What are the key clinical features that should raise suspicion for Thrombotic Thrombocytopenic Purpura (TTP) in a patient?

Suspicion for Thrombotic Thrombocytopenic Purpura (TTP) should be raised by a combination of key clinical features, which are often described as a pentad, though not all features may be present NICE CKS Patel et al. 2009.

The hallmark features include microangiopathic haemolytic anaemia (MAHA) and severe thrombocytopenia NICE CKS Thompson et al. 1992. MAHA is indicated by evidence of red blood cell fragmentation (schistocytes) on a blood film, elevated lactate dehydrogenase (LDH), and undetectable haptoglobin NICE CKS. Thrombocytopenia refers to a low platelet count NICE CKS.

Additional features that raise suspicion for TTP include neurological abnormalities, such as confusion, seizures, or focal neurological deficits NICE CKS Thompson et al. 1992. Renal impairment, indicated by elevated creatinine or proteinuria, is another important sign NICE CKS Thompson et al. 1992. Fever may also be present NICE CKS Thompson et al. 1992.

It is important to note that TTP can present as a “masquerader,” meaning its symptoms can be varied and non-specific, making diagnosis challenging NICE CKS Patel et al. 2009. Therefore, a high index of suspicion is crucial, especially when thrombocytopenia and MAHA are present NICE CKS. In pregnant women, TTP or similar thrombotic microangiopathies should be considered when evaluating suspected cases of pre-eclampsia or HELLP syndrome, as their presentations can overlap NICE NG121 McMinn & George 2001. Abnormal platelet counts, including thrombocytopenia, warrant investigation to rule out serious underlying conditions like TTP NICE CKS.