The standard plain x-ray of abdomen are supine AP and erect AP views. If the patient cannot stand, a lateral decubitus view may be taken. In the plain film of the abdomen, identify and look for the following:
1. The lateral border of psoas muscle may be hazy in retroperitoneal abnormalities.
2. Sub-diaphragmatic areas may contain gas due to rupture of an abdominal viscous (Figure 58). An air–fluid level can be appreciated in case of an abscess.
3. The diaphragm may also be raised due to absorption collapse of the lung or from push from the abdomen as with enlarged liver (liver abscess), or gross splenomegaly. It may also be seen with weakness of the diaphragmatic muscle (eventration of the diaphragm).
4. Renal outline may be enlarged in hydronephrosis.
5. Ureteric and urinary bladder areas may demonstrate calcific areas due to stones. Calcification is seen with stones in the gallbladder and urinary tract. Phleboliths, fecoliths, mesenteric lymph nodes, blood vessels, adrenal glands (TB), uterus (fibroids), liver, spleen, and pancreas may also demonstrate calcific areas.
7. Dilatation and fluid levels may be seen in obstruction of the large and small bowel (Figure 60). In toxic dilatation of the colon, as in ulcerative colitis, Crohn’s disease, or severe diarrhea, the transverse colonic diameter is more than 6 cm (Figure 68).
8. Spine and sacroiliac joints may also demonstrate abnormalities on a plain x-ray of the abdomen.
Barium swallow is done to detect esophageal pathologies like esophageal stricture (smooth outline), carcinoma (irregular margin with overhanging edges), and motility disorders (producing a corkscrew appearance). In achalasia, the proximal part is markedly dilated with distal tapering (Figure 52 in Volume I). At times, there may be indentation of the esophageal outline, for example, along the upper margin in aortic dilatation and along the middle in left atrial enlargement.
1. Irregular filling defect.
2. Irregular edges.
3. Location at the antrum or greater curvature is more commonly malignant.
4. The mucosal folds do not reach the edge of the ulcer in malignancy.
5. Linitis plastica (infiltrating adenocarcinoma in Figure 61).
Carcinoma of the colon may present with an obstructing mass with shouldering sign (overhanging edges) and irregular pattern (Figure 62 and page 121, Volume I). The diagnosis is established on colonoscopy and biopsy (Figure 101).
Ulcerative colitis is characterized by uninterrupted inflammation and ulceration of the colon. These continuous lesions especially involve the rectum. The ulcers are usually shallow, with granularity of the wall, loss of haustrations, and hosepipe-like colon on barium study, in later stages (Figure 63). The colon may be narrowed and shortened. Pseudopolyps are swollen mucosa between areas of ulcerations that project into the lumen (Figure 63). Also see endoscopic features in Figure 99 in the endoscopy section and details on page 108, Volume I.
Crohn’s disease is associated with transmural inflammation, fibrosis, narrowing, producing skip lesions (normal intervening bowel). Sinus tracts, micro-perforations, and fistula may be seen. It classically involves the terminal ileum, but may involve any part of the gut. About 20 percent have disease limited to the colon and one-third have perianal disease (skin tags, fissure, abscess, and fistula). Fatigue, chronic diarrhea, crampy abdominal pain, weight loss, and fever, with or without overt bleeding (uncommon), are the hallmarks of Crohn’s disease. The major signs are stricture and mucosal lesions. Strictures are of variable length and are responsible for the string sign (Figure 64). Fine ulcerations produce a cobblestone appearance. Rose thorn ulcers are characteristic. Thickening of the bowel wall and inflammation produce displacement of the bowel. Malabsorption may be present. Extraintestinal manifestations include eye, skin, joint involvement. Also see endoscopic features in Figure 88 in the endoscopy section and page 108, Volume I for details.
Lymph node biopsy and MBTB PCR may be necessary to make a definitive diagnosis.
Esophageal varices are best seen on endoscopy (Figure 87) when they can be counted and graded according to the size in relation to the lumen of the esophagus. They are characteristically seen in chronic liver disease with portal hypertension. Any other cause is rare. A barium esophagogram with varices is shown in Figure 65 and page 66, Volume I for details.
Intestinal tuberculosis (tuberculous enteritis) classically affects the terminal ileum and may be indistinguishable from Crohn’s disease. The lesions can be ulcerative, hyperplastic, or a combination. The caecum exhibits irritability, causing the barium to rush off. Intestinal tuberculosis (TB) may also take the form of ascites, lymphadenopathy, or miliary dissemination. It is important to remember that the terminal ileum is involved classically in both TB and Crohn’s disease, which even might look similar on endoscopy. Colonoscopy and biopsy of the area should, therefore, be done and stained for acid-fast bacteria, culture, and PCR for mycobacteria done. Lymphoma and malignancy need to be excluded. A missed diagnosis of Crohn’s disease and use of steroids in TB may be disastrous. Also see page 134 in Volume I for workup of tuberculosis.
Short bowel syndrome usually occurs when less than 120 cm of small bowel remains functional. It may be associated with GI operations (cancer, mesenteric vascular disease, inflammatory bowel disease, bariatric surgery, strangulated hernia, bowel injury, volvulus, and radiation or may be congenital) (Figure 66).
• Watery diarrhea due to loss of small intestinal surface and bacterial over growth and electrolyte disturbance with metabolic acidosis.
• May require parenteral nutrition, which may be associated with sepsis, liver disease, gallbladder disease, and nephrolithiasis.