**Core Concept**
Thrombotic thrombocytopenic purpura (TTP) is a rare blood disorder characterized by the formation of blood clots in small blood vessels throughout the body. This leads to a decrease in the number of platelets in the blood, which can cause bleeding and other complications.

**Why the Correct Answer is Right**
TTP is typically associated with hypertension due to the consumption of anticoagulant proteins and the release of vasoconstrictors from platelets. However, hypertension is not a hallmark feature of TTP, which is more commonly associated with hypotension or normal blood pressure. In contrast, fever, haemolysis, and low platelet count are characteristic features of TTP. Haemolysis occurs due to the mechanical damage to red blood cells as they pass through the microthrombi, while low platelet count is a result of platelet consumption and destruction.

**Why Each Wrong Option is Incorrect**
**Option A:** Fever is a common feature of TTP, often occurring due to the inflammatory response to the formation of microthrombi and the release of inflammatory mediators.
**Option B:** Haemolysis is a key feature of TTP, resulting from the mechanical damage to red blood cells as they pass through the microthrombi.
**Option D:** Low platelet count is a characteristic feature of TTP, resulting from platelet consumption and destruction.

**Clinical Pearl / High-Yield Fact**
It's essential to differentiate TTP from other causes of thrombocytopenia, such as disseminated intravascular coagulation (DIC), which is often associated with hypertension due to the release of vasoconstrictors from platelets and the consumption of anticoagulant proteins.

**✓ Correct Answer: C. Hypeension**