Download Lyme Disease in Connemara: Case Cluster Report:

Lyme Disease in Connemara: Case Cluster Report:
Introduction/ Background
The incidence of Lyme disease in Ireland is unknown. It is currently not a notifiable disease
in this country (national disease surveillance centre – www.ndsc.ie).
My own previous understanding was that this condition was a rarity and somethingone only
came across on grand rounds / CPC meetings in secondary care where in house physicians
were keen to show off their curiosities to colleagues or as MCQ material for part 1
membership examinations as part of a question on differential diagnoses. My clinical
knowledge of the condition extended no further than a hazy recollection of a funny rash
followed by an ability of the disease to progress to give any symptom affecting any organ
system as a “great pretender” just like syphilis was in the pre-antibiotic era or akin to lupus
presenting in a vague manner.
In the summer of 2005 I met two patients in my practice with Lyme disease. One presented
with the classic rash and the condition was confirmed with a positive Lyme titre. I cannot
take any credit for being an accomplished diagnostician as it was the rash in this instance that
gave the diagnosis. The second presented with nothing more specific than fatigue. Lyme
titres were requested by me more as a blunderbuss approach than as a focused considered
diagnosis. Not good role modeling for trainees as how to get to the root of a “TATT”
consultation. I was surprised that the result came back positive. Both patients remembered a
tick bite when questioned retrospectively.
Off I plodded to the next small group CME meeting full of self importance and smug
satisfaction ready to impart these fascinating cases from within my small practice population
to my colleagues. One by one my colleagues replied “me too”, “me too”. As everyone had
stolen my thunder, deflation and intrigue were present in equal amounts. It seemed that we
had a cluster of cases spread right through the Connemara area.
This study was done to try to quantify the incidence of Lyme disease locally and if there was
an emergence of an indigenous reservoir of disease to be in a position to alert our colleagues
nationally to consider Lyme disease as a differential in their patients should they present with
unexplained symptoms and a history of travel to Connemara.
Data was collected in 2006 and the delay in writing up is because of the time pressures of
single handed practice combined with trying to control the three wild Indians living at home.
Apologies to all.
Brief Synopsis of Lyme Disease
Lyme disease first began to emerge as an individual disease in North America (Lyme,
Conneticut) in the 1980s?
It is now known that the infectious organism (borriella burgdorferi, a spirochaete bacterium),
which is tick borne, is the cause. The tick is the vector but other animals are the
host/reservoir.
The characteristic rash, which is not always present, is known as Erythema Chronicum
Migrans (ECM for the rest of this report). It is evident below in this photograph taken on the
first patient to present to me. The creeping erythema is seen extending from the proximal
1/3rd of the rt calf/shin extending towards the foot.
Permission was obtained from the patient to show this photograph.
Case clusters have been reported in Wales and possibly in the Kerry.
Methods
A short one page questionnaire was circulated to all General Practitioners in the greater
Connemara and surrounding areas. It had to be short as in General Practice nationally we are
all suffering from questionnaire fatigue. Ethical approval from the ICGP was not sought as
this was a survey of GPs memory and only patient initials and approximate ages in years
were used as identifiers from the responding GPs. The ICGP ethical committee has enough to
be doing and this report is a cluster case report as opposed to a clinical trial. It was not
initially intended that this cluster be reported in a peer reviewed journal but rather in a peer
“read” publication.
Recipients were asked to fill out the one page per case of Lyme disease that they had and to
return it by email, post, fax, horse or pigeon. Recipients were asked not to pull out the
medical reports but to fill them in by memory. Both the brevity of the form and the filling in
from memory were deemed necessary to get the maximum participation by making it easier
to return data. As one would presume that a diagnosis of Lyme disease in a practice is a rarity
patient’s initials and approximate age as identifiers to prevent duplication were deemed
adequate to be used. It would be expected that the small amount of clinical information that
was being sought would be remembered by the treating GP.
