Differential diagnosis of thrombotic thrombocytopenic purpura

Condition analysis:
TTP is characterized by thrombotic microangiopathy (TMA), the formation of blood clots in small blood vessels throughout the body, which can lead to microangiopathic hemolytic anemia and thrombocytopenia. This characteristic is shared by two related syndromes, hemolytic-uremic syndrome (HUS) and atypical hemolytic-uremic syndrome (aHUS). Consequently, differential diagnosis of these TMA-causing diseases is essential. In addition to TMA, one or more of the following symptoms may be present in each of these diseases: neurological symptoms (e.g. confusion, cerebral convulsions seizures; kidney impairment (e.g. elevated creatinine, decreased estimated glomerular filtration rate [eGFR], abnormal urinalysis; and gastrointestinal (GI) symptoms (e.g. diarrhea nausea/vomiting, abdominal pain, gastroenteritis. Unlike HUS and aHUS, TTP is known to be caused by an acquired defect in the ADAMTS13 protein, so a lab test showing ≤5% of normal ADAMTS13 levels is indicative of TTP. ADAMTS13 levels above 5%, coupled with a positive test for shiga-toxin/enterohemorrhagic E. coli (EHEC), are more likely indicative of HUS, whereas absence of shiga-toxin/EHEC can confirm a diagnosis of aHUS.

Instructions:
Surgery: Splenectomy is the surgical removal of the spleen. Removal of the spleen stops the destruction of platelets by antibodies produced in the spleen, but it also leaves the body more vulnerable to infection from other sources. This surgery is usually not performed until it has been determined that the medications are not effective.