Acquired Thrombotic Thrombocytopenic Purpura (aTTP)

What is Acquired Thrombotic Thrombocytopenic Purpura (aTTP)?

Acquired Thrombotic Thrombocytopenic Purpura (aTTP) is an acquired, life-threatening thrombotic microangiopathy that typically manifests with microangiopathic hemolytic anemia, thrombocytopenia, and organ injury secondary to thrombin formation. It is an autoimmune disorder characterised by systemic microvascular thrombosis that leads to organ injury. Clinical presentation is variable and can include skin rash, folic acid deficiency, neurological symptoms, and even death. It has an estimated incidence rate of 1 to 2 cases per million and occurs most often in women.

Causes of aTTP

The exact cause of aTTP is not known, but it is believed to be an autoimmune disorder, in which the body's own immune system mistakenly targets and attacks healthy cells.

In aTTP, the body's immune system produces autoantibodies that attack and damage components of the blood clotting system. This leads to abnormal clot formation and breakdown, resulting in a persistent decrease in the number of platelets (thrombocytopenia), and premature destruction of the red blood cells (hemolytic anemia).

Risk Factors

The following risk factors may increase the likelihood of developing aTTP:

  • Age over 40
  • Having recently taken medications, such as certain antibiotics, HIV medications, chemotherapy drugs, and others
  • Being female, especially pregnant women
  • Having an underlying medical condition, such as lupus, HIV, or cancer
  • Having certain genetic conditions

Signs and Symptoms

The most common signs and symptoms of aTTP include:

  • Fatigue
  • Painful or swollen joints
  • Headache
  • Cough
  • Fever
  • Abdominal pain
  • Nosebleed
  • Shortness of breath
  • Chest pain
  • Easy bruising or bleeding
  • Paleness
  • Bruising
  • Spontaneous red spots on the skin (purpura)
  • Impaired vision
  • Difficulty walking
  • Extreme thirst

Diagnosis and Treatment

The diagnosis of aTTP is usually made by a combination of clinical evidence and laboratory findings. The laboratory investigations include complete blood count, coagulation profile, Renal & Liver Function, and Imaging. Depending on the severity of the condition, the patient may be put on steroids and other treatments. Plasmapheresis is often recommended to remove the autoantibodies. In some cases, aTTP can be fatal if left untreated. It is important to seek medical attention as soon as the signs and symptoms appear.