GPs that did not return forms were followed up by a phone call and if they had no cases of
Lyme disease the forms were left blank but included in the study as a GP who had no cases.
If the followed up GPs had cases then they were re-sent fresh forms. All were subsequently
received. This way a response rate of 100% was achieved.
The clinical information sought mainly related to presenting features, treatment and follow
up. Non clinical information sought included items such as probable location of coming into
contact with the illness/tick bite and whether a tick bite was remembered.
Results
20 GPs in 15 practices were sent questionnaires. Results were received from all of them
either as a filled out form returned or a telephone call confirming no cases were seen. Six
GPs had not seen any cases of Lyme disease in their practices. From the fourteen GPs that
had seen Lyme disease in their patients nineteen (19) cases were identified.
Excluded Data/Amendments
One of the GPs reported seeing multiple cases over the previous 20 years but as only one
form was filled out the information retrieved was treated as only one case. As the
questionnaire was designed for the participants to fill out from personal memory to ease the
administrative burden on busy GPs I felt it would be unfair to forward multiple repeat
questionnaires that would have had to involve a trawl of charts to fill out accurately. The
information on this form was treated as one case even though it represents a pooled
experience of many patients/cases. For numerical calculations such as average ages this data
was omitted and calculations were based on a total of 18 cases. For non mathematical / non
statistical calculations / presentations the total used was 19 cases even though the true
incidence is probably higher.
There was no duplication in the reported cases. Affected patients ages ranged from four (4) to
seventy five (75). Average age was 41. Most cases were diagnosed in summer and autumn
and most were diagnosed in the immediate few years prior to the data being collected. The
data is best presented in tabulated form as follows.
Approximate season and year when cases diagnosed/presented
Winter
0
2005
10
Spring
0
2004
4
Summer
11
2003
0
Autumn
7
2002
2
Unknown/unspecified
1
2001
1
1996
1
1986
1
Most probable location where patient contracted the Lyme disease
IRELAND
17 ABROAD
2
Connemara mainland
16
USA
1
Aran Islands
1
PRAGUE
1
Patient’s recollection of a tic bite
Yes
14
No
5
Main presenting complaint (some may have presented with more than one complaint)
Rash (but not necessarily ECM rash)
Fatigue / weakness
11
3
Tic Bite (presented with tic as the problem)
Bell’s palsy
Depression
Fever
Pruritis
3
3
1
1
1
Of the 19 cases those who presented with the classic ECM rash
Present at presentation
11
Absent at presentation
8
The features present that made the GP suspect Lyme disease as the diagnosis
GP did not suspect Lyme disease was present
11
Rash
5
Bell’s Palsy
2
Tic bite
2
Fatigue
1
History
1
More than one feature may have been present initially
Did the GP perform Lyme titres him/herself?
Yes
15 cases
No
4
cases
GPs responses to why Lyme titres were done if done
To confirm a probable diagnosis
9
As a coverall approach to unexplained symptoms
6
Patient requested the blood test
1
Blood test performed by another source
1
More than one reason may have been given per case
What ultimately confirmed your diagnosis?
10
6
4
Dermatologist
1
Physician
1
Neurologist
1
Multiple
1
Confirmatory reasons > total no. of cases because many of the GPs used the lyme titres as an
adjunct to an already made definite clinical diagnosis.
Lyme Titres
Clinical Diagnosis
Hospital Physician
Choice of treatment when initiated by GP
Doxycycline
10
Amoxicillin
4
Amoxicillin was correctly selected as the antibiotic of choice in the paediatric cases
Did the GP refer the patient to secondary care and if so to whom?
