ACUTE ABDOMEN IN OLDER CHILDREN. Carlos J. Sivit M.D.

ACUTE ABDOMEN IN OLDER CHILDREN Carlos J. Sivit M.D.

ACUTE ABDOMEN Clinical condition characterized by severe abdominal pain developing over several hours

ACUTE ABDOMINAL PAIN Common childhood complaint 4-5% office / ER visits Frequent associated symptoms fever, emesis, anorexia, sore throat Majority w/self limited disease uri, om, pharyngitis,, viral syndrome, gastroenteritis, constipation

ROLE OF IMAGING 1 o in patients w/confusing signs & symptoms or when surgery considered Diagnosing 1 o abnormality Characterizing disease extent Establishing alternative diagnosis

INTUSSUSCEPTION ACUTE APPENDICITIS SEGMENTAL OMENTAL INFARCTION MESENTERIC LYMPHADENOPATHY

INTUSSUSCEPTION

INTUSSUSCEPTION Most common early childhood emergency Peak incidence 5-9 mos 95% idiopathic (3( 3 mo - 3 yr) Most common type ileocolic

INTUSSUSCEPTION Pathologic lead points <3 mos or >3 yrs Enteric duplication Meckels diverticulum Intramural hematoma - Polyp - Lymphoma - CF

INTUSSUSCEPTION RADIOGRAPHY Low sensitivity & specificity Include supine & upright views Scrutinize for mass, sbo,, free air Cecal / t.i. visualization excludes ileocolic

INTUSSUSCEPTION US Primary exam for screening High sensitivity & specificity Graded compression technique

US FINDINGS PREDICTIVE OF REDUCTION Flow on Color Doppler Absence of trapped fluid Thin external hypoechoic rim

INTUSSUSCEPTION IMAGING INTERVENTION Fluoroscopic reduction Water soluble contrast, air, barium US guided reduction Tap water

INTUSSUSCEPTION ADVANTAGES OF AIR Decreased fluoroscopy times Less peritoneal contamination w/ perforation

INTUSSUSCEPTION ADVANTAGES OF LIQUID Proven track record Better contrast resolution Earlier visualization of perforation

INTUSSUSCEPTION Fluoroscopic reduction Immobilization Tight anal seal Contrast flow into distal ileum & disappearance of soft tissue mass 1% perforation rate

APPENDICITIS

APPENDICITIS Most common surgical emergency Difficult clinical diagnosis Many nonsurgical conditions mimic Classic constellation of periumbilical pain migrating to rlq,, n/v & fever in <1/3

CURRENT STATUS Great variability in utilization Limited consensus on best way US 1 o technique late 80 s-mid 90 s CT becoming 1 o modality

APPENDICITIS ADVANTAGES OF US Lower exam cost No preparation required Lack of ionizing radiation Accurately delineates adnexal disease

APPENDICITIS ADVANTAGES OF CT Higher diagnostic accuracy High accuracy in diagnosing perforated appendicitis Enhanced delineation of disease extent in perforated appendicitis Associated with improved outcomes

APPENDICITIS CT TECHNIQUE Targeted exam vs entire abdomen-pelvis No gi contrast vs oral vs rectal contrast No IV contrast vs IV contrast Multiplanar reformation ALARA

RECTAL CONTRAST Differentiate bowel from appendix Delineates cecal wall thickening Opacifies normal appendix

IV CONTRAST Easier identification of appendix Wall enhancement in appendicitis Abscess detection Alternative diagnoses

MULTIPLANAR REFORMATION Single breath hold scan of entire abdomen & pelvis at 1-22 mm collimation Similar spatial resolution for multiplanar reformations Provides increased confidence in diagnosis

APPENDICITIS CT FINDINGS - Enlarged appendix - Wall enhancement - Appendicolith - Cecal apical changes - Inflammatory rlq changes

ENLARGED APPENDIX Overlap between normal & abnormal < 6 mm normal 7-99 mm indeterminate > 9 mm - abnormal Increasing importance of other findings with indeterminate diameter May only involve distal appendix

DISTAL APPENDICITIS 10-15% of cases Inflammation more pronounced/localized distal end

CECAL APICAL THICKENING

ARROWHEAD SIGN Triangular shaped contrast collection 2 o cecal apical thickening

INFLAMMATORY CHANGES Periappendiceal fat stranding Thickening lateral conal fascia Ileocecal lymphadenopathy Thickening of contiguous structures

APPENDICOLITH Present in ~1/3 Within lumen, phlegmon or abscess Increased likelihood of perforation Lacks specificity

PERFORATED APPENDICITIS Focal fluid Phlegmon Appendiceal wall defect Extraluminal appendicolith Peritonitis

PERITONITIS Serious complication Early rupture prior to adhesion development More common in young Free fluid Enhancement/thickenin g along peritoneal reflections

ALARA Increased radiosensitivity & larger window for expressing damage Age/size specific protocols Low tube currents: 60-175 ma Low kvp: : 100-120 120 kvp Avoid repeat scanning

SEGMENTAL OMENTAL INFARCT

SEGMENTAL OMENTAL INFARCT 1 o form: anomaly of venous drainage involving right lateral segment Venous kinking 2 o patient position or post- prandial congestion may contribute 2 o form: hypercoagulable states, trauma, vasculitis

SEGMENTAL OMENTAL INFARCT Ovoid or cake like right-sided mass Anterolateral peritoneal cavity Mass effect on adjacent organs Complications include abscess & peritonitis

MESENTERIC LYMPHADENOPATHY

MESENTERIC LYMPHADENOPATHY Nodes located along ileal & jejunal arteries & SMV in folds of small bowel mesentery Extend from LUQ obliquely down to RLQ Most frequently noted in RLQ Oval shape Homogenous attenuation/echotexture echotexture

MESENTERIC LYMPHADENOPATHY Nonspecific finding Associated w/ variety of conditions Most commonly infectious or inflammatory May be associated w/appendicitis Mesenteric lymphadenitis is clinical syndrome associated w/acute abdomen

ACUTE ABDOMEN IN OLDER CHILDREN