1. S CONCLUSION Seasonal Variation in the Occurrence of Thrombotic
Thrombocytopenic Purpura in Egypt
Eiman Hussein and Azza A. Aboul Enein
Clinical Pathology
Cairo University, Cairo, Egypt
INTRODUCTION
METHODS
RESULTS
Thrombotic Thrombocytopenic Purpura (TTP) is defined by microangiopathic hemolytic anemia and hrombocytopenia with no other possible explanation. Being a rare disease, its epidemiology is still poorly understood. Limited data have been published on its seasonal trends. These data came from different regions in the US. Most of these studies point toward an increased incidence of TTP in the summer and the spring. Warm weather has been speculated for being a possible trigger in individuals who are at risk. The role of certain allergens and infections was suggested as a potential explanation for such seasonality.
Patients with TTP who received TPE at our apheresis unit during the study period from January 2008 through March 2016 were investigated. We only included patients with ADAMTS 13 activity of less than 10% caused by IgG antibodies to ADASMTS 13. Laboratory and demographic characteristics of patients were collected. Data on initial and relapsed episodes, month of presentation, as well as mortality rate were analyzed. Seasons were defined as follows: winter, December to February; spring, Mach to May; summer, June to August and fall, October to November.
Records of 37 patients with TTP were reviewed, of whom 23 (62.2%) were females. Their median
age was 25 years. The overall mortality rate was 5/37 (13.5%). Their laboratory findings revealed thrombocytopenia, microangiopathic hemolytic anemia and schistocytes in the peripheral blood smear. Twenty nine patients (78.4%) were described as idiopathic and 8 (21.6%) had secondary causes including pregnancy (7 patients) and clopidogrel use (1 patient). Thirty seven patients had 39 episodes with 34 initial episodes and 5 relapses. Of the 5 relapses two occurred within two months, two occurred after 1 year, and one presented 20 years after complete remission. All episodes for both the idiopathic and secondary TTP demonstrated winter predominance, with 74.4% of all episodes presenting between November and April (29/39). Winter had significantly higher incidence for TTP (15/39 (38.5%)), compared with the summer (5/39 (12.8%) (P=0.009). This, However, was not significant when compared with the incidences in the spring (10/39 (25.6%)) and the fall (9/39 (23.1%)). Patients with secondary TTP had 10 episodes, with 80% of all episodes presenting between November and April. Table
OBJECTIVES
The aim of this study was to explore the seasonal factors that may influence the occurrence of TTP in Egypt, with the hope that this study can help better understand the epidemiology of this autoimmune disease.
Table: Monthly distribution for idiopathic and secondary TTP episodes in Egypt
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Idiopathic TTP
Initial episodes
Earl relapses
Late relapses
All episodes 3 - 1 4 5 2
Secondary TTP S
CONCLUSION
Compared to the seasonal trend in the occurrence of TTP in the US, seasonal trend in Egypt appears to be different. Our cohort of patients demonstrated winter predominance. Future studies, looking into the seasonal variation influencing the occurrence of TTP in different geographic locations may be warranted. This can help gain additional insight into the possible environmental factors involved in the occurrence of TTP, ultimately providing a better understanding for the pathophysiology of this rare disease entity.