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 ¹ (Patel et al., 2009).

The hallmark features include microangiopathic haemolytic anaemia (MAHA) and severe thrombocytopenia ¹ (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 ¹. Thrombocytopenia refers to a low platelet count ¹.

Additional features that raise suspicion for TTP include neurological abnormalities, such as confusion, seizures, or focal neurological deficits ³ (Thompson et al., 1992). Renal impairment, indicated by elevated creatinine or proteinuria, is another important sign ¹ (Thompson et al., 1992). Fever may also be present ¹ (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 ¹ (Patel et al., 2009). Therefore, a high index of suspicion is crucial, especially when thrombocytopenia and MAHA are present ¹. 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 ² (McMinn and George, 2001). Abnormal platelet counts, including thrombocytopenia, warrant investigation to rule out serious underlying conditions like TTP ¹.