DiagnosisDude is now more a website than blog. On Desktop, scroll down the menu in right-hand margin for interesting symptoms.
Haven’t posted for quite a while; partly because I’m low on new topics, muchly because WordPress changed its format so I’d have to learn code to make new tables. So DiagnosisDude will struggle along, with interesting cases, & occasional work-up of various symptoms.
Today, a Lyme Disease case, with interesting subtleties in clinical decision-making. A friend in his early 60’s called in July from rural Long Island, NY. He’d arrived on vacation 2-3 weeks prior, lots of tick exposure, and now had low-grade fever, malaise, and a new rash: “red, with pale center.”
Sure sounded like classic Lyme Disease erythema migrans (EM). He asked if it could wait 1-2 days to be seen. For Lyme itself, yes; but the problem is that ticks in endemic areas can carry multiple pathogens causing other diseases:
- Lyme (Borrelia burgdorfer)
- Erlichosis (Ehrlichia chaffeensis)
- Anaplasmosis (Anaplasma phagocytophilum)
- Babesiosis (Babesia microti)
- Rocky Mountain Spotted Fever [RMSF] (Rickettsia rickettsii)
Other rare tickborne diseases occur in other regions. These include Southern Tick-Associated Rash Illness (STARI) in the south (unknown etiology with rash like early Lyme), Relapsing Fever in the west & south (various Borrelia species), and spotted-fever syndromes from various rickettsial species.
Among the 5 tickborne illnesses on Long Island, Lyme is benign when caught early. RMSF is the most serious, progressing perhaps even before petichiae appear, causing septic shock. Ehrlichosis and Anaplasmosis can have a case-fatality rate of up to 10%, Babesiosis maybe 5%.
So I suggested he not wait to be seen. In the local ER (which has lots of experience with these diseases), he had various labs drawn, few of which would help. Babesia may occasionally be seen on a CBC, but sensitivity is poor. The best test is by PCR, usually with 1-day turn-around. Erlichia and Anaplasma serology has a longer lag time. Early Lyme has no test, but is diagnosed clinically as in this case. RMSF is also a completely clinical diagnosis.
Doxycycline would treat all the above pathogens except for Babesia, which requires atovaquone plus azithromycin. So it would seem best to treat his certain Lyme with Doxy, and await Babesia results. But that might wreck the vacations of pale persons in Long Island summertime (lots of photosensitivity), so they gave him Amoxicillin. That’s fine for Lyme, but what about the unlikely but still possible chance of a co-existing bug?
I called the next day — he was feeling OK, but his temperature had risen to >103°. Early Lyme, defined by a single EM skin lesion, can be accompanied by mild systemic symptoms, but >103 sounded high. However, since Lyme is a spirochete, like syphilis, around 25% of patients experience a Jarisch-Herxheimer reaction during the first 24 hrs. of treatment, consisting of fevers (maybe high), malaise, and myalgias, presumably due to dying organisms.
J-H is benign, treated with simple antipyretics. But it’s important to warn patients about, so a) they don’t get scared; and b) they don’t think they’re “allergic” & stop treatment. And as an aside, if a fever occurs or spikes on the first day of antibiotic treatment for any infection, consider a J-H reaction from occult syphilis.
It was now exactly 23 hrs. since he’d begun meds. What was the chance J-H lasts that long [no data]? What was the likelihood of something more than Lyme? According to the CDC’s most recent tally of notifiable diseases, in 2013 in ” NY (upstate)” [i.e. not NYC] there were around 450 each of Babesiosis and Anaplasmosis, 90 of Erlichosis, 25 of RMSF, and almost 3,900 of Lyme. Numbers were in his favor, certainly in terms of RMSF.
Of course, when your making telephone decisions long-distance, it’s easy to chicken out. It was nighttime already; I advised him to at least call the ER for advice. Don’t know if he did, but a day or two later he was avidly bicycling and feeling fine. Labs eventually all came back normal.
So what’s the message? Mainly that clinical decision-making doesn’t just involve signs & symptoms. It also includes knowing the natural history of disease, epidemiological probabilities, worst-case scenarios (and the ability to intervene before it’s too late). All that is what makes the profession fun.
What about doxycycline for children under 8 y.o., or for pregnant women? We all learned that as an absolute contraindication due to interference with bone & tooth formation. But as it turns out, there’s no good data, mostly anecdotal cases that aren’t really representative. Since 1997, the American Academy of Pediatrics has endorsed doxycycline for empiric treatment of suspected RMSF in all kids. See a review in CDC’s MMWR (section on treatment & management):
http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5504a1.htm
And where is RMSF most prevalent? Take a guess before we tell you…………..
Take a guess before we tell you…………..
Take a guess before we tell you…………..
Take a guess before we tell you…………..
In 2013, Tennessee won, followed by Arkansas. RMSF basically follows a belt from NC to the Ozarks, including OK and the northern counties in MS, AL, GA. Fortunately, it’s rare in most areas with highest incidence of Lyme disease (New England, Wisc. and Minn.). And “Rocky Mt.” Spotted Fever is also rare in Colorado, Utah, Wyoming, and Idaho!
Next time, another case, or maybe a symptom.
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DiagnosisDude 