Micro angiopathic hemolytic anaemia is seen in all of the following diseases except –
**Core Concept**
Microangiopathic hemolytic anemia (MAHA) is a condition characterized by the fragmentation of red blood cells due to their passage through small blood vessels with damaged endothelium. This leads to the formation of schistocytes, also known as fragmented red blood cells, which are a hallmark of MAHA. The pathophysiology involves the mechanical damage to red blood cells as they pass through narrowed or damaged blood vessels.
**Why the Correct Answer is Right**
MAHA is commonly seen in conditions that cause endothelial damage, such as thrombotic thrombocytopenic purpura (TTP) and hemolytic uremic syndrome (HUS). The endothelial damage leads to the formation of microthrombi, which in turn cause the red blood cells to be damaged as they pass through the affected blood vessels. Other conditions that can cause MAHA include malignant hypertension, severe burns, and vasculitis. The underlying mechanism involves the interaction between the damaged endothelium and the red blood cells, leading to their fragmentation.
**Why Each Wrong Option is Incorrect**
**Option A:** While not a primary cause of MAHA, certain infections such as malaria can cause hemolytic anemia, but it is not typically classified as microangiopathic. This option is incorrect because the pathophysiology of malaria-induced hemolytic anemia is different from MAHA.
**Option B:** This option is incorrect because HUS is a classic cause of MAHA, characterized by the triad of hemolytic anemia, thrombocytopenia, and acute kidney injury.
**Option C:** This option is incorrect because TTP is another classic cause of MAHA, characterized by the pentad of MAHA, thrombocytopenia, renal failure, fever, and neurological symptoms.
**Clinical Pearl / High-Yield Fact**
One important clinical correlation to remember is that MAHA is often associated with a low platelet count, which can make it difficult to diagnose. A low platelet count in the presence of MAHA should raise suspicion for conditions such as TTP or HUS.
**Correct Answer: A. While not a primary cause of MAHA, certain infections such as malaria can cause hemolytic anemia, but it is not typically classified as microangiopathic.**