Lyme disease

Question 1

Causative organism and shape?

Answer 1

Borrelia burgdorferi which is a spirochaete

Question 2

How is the disease spread?

Answer 2

By ticks

Question 3

What is the characteristic symptom?

Answer 3

Erythema migrans - a small papule often at the site of the tick bite which develops into a larger annular lesion with central clearing (like a bulls-eye)

Question 4

Early symptoms?

Answer 4

Erythema migrans and systemic symptoms such as malaise, fever and arthralgia

Question 5

Late symptoms?

Answer 5

CVS: heart block, myocarditis
Neurological: cranial nerve palsies, meningitis
Polyarthritis

Question 6

Diagnosis?

Answer 6

• Can be diagnosed clinically if erythema migrans present

- enzyme-linked immunosorbent assay (ELISA) antibodies to Borrelia burgdorferi

Question 7

What if the ELISA test is negative and lyme disease is still suspected in people tested within 4 weeks of symptom onset?

Answer 7

Repeat ELISA 4-6 weeks after first ELISA test. If still still suspected in people who have had symptoms for 12 weeks or more, then an immunoblot test should be done

Question 8

What if positive or equivocal ELISA test?

Answer 8

Perform an immunoblot test

Question 9

Management of asymptomatic tick bites?

Answer 9

NICE does not recommended routine antibiotic treatment

Question 10

Management of suspected/confirmed lyme disease?

Answer 10

• Doxycycline if early disease. (Amoxicillin if contraindicated e.g. pregnancy)
• Ceftriaxone if disseminated disease.

Question 11

What reaction can occur after commencing therapy for this disease?

Answer 11

Jarish-Herxheimer reaction: fever, rash and tachycardia after first dose of antibiotics (also seen in syphilis, another spirochaetal disease)