Differentials
Common
Constipation
poor diet and fluid intake; hx of cerebral palsy, mental retardation, or spinal cord problems; psychological factors (e.g., depression, abuse, ADHD, autism, oppositional disorder), weaning, toilet training, start of schooling or other causes of stress may be present; vague abdominal pain, painful defecation (infants may extend their legs and squeeze anal and buttock muscles to prevent stooling; toddlers often rise up on their toes, shift back and forth, and stiffen their legs and buttocks), fecal incontinence; medication with known constipating agents (e.g., iron supplements); obesity, low birth weight
exam findings may be minimal (mild abdominal tenderness, stool in rectum); abdominal distension in severe cases or in small children; fecal mass palpable on abdominal or rectal exam; absence of peritonitis (guarding or rebound tenderness); sacral dimples or pits and/or tags/tufts indicative of spinal cord abnormality (i.e., spina bifida); anal fissure, hemorrhoids (rare in children; may be mistaken for skin tags from Crohn disease); imperforate anus or anal stenosis; evidence of depression, abuse, autism, ADHD, or oppositional disorder
- abdominal x-ray:
stool visible throughout colon
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- CT scan abdomen:
stool throughout colon; absence of other etiologies of abdominal pain
Acute appendicitis
hx of sharp or stabbing periumbilical pain that migrates to the RLQ; anorexia, fever, vomiting, and/or diarrhea may be present; occurs in all age groups but is rare in infants
patient lies still, tries not to move (especially in severe cases with significant peritoneal irritation); positive McBurney sign (RLQ pain and tenderness to palpation at a point two-thirds along a line from the umbilicus to the anterior superior iliac spine); positive Rovsing sign (pain in the RLQ in response to left-sided palpation, suggesting peritoneal irritation); positive psoas sign (pain in the RLQ when child placed on left side and right hip gently hyperextended, suggesting irritation to the psoas fascia and muscle); positive obturator sign (RLQ pain on internal rotation of the flexed right thigh); rectal tenderness and/or palpable abscess in RLQ
- abdominal ultrasound:
dilated appendix, free fluid; appendicolith may be present
More - CT scan abdomen and pelvis:
dilated appendix, free fluid, mesenteric stranding, or appendicolith; abscess or phlegmon consistent with perforated appendicitis
More - MRI scan abdomen and pelvis:
dilated appendix; hyperintensity of the luminal contents of the appendix, periappendiceal tissue and thickened wall
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Gastroenteritis
vague abdominal pain with nausea and vomiting; diarrhea with or without mucus in stool; recent travel or contact with sick individual(s) or ingestion of suspected food and drink; >10 days suggests parasitic or noninfectious cause; fever, chills, myalgia, rhinorrhea, upper respiratory symptoms
diffuse abdominal pain without evidence of peritonitis (no guarding or rebound tenderness); abdominal distension; hyperactive bowel sounds; mucus in stool (bacterial or parasitic); signs of volume depletion (tachycardia, hypotension, dry mucous membranes, poor capillary refill, sunken fontanelle in infants); low-grade fever, lethargy and/or irritability, reduced response to noxious stimuli, abnormal temperature (elevated or low)
- serum electrolytes:
normal or low sodium and potassium
- stool microscopy and culture:
fecal leukocytes; ova or parasites; culture positive for infectious agent in bacterial gastroenteritis
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- BUN and creatinine:
normal; may have evidence of renal failure in patients with hemolytic uremic syndrome
- urine dipstick:
may detect presence of albumin or blood in hemolytic uremic syndrome
- CBC:
variable
More - blood culture:
may be positive for infectious agent in presence of sepsis
More - endoscopy with biopsy:
variable
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Urinary tract infection
neonates and infants: fever, vomiting, lethargy, irritability, and poor feeding; older children: dysuria, urinary frequency and urgency, back pain if pyelonephritis
variable; fever >102.2°F (39°C); suprapubic and/or costovertebral angle tenderness; irritability; foul-smelling urine; gross hematuria
- renal ultrasound:
abnormalities may be present such as dilatation of the renal pelvis or ureters, or distension of thick-walled bladder; renal abscess: area of radiolucency to the renal parenchyma with local hypoperfusion on color Doppler; perinephric abscess: hypoechoic fluid
More - voiding cystourethrogram (VCUG):
if vesicoureteral reflux is present: contrast seen ascending out of the bladder into the upper urinary tract
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Abdominal trauma (blunt or penetrating)
hx of trauma; abdominal pain may be out of proportion to exam findings; may have multiple complaints; hx may suggest child abuse or nonaccidental trauma (e.g., inconsistent or changing history)
abdominal tenderness; skin marks reflecting mechanism of injury (e.g., seatbelt mark); referred left shoulder pain (due to splenic injury); blood at the urethral meatus, or hematuria (indicate urinary tract or kidney injury); signs of nonaccidental trauma may be present (e.g., cigarette burns, subdural hemorrhages in an infant/young toddler)
Cholelithiasis/cholecystitis
recurrent, episodic RUQ pain, may radiate to the back and is classically colicky in nature; often occurs after eating, particularly fatty foods; nausea, vomiting, and anorexia may be present; persistent pain and fever may signify acute cholecystitis; referred pain to right shoulder can occur; presence of risk factors (e.g., sickle cell disease, cystic fibrosis)
