Abdomen Flashcards
Level of obstruction can be either proximal or distal, in relation to what structure
Ampulla of Vater
Most common cause of congenital esophageal obstruction
Esophageal atresia
It is the result of abnormal development of the foregut early in gestation, which leads to discontinuity of the esophagus and frequently an associated fistulous connection between the esophagus and the trachea
Esophageal atresia
Most common subtype of esophageal atresia/TEF
Complete esophageal atresia with a blind-ending esophageal pouch and distal fistulous connection between the lower portion of the trachea and distal segment of esophagus
Occurs due to failure of the normal sequence of rotation of the bowel and mesentery during development
Malrotation
Ligament of treitz is normally fixed on what side
Left of midline, at similar level of duodenal bulb
Condition in which the base of the mesentery is relatively short and is thus prone to twisting (volvulus)
Malrotation
If VOLvulus occurs, the resulting obstruction is typically seen in the
3rd portion of the duodenum
VOL = 3
Midgut volvulus can be catastrophic as it involves the
Mesenteric vessels which can result to venous and arterial ischemia of bowel
Normally, the 3rd portion of duodenum in the AP view is seen on _______, and on the lateral view it is seen on ______
Cross midline to the left on AP view, located posteriorly just in front of the spine on the lateral view
In malrotation, the 3rd portion of duodenum appears
It does not cross the midline and extend anteriorly in the lateral view
In malrotation, the ligament of Treitz is located where
Right of midline or may be abnormally low
normally nasa left = edi ngayon nasa right
In malrotation, cecum is located where
Either in midline or high in the right upper quadrant
RLQ → RUQ
On ct/mri or ultrasound, the 3rd portion of duodenum in malrotation appears
Not passing between the SMA and aorta
Small bowel loops and colon in malrotation appears where
Small bowel loops primarily appear on the right side and colon on the left side
In malrotation, SMA appears where, and SMV is located where
SMA is in the right
SMV to the left
Normally, SMA and SMV are located where
Mimics position of aorta and IVC, SMA on the left and IVC on the right
The 3rd portion of duodenum in malrotation with volvulus appears as
Corkscrew appearance or beaking
Corrective procedure in malrotation with midgut volvulus
Ladd procedure
Etiology of duodenal atresia
During embryologic development, duodenal lumen undergoes occlusion due to normal cellular proliferation and subsequent recanalization. Failure to recanalize is results in duodenal atresia
DUOdenal atresia most commonly occurs on what part of the duodenum
Second
Treatment for duodenal atresia
Duodenoduodenostomy bypassing the atretic segment
Cause of obstruction of the 2nd portion of duodenum when there is abnormal rotation and fusion of the dorsal and ventral bud of pancreas, causing circumferential narrowing of duodenum due to extrinsic compression
Annular pancreas
Treatment for annular pancreas
Surgical bypass of the narrowed segment of duodenum
Caused by the redundancy of the duodenal mucosa which may result in a circumferential area of relative narrowing or a pouch-like structure (Windsock deformity) that can cause partial duodenal obstruction
Duodenal web
3 Treatment for duodenal web
Resection of redundant tissue,
bypass of involved segment, or
endoscopic balloon dilation
Appears as a wedge shaped mesenteric defect associated with the atretic segment of small bowel
Small bowel atresia
This finding indicates that there has been an in utero bowel perforation, with spillage of meconium into the peritoneal cavity, resulting in inflammation and resultant calcification (meconium peritonitis). Occasionally, a discrete peripherally calcified cystic mass called a meconium pseudocyst may be present
Peritoneal calcifications
In distal ileal atresia, colon appears
Small in caliber “microcolon” due to lack of contiguity of the GI tract in utero which prevents normal colonic development by obstructing the normal flow of intestinal secretions into the colon
If small bowel atresia is present in the more proximal jenunal or ileal segment, the appearance of the colon is
Normal
Treatment for bowel atresia
Surgical bypass or resection of the affected segment
