ticks and lyme

Having discussed tick bite prevention, let’s now turn to lyme disease.  Lyme is an acute infection caused by a strange, primitive bacteria strain called “Ricketsiae” named “Borrelia Bergdorfii” and spread by infected  deer ticks ( in the East).  It is mostly an April-October affair with 50% occuring in June-July, incubating for about 11 days after the bite(range 1-55 days).  Note that there are some credible reports of symptom onset years after the tick bite.

When ticks land on hosts they are programmed to seek a warm moist area where blood flow tends to be most generous; thus the prediliction to find ticks in the groin and armpits.  Recall from my last post that a tick needs to be engorged from > 36 hrs of feeding on a blood meal to transmit the infection–little guys, especially those simply crawling on the skin, are no risk.

The classic marker for early lyme disease, present in 60-80% of infections is “erythema chronica migrans.” The name is descriptive (as I often say, doctors like to use big words so we can charge more!), so erythema=red, chronica=lasts a long time, migrans=spreads.  Lots of insect bites give you a red “splotch” for a few days. That is not significant.   This lesion lasts at least a week or so and grows to at least 5 cm in diameter.

Now, the clinical course of lyme can have a variety of manifestations.  Early on people have the above rash with fever, head and neck pains, joint and muscle aches, and fatigue.  Sometimes a child may develop multiple ECM lesions(15%). Note that lymes infected children are sick.  Vague complaints of aches and fatigue in generally well, active children are not symptoms of lyme.

Untreated, lyme can have many complications: neurologic (Bell’s facial palsy almost 50%), arthritis (10%) and cardiac rhythm disturbance (5%).  Mostly these are unusual occurrences in children when treated promptly.  It is not uncommon for the fatigue and aches to persist for weeks even after successful treatment.  The serologic test for lyme is quite inexact.  There are frequent false positives( test inaccurately says yes) so routine testing after tick bite in the absence of specific symptoms is not recommended.  Also, after actual infection the antibody response can remain positive–perhaps permanently–so repeat testing to assess for resolution of infection is unhelpful and counter-productive.

Treatment for lyme is antibiotics–typically 3-4 weeks orally for early infection and less serious complications like Bell’s palsy.  More severe neurologic problems(meningitis), severe arthritis, or cardiac problems require IV medication.  The AAP does not recommend treatment for > 4 weeks.  No credible advantages for prolonged treatment have been demonstrated. Side effects, complications, and financial advantages for those advocating prolonged treatments have been reported.

Last point: to avoid sun risk, limit mid-day outdoor activity; limit insect bite risk with no early or late outdoor activity.  But don’t stay indoors to avoid sedentary life and obesity.  What to do?  Don’t completely ignore me: moderation in all things.  Not too much sun or too much around thick vegetation or standing water.  But its the summer: so go out and have fun.

Questions or comments? And thanks for following.

Advertisements

One thought on “ticks and lyme

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s