Thrombotic thrombocytopenic purpura (TTP) is a rare microangiopathy characterised by thrombocytopenia, microangiopathic haemolytic anaemia, fever, impaired renal function and neurological disorders. The cause of TTP is deficiency of an enzyme that cleaves von Willebrand's factor called ADAMTS13. Lower serum level of ADAMTS13 activity leads to the formation of microthrombi causing ischaemia and organ damage. ADAMTS13 deficiency is mostly immune-mediated in adults as a result of anti-ADAMTS13 antibody formation (immune-mediated TTP, iTTP). These antibodies either neutralise the proteolytic activity of ADAMST13 or accelerate its removal from plasma. The hereditary congenital form of TTP (cTTP) is mostly detected in younger age or during pregnancy. This type of TTP is a result of mutation characterised by autosomal recessive inheritance and it causes decreased ADAMTS13 excretion. An acute episode of TTP is characterised by nonspecific initial clinical presentation. The patient can suffer from headache, confusion, weakness, vomiting or diarrhoea, while the laboratory results can show thrombocytopenia and microangiopathic haemolytic anaemia, along with microcirculatory ischaemia of various organs. The typical pentad including fever, altered mental status, anaemia, thrombocytopenia and kidney failure develops in less than 10% of cases. Timely diagnosis is important because this condition is considered a medical emergency and has a high mortality rate if untreated. In patients with a high clinical suspicion of TTP it is recommended to collect a plasma sample for testing ADAMTS13 activity and anti- ADAMTS13 IgG antibodies before initiating therapy. For the first acute episode and relapses of iTTP, it is strongly recommended to add corticosteroids to therapeutic plasma exchange (TPE) and to consider adding rituximab and caplacizumab. In asymptomatic cases of iTTP with low plasma ADAMTS13 activity it is recommended to use rituximab, whereas during pregnancy prophylactic TPE is advised . For asymptomatic cases of cTTP it is suggested to use plasma infusion during pregnancy as a prophylaxis. For asymptomatic cases of cTTP outside of pregnancy it is recommended to use either plasma infusion periodically or a watch and wait approach. Some new drugs are currently being tested, such as recombinant ADAMTS13. In conclusion, TTP is a rare life-threatening disease which should always be suspected in cases with microangiopathic haemolytic anaemia with thrombocytopenia. It has various clinical presentations with ischaemia and thrombosis affecting various organs, timely diagnosis and treatment are needed to prevent the otherwise high mortality rate.