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36 Cards in this Set
- Front
- Back
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NEC
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-usually premature infants (under 1000 g), 1-3 wks after birth
-can occur in older infants under extreme stress (i.e. after cardiac sx) -mortality rate is 20-30% -idiopathic enterocolitis, likely related to infection and ischemia -Most commonly affects the ilium and right colon -abdominal distension, feeding intolerance, increased NG aspirates, and sepsis -tx is NPO, abx, and monitored by serial abdominal radiographs -Xray findings range from normal to suggestive to diagnostic -Suggestive findings include focal dilatation of bowel (esp RLQ), or featureless small bowel loops with separation of loops suggesting bowel wall thickening. An unchanging bowel gas pattern over time is worrisome. -Most definitive sign is pneumatosis. Can be similar to stool (stool is uncommon in sick, premature neonates) -Portal venous gas can occur -Free air is the only radiographic finding that is considered an absolute indication for surgery. -Where abdo is distended but relatively gassless, US can be useful: thickened bowel loops with increased or absent doppler flow is suggestive of inflamed or infarcted bowel. Large amount of free fluid is also a poor prognostic finding -Delayed complication is bowel stricture (most commonly in the left colon) |
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DDx high obstruction in neonates
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Midgut volvulus/malrotation or obstruction by Ladd bands
Duodenal atresia/stenosis Duodenal web Annular pancreas Jejunal atresia -Present with vomiting -Distension of stomach, duodenum, jejunum, or all 3 -Number of dilated bowel loops far less than with low obstruction -remember, can't tell large from small bowel in neonates! |
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DDx low obstruction in neonates
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Hirschspring disease
Meconium plug syndrome (small left colon syndrome) Ileal atresia Meconium ileus Anal atresia/anorectal malformations --dilatation of multiple bowel loops -the only proximal obstructive process that can have dilatation of multiple bowel loops is midgut volvulus with bowel dilatation secondary to ischemia or infarction. (very ill) -contrast enema is indicated. -in a patient without anal atresia on physical exam, dx is likely one of 4: hirschprung disease and meconium plug (colon) and ileal atresia and meconium ileus (ileum) -neonatal contrast enemas are typically performed using dilute ionic, water-soluble agents and a non-balloon tip catheter of appropriate size. (water soluble enemas can be therapeutic for meconium plugs or meconium ileus, but barium won't be) -Microcolon: narrow calibre colon secondary to disuse. Cause is likely to be ileal pathology! If contrast refluxes into a collapsed terminal ileum and the more proximal non-contrast filled bowel loops are disproportionately dilated, the diagnosis is likely to be ileal atresia. If the ti is distended and had multiple filling defects, likely to be meconium ileus. |
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Duodenal atresia, stenosis, web, and annular pancreas
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-all cause either complete or partial duodenal obstruction and usually present at birth or within the first few days of life.
-Often, components of more than one dx are present (i.e. duodenal atresia with annular pancreas, annular pancreas with intrinsic duodenal stenosis) -Duodenum is the most common site for intestinal atresia -Duodenal stenosis/atresia almost always occur in the region of the ampulla of vater -30% of cases of duodenal atresia are associated with T21. Other associations include other intestinal atresias, biliary abnormalities, CHD, and VATER (vertebral defects, imperforate anus, TEF, and radial and renal dysplasia) -duodenal atresia: dilated stomach and proximal duodenum with NO gas distal. Double bubble sign -Double bubble is diagnostic for duodenal atresia in the appropriate clinical setting, and UGI series is not needed! -How do you know this isn't a midgut volvulus? Dilatation of duodenal bulb only occurs with chronic things, not with acute obstruction. If not clear, an UGI can be performed. -Duodenal stenosis: the double bubble is seen PLUS distal bowel gas! -Duodenal web: obstructing membrane with pin sized hole in center. The web may stretch and form a wind-sock deformity. May present later in life than with atresia. |
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Malrotation and midgut volvulus
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-One of the few true emergencies in peds GI imaging
-both DJ and ileocolic portions of the bowel rotate 270 degrees about the axis of the SMA. Results in long mesentery and normal position of DJ and cecum. -If DJ and ileocecal junctions are not normal, small bowel mesentery may be short and predispose to twisting, resulting in a midgut volvulus. -malrotation: abnormal fixation of small bowel mesentery -midgut volvulus: abnormal twisting of small bowel around axis of SMA. Can result in obstruction, ischemia, or infarction -Ligament of trietz: where duodenum passes through transverse mesocolon and becomes jejunum. Also where bowel changes from retroperitoneal (duodenal) to intraperitoneal (jejunum). -Ladd bands: abnormal fibrous peritoneal bands that can occur in patients with malrotation. Potential cause of duodenal obstruction, in addition to volvulus! -Dx is made on UGI: DJJ is abnormally positioned. -DJJ is normal when: to left of spine AND at the same level or superior to the duodenal bulb. -NOT always straightforward -DJJ is mobile in children, can be moved by a lesion such as a mass or distended bowel loops. The presence of an NJ tube can also change the position! -over 90% of those who are malrotated will present in the first 3 mos of life!! -Midgut volvulus is seen on UGI as a corkscrew appearance of the duodenum and proximal jejunum or as duodenal obstruction. -Bilious vomiting and findings of malrotation, with or without findings of midgut volvulus, are a surgical emergency!!! -CT: bowel shows a swirling pattern around SMA -SMV (usually to right of SMA) is to the left of SMA -SMA is smaller and rounder, and surrounded by echogenic fat, compared with SMV. |
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Meconium ileus
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-occurs secondary to obstruction of the distal ileum due to accumulation of abnormally tenaceous meconium.
