Gastrointestinal angiodysplasias or angioectasias are one of the most common causes of occult gastrointestinal bleeding.
Peak incidence occurs in patients in their 60-70s 3.
Patients can present with symptoms and signs upper or lower gastrointestinal bleedi...
Cytomegalovirus infection of the gastrointestinal tract is usually seen in patients who are severely immunocompromised, such as solid organ transplantation and is common in HIV/AIDS, and is, in fact, the most common gastrointestinal manifestation of AIDS 1-2.
Approximately 30% of...
Gastrointestinal MRI contrast agents are varied and can be either positive or negative agents. Acceptance of the use of MRI in abdominal imaging has been limited in part by difficulty in distinguishing bowel from intra-abdominal masses and normal organs. The use of enteric contrast agents can ai...
Gastrointestinal neuroendocrine tumours (GI NETs) can be functional or non-functional:
functional NETs can be challenging to localise as:
they are often small in size at the time of diagnosis
arise in many sites throughout the body
non-functioning and/or malignant NETs often are larger at ...
Gastrointestinal nodular lymphoid hyperplasia is a type of nodular lymphoid hyperplasia that can be found elsewhere in the body. It is formed out of gut-associated lymphoid tissue (GALT), and most often is a diagnostic dilemma for radiologists in the stomach and terminal ileum.
A gastrointestinal schwannoma is an extremely rare mesenchymal neoplasm which arises in relation to the gastrointestinal tract.
They are reported to typically present at about the 3rd to 5th decades of life 4.
Patients are often asymptomatic but may occasio...
Gastrointestinal stromal tumours (GIST) are the most common mesenchymal tumours of the gastrointestinal tract. They account for ~5% of all sarcomas. They respond remarkably well to chemotherapy.
Previously these tumours have been variably referred to as leiomyomas, leiomyosarcomas...
The gastrointestinal tract includes any part of the oral cavity, oropharynx, hypopharynx, oesophagus, stomach, small bowel, colon, rectum and anal canal.
Gastrointestinal tract (GIT) lipomas are not common and can be found anywhere along the entire length of the gastrointestinal tract.
GIT lipomas are most frequently encountered between the ages of 50 and 70 years 3.
The majority of lipomas are asymptomatic...
Gastrointestinal tuberculosis refers to the infection of abdominal organs with Mycobacterium tuberculosis. It generally affects the following organs:
ileocaecal junction (terminal ileum and caecum): most commonly due to the abundance of lymphoid tissue 1
The gastro-oesophageal junction (GOJ) (also known as the oesophagogastric junction) is the part of the gastrointestinal tract where the oesophagus and stomach are joined.
The GOJ is normally mostly intra-abdominal and is 3-4 cm in length. To some extent, the oesophagus slides in ...
Gastro-oesophageal reflux disease (GORD) is a spectrum of disease that occurs when gastric acid refluxes from the stomach into the lower end of the oesophagus across the lower oesophageal sphincter (LOS).
Common clinical features in adults include epigastric and retroster...
Gastric-oesophageal reflux disease (GORD) is a spectrum of disease that occurs when gastric acid refluxes into the lower oesophagus
This is a summary article; read more in our article on gastro-oesophageal reflux disease.
Gastroschisis refers to extra-abdominal herniation (evisceration) of fetal or neonatal bowel loops (and occasionally portions or the stomach and or liver) into the amniotic cavity through a para-umbilical abdominal wall defect.
The estimated incidence is at around 1-6 per 10,000...
The gastrosplenic ligament is a peritoneal ligament which is formed by ventral part of dorsal mesentery.
The gastrosplenic ligament extends from the greater curvature of the stomach to the hilum of the spleen. It contains the short gastric arteries.
Gaucher disease (GD) is the most common lysosomal storage disease in humans. It is an autosomal recessive, multisystem disease arising from a deficiency of glucocerebrosidase or beta-glucosidase activity, resulting in accumulation of a glycolipid (glucocerebroside) within the lysosomes of macrop...
A mnemonic to remember the causes of generalised colitis is:
I: infectious colitis e.g. E. coli, cytomegalovirus
I: inflammatory, e.g. pseudomembranous colitis, Crohn disease, ulcerative colitis
I: ischaemic colitis
N: neoplastic, e.g. lymphoma
R: radiation colitis
To facilitate clinical description, the general topography of the abdomen is divided into four quadrants or nine regions by lines on the surface of the anterior abdominal wall. The four quadrants are created by vertical and horizontal lines passing through the umbilicus, whereas the nine regions...