right subcostal region tenderness; positive Murphy sign (during palpation, deep inspiration causes pain to suddenly become worse and produces inspiratory arrest); palpable distended, tender gallbladder; fever suggests acute cholecystitis; jaundice rare
Primary dysmenorrhea
hx of recurrent crampy abdominal pain associated with menstruation
lower abdominal tenderness; normal pelvic exam
- none:
diagnosis is clinical
- CT scan abdomen/pelvis:
normal; however, useful to rule out other diagnoses
- abdominal/pelvic ultrasound:
normal; however, useful to rule out other diagnoses
Pneumonia
cough; purulent sputum production; upper respiratory tract symptoms (rhinorrhea, sore throat, nasal congestion), shortness of breath, fever, and chills; splinting secondary to pain; vomiting, diarrhea, anorexia
tachypnea, cyanosis, decreased breath sounds, crackles/rales on auscultation, dullness on percussion; abdominal tenderness and distension without guarding or rebound
- CBC:
variable
More - chest x-ray:
infiltration, consolidation, effusion
- sputum culture:
growth of infecting organism
Functional abdominal pain
hx may be acute, chronic, or cyclic (frequently girls ages 8-12 years), complaint of vague, persistent, central abdominal pain common, may be associated nausea and vomiting, particularly in chronic cases; FHx of functional disorders common (e.g., irritable bowel syndrome, anxiety, psychiatric disorders, and migraine); Rome IV criteria use symptoms for diagnosis [27]
periumbilical tenderness, abdomen is soft, undistended, no guarding or rebound tenderness; exam of other systems normal
- none:
diagnosis is clinical after exclusion of possible organic causes
- CBC:
normal
- ESR:
normal
- urinalysis:
normal
- stool microscopy:
normal
Uncommon
Intussusception
usually infant between 3 and 12 months of age presenting with colicky abdominal pain, flexing of the legs, fever, lethargy, and vomiting; Henoch-Schonlein purpura (HSP) may be initiating factor in an older child (usually <11 years of age); vague abdominal complaints; severe, cramp-like abdominal pain; child may be inconsolable
may see gross or occult blood that may be mixed with mucus and have "redcurrant jelly" appearance, abdominal tenderness, and palpable abdominal mass; signs of HSP may be present in older child (rash of palpable purpura, blood in the stools)
- barium enema:
filling defect or cupping in the head of contrast as it advances to the site of the intussusception
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- CT scan abdomen and pelvis:
target lesion: intraluminal soft-tissue density mass with an eccentrically placed fatty area; reniform mass: high attenuation peripherally and lower attenuation centrally; sausage-shaped mass: alternating areas of low and high attenuation representing closely spaced bowel wall, mesenteric fat and/or intestinal fluid and gas
More - abdominal ultrasound:
tubular mass in longitudinal view; target lesion in transverse view
More - CBC:
may show elevated WBC (suggests intestinal ischemia)
Meckel diverticulum
typically aged <2 years; may present with abdominal pain (may be intermittent or mimic acute appendicitis), and/or painless passage of bright red blood per rectum (hematochezia); often asymptomatic
dark red, maroon, or "red currant jelly" stools; abdominal tenderness with guarding and rebound (may suggest diverticulitis); palpable abdominal mass (may suggest intussusception)
- CT scan abdomen and pelvis:
may show intussusception, Meckel diverticulitis, and/or dilated bowel consistent with bowel obstruction
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Mesenteric adenitis
diffuse abdominal pain; hx of recent or current upper respiratory tract infection
fever, abdominal tenderness not localized to RLQ, rhinorrhea, hyperemic pharynx or oropharynx (pharyngitis), and/or associated extramesenteric lymphadenopathy (usually cervical)
- abdominal ultrasound:
enlarged mesenteric lymph nodes
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- CT scan abdomen and pelvis:
enlarged mesenteric lymph nodes
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Hirschsprung disease
males affected more commonly, mainly presents in early infancy (prior to 6 months); failure to pass meconium in first 36 hours of life strongly suggestive
abdominal distension, fullness in LLQ; palpable fecal mass on abdomen exam; absence of peritonitis (no guarding or rebound tenderness); small rectum and absence of stool on rectal exam; dysmorphic features of Down syndrome may be present
Ulcerative colitis
positive FHx, bloody diarrhea, cramping abdominal pain, anorexia, weight loss, fever, rash
evidence of weight loss, pallor, abdominal tenderness, abdominal mass, iritis (inflamed irritated eyes), arthritis, sacroiliitis, erythema nodosum, pyoderma gangrenosum
- CBC:
leukocytosis, anemia, thrombocytosis
More - colonoscopy with biopsy:
continuous uniform rectal involvement, loss of vascular marking, diffuse erythema, mucosal granularity and friability, mucosal edema ulcers, fistulas (rarely seen), normal terminal ileum (or mild backwash ileitis in pancolitis)
More - ESR:
elevated
More - CRP:
elevated
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- plain abdominal x-rays:
dilated loops with air-fluid level secondary to ileus; free air is consistent with perforation; in toxic megacolon, the transverse colon is dilated to 6 cm or more in diameter
More - CT scan abdomen:
thickened inflamed bowel mucosa, thumbprinting, intestinal dilatation or evidence of stricture; inflamed mesentery; intra-abdominal abscesses
More - serologic markers