-exclusively in CF! -presenting finding of CF in 10% -may be complicated by perforation, volvulus of the bowel involved, or meconium peritonitis -distal obstruction on xrays, may see bubblelike lucencies due to accumulated meconium or calcification if perforation occurred. -serial water soluble contrast enemas are commonly used to remove obstruction |
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Distal obstruction: if colon is distended on contrast enema
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Hirschprung disease
Meconium plug syndrome |
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Hirschprung disease
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-absence of ganglion cells that innervate the colon
-denervated colon spasms and causes a functional obstruction -affected portions of colon are small in calibre, and the more proximal normal colon is dilated secondary to the obstruction -the rectum and a variable amount of more proximal colon are affected in a contiguous fashion; there are no skip lesions!! -90% present in the neonatal period with failure to pass meconium -but, can present later in life with constipation problems -much more common in boys (4:1), and associated with T21 (5% of cases) -enema: must obtain early filling views including rectum and sigmoid colon in lateral and frontal position! -hirschprung: transition zone from an abnormally small rectum and distal colon to a dilated proximal colon! -n patient: rectum has largest luminal diameter of the left sided colon -when the rectum alone is involved, the sigmoid has a larger diameter (abnormal rectosigmoid ratio). -fasciculations or sawtooth irregularity of the denervated segment -if the entire colon is involved (rare), may mimic a microcolon -can present with a colitis -in ill patients, a contrast enema should be avoided -definitive dx is rectal bx -tx is surgical resection of the denervated segment -transition point does NOT always accurately predict real transition of pathology |
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DDx excessive vomiting in infants
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Hypertrophic pyloric stenosis (5:1 m:f, 1 week - 3 mos)
GERD congenital stenosis lactobezoar midgut volvulus |
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DDx Intestinal obstruction in older children: AAIIMM
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Adhesions
Appendicitis (perforated) Intussusception Incarcerated inguinal hernia Malrotation with volvulus Meckel Diverticulum |
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Plain film findings of appendicitis
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-Appendicolith (5-10%)
-air/fluid levels in the RLQ -splinting -loss of psoas margin Perforated: -small bowel obstruction -RLQ extraluminal gas -displacement of bowel loops from the RLQ -free air is extremely uncommon secondary to appendicitis |
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Intusussception
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-90% in children is idiopathic ileocolic intusussception
-3 mos to 1 year (mean age 8 mos) -almost all cases occur before age 3 yrs -If the child is older than 3 yrs, a pathologic lead point should be suspected radiographs: -paucity of gas in the right abdomen -absence of an air filled cecum or ascending colon -meniscus of a soft tissue mass typically within the ascending or transverse colon -small bowel obstruction -if air-fluid levels are seen within the distal colon, intussusception is unlikely and viral gastroenteritis is more likely US -trans: doughnut -sag: pseudokidney -must perform US in all 4 abdominal quadrants because the intussusception can travel -small bowel/small bowel intussusceptions are often seen incidentally on ultrasound or CT and are a normal, transient phenomenon -but, pathologic causes include lymphoma, meckel diverticulum, duplication cyst, henoch-schonlein purpura. -findings that help to differentiate pathologic from incidental intussusception include: -transient presence -lack of associated small bowel obstruction -length less than 3.5 cm |
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Image guided reduction of intussusception
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-air reduction: (can also use contrast enema, and hydrostatic reduction with ultrasound guidance)
