy.
  • Radiculopathy
  • Arthritis
  • Myocarditis / heart block / pericarditis

Neurological symptoms are termed Neuroborreliosis


Diagnosis and Investigations

Diagnosis requires clinical suspicion. Symptoms are non-specific though Erythema Chronicum Migrans is characteristic. Identifying the bacteria is difficult and so testing relies of serology for anti-Borrelia antibodies. Serology may be negative in the first few weeks following infection.


History of being in a tick-endemic area should be actively sought.


Management

Treatment with 14 days of Doxycycline or Amoxicillin is usually sufficient.

  • Early treatment is important.


Where late complications have occurred, prolonged IV treatment may be required. Chronic symptoms may take a long time to resolve and will do so to a variable extent.


References

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