The human gut is a long and hollow tube that runs from the mouth to the anus. Also known as the alimentary canal, the human gut is responsible for the digestion of food, absorption of the nutrients released during digestion of food, and the production and elimination of feces. The intestine (also called the bowels), which constitutes the part of the alimentary canal that lies between the stomach and the anus, is the longest section of the human gut.
The human intestine is subdivided into two main parts: the small intestine and the large intestine. The small intestine is around 6 meters in length, whereas the large intestine is around 1.5 meters in length. The width of the small intestine is relatively narrow when compared to the width of the large intestine. The majority of the processes of digestion and absorption occur within the small intestine. The large intestine is mainly responsible for the formation of feces.
The intestine is not a freely floating structure in the abdomen. Some regions of the intestine are firmly attached to the walls of the abdomen. Other regions of the intestine have more mobility since they are either free or held via supporting ligaments. The hollow space within the abdominal cavity that contains the intestine is technically referred to as the peritoneal cavity.
The lining of the peritoneal cavity is covered by a membranous tissue known as the peritoneum, which secretes the peritoneal fluid. Certain parts of the intestine within the peritoneal cavity are also held by a double layer of the peritoneum (also known as the mesentery). The lubrication provided by the peritoneal fluid aids the movements of the organs within the abdomen and prevents abrasion injuries.
What is Volvulus?
Despite the support structures that prevent a free movement of abdominal organs within the peritoneal cavity, the intestines have considerable mobility on account of their long length. The movements of the intestine can sometimes cause problems that arise from entanglement or displacement of certain regions of the intestine. Such conditions can affect the proper functioning of the intestine, and may even cause life-threatening complications due to constriction of blood supply to the walls of the gut.
Volvulus (also known as twisted bowels) is a rare condition which is characterized by a complete twisting of the bowels around the supporting mesentery. Volvulus can affect the stomach, small intestine, and parts of the large intestine. Infants and small children are relatively more susceptible to volvulus when compared to adults. The twisting of the bowels in volvulus can cause a variety of complications.
The twisting may result in an obstruction of the lumen of the intestine, which would affect the movement of the contents of the gut. Twisting of the bowels can also cause strangulation of the blood vessels that supply the walls of the bowel. Cessation of blood supply can then lead to ischemic injury to different regions of the intestine. The ischemic injury may even be irreversible, causing death of intestinal tissue and gangrene formation.
Types of Volvulus
There are many different types of volvulus. Some types of volvulus are specific to particular age groups or regions of the gut. The following are some of the common types of volvulus:
As the name suggests, neonatal volvulus affects the newborns. Neonatal volvulus is also known as volvulus neonatorum. The main cause of neonatal volvulus is a malrotation of the gut during fetal development. During the normal course of the development of the fetus, the gut begins as a straight tube and rotates gradually as its length increases. A partial rotation occurs in order to pack the long intestines within the small space of the abdominal cavity.
In some abnormal cases, this partial rotation may not happen at all (a condition known as non-rotation). In other cases, the rotation itself may be abnormal (also known as malrotation), leading to a complete twisting or strangulation of the bowels. A midgut volvulus, which is characterized by a twisting of the midgut around the superior mesenteric artery, is the most common type of neonatal volvulus.
The sigmoid colon is typically attached to the abdominal wall. However, it may become free or twisted due to certain anatomical abnormalities. It is also possible for a sigmoid volvulus to occur without any underlying anatomical abnormality.
The cecum forms the junction between the ileum (the last part of the small intestine) and the ascending colon (the first part of the large intestine). Normally, the cecum is attached to the abdominal wall. Cecal volvulus occurs when certain anatomical abnormalities in this region leave the cecum free to move and twist.
Gastric volvulus refers to a twisting of the stomach. The volvulus may affect either a part of the stomach (such as the cardia) or the whole stomach. Hiatal hernia is one of the common causes of gastric volvulus. In hiatal hernia, the upper part of the stomach manages to enter the chest cavity via the opening in the diaphragm.
Read more on twisted stomach.
Signs and Symptoms
The following are some of the signs and symptoms that may arise in cases of volvulus:
- Vomiting, which may or may not contain bile.
- Loss of appetite
- Abdominal pain
- Hematochezia (bloody stools)
The exact signs and symptoms depend on the extent of the twisting. Peritonitis and abdominal distension may occur if ischemic injury happens due to volvulus. Septic shock occurs when the tissues of the gut wall die due to ischemia.
Causes of Volvulus
Anatomical abnormalities are the most common causes of volvulus. However, volvulus can occur even in the absence of any anatomical abnormalities. The following are some of the diseases which may cause volvulus:
- Meckel’s diverticulum
- Hirschsprung disease
- Meconium ileus
- Cystic fibrosis
- Intestinal pseudo-obstruction
- Stenosis or atresia
- Diaphragmatic hernia
Diagnosis and Treatment
Volvulus is a rare gastrointestinal condition. This rarity, along with the nonspecific nature of the symptoms, makes it difficult to diagnose volvulus promptly. Initially, a twisting of the bowels may be suspected after an ultrasound study. However, a CT scan is required for a confirmed diagnosis. Radiological tests with contrast dyes (such as a barium meal) can also help in the identification of the twisted bowels.
When volvulus does not present with any symptoms, then the treatment may be delayed. However, the patient should be monitored regularly in such a case. When volvulus causes intestinal obstruction, surgery should be done immediately to relieve the obstruction. The surgical procedure may involve either an open surgery or a laparoscopic surgery.