-MUST have adequate hydration with IV fluids -a working IV -abdominal exam by an experience physician -consultation with pediatric gen surg service -members of sx service must at least know that the reduction is being attempted -Contraindications are: peritonitis or free air!!!!!!! -findings associated with decreased success rate: small bowel obstruction, long duration of sx (over 24 hrs), and lethargy -need adequate rectal seal -pressure should not exceed 120 mmHg when child is at rest -intussusception looks like a mass, it moves retrograde to the level of the ileocecal valve -criteria for successful reduction: resolution of the soft tissue mass and reflux of gas into the small bowel -overall success rates for reduction enemas are 70-90% -risk of perforation is less than 0.5% -risk of recurrent intussception is 5-10%, most occurring within 72 hours after the reduction -recurrence can be treated with repeated reduction enemas up to a recommended three times. |
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Meckel Diverticulum
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-omphalomesenteric duct
-can be associated with bleeding, focal inflammation, perforation, or intussusception -bleeding is the most common complication and occurs secondary to the presence of ectopic gastric mucosa -most do not contain ectopic gastric mucosa, but those associated with bleeding do -the imaging modality of choice to detect a bleeding Meckel diverticula is nuclear scintigraphy with Tc99m pertechnetate |
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gastrointestinal duplication cysts
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-round, attached to the GI tract, and do not communicate with the lumen
-most common locations are the terminal ileum and distal esophagus -most likely to be present during the first year of life -can obstruct, even ulcerate and perforate -cystic mass with bowel wall signature -less commonly, can appear tubular rather than round and can communicate with the gastrointestinal lumen |
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ingested foreign bodies
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-once it passes the esophagus, likely to pass and repeat radiographs are not necessary unless signs of obstruction of peritonitis develop
-most common location to get stuck is the proximal esophagus at the thoracic inlet -chronic esophageal foreign bodies can result in complications such as TEF -can also cause inflammatory mass and lead to compression of the trachea -lodged esophageal foreign bodies can also be a sign of underlying pathology such as stricture or ring. -foreign bodies that deserve special attention: 1. zinc pennies: if retained in the stomach, can corrode and react with the HCL in the stomach to create gastric ulcerations. Radiographs may show irregular coin margins and radiolucent holes in the coins. If patient is symptomatic and coin is retained in stomach, removal endoscopically is indicated. 2. multiple magnets: can become attracted to each other across the small bowel walls, leading to ischemia, necrosis, obstruction, and perforation. It is a surgical emergency when identified! 3. button batteries: disc shaped batteries. Can cause caustic injury to the mucosa, esp when lodged in the esophagus. Shape is slightly different than a coin!! On the lateral view, the edge is bevelled with the central part wider than the edges. On a frontal view, the periphery may appear to have two circular edges. May also develop corrosive holes if present for some time. Should be communicated immediately to allow for removal!!! |
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Mesenteric abnormalities
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Diffuse:
-Edema -Hemorrhage -Inflammation Focal masses: -Lymphoma -Mesenteric cysts (= lymphatic malformations) -desmoids -teratomas -lipomas Multifocal mesenteric masses: -most commonly represent lymphadenopathy -mesenteric lymph nodes are considered abnormal if over 5 mm in diameter -malignant or inflammatory processes -Malignant: lymphoma (usually NHL), lymphoproliferative disorders, and metastatic disease -infectious: TB, cat scratch disease, or fungal infection. Central low attenuation with peripheral enhancement favours an inflammatory over a neoplastic cause (characteristic of TB) -with TB, the mesenteric lymphadenopathy is more pronounced compared with retroperitoneal lymphadenopathy -mesenteric adenitis: benign inflammation of the mesenteric lymph nodes, sometimes associated with enteritis. Present with nausea, vomiting, rlq pain, diarrhea, fever, leukocytosis. Enlarged and clustered ln's in the bowel mesentery just anterior to the psoas muscle (78%), the small bowel mesentery(56%), or ileal wall thickening (33%) and inflammatory changes in the mesentery |
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Neonatal jaundice
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-jaundice that persists beyond 4 weeks is due to biliary atresia or neonatal hepatitis in 90% of cases. Or, less likely choledochal cyst.
