hernia hernia a hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. various types of hernias can occur, most commonly involving the abdomen, and specifically the groin. groin hernias are most commonly of the inguinal type but may also be femoral. other types of hernias include hiatus, incisional, and umbilical hernias. symptoms are present in about 66% of people with groin hernias. this may include pain or discomfort in the lower abdomen, especially with coughing, exercise, or urinating or defecating. often, it gets worse throughout the day and improves when lying down. a bulge may appear at the site of hernia, that becomes larger when bending down. groin hernias occur more often on the right than left side. the main concern is bowel strangulation, where the blood supply to part of the bowel is blocked. this usually produces severe pain and tenderness in the area. hiatus, or hiatal hernias often result in heartburn but may also cause chest pain or pain while eating. herniadiagram of an indirect inguinal hernia (view from the side)specialtygeneral surgerysymptomspain especially with coughing, bulging areacomplicationsbowel strangulationusual onset< 1 year and > 50 years old (groin hernias)risk factorssmoking, chronic obstructive pulmonary disease, obesity, pregnancy, peritoneal dialysis, collagen vascular disease, connective tissue diseasediagnostic methodbased on symptoms, medical imagingtreatmentobservation, surgeryfrequency18.5 million (2015)deaths59,800 (2015) risk factors for the development of a hernia include smoking, chronic obstructive pulmonary disease, obesity, pregnancy, peritoneal dialysis, collagen vascular disease and previous open appendectomy, among others. predisposition to hernias is genetic and occur more often in certain families. deleterious mutations causing predisposition to hernias seem to have dominant inheritance (especially for men). it is unclear if groin hernias are associated with heavy lifting. hernias can often be diagnosed based on signs and symptoms. occasionally, medical imaging is used to confirm the diagnosis or rule out other possible causes. the diagnosis of hiatus hernias is often by endoscopy. groin hernias that do not cause symptoms in males do not need to be repaired. repair, however, is generally recommended in women due to the higher rate of femoral hernias, which have more complications. if strangulation occurs, immediate surgery is required. repair may be done by open surgery or laparoscopic surgery. open surgery has the benefit of possibly being done under local anesthesia rather than general anesthesia. laparoscopic surgery generally has less pain following the procedure. a hiatus hernia may be treated with lifestyle changes such as raising the head of the bed, weight loss and adjusting eating habits. the medications h2 blockers or proton pump inhibitors may help. if the symptoms do not improve with medications, a surgery known as laparoscopic nissen fundoplication may be an option. about 27% of males and 3% of females develop a groin hernia at some point in their lives. inguinal, femoral and abdominal hernias were present in 18.5 million people and resulted in 59,800 deaths in 2015. groin hernias occur most often before the age of 1 and after the age of 50. it is not known how commonly hiatus hernias occur, with estimates in north america varying from 10% to 80%. the first known description of a hernia dates back to at least 1550 bc, in the ebers papyrus from egypt. signs and symptoms frontal view of an inguinal hernia (right). incarcerated umbilical hernia with surrounding inflammation by far the most common hernias develop in the abdomen when a weakness in the abdominal wall evolves into a localized hole, or "defect", through which adipose tissue, or abdominal organs covered with peritoneum, may protrude. another common hernia involves the spinal discs and causes sciatica. a hiatus hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm. hernias may or may not present with either pain at the site, a visible or palpable lump, or in some cases more vague symptoms resulting from pressure on an organ that has become "stuck" in the hernia, sometimes leading to organ dysfunction. fatty tissue usually enters a hernia first, but it may be followed or accompanied by an organ. hernias are caused by a disruption or opening in the fascia, or fibrous tissue, which forms the abdominal wall. it is possible for the bulge associated with a hernia to come and go, but the defect in the tissue will persist. symptoms and signs vary depending on the type of hernia. symptoms may or may not be present in some inguinal hernias. in the case of reducible hernias, a bulge in the groin or in another abdominal area can often be seen and felt. when standing, such a bulge becomes more obvious. besides the bulge, other symptoms include pain in the groin that may also include a heavy or dragging sensation, and in men, there is sometimes pain and swelling in the scrotum around the testicular area. irreducible abdominal hernias or incarcerated hernias may be painful, but their most relevant symptom is that they cannot return to the abdominal cavity when pushed in. they may be chronic, although painless, and can lead to strangulation (loss of blood supply), obstruction (kinking of intestine), or both. strangulated hernias are always painful and pain is followed by tenderness. nausea, vomiting, or fever may occur in these cases due to bowel obstruction. also, the hernia bulge, in this case, may turn red, purple or dark and pink. in the diagnosis of abdominal hernias, imaging is the principal means of detecting internal diaphragmatic and other nonpalpable or unsuspected hernias. multidetector ct (mdct) can show with precision the anatomic site of the hernia sac, the contents of the sac, and any complications. mdct also offers clear detail of the abdominal wall allowing wall hernias to be identified accurately. complications complications may arise post-operation, including rejection of the mesh that is used to repair the hernia. in the event of a mesh rejection, the mesh will very likely need to be removed. mesh rejection can be detected by obvious, sometimes localized swelling and pain around the mesh area. continuous discharge from the scar is likely for a while after the mesh has been removed. a surgically treated hernia can lead to complications such as inguinodynia, while an untreated hernia may be complicated by: inflammation obstruction of any lumen, such as bowel obstruction