Raoult et al developed a score for diagnosing Mediterranean Spotted Fever, a febrile condition caused by Rickettsia conorii and transmitted by the dog tick.
Parameters:
(1) epidemiologic data (3 items)
(2) clinical findings (3 items)
(3) nonspecific laboratory findings (2 items)
(4) bacteriologic findings (2 items)
(5) serologic findings (3 items, using immunofluorescence assay, IFA)
|
Parameter |
Finding |
Points |
|
residence or recent travel in an area where endemic |
yes |
2 |
|
|
no |
0 |
|
onset of fever |
during May to September |
2 |
|
|
during October to April |
0 |
|
contact with dog ticks |
yes |
2 |
|
|
no |
0 |
|
temperature |
> 39°C |
5 |
|
|
<= 39°C |
0 |
|
tache noire (black eschar at site of tick bite) |
present |
5 |
|
|
absent |
0 |
|
eruption |
maculopapular or purpuric |
5 |
|
|
none or other |
0 |
|
platelet count |
< 150,000 per µL |
1 |
|
|
>= 150,000 per µL |
0 |
|
AST or ALT |
> 50 IU/L |
1 |
|
|
<= 50 IU/L |
0 |
|
detection of Rickettsia conori in skin biopsy using IFA |
yes |
25 |
|
|
no |
0 |
|
isolation of Rickettsia conori from blood |
yes |
25 |
|
|
no |
0 |
|
serologic titers |
sample with IgG >= 1:128 and IgM >= 1:64 |
10 |
|
|
sample with IgG >= 1:128 |
5 |
|
|
else |
0 |
|
change in titers |
4-fold titer elevation or greater within 2 weeks |
20 |
|
|
else |
0 |
where:
• My guess is that the upper limit of the normal reference range for the ALT or AST is 50 IU/L.
|
Clinical Findings Present |
Additional Points |
|
all 3 clinical findings (temperature, tache noire, eruption) |
+ 5 |
|
2 of the 3 clinical findings are present |
+ 3 |
|
0 or 1 of the 3 clinical findings are present |
+0 |
diagnostic score =
= SUM(points for all of the parameters) + (additional points)
Interpretation:
• minimum score: 0
• maximum score: around 108
• A score > 25 points is consistent with a presumptive diagnosis of Mediterranean Spotted Fever.
Specialty: Infectious Diseases
ICD-10: ,
