Upon protrusion through the hernial orifice, blood vessels of a hernia may become constricted. This condition is referred to as strangulated hernia; it may be associated with gangrenous necrosis of affected tissues and life-threatening complications.
Strangulation may occur within distinct periods of time after the initial protrusion of viscera . It should be noted that a considerable subset of individuals suffering from hernia remains asymptomatic until strangulation occurs. Rarely, SH is observed in patients previously diagnosed with hernia, who have been recommended watchful waiting or opted against elective surgery.
Most commonly, the hernial sac corresponds to a visible and palpable bulge, but this may not be the case in obese SH patients. The hernial sac and surrounding tissues are often erythematous and extremely tender, and patients claim intensifying discomfort when adopting a determined posture or coughing. In SH patients, intense pain usually leads to the diagnosis of acute abdomen. As per definition, SH is not manually reducible . With regards to hernia contents, functional impairment of protruded viscera usually manifest as the inability to pass stools or gasses. Bowel sounds may be decreased or absent . Compromise of the urogenital tract may cause micturition problems. Diaphragmatic SH may also be associated with respiratory symptoms. Any strangulated tissue may undergo gangrenous necrosis and serve as a source of toxins released upon cell death. If portions of the intestines are affected, microorganisms may pass the mucosal barrier and cause sepsis. Patients may thus present with systemic symptoms such as general malaise, fever, tachycardia, nausea, and vomiting.
Hernias are usually diagnosed clinically. Additional measures are rarely necessary, but sonography as well as plain radiography, computed tomography, or magnetic resonance imaging may be employed in selected cases  . An appropriate technique should be chosen to allow the identification of the hernial orifice and hernial contents as well as the assessment of the protruded tissues condition.
In general, the medical term hernia refers to the protrusion of viscera through an orifice into the so-called hernial sac. A specific case of hernia is defined by hernial location and its content.
In any case, the more or less rigid boundaries of an hernial orifice may interfere with arterial blood supply and venous return from tissues contained in the hernial sac. This condition is known as strangulated hernia (SH) and may lead to blood stasis, functional impairment of affected organs and acute inflammation . In the case of protruded intestines, for instance, strangulation is associated with an increased permeability of the intestinal wall and a possible breach of microorganisms. Walls of the hernial sac may eventually become gangrenous and necrotic, thus rendering SH a surgical emergency that may be associated with life-threatening sepsis.