Geophagy is the intentional ingestion of earth, soil or clay and is a form of pica. This practice is not uncommon in the southern regions of the United States or provinces of Africa. It may be seen in pregnant or iron-deficient patients 3. Although geophagia may be seen in the context of a varie...
A giant colonic diverticulum is a rare form of presentation of colonic diverticulosis and is characterised by a large diverticular mass, usually filled with stool and gas, that communicates with the colonic lumen.
The most common presentation is abdominal pain. Other pr...
Globus pharyngeus is the subjective feeling of a lump in the throat which can have a variety of causes. In modern practice globus is often evaluated by flexible nasoendoscopy in the first instance since many patients present to otolaryngology services. If no cause is identified or if nasoendosco...
Glucagonomas are pancreatic endocrine tumours that secrete glucagon. Most lesions are malignant.
They are rare with an incidence of 0.000005%. Equal incidence in middle-aged men and women.
Most patients present with a necrolytic migratory rash and various ...
Glycogenic acanthosis is a benign finding on oesophagography in elderly patients.
It most commonly occurs in patients >40 years of age and incidence and numbers of lesions increase by age. No gender predilection exists. Typically patients are asymptomatic.
It occurs f...
A gossypiboma, also called textiloma or cottonoid, refers to a foreign object, such as a mass of cotton matrix or a sponge, that is left behind in a body cavity during an operation. It is an uncommon surgical complication.
The manifestations and complications of gossypibomas are so variable tha...
Graft versus host disease (GvHD) is a frequent complication of allogeneic post haematopoietic stem cell transplantation (HSCT), commonly known as bone marrow transplantation. Anti-rejection drugs have reduced the incidence, although it does still frequently occur.
GvHD can present e...
Granular mucosal pattern of the oesophagus represents very fine nodularity of the oesophageal mucosal surface. This finding is nonspecific and may represent:
reflux oesophagitis (most common)
superficial spreading oesophageal car...
The great vessel space is the fourth retroperitoneal space along with the anterior and posterior pararenal spaces, and the perirenal space 1, 2. Unlike other retroperitoneal spaces, it is not well-defined by fascial planes and thus disease process affecting other retroperitoneal spaces can also ...
The Griffiths point (or Griffiths critical point) refers to the site of watershed anastomosis between the ascending left colic artery and the marginal artery of Drummond occurring in the region of the splenic flexure. Most anatomy texts describe the location as two-thirds along the transverse co...
A gastrointestinal fistula is an abnormal connection between the gut and another epithelial / endothealial - lined surface, such as another organ system, the skin surface, or elsewhere along the gastrointestinal tract. Some authors exclude fistulas involving the large bowel and oesophagus when c...
The gut signature sign is an ultrasound term used to describe the appearance of the gastrointestinal wall.
The bowel wall has five layers, composed of alternating hyperechoic and hypoechoic appearances. Anatomically these layers are as follows (innermost to o...
Haemangiopericytomas of the spleen are very rare vascular neoplasm with only a few case reports available at the time of writing.
Splenic haemangiopericytomas are typically asymptomatic or can result in splenomegaly.
These are soft tissue vascular neoplasms ar...
Abdominal complications of haematopoietic stem cell transplantation can occur early (0-100 days) or late (>100 days) post-transplant.
bacterial infections, e.g. pseudomembranous colitis
fungal infections, often affecting the oesophagus or as hepatic/splenic microabscesse...
Pancreatic manifestations of haemochromatosis typically occur with primary haemochromatosis, as the organ is usually spared in the secondary form of the disease.
Iron deposition can occur in the pancreas with primary hemochromatosis. Pancreatic involvement is uncommon in patients wi...
Haemoperitoneum is the presence of blood within the peritoneal cavity.
penetrating or non-penetrating abdominal trauma (often with associated organ injury) 1
ruptured ectopic pregnancy
ovarian cyst rupture
aneurysm or pseudoaneurysm rupture
Haemorrhagic pancreatitis is a possible uncommon complication that can occur with pancreatitis and is characterised by bleeding within or around the pancreas. It is usually considered a late sequela of acute pancreatitis.
Haemorrhage can occur in patients with severe necrotising panc...
Haemosuccus pancreaticus, also known as pseudohaemobilia or haemoductal pancreatitis, is defined as upper gastrointestinal tract haemorrhage originating from the pancreatic duct into the duodenum via the ampulla of Vater, or major pancreatic papilla.
male:female ratio is 7:1
The Haggitt level is a histopathological term used for describing the degree of infiltration from a malignant polypoidal lesion.