Not referred / treated entirely in primary care
9
Referred to hospital specialist or other care
10
Infectious Disease
2
Paediatrics
3
Dermatology
1
Physiotherapy
1
Physician
1
Neurologist
1
In native country
1
Multiple
1
There is overlap in the numbers as many of the referred cases may have seen more than one
secondary care specialist. (native country = non Irish patient when returned home)
Presence of residual symptoms/problems after treatment
No symptoms / problems
12
Residual problems
7
Residual symptoms included myalgia / weakness and depression
Confounding Issues
The pooled data from one GP was treated as one case although that GP reported seeing many
cases. This was to enable cross checking patient initials and approximate age at presentation
to ensure there was no duplication of cases. I am certain now there is no duplication even
though many patients attend more than one GP. The true number of cases is probably higher
than the 19 reported but is definitely no lower.
Conclusions
Nearly all cases were contracted in Connemara during the summer and autumn months.
There is no doubt that Lyme disease is here with us now. There is no doubt that the cases are
occurring de novo here and it is no longer a rare illness that someone brings home having
travelled to North America. The number of cases seems to be increasing and culminates in
the majority of cases being detected in the year before the study was carried out. GPs here
appear confident to treat a large number of the patients entirely in the primary care setting
(almost 50%).
Discussion
As nearly all the cases were contracted in Connemara and during the holidaymaker /
gaeltacht student season (summer and autumn) it would be a reasonable assumption that
further cases were contracted in the area but only presented to their GPs on return home. The
figures only apply to those patients who attended to Connemara GPs with the illness and not
those who contracted the illness here and presented to their own GPs elsewhere in the
country. The true incidence of cases contracted here is therefore likely to be higher than
reported in this small study.
Over 42%(8) of the cases did not have the classic Erythema Chronicum Migrans rash at
presentation. Making a clinical diagnosis in its presence is easy. When it is absent in such a
large number of cases accurate early diagnoses will be difficult and some cases may go
undiagnosed initially especially as performing routine bloodwork for non specific symptoms
that can be present in any condition including the common cold would be a nonsense.
At presentation the majority of GPs did not suspect that Lyme disease was present. Who
could blame us. Now that we know about our cluster we might have an even lower threshold
to considering it at initial presentations in the future but on a practical note it would not be
beneficial to our patients or ourselves for us to be imagining Lyme disease to be behind every
myalgia or fever that we see.
It appears that the cases are increasing year on year and therefore an assumption can be made
that we have a reservoir of infection and possibly an increasing population of borriela
carrying tics. It is interesting to note from veterinary sources nationally that with the milder
wetter summers we have been having of late that there has been an increase in the tic
population affecting animal health. Is this another phenomenon that will get blamed on
global warming.
Interestingly stray deer (hosts for the disease causing agent) are being spotted increasingly on
the roads in Connemara as a traffic hazard. Only last week I had a close encounter with a
magnificent stag. These populations are not native and have been introduced in recent
decades by sporting estates for commercial shooting holidays. A link is possible. Should the
confirmed incidence continue to increase I am sure that calls for culling this deer population
will come and probably would be fiercely resisted as the game sports industry in connemara
does employ quite a large number of people in an area with very little sustainable
employment. Coillte, the state forestry agency, has noted that they find such non native deer
populations a pest as they destroy newly forested areas.
Why are smallpox, anthrax (excepting terrorist activity) and plague which are extinct
conditions and campylobacter which is most often a self limiting nuisance infection still on
the list of notifiable diseases and Lyme disease which has taken a foothold here not on it.
Previously most of our cases in this country were cases contracted abroad and diagnosed on
return but now many of the cases seen in primary or secondary care are being contracted
here.
The learning point from this study is (I think) that should you have a patient with
unexplained symptoms with or without a funny rash presenting in the summer or autumn
months it might be prudent to ask them if they spent their holidays in Connemara.
Conflict Of Interests
I think deer are beautiful animals.
Acknowledgements
Thank you to all my Connemara colleagues for filling in yet another blasted questionnaire.
Please Note: Tick Talk has removed the author name to avoid the GP being inundated with
enquiries. He is unable to take individual enquiries & has no specific expertise in the
treatment of Lyme disease. We would like to respect his privacy but thank him hugely for
bringing this great study to our attention!