Neonatal obstruction of the distal ileum by retained meconium is termed
Meconium ileus
Meconium ileus is strongly associated with
Cystic fibrosis
Meconium ileus is likely secondary to what pathophysiology
Abnormally viscous intestinal secretions and meconium, resulting in obstruction at the ileocecal valve
In contrast enema, it demonstrate diffuse microcolon, with contrast refluxing into a dilated terminal/distal ileum containing multiple filling defects representing the retained meconium
Meconium ileus
Why a hyperosmotic water-soluble contrast is the contrast of choice in the enema for suspected meconium ileus
It causes shift of water into the bowel lumen, loosening up the tenacious meconium and allowing it to pass through the colon
This condition, which is also called “functional immaturity of the colon” and “meconium plug syndrome” occurs in infants of diabetic mothers and in infants whose mothers received tocolytics during pregnancy
Small left colon
Treatment of small left colon
Contrast enema is both diagnostic and therapeutic
Why is colonic atresia less common than small bowel atresia
Due to redundant blood supply of colon
Atretic segment in colonic atresia is usually located where
Junction of the descending and sigmoid colon
Treatment of choice for colonic atresia
Surgical bypass or resection
Occurs due to lack of normal ganglion cells innervating the colon which leads to abnormal colonic peristalsis and varying degrees of obstruction. Rectum is always involved and extend of proximal involvement varies
Hirschsprung disease
Common symptom of Hirschsprung disease
Chronic refractory constipation
Diagnostic measure for Hirschsprung disease
Rectosigmoid ratio
In normal colon, rectum is smaller or larger in diameter than the more proximal colon?
Rectum is larger
In Hirschsprung, rectum is smaller or larger in caliber than the more proximal, unaffected colon?
Smaller or contracted
Additional finding in Hirschsprung that may also be helpful; it is caused by abnormal peristalsis and spasm
Irregular “sawtooth” appearance of the rectal wall on the lateral view
Rare form of Hirschsprung disease that involves the entire colon
Total colonic aganglionosis
Definitive diagnosis of Hirscsprung
Rectal suction biopsy
Caused by failure of normal development of the hindgut, resulting in a distal colonic obstruction
Imperforate anus/anorectal malformation
Associated with imperforate anus or anorectal malformations
Rectovesical or rectourethral fistula in boys and cloaca in girls
High or low anorectal malformations are related to what line
Pubococcygeal line
• The “M” line of Cremin has been utilized to determine the level at which the blind pouch ends on lateral radiographs (Fig. 51.24).
o This line is drawn perpendicular to the long axis of the ischia on lateral view and passes through the junction between the middle
and lower third of the ischia.
o If the blind pouch and fistula end above the line, the fistula is considered high
o If they end below the line, it is considered low
Skeletal abnormalities related to imperforate anus/anorectal malformation
Dysplasia/hypoplasia of sacrum
It is an allergic inflammatory condition that occurs in susceptible patients, often in patients with asthma and other forms of atopy. The resultant inflammatory response can cause esophageal dysmotility, focal strictures or diffuse esophageal narrowing
Eosinophilic esophagitis
Esophagram findings in eosinophilic esophagitis
Focal strictures which are typically located relatively high in the esophagus
Caused by abnormal hypertrophy of the pyloric muscle, resulting in gastric outlet obstruction
Hypertrophic pyloric stenosis
Exact etiology of hypertrophic pyloric stenosis is not known, but may be related to
Abnormal innervation or nitric oxide synthase activity leading to prolonged pylorospasm and ultimately hypertrophy of the muscle and gastric outlet obstruction
Imaging test of choice for HPS
Ultrasound
Diagnostic cut off measurements to diagnose HPS
Pyloric wall thickness of greater than 3mm, pyloric channel length of greater than 14 mm
True or false, diagnosis of HPS depends on the peristent abnormal morphology of the pylorus, not whether contents pass through the pylorus
True
Treatment of HPS
Pyloromyotomy
6 Commonly acquired cause of small bowel obstruction in children