Levels of invasion
0: carcinoma in situ or intramucosal carcinoma
1: invasion of the submucosa, but limited to the head of the polyp
2: invasion extending into the...
The Hampton line is a thin millimetric radiolucent line seen at the neck of a gastric ulcer in barium studies (profile view), indicating its benign nature. It is caused by a thin line of mucosa overhanging the ulcer's crater.
History and etymology
It was originally described by Aubrey Otis Ham...
The haustral folds represent folds of mucosa within the colon. They are formed by circumferential contraction of the inner muscular layer of the colon.
The outer longitudinal muscular layer is organised into three bands (taeniae coli) which run from the caecum to the rectum. These muscular band...
Haustral markings are the radiological appearance of the haustral folds within the colon. Disappearance of the haustral folds results in the lead pipe appearance of ulcerative colitis.
Hepatic and splenic tuberculosis refers to tuberculosis affecting liver and spleen. It generally occurs due to spread from the primary site of infection, commonly from pulmonary tuberculosis.
Two types of lesions are known:
Hepatic pseudolesions near the falciform ligament show abnormal attenuation without mass effect. They may be seen on contrast-enhanced CT scans as either a region of high or low attenuation relative to the rest of the liver. They are typically located in the medial segment of the left lobe of th...
Hepatoduodenal ligament is the peritoneal ligament of lesser omentum, which attaches the duodenum to the liver.
Hepatoduodenal ligament contains:
common hepatic duct
part of cystic duct
Hepatoduodenal ligament is a rout of spread of diseases of pancratic head t...
The hepatogastric (gastrohepatic) ligament is a peritoneal ligament that together with the hepatoduodenal ligament forms the lesser omentum. It derives from the embryonic ventral mesentery.
The hepatogastric ligament extends from the fissure of the ligamentum venosum and porta he...
Hereditary breast and ovarian cancer (HBOC) syndrome is caused by a mutation to either BRCA1 or BRCA2 genes. These patients have an increased risk of breast cancer, ovarian cancer, pancreatic cancer and prostate cancer. However, these gene mutations are not the only cause of hereditary breast ca...
Hereditary haemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is a rare inherited disorder characterised by abnormal blood vessel formation in the skin, mucous membranes, and organs including the lungs, liver, and central nervous system.
Hereditary non-polyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is an inherited condition which predisposes to a host of malignancies, including colorectal carcinoma. It is considered the most frequent form of hereditary colorectal cancer. Diagnosis requires evaluation using cl...
Hereditary pancreatitis is a rare subtype of chronic pancreatitis that has an autosomal dominant inheritance. Imaging plays a role in excluding underlying abnormalities.
As a congenital condition, presentation with acute pancreatitis attacks typically occurs in childhood,...
Herpes oesophagitis is one of the infectious oesophagitis that usually affects immunocompromised patients.
It occurs as an opportunistic infection in immunocompromised patients, particularly those with AIDS. It has also been described in immunocompetent individuals 3.
Heyde syndrome is an association between aortic valve stenosis and gastrointestinal haemorrhage.
The aetiology of the gastrointestinal bleeding in this setting is uncertain, but it is thought to be related to intestinal angiodysplasia. The strength of this association independent of age-related...
Hiatus hernias (HH) occur when there is herniation of abdominal contents through the oesophageal hiatus of the diaphragm into the thoracic cavity.
The prevalence of hiatus hernia increases with age, with a slight female predilection.
Many patients with hiat...
The hide-bound bowel sign refers to an appearance on a barium study of the small bowel in patients with scleroderma. The sign describes the narrow separation between the valvulae conniventes which are of normal thickness despite dilatation of the bowel lumen.
Although the term hide-bound is u...
High-grade appendiceal mucinous neoplasms (HAMN) are rare mucinous tumours of the appendix showing high-grade cytologic atypia, c.f. low-grade appendiceal mucinous neoplasms (LAMN). The distinction between both LAMN and HAMN is done on a histologic ground and those tumours basically look the sam...
E J Hinchey et al. 3 proposed a classification for acute diverticulitis, that has been variously adapted, and is useful not only in academia but also in outlining successive stages of severity.
stage 1a: phlegmon
stage 1b: diverticulitis with pericolic or mesenteric abscess
Hirschsprung disease is the most common cause of neonatal colonic obstruction (15-20%). It is commonly characterised by a short segment of colonic aganglionosis affecting term neonates, especially boys.
Hirschsprung disease affects approximately 1:5000-8000 live births. In short ...
