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Postoperative Free Air and Fluid

KEY FACTS Terminology Presence of intraperitoneal or body wall gas/fluid following surgery Imaging Pneumoperitoneum is common imaging finding after surgery on both plain radiographs and CT CT has 2x sensitivity of plain films for detection of pneumoperitoneum Pneumoperitoneum is seen on CT in 87% of patients following uncomplicated laparotomy at 3 days post surgery and 50% of patients at 6 days No upper limit to normal…

Barotrauma

KEY FACTS Terminology Alveolar rupture caused by elevated transalveolar pressure during mechanical ventilation Imaging CT definitive test for presence & source of extraluminal gas Pleural spaces, mediastinum, subcutaneous, intra- and retroperitoneal, bowel wall Radiographic findings Pneumothorax – Radiolucent gas between visceral and parietal pleura – Inferiorly displaced costophrenic angle on supine films (deep sulcus sign) Pneumomediastinum – Radiolucent streaks outlining heart and trachea Pneumoperitoneum – Best…

Foreign Bodies

KEY FACTS Imaging Ingested foreign bodies Commonly affect children, developmentally challenged or psychiatric patients, and inebriated adults Most ingested foreign bodies traverse GI tract without problem: < 1% cause obstruction or perforation – Elongated or sharp objects may impact at point of intestinal narrowing or sharp angulation Foreign bodies vary in radiopacity and conspicuity on radiography vs. CT For most nonsharp foreign bodies, begin with visual inspection…

Eosinophilic Gastroenteritis and Esophagitis

KEY FACTS Terminology Inflammatory disease of GI tract characterized by tissue eosinophilia that can involve all layers of wall "Eosinophilic gastroenteritis" is misnomer; can affect any portion of GI tract Requires 4 criteria for diagnosis Presence of GI symptoms Biopsy proof of eosinophilic infiltration of 1 or more areas of GI tract Absence of eosinophilic involvement of multiple organs outside GI tract Absence of parasitic infestation…

HIV/AIDS

KEY FACTS Terminology Abdominal opportunistic infections and neoplasms resulting from HIV/AIDS-related immunodeficiency Imaging Liver and spleen Small hypodense nodules may be microabscesses Larger hypodense lesions might be infectious, but AIDS-related lymphoma should be considered Pneumocystis may result in tiny calcifications Biliary tree Cholangitis or acalculous cholecystitis caused by opportunistic infections Stomach, small bowel, and large bowel Wall thickening raises concern for opportunistic infection, which can involve…

Postoperative and Postprocedure Bowel Imaging

KEY FACTS Imaging Afferent loop (AL) syndrome AL becomes obstructed by adhesions, recurrent tumor, internal hernia, etc. CT is better than fluoroscopic studies for this diagnosis Colonoscopy and other endoscopic procedures Prevalence of complications is 1-2% CT shows perforation best and more safely Enterectomy and anastomosis Low rectal anastomoses are especially prone to ischemia, stricture, leak, and fistulas Small bowel anastomoses Side-to-side anastomosis may simulate obstruction…

Imaging of Bariatric Surgery

KEY FACTS Imaging CT and upper GI radiography have complementary roles Laparoscopic adjustable gastric banding (LAGB) procedure (a.k.a. "lap band") Less effective for sustained weight loss Complications: Less common and less varied May be too tight or too loose Band may erode into stomach or esophagus Sleeve gastrectomy (gastric sleeve) 75% of stomach is removed by dividing stomach along its long axis – Complications: Less or…

Iatrogenic Injury: Feeding Tubes

KEY FACTS Terminology Patient injury caused by improper feeding tube placement Feeding tubes Small, soft enteric tubes Some with flexible metallic tips Tip of feeding tube should be located beyond stomach (distal duodenum or jejunum) Nasogastric tubes Large bore, moderately stiff Used for temporary gastric and bowel decompression Tip placed in pylorus can cause outlet obstruction Gastrostomy and jejunostomy tubes Balloon-tipped catheters should not be placed…

Abdominal Abscess

KEY FACTS Terminology Localized abdominal collection of pus or infected fluid Imaging CT is imaging test of choice : Low density, loculated, encapsulated fluid collection with peripheral rim enhancement Simple fluid density (0-10 HU) or slightly hyperdense Internal gas in absence of intervention/drainage highly suspicious for infected collection "Abscess" suggests discrete, drainable fluid collection: Differentiate from ill-defined inflammation and fluid that is not drainable (i.e., phlegmon)…

Abdominal Trauma

KEY FACTS Imaging CT of chest, abdomen, and pelvis can be performed in < 1 minute of scan time Multiplanar, multiphasic CECT shows extent of bowel and solid visceral injuries and bleeding Evaluation of brain and spine injuries can be done quickly in the same setting "Sentinel clot": High density (> 60 HU); near the source of bleeding "Active extravasation": Isodense to enhanced arteries Active bleeding…

Jaundice

Overview Jaundice (icterus) is a condition characterized by yellow discoloration of the skin and mucus membranes resulting from deposition of bilirubin, a pigmented metabolite of heme. Jaundice is most commonly due to disorders of the liver or bile ducts, but precise diagnosis and management may be challenging. Patients may have isolated disorders of bilirubin metabolism (e.g., hemolysis, congenital or acquired errors of hepatocellular uptake or conjugation);…

Gastrointestinal (GI) Bleeding

Introduction Gastrointestinal bleeding (GIB) is a common clinical problem, the presentation of which may be acute or chronic. GIB is classified as arising from the upper (proximal to ligament of Treitz) or lower (distal to the ligament of Treitz) GI tract. Classically, acute upper GIB (UGIB) presents with overt hematemesis or melena, while acute lower GIB (LGIB) presents with hematochezia, although there is substantial overlap in…

Constipation

Clinical Classification of Functional Constipation Category Features Physiologic and Imaging Test Results Normal-transit constipation Incomplete evacuation; abdominal pain may be present but not predominant feature Normal; may show excessive stool in colon Slow-transit constipation Infrequent stools (e.g., ≤ 1/week), lack of urge to defecate, poor response to fiber and laxatives, generalized symptoms (e.g., malaise, fatigue); more prevalent in young women Delay in colonic transit [e.g., retention…

Diarrhea

Overview Diarrhea is a symptom experienced by nearly everyone, generally considered an increase in the volume, fluidity, &/or frequency of stools. Most episodes are transient and self-limited or self-treated with nonprescription medications. However, diarrhea may be persistent or complicated by pain, fever, rectal bleeding, or other factors that bring patients to medical attention. Chronic diarrhea may affect ~ 5% of people in industrialized countries, and acute…

Nausea and Vomiting

Overview Nausea and vomiting are experienced by almost everyone, and most episodes and causes are self-limited, rarely coming to medical attention. Patients are often aware of the common causes, such as acute viral infections, "traveler's" nausea and diarrhea, or the after effects of excessive alcohol consumption, and self-medicate or wait for the symptoms to pass. Other episodes are sufficiently severe or atypical that patients seek medical…