Thrombotic Thrombocytopenic Purpura in Oman; Manifestations and Outcome. Retrospective Study

Abstract:

Background: Thrombotic Thrombocytopenic Purpura( TTP) is a rare life threatening disease. It is caused by congenital deficiency of metalloprotease ADAMTS -13 or acquired autoantibodies to this enzyme which normally cleaves vWF macromolecules. This results in Microangiopathic hemolytic anemia (haemolytic anemia, low platelets, and schiztocytes), systemic microvascular thrombi formation and subsequent end organ ischemia (renal and neurological manifestations). Nowadays the early recognition and treatment modalities resulted in survival rate reaching up to >=90%. So far, in Oman there have been no studies evaluating this rare disease.

Aim: This is a retrospective study conducted in a tertiary center in Oman aims to describe the clinical and the demographic characteristics of Omani patients diagnosed of TTP, their remission rate, and survival.

Methods:. We included all patients who were diagnosed between 2006 and 2018 who meet the diagnostic criteria of TTP and aged ≥ 12 years old. Data on patients' age, gender, region, ADAMTS-13 level, clinical presentation, lab results, treatment modalities and condition on discharge are described.

Results: Total of 38 patients met diagnostic criteria of TTP during the study period. 25 Females (66%) and 13 Males (34%),with Female: Male ratio was 1.9:1. Age ranges between12-83 years (mean: 42 years). Mean age at onset: 36 years (range 1- 79 years). Majority of patients were from Governates Al-Batinah 39% and Muscat 21%. Clinical features in descending order of frequency: fever (63%), petechiae/ ecchymosis (31%), seizures (21%), high BP reading(21%), headache(15%) , confusion(15%), postpartum presentation(15%) and stroke (7.9%). The mean values at presentation are consistent with microangiopathic hemolytic anemia. Deranged RFT was found in 19 patients (50%), ADAMTS 13% was tested in 18 cases, congenital deficiency was found in 4 patients, deficiency due to autoantibodies was found in 7 patients. Treatment modality received were steroids and Plasma exchange (number of sessions ranges between 3-30 sessions, average 9 sessions). 19 cases required rituximab and 10 patients required cyclosporin. 5 patients (13%) had renal derangement requiring dialysis as inpatients, only 1 patient continued to dialyze after discharge. None of the 3 patients with documented stroke had neurological deficits on discharge. Patients who had seizures (3 patients) were free of seizures and on maintenance antiepileptic medications. Relapses after first presentation was noted in 7 patients (17%) with mean relapse ranges 1 to 7 years (mean of 3 years) after first presentation. There was 1 death with TTP in a relapsed Non- Hodgkin's lymphoma pateint. Overall survival rate was 97% at 10 years study period.

Conclusion:This is the first study that demonstrates the demographic, clinical and survival rate of TTP patients in Oman, and provides a general picture of the TTP patients in our country