The answer in brief:
The Ileus commonly means partially or totaly absence of intestinal passage
it's generally divided into mechanical and functional "paralytic ileus"
The mechanical is due to obstruction anywhere in the bowel which can be inside or outside, and it can be caused by volvulus, malignancy....etc - require surgery!
The functional one refers to a lack of passage due to paralysis of the bowel and it can be caused by intra-abdominal surgery, infection, hypokalemia... etc
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Things you should know about Ileus as medical student:
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Check your reference about symptoms & signs, Risk factors, Diagnosis especially radiological investigation and why it's not used in case of paralytic ileus and don't forget the treatment according to types!
For more information related ask it below
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By:Dr.Mahdi