AAIIMM
Adhesions, appendicitis, inguinal hernia, intussusception, midgut volvulus, meckel diverticulum
Aside from prior intra-abdominal infections or other inflammatory processes as a cause for having adhesions, what else can cause this condition
Those with omphalomesenteric duct remnant
Decreased mural enhancement, bowel wall thickening, pneumatosis, and extensive mesenteric edema/ascites are signs of
Bowel ischemia
One of the most common causes of bowel obstruction in a previously healthy older child
Perforated appendicitis
Relatively common cause of obstruction in infants under 6 months of age and are common in boys
Incarcerated inguinal hernia
This is caused by failure of the normal closure of processus vaginalis, resulting in persistent communication between peritoneal cavity and the scrotum
Indirect hernias
Common cause of obstruction after 6 months of age
Ileocolic intussusception
Why is the ileocolic segment prone to intussusceptions
Idiopathic, but likely related to reactive lymph nodes
4 Pathologic lead points of intussusceptions
Tumor,
polyps,
diverticula,
inflammatory bowel wall thickening (henoch-schonlein purpura)
Imaging signs that may say the intussusception may be difficult to reduce
Diminished blood flow due to venous ischemia and trapped fluid between the layers of the bowel wall
What are the common ultrasound findings in ileocolic intussusception
Mesenteric fat and lymph nodes
Most cases of intussusception are treated with
Fluoroscopic air enema reduction
Intraluminal pressure below ____ mmHg are maintained to prevent bowel perforation in fluoroscopic air enema reduction
Below 120 mmHg
Contraindications for air enema in treatment of intussusception
Pneumoperitoneum and peritoneal signs
Results from persistence of normal embryologic structure, vitelline duct. This results in varying degrees of abnormality from a fibrous band connecting the umbilicus to the distal ileum (omphalomesenteric band) to a true diverticulum
Meckel diverticulum
A true Meckel diverticulum usually arises from
Distal ileum, typically located approximately 2 ft from ileocecal valve
An inflammatory process of the small and large bowel seen in infants that were born prematurely, or in infants with a history of underlying congenital heart disease
Necrotizing enterocolitis
Presents usually in infants 2 weeks to 4 months, prolonged hospitalization, with nonspecific ileus, often with associated bowel wall thickening visible as separation of bowel loops and an elongated, tubular appearance of the bowel lumen. Associated with portal venous gas
Necrotizing enterocolitis
NEC is treated with surgical intervention or with percutaneous drain placement if the ff is present
Pneumoperitoneum
If perforation is not suspected, NEC is treated
Medically with bowel rest and antibiotics
At what age does appendicitis become common
2 years and above
Diameter of appendix for it to be considered dilated
More than 6 mm
IBD that causes transmural inflammation and can affect any portion of the GI tract from the mouth to the anus and can affect the skin of the perineum and perioral region. Younger patients present often with more extensive proximal small bowel disease affecting the jejunum, while older children typically present with involvement of the terminal ileum and/or colon
Crohn disease
One important association with UC is _____, which typically manifests as irregular biliary dilation with beading of the bile ducts, representing areas of alternation strictures and dilation
Increased frequency of sclerosing cholangitis
2 Imaging modalities of choice when evaluating known or suspected CD
CT enterography and MR enterography
IBD that presents as discontinuous involvement, with intervening bowel between inflamed segments. Other findings include fibrofatty proliferation, engorgement of vasa recta, ulceration of bowel wall and localized bowel wall thinning (pseudosacculation)
Crohn disease
Manifest as fixed luminal narrowing with upstream dilation (often over 3cm un diameter)
Strictures
Penetrating Crohn disease includes both (2)
Fistulae and sinus tracts
Connects two epithelialized surfaces
Fistulae
Does not connect two epithelialized surfaces and typically appears as a linear enhancement arising from the bowel wall, extending into the adjacent fat
Sinus
