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What is Splenomegaly and explain in detail?
Splenomegaly is an enlargement of the spleen. The spleen usually lies in the left upper quadrant (LUQ) of the human abdomen. Splenomegaly is one of the four cardinal signs of hypersplenism which include: some reduction in number of circulating blood cells affecting granulocytes, erythrocytes or platelets in any combination; a compensatory proliferative response in the bone marrow; and the potential for correction of these abnormalities by splenectomy. Splenomegaly is usually associated with increased workload (such as in hemolytic anemias), which suggests that it is a response to hyperfunction. It is therefore not surprising that splenomegaly is associated with any disease process that involves abnormal red blood cells being destroyed in the spleen. Other common causes include congestion due to portal hypertension and infiltration by leukemias and lymphomas. Thus, the finding of an enlarged spleen, along with caput medusae, is an important sign of portal hypertension.

Definition
The standard system for classifying splenomegaly on radiography is:
Normal (not splenomegaly): the largest dimension is less than 11 cm
Moderate splenomegaly: the largest dimension is between 11 and 20 cm
Severe splenomegaly: the largest dimension is greater than 20 cmAlso, a cutoff of a craniocaudal height of 13 cm is also used to define splenomegaly. In addition, individual intervals have been established:

For children, the cutoffs for splenomegaly are given in this table, when measuring the greatest length of the spleen between its dome and its tip, in the coronal plane through its hilum while breathing quietly.At autopsy, splenomegaly can be defined as a spleen weight above the upper limit of the standard reference range of 230 g (8.1 oz).Splenomegaly refers strictly to spleen enlargement, and is distinct from hypersplenism, which connotes overactive function by a spleen of any size. Splenomegaly and hypersplenism should not be confused.  Each may be found separately, or they may coexist. Clinically, if a spleen is palpable (felt via external examination), it means it is enlarged as it has to undergo at least twofold enlargement to become palpable