-Must identify children with biliary atresia prior to 3 mos of age, because they can benefit from early surgical intervention. -both entities have similar clinical, laboratory, and pathologic findings. -biliary atresia: congenital obstruction of the biliary system with bile duct proliferation intrahepatically and focal or total absence of the extrahepatic bile ducts. Cirrhosis will develop without sx. Association with abdominal heterotaxy syndromes and trisomy 18. -ultrasound is first test in neonate with jaundice: look for biliary dilatation due to choledochal cyst or other causes of obstruction -Absence of a visualized gallbladder is suggestive of biliary atresia, although 20% of normal pts have small or barely visible gb's. -normal or enlarged gb is supportive of neonatal hepatitis. -visualization of a triangular echogenic structure adjacent to the main portal vein is the triangular cord sign, is the remnant of the cbd in biliary atresia. -the hepatic parenchyma and intrahepatic bile ducts usually appear normal in patients with neonatal hepatitis and biliary atresia! -hepatobiliary scintigraphy with 99m technetium-IDA derivatives is the test to differentiate. -administered after pretreatment with phenobarbital! -normally, radiopharmaceutical uptake and clearance by hepatocytes exceeds cardiac blood pool tracer activity and can be visualized within the biliary tree and intestines 15 mins after administration. -neonatal hepatitis: delayed uptake of radiotracer by hepatocytes, slow clearance of blood pool radiotracer, but eventual radiotracer excretion into the intestines. -biliary atresia: radiotracer uptake and clearance by hepatocytes are adequate, with prominent low activity identified, but the tracer never reaches the gi tract, even on 24 hour delayed imaging. -choledochal cyst: presents with jaundice, abdominal mass, or abdominal pain. US shows a cystic mass in the region of the porta hepatis that is separate from the gb. The presence of a dilated cbd or cystic duct or visualization of the hepatic duct directly emptying into the cystic mass confirms the dx. If there is a nonspecific cyst in the region of the porta hepatis, hepatobiliary scintigraphy can be used to demonstrate radiotracer accumulation within the cyst, confirming the dx. |
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Liver masses (general)
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-Primary hepatic neoplasms are third most common peds malignancy, after Wilms and neuroblastoma (but only 0.5% of all pediatric malignancies).
-there are no pathognomonic imaging features for hepatic malignancies. Imaging to determine extent and for preop planning. Complete tumor resection or tx is usually essential for cure. -A mass must be confined to the left or right lobe, or the right lobe plus the medial segment of the left lobe to be considered resectable. -If a lesion is not resectable initially, chemo +/- radiation and then reimaged. |
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Liver masses: age under 5 yrs
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Hepatoblastoma (+ AFP)
Hemangoendothelioma (elevated AFP in less than 3% of lesions) Mesenchymal hamartoma Mets (Wilms, Neuroblastoma) |
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Liver masses: age greater than 5 yrs
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HCC (+ AFP)
Undifferentiated embryonal sarcoma Hepatic adenoma Hemangioma Megs |
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Nonneoplastic causes of liver masses
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Abscesses (fungal, bacterial, or granulomatous)
Hematomas |
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Multiple liver masses
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Mets
Abscesses Cat scratch disease Lymphoproliferative disorder Hepatic adenomas associated with a predisposing syndrome (Gaucher disease, fanconi anemia) |
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Liver masses in immunocompromised children
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Lymphoproliferative disorder
Fungal infection |
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Hepatoblastoma
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-Most common primary liver tumor of childhool (43% of total liver masses)
-Primarily less than 3 yrs -Predisposing conditions: Beckwith-Wiedemann syndrome, hemihypertrophy, familial polyposis coli, Gardner syndroma, Wilms tumor, and biliary atresia. -AFP levels elevated in more than 90% -Usually well defined and have a tendency to displace rather than invade adjacent structures such as the falciform ligament. May be heterogeneous due to necrosis or hemorrhage -Overall survival rate is 60-70% |
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Infantile hemangoendothelioma
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-The most common symptomatic vascular lesion of infancy
-abdominal mass associated with either high output cardiac failure, consumptive coagulopathy (thrombocytopenia), or hemorrhage -85% present by 6 mos of age -Well defined or diffuse -Usually heterogeneous, typically enhance (may look like hemangioma), may be prominent vessels within the lesions. -The descending aorta superior to the hepatic branches of the celiac artery may appear abnormally enlarged compared to the infrahepatic aorta due to differential flow!! -Hemangoendotheliomas tend to involute without therapy over mos to yrs! Sequential US often used to follow lesions and usually demonstrate a progressive decrease in size and increase in the degree of calcification. |
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Mesenchymal hamartoma
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-very rare, benign, predominantly cystic liver mass