IBD that involves the colon in a contiguous fashion. The degree of wall thickening may be relatively mild compared to the crohn disease
Ulcerative colitis
In the setting of pancolitis, this condition may present with mild thickening and hyperenhancement of the terminal ileum due to reflux if inflammatory secretions from the cecum, termed “backwash ileitis”
Ulcerative colitis
Most common cause of neonatal cholestasis and is the result of an obliterative cholangiopathy in which the central intrahepatic bile duct and extrahepatic bile ducts become atretic due to a poorly understood inflammatory process
Biliary atresia
Patients present with jaundice and acholic stools at the time of birth or shortly thereafter
Biliary atresia
Treatment for biliary atresia
Kasai procedure or portoenterostomy, where a loop of bowel is brought up to the liver and anastomosed to the liver hilum, with resection of more distal bile ducts
In ultrasound, this condition shows a lack of a visible common hepatic duct. Instead there is a triangular echogenic tissue, the so-called “triangular cord” sign
Biliary atresia
What happens during hepatobiliary scintigraphy in patients with biliary atresia
There is uptake of the tracer but there is no biliary excretion into bowel on delayed post 24 hr images
Characterized by focal or diffuse dilation of intra-and/or extrahepatic bile ducts
Choledochal cysts
Most widely accepted theory for choledochal cysts
Anomalous pancreaticobiliary junction, with a common channel draining the common bile duct and pancreatic duct, which allows reflux of pancreatic enzymes into the common bile duct and causes inflammation and mural damage
Todani classification of choledochal cyst, with diffuse dilation of the extrahepatic bile ducts and is the most common
Type 1
Imaging modality of choice for choledochal cyst to fully characterize a suspected choledochal cyst and identify an anomalous pancreaticobiliary junction
MRI with MRCP
Todani type of choledochal cyst wherein there is saccular diverticulum from the common bile duct
Type 2
Todani type of choledochal cyst that presents as saccular dilation (choledochocele) that herniates into the duodenum
Type 3
Todani type of choledochal cyst that presents as fusiform dilation of both intra and extrahepatic bile ducts
Type 4
Treatment of choledochal cyst to improve biliary drainage and reduce the risk of development of cholangiocarcinoma in adulthood
Surgical resection
Caused by a congenital ductal plate malformation involving the intrahepatic bile ducts. The end result is cystic dilation of multiple intrahepatic biliary ducts. The extrahepatic bule ducts are typically normal
Caroli disease
In US, CT and MRI, Caroli disease will all present with a ______ which represents a portal vein branch completely surrounded by the dilated intrahepatic bile duct
Central dot sign
Other pathologies associated with Caroli disease
Other ciliopathies, including polycystic kidney disease
Reflects complete or segmental renal dysplasia as a result of abnormal development of the kidney. Postnatally, it can be diffusely or segmentally small, but can rarely be enlarged. Renal parenchyma will be replaced by multiple cysts of varying sized with little or no recognizable renal tissue
Multicystic dysplastic kidney
Multicystic dysplasia of kidneys can be differentiated with a very dilated collecting system by
Cysts of MCDK do not communicate
Bilateral MCDK is associated with these conditions
Oligohydramnios and its associated effects (Potter sequence: specific facies, pulmonary hypoplasia, clubbed feet)
Unilateral renal dysplasia is often asymptomatic and is generally associated with (3)
Compensatory hypertrophy of the contralateral kidney,
vesicoureteral reflux and
ureteropelvic junction obstruction
5 Imaging modalities of MCDK
Ultrasound for anatomy,
scintigraphy for function,
rule out abnormalities of the contralateral kidney (ultrasound, voiding cystourethrography or nuclear cystography)
Most common finding in collecting system duplication of any type is
Asymmetry in renal size (>1 cm)
What is the Weigert-Meyer rule in renal collecting system duplication
In a duplicated collecting system, the upper moeity collecting system is typically obstructed with ectopic insertion of the draining ureter which terminates in a ureterocele. The lower moeity ureter typically inserts orthotopically but allows VUR. Not all ureters in the context of collecting system duplication insert into the bladder