Acquired immunodeficiency syndrome (AIDS) is an immunosuppressed state, caused by infection with the human immunodeficiency virus (HIV). It is characterised by opportunistic infections, neoplasms and neurological manifestations.
According to the United Nations programme on HIV/AID...
Gastrointestinal manifestations of AIDS are protean and can be broadly divided into opportunistic infections and tumours:
herpes simplex virus (HSV)
primary infection with HIV
HIV-associated neoplasms are numerous and can be broadly divided into two groups:
associated but not AIDS defining malignancies
The development of these malignancies in HIV affected individuals generally implies progression to AIDS 4:
HIV oesophagitis is a possible cause of odynophagia in immunosuppressed patients with HIV.
The actual incidence and prevalence of Idiopathic oesophagitis of HIV are unknown. Most of the patients have acquired immunodeficiency syndrome (AIDS) and CD4 count <100 3.
Hydatid cysts result from infection by the Echinococcus, and can result in cyst formation anywhere in the body.
There are two main species of the Echinococcus tapeworm 1,2:
pastoral: dog is a main host; most common form
sylvatic: wolf is a main h...
The hyperattenuating ring sign is a sign that has been described with epiploic appendagitis and refers to a hyperattenuating ring of visceral peritoneum surrounding an inflamed epiploic appendage 1. On CT it can be seen as a ring of soft tissue surrounding a region of fat attenuation adjacent to...
Hypercontracting (nutcracker) oesophagus is a motility disorder of the oesophagus. This condition is primarily diagnosed with manometry with high intra-oesophageal pressure and normal peristalsis. Most patients will have a normal barium swallow.
Hypercontracting oesophagus ("nutcracker oesopha...
Hypertrophic pyloric stenosis can be characterised in ultrasound studies by the measurements of the hypertrophic muscle. Although the criteria can vary from publication to publication, an easy way to keep in mind those values is remembering the first digits of the number "pi", also represented b...
The ice pick sign is a smooth tapered narrowing of the upstream pancreatic duct distal to the pancreatic lesion seen frequently in benign pancreatic lesions such as a focal autoimmune pancreatitis, this is due to the extrinsic narrowing of the duct secondary to periductal fibrosis and inflammati...
Idiopathic eosinophilic oesophagitis is a cause of dysphagia, most commonly seen in males aged 20-40. On a barium swallow, there is a distinctive stricture seen with ring-like indentations.
IgG4-related disease (IgG4-RD) is a systemic disease that is characterised by extensive IgG4-positive plasma cells and T-lymphocyte infiltration of various organs.
This condition has been known by many other names in the past, such as IgG4-related sclerosing disease, IgG4-related s...
Ileal atresia is a congenital abnormality where there is significant stenosis or complete absence of a portion of the ileum. There is an increased incidence in those with chromosomal abnormalities.
This article will focus on ileal atresia alone but bear in mind that some cases correspond to jej...
The ileocaecal valve separates the terminal ileum from the caecum and functions to regulate flow between these two structures and prevent reflux from the caecum into the small intestine.
The ileocaecal valve consists of two muscular layers of ileum, an upper and lower lip, that ...
The ileocolic artery is a branch of the superior mesenteric artery (SMA) that runs obliquely to the ileocaecal junction.
It divides into an ileal branch that supplies the terminal ileum and anastomoses with the terminal SMA and a colic branch that supplies the proximal ascending colon and anast...
The ileum is the final part of the small intestine, following the duodenum and jejunum.
The ileum is not to be confused with the ilium.
The ileum is 2-4 m in length and is separated from the caecum by the ileocaecal valve (ICV). While there is no discrete line demar...
The medical terms ileum and ilium have been causing great confusion to medical students and junior doctors alike for decades now. Only separated by one letter, the second vowel, the pronunciation may be identical, or differ slightly with the i sound resembling that in "bit" for ilium (ɪlɪəm) or ...
The majority of splenic lesions are benign and when an incidental splenic lesion is found in an asymptomatic patient, it may pose a dilemma in workup because imaging findings are often nonspecific.
benign imaging features: no follow up
Indirect inguinal hernias are the most common type of abdominal hernias.
It is five times more common than a direct inguinal hernia, and is seven times more frequent in males, due to the persistence of the processus vaginalis during testicular descent.
In children, the vast majo...
Indium-111 OncoScint is a radiopharmaceutical used in SPECT imaging. It is a labelled monoclonal antibody that is directed against TAG-72, which is a tumour-associated antigen associated with ~95% of colorectal carcinomas and 100% of ovarian carcinomas 1,2. Background hepatic uptake limits sensi...