-usually presents before 2 yrs of age -considered a developmental anomaly rather than a true neoplasm -Usually present with a large, painless abdominal mass and a normal serum AFP. -Large, multilocular, cystic asses withi thin internal septation -Occasionally, the solid component can be more predominant, with multiple smaller cysts giving the lesion the appearance of swiss cheese |
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Most sensitive finding of pancreatic trauma
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Fluid between the splenic vein and pancreas
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Hypoperfusion complex
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= "shock bowel"
-abnormal intense enhancement of the bowel wall, mesentery, adrenal glands, liver, kidneys, and pancreas -intense enhancement and decreased caliber of the IVC and aorta -diffusely dilated, fluid filled bowel loops These appearances on CT are identified prior to the clinical findings of shock and is associated with the potential development of hemodynamic instability -The bowel findings should not be confused with the focal dilatation and bowel wall thickening or enhancement more typical of bowel injury. |
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Causes of immunocompromise in children
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Therapy for malignancy
Bone marrow transplantation Solid organ transplantation Primary immunodeficiency HIV -Can have many types of problems including those related to immunodeficiency (infection), thrombocytopenia (bleeding), other therapy related complications (mucositis, radiation injury), development of secondary neoplasm, recurrence of primary neoplasm, and normal childhood illnesses that are unrelated to the oncologic problems. -intra abdominal abscesses (drainable) are uncommon in immunocompromised children -When intraabdominal abscesses are present, they are often related to systemic fungal infection i.e. candida or aspergillus (multiple small, low atten lesions in liver, spleen, or kidneys) |
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Pseudomembranous colitis
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-immunocompromised pts commonly receive abx
-diffuse colonic involvement (pancolitis) -marked colonic wall thickening (average 15 mm), greater in degree than seen in other types of colitis -Accordion sign (contrast material insinuates between the pseudomembranes and swollen haustra -involves the mucosa and submucosa mostly, so the degree of inflammatory change in the pericolonic fat is often disproportionately subtle compared to the degree of colonic wall thickening! |
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Neutropenic colitis (typhlitis)
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-life threatening right sided colitis
-associated with severe neutropenia -bowel wall thickening, pericolonic fluid, and inflammation of pericolonic fat -usually isolated to the cecum and ascending colon -adjacent terminal ileum may also appear abnormal |
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Graft versus Host disease
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-Acute GVHD is specific to bone marrow transplantation
-diffuse destruction of mucosal throughout the large and small bowel -CT: diffuse enterocolitis from the duodenum to the rectum -bowel wall thickening may be mild, isolated to the small bowel, or absent -more commonly, there is abnormal bowel wall enhancement in a central, mucosal location. -Both small and large bowel are usually dilated and filled with fluid -Often prominent infiltration of the mesenteric fat and soft tissue attenuation |
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Mucositis
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-gut mucosal damage due to chemotherapy agents
-ileus pattern on abdominal radiographs -CT: dilated, fluid filled loops of small and large bowel -May be mild associated small bowel wall enhancement -Marked bowel wall thickening, predominance of colonic involvement, and marked abdominal inflammatory changes suggest other diagnoses -treatment is supportive |
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Lymphoproliferative disorder
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-lymphoma-like diseases related to EBV in an immunocompromised host
-usually after solid organ transplantation -spectrum of imaging findings including focal parenchymal mass, diffuse lymphadenopathy, mesenteric mass, bowel wall thickening, and associated aneurysmal dilatation of the small bowel lumen -as opposed to lymphoma, which more often manifests as abdominal lymphadenopathy, lymphoproliferative disorder usually manifests with parenchymal organ involvement (most commonly the liver). -in solid organ transplants, the distribution of disease tends to occur in the vicinity of the transplant organ -tx is reduction of immunosuppressive therapy, and chemotherapy |
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Complications related to cystic fibrosis
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-meconium ileus
-Older children/adults: distal intestinal obstruction syndrome, also known as meconium ileus equivalent (obstruction secondary to inspissated, tenacious intestinal contents). X-rays: abundant stool within the right colon and distal small bowel and findings of obstruction. Contrast enemas with gastrograffin may work. -BUT, can get pseudomembranous colitis (don't have diarrhea like normal pts)....so if see colonic wall thickening, do NOT do enema. -colonic thickening or stricture resulting from iatrogenic damage caused by pancreatic enzyme replacement therapy -cirrhosis -portal hypertension and varices -gallstones -pancreatic atrophy -fatty replacement of the pancreas - |