Imaging test of choice for identification of distant ectopic ureters and can assist in surgical planning
MRU and scintigraphy
Hydronephrosis that persist after birth suggests either collecting system obstruction, most commonly a
Ureteropelvic junction obstruction or VUR
Reflects incompetence of the ureterovesical junction, allowing retrograde flow of urine from the bladder into the ureters and up to the kidney
VUR
VUR is likely the result of
An abnormally perpendicular ureteral insertion angle, which allows the UVJ to remain open during bladder contraction and voiding
3 Goal of imaging in febrile urinary tract infection
Assess for anatomic abnormalities,
to document the presence of VUR, and
to assess for uncommon complications (renal abscess)
4 Primary imaging modalities utilized in the assessment of the child with febrile UTI are
Ultrasound,
voiding cystourethrography,
nuclear cystography and
potentially renal cortical scintigraphy
AP diameter of renal pelvis is measured on what plane and position
Transverse plain, preferably prone
Segmental or geographic areas of increased renal parenchymal echogenicity and decreased perfusion are imaging signs of
Pyelonephritis
Image of urethra during voiding in both boys and girls should be made in what position
Frontal for girls, oblique for boys
True or false: any retrograde flow of contrast into the ureters or renal collecting system during voiding cystourethrography is considered abnormal
True
Initial test of choice in boys with febrile UTI
Fluoroscopic VCUG
Acceptable as a first test in a girl with febrile UTI but otherwise is primarily used for follow-up of children with previously identified VUR in whom anatomic assessment is no longer necessary
Nuclear cystography
Important differential diagnosis in male infants and neonates with renal collecting system dilation
Posterior urethral valve
It is a thin membrane of tissue at the level of the prostatic urethra partially or completely obstructs the outflow of the urinary tract, leading to upstream dilation
Posterior urethral valves
Treatment of posterior urethral valve
Ablation and additional medical and surgical treatment due to extensive damage to the kidneys and bladder in utero
Posterior urethral valve is suspected in utero in a male baby presenting with (2)
Oligohydramnios and bilateral collecting system dilation
Two studies that are generally performed in the setting of suspected posterior urethral valves
Ultrasound and voiding cystourethrography
Occurs when there is inadequate fixation of the gonad, allowing the gonad to twist on its vascular pedicle. This twisting initially results in impaired venous drainage and progresses to compromised arterial flow as the number of twists increases
Gonadal torsion
Appearance of testicular torsion in ultrasound
Decreased or absent flow, larger, more heterogeneous, with associated swirling/twisting of the spermatic cord above the level of the testicle
True or false: assessment of blood flow is not as helpful in evaluating ovarian torsion
True
Appearance of a torsed ovary
Larger, increased heterogeneity and peripheral follicles
Suggested specific findings for ovarian torsion
Cutoffs of 20cc ovarian volume and a 15x size discrepancy from the other normal ovary
A tumor or neural crest origin, one of the most common abdominal tumors in children
Neuroblastoma
Most common site of origin of neuroblastoma, but tumors can arise anywhere along the sympathetic chain, from the skull base to pelvis
Adrenal gland
True or false: growth pattern of neuroblastoma is frequently more infiltrative than the other common abdominal tumor (wilms tumor), with tumors commonly encasing vessels and capable of invading adjacent solid organs and extending into the spinal canal
True
Assessment for metastatic neuroblastoma is via
Radioiodine (123I) labeled metaiodibenzylguanidine (MIBG) scanning
Most common primary renal mass in children. It arises from persistent immature metanephric blastemas which are embryologic precursors to normal renal tissue
Wilms tumor
Presence of these tissue that persists beyond 4 months of age increases the risk for development of Wilms tumor
Nephrogenic rests