Infectious colitis refers to inflammation of the colon due to an infective cause, including bacterial, viral, fungal, or parasitic infections.
In Western countries, bacterial infection is the most common cause, while in developing countries parasitic infection is much more common....
The inferior lumbar triangle (also known as Petit triangle) is an anatomical space through which inferior lumbar hernias can occur.
inferiorly: iliac crest
anteriorly: external oblique muscle
posteriorly: latissimus dorsi muscle
floor: internal oblique muscle
The inferior mesenteric artery (IMA) is an anterior branch of the abdominal aorta that supplies the hindgut. It is the smallest of the three anterior branches of the abdominal aorta.
within the mesentery of the hindgut
unpaired vessel from the anterior aspect o...
The inferior mesenteric vein drains blood from the distal portion of the colon as well as the rectum (i.e. the hindgut).
Origin and course
The inferior mesenteric vein drains the mesenteric arcade of the hindgut (comprising of distal transverse, descending, and sigmoid colon). ...
The inferior pancreaticoduodenal artery is the first branch of the superior mesenteric artery (SMA), though it often arises from the first jejunal branch.
It anastomoses with branches of the superior pancreaticoduodenal artery (from the gastroduodenal artery) and it supplies the head of the pan...
The inferior thoracic aperture connects the thorax with the abdomen.
The inferior thoracic aperture is irregular in shape and is more oblique and much larger than the superior thoracic aperture. The diaphragm occupies and closes the inferior thoracic aperture, thereby separating ...
Inflammatory bowel disease (IBD), although occasionally used to encompass a variety of infective and purely inflammatory bowel conditions, usually refers to two idopathic conditions
Indeterminate colitis is added to the list, and represents approximately 6% ...
Inflammatory bowel disease is a generic term used to describe diseases of the GI tract that have an inflammatory cause. Crohns disease (CD) and ulcerative colitis (UC) are the commonest causes of inflammatory bowel disease.
This is a summary article; read more in our article ...
Thoracic manifestations of both ulcerative colitis and Crohn's disease can be variable and can't be used to differentiate between these entities.
They can develop at any time with respect to the clinical onset of the underlying disease. Actually, they can also predate the colonic disease or dev...
An inflammatory pseudopolyp is an island of normal colonic mucosa which only appears raised because it is surrounded by atrophic tissue (denuded ulcerative mucosa). It is seen in long-standing ulcerative colitis.
It must be distinguished from inflammatory polyps, which are regions of inflamed a...
The inframesocolic space is the peritoneal space below the root of the transverse mesocolon. The supramesocolic space lies above the transverse mesocolon's root.
The compartment can be divided into two unequal spaces posteriorly by the mesentery of the small bowel as it runs from...
Ingested bones that become lodged in the throat or gastrointestinal tract are a common presentation to the emergency department. Recognition is important because these cases can be potentially fatal.
Patients may present with a 'foreign body' feeling in the throat after eating fish ...
Ingested foreign bodies in children are common as the world is a curious place to young children, who will put anything and everything into their mouth, and will often inadvertently swallow.
The usual practice is for plain films of the chest/abdomen to identify a foreign body.
The inguinal canal is a passage in the anterior abdominal wall that transmits structures from the pelvis to the perineum formed by the fetal migration of the gonad from the abdomen into the labioscrotal folds.
The inguinal canal has an oblique course, is 4 cm in length and has tw...
Inguinal canal lipomas are a relatiely common but often under-recognised finding on abdominopelvic CT. They are also referred to as spermatic cord or round ligament lipomas.
They have no communication with the peritoneal fat. They are not considered as true tumours of fat but as ext...
Inguinal herniation is a type of abdominal wall hernia 1.
They are the commonest type abdominal wall herniation (up to 80% 3) and are most often acquired. There is recognised male predilection with a M:F ratio of up to 7:1 3.
It is broadly divided into two types:
Insulinomas are the most common sporadic endocrine tumour of the pancreas.
Account for 40% of syndromic pancreatic endocrine tumours. Overall incidence of ~0.0003%.
Typically insulinomas present with Whipple's triad consisting of:
fasting hypoglycemia (<50...
Internal hernias are protrusions of the viscera through the peritoneum or mesentery but remaining within the abdominal cavity.
Internal hernias have a low incidence of <1% and represent a relatively small amount of presentations, of ~5% 1.
The most common p...
Internal hernias due to gastric bypass surgery are more common after laparoscopic gastric bypass than after an open procedure.
It is a particularly sinister complication with variable, nonspecific clinical presentations. Most patients report a combination of postprandial...