in intestinal hernias strangulation hydrocele of the hernial sac hemorrhage autoimmune problems irreducibility or incarceration, in which it cannot be reduced, or pushed back into place, at least not without very much external effort. in intestinal hernias, this also substantially increases the risk of bowel obstruction and strangulation. causes causes of hiatus hernia vary depending on each individual. among the multiple causes, however, are the mechanical causes which include: improper heavy weight lifting, hard coughing bouts, sharp blows to the abdomen, and incorrect posture. furthermore, conditions that increase the pressure of the abdominal cavity may also cause hernias or worsen the existing ones. some examples would be: obesity, straining during a bowel movement or urination (constipation, enlarged prostate), chronic lung disease, and also, fluid in the abdominal cavity (ascites). also, if muscles are weakened due to poor nutrition, smoking, and overexertion, hernias are more likely to occur. the physiological school of thought contends that in the case of inguinal hernia, the above-mentioned are only an anatomical symptom of the underlying physiological cause. they contend that the risk of hernia is due to a physiological difference between patients who have hernia and those who do not, namely the presence of aponeurotic extensions from the transversus abdominis aponeurotic arch. abdominal wall hernia may occur due to trauma. if this type of hernia is due to blunt trauma it is an emergency condition and could be associated with various solid organs and hollow viscus injuries. diagnosis inguinal main article: inguinal hernia ultrasound showing an inguinal hernia an incarcerated inguinal hernia as seen on ct x-ray of colonic herniation by far the most common hernias (up to 75% of all abdominal hernias) are inguinal hernias, which are further divided into the more common indirect inguinal hernia (2/3, depicted here), in which the inguinal canal is entered via a congenital weakness at its entrance (the internal inguinal ring), and the direct inguinal hernia type (1/3), where the hernia contents push through a weak spot in the back wall of the inguinal canal. inguinal hernias are the most common type of hernia in both men and women. in some selected cases, they may require surgery. there are special cases where a direct and indirect hernia appear together. a pantaloon hernia (or saddlebag hernia) is a combined direct and indirect hernia when the hernial sac protrudes on either side of the inferior epigastric vessels. additionally, though very rare, two or more indirect hernias may appear together such as in a double indirect hernia. femoral main article: femoral hernia femoral hernias occur just below the inguinal ligament, when abdominal contents pass into the weak area at the posterior wall of the femoral canal. they can be hard to distinguish from the inguinal type (especially when ascending cephalad): however, they generally appear more rounded, and, in contrast to inguinal hernias, there is a strong female preponderance in femoral hernias. the incidence of strangulation in femoral hernias is high. repair techniques are similar for femoral and inguinal hernia. a cooper's hernia is a femoral hernia with two sacs, the first being in the femoral canal, and the second passing through a defect in the superficial fascia and appearing almost immediately beneath the skin. umbilical main article: umbilical hernia they involve protrusion of intra-abdominal contents through a weakness at the site of passage of the umbilical cord through the abdominal wall. umbilical hernias in adults are largely acquired, and are more frequent in obese or pregnant women. abnormal decussation of fibers at the linea alba may be a contributing factor. incisional main article: incisional hernia an incisional hernia occurs when the defect is the result of an incompletely healed surgical wound. when these occur in median laparotomy incisions in the linea alba, they are termed ventral hernias. these can be the most frustrating and difficult to treat, as the repair utilizes already attenuated tissue. these occur in about 13% of people at 2 years following surgery. diaphragmatic main article: diaphragmatic hernia diagram of a hiatus hernia (coronal section, viewed from the front). higher in the abdomen, an (internal) "diaphragmatic hernia" results when part of the stomach or intestine protrudes into the chest cavity through a defect in the diaphragm. a hiatus hernia is a particular variant of this type, in which the normal passageway through which the esophagus meets the stomach (esophageal hiatus) serves as a functional "defect", allowing part of the stomach to (periodically) "herniate" into the chest. hiatus hernias may be either "sliding", in which the gastroesophageal junction itself slides through the defect into the chest, or non-sliding (also known as para-esophageal), in which case the junction remains fixed while another portion of the stomach moves up through the defect. non-sliding or para-esophageal hernias can be dangerous as they may allow the stomach to rotate and obstruct. repair is usually advised. a congenital diaphragmatic hernia is a distinct problem, occurring in up to 1 in 2000 births, and requiring pediatric surgery. intestinal organs may herniate through several parts of the diaphragm, posterolateral (in bochdalek's triangle (lumbocostal triangle), resulting in a bochdalek hernia), or anteromedial-retrosternal (in the cleft of foramina of morgagni (sternocostal triangle), resulting in a morgagni's hernia). other hernias since many organs or parts of organs can herniate through many orifices, it is very difficult to give an exhaustive list of hernias, with all synonyms and eponyms. the above article deals mostly with "visceral hernias", where the herniating tissue arises within the abdominal cavity. other hernia types and unusual types of visceral hernias are listed below, in alphabetical order: abdominal wall hernias: umbilical hernia epigastric hernia: a hernia through the linea alba above the umbilicus. spigelian hernia, also known as spontaneous lateral ventral hernia amyand's hernia: containing the appendix vermiformis within the hernia sac brain herniation, sometimes referred to as brain hernia, is a potentially deadly side effect of very high intracranial pressure that occurs when a part of the brain is squeezed across structures within the skull. broad ligament hernia, of the uterus. double