Presence of extensive nephrogenic rests is termed
Nephroblastomatosis
Wilms typically presents in children of what age
1 and 6 years
Most common clinical presentation of wilms tumor
Palpable abdominal mass
Local spread of wilms tumor
Retroperitoneal lymph nodes and contiguous tumor extension into blood vessels, including renal vein and IVC
Most common solid renal mass in children under 6 months of age. It is a hamartomatous lesion that can appear identical to wilms tumor at imaging
Mesoblastic nephroma
Typically occurs in older children and is often associated with genetic translocations, most commonly the Xp11 translocation
Renal cell carcinoma
True or false: pediatric RCC typically presents with hematuria, abdominal pain, and occassionally a palpable abdominal mass. It is smaller in presentation than Wilms tumor
True
Pretext staging of hepatoblastoma: either left lateral or right posterior sections are involved
Pretext 1
Pretext staging of hepatoblastoma: either the right anterior or left medial sections are involved by tumor and half of the liver (entire right lobe or entire left lobe) will need ti be resected
Pretext 2
Pretext staging of hepatoblastoma: means either 3 adjacent sections are all involved by tumor or the right anterior and left medial sections are involved by tumor. Trisectionectomy will need to be performed
Pretext 3
Pretext staging of hepatoblastoma: either a large tumor involves all sections of the liver or multifocal tumor involves all sections
Pretext 4
Renal mass that occurs on the same age as Wilms tumor and appears identical to Wilms at imaging, with the exception that calcifications and bone metastasis are relatively more frequent
Clear cell sarcoma
Aggressive renal neoplasm with a poor prognosis that typically occurs in younger children. It manifests as a large, aggressive-appearung mass. Crescentic subcapsular fluid is characteristic but not always present
Rhabdoid tumor
Rhabdoid tumor is usually associated with
Synchronous brain tumors, often in posterior fossa
Aggressive renal neoplasm with a very poor prognosis that occurs in teenagers and young adults with sickle cell trait
Renal medullary carcinoma
Most common primary liver tumor in young children
Hepatoblastoma
Hepatoblastoma are common in what condition and age
Premature, 6 months to 4 years
Tumor marker elevated in hepatoblastoma
Serum alpha fetoprotein
Other than serum AFP, what else is elevated in the blood in patients with hepatoblastoma
Platelets as a paraneoplastic effect
Liver mass that appears as a large, heterogeneous mass, generally hypoenhancing relative to the normal liver. Areas of hemorrhage and dystrophic calcifications are common. Tumor also has propensity for vascular invasion, often into hepatic veins and IVC, but also into the portal vein
Hepatoblastoma
Treatment for hepatoblastoma
Neoadjuvant chemotherapy and subsequent surgical resection, liver transplant
Liver tumor that presents with loss of signal on out phase images indicating intracellular lipid, mild T2 hyperintensity and restricted diffusion. Arterially enhance and demonstrate venous phase washout.
Hepatocellular carcinoma
Appearance of HCC on mri using hepatocyte specific contrast agent
Hypoenhancing relative to the rest of the liver
4 Treatment for HCC
Chemotherapy and surgery,
liver transplantation,
percutaneous ablation or
transarterial chemoembolization (TACE)
Variant of HCC in older children and young adults. Tumors are often well circumscribed and have exuberant fibrosis, interspersed with parallel sheets of tumor cells. They do not produce or excrete AFP. Demonstrates a central fibrous scar
Fibrolamellar HCC
Common lymphoma in children
Non hodgkin lymphoma
More common location for non hodgkin lymphoma in children
Abdomen
Intestinal masses in this condition can present with intussusception, either outside of the typical age range or that recurs or fails to reduce
Lymphoma
Type of lymphoma that is highly FDG avid and thus 18F-FDG PET is typically used in staging and follow-up. Its doubling times can be short as 24 hours, meaning these masses can grow rapidly, causing acute symptoms
Burkitt lymphoma
Treatment for lymphoma
Chemotherapy with surgical resection reserved for tumors causing intestinal obstruction
One of the tumors in children that is known to spread to the peritoneum
Burkitt lymphoma
