Ileus is intestinal obstruction and it occurs in the absence of a mechanical cause. It is usually due to the inability of the bowel to undergo its normal propulsive peristaltic movement.
The usual presenting complain is pain and bloating. This pain is often mild and vague initially but is later described as cramps. They may also present with poor appetite, nausea and vomiting. Patients could also present with inability to pass faeces or flatus but this is not common in all patients. There is abdominal distension and the degree will depend in the level of the ileus. The abdomen will also be tympanic to percussion and there may be some degree of tenderness. A distinctive feature of ileus is the reduced or complete absence of bowel sounds on auscultation which is usually referred to as the silent abdomen .
The prognosis is generally good as most cases of postoperative ileus resolve within 72 hours. Very rarely is there complication. The risk of a future occurrence is however increased in a patient who has had ileus .
The cause of ileus is still uncertain but there have been strongly linked associated risk factors. The main identified risk factor is major gastrointestinal surgery and the postoperative state is the most popular setting for development of ileus and it is an expected complication. Other contributing factors are electrolyte imbalance, hypothyrpidism, metabolic acidosis e.g. diabetic ketoacidosis, drugs like antimuscarinics and opiates, spinal cord injury above the fifth thoracic vertebrae, chest infections, cardiopulmonary failure like myocardial infarction, sepsis, intraabdominal inflammation and peritonitis, as well as biliary and renal colic .
Approximately 50% of people who undergo major abdominal surgery will develop ileus postoperatively. It is seen in all age groups although it is becoming more common in the elderly, probably due to increased surgical procedures now being performed in this age group. It has no sex preferences and affects individuals of all races .
The exact pathway by which ileus occurs is still unclear. It has been hypothesised that it might be mediated through activation of inhibitory spinal reflex arcs. 3 separate reflexes are involved, the long, short and ultrashort reflex. The long reflexes which involve the spinal cord is the most significant. Nerve cutting techniques have been seen to either diminish or prevent the development of ileus.
Usually, the response to surgical stress leads to systemic generation of endocrine and inflammatory mediators that then promote the development of ileus. Abdominal surgeries causes increased number of monocytes, macrophages, dendritic cells, natural killer cells, T cells and mast cells. Macrophages and mast cells are the key players in the inflammatory cascade. Other mediators are nitric oxide, calcitonin gene-related peptide, substance P and vasoactive inhibitory peptide and these serve as inhibitory neurotransmitters in the nervous system of the bowel .
Not much is available in terms of prevention of this condition. It occurs as a result of surgery, medical conditions and injuries which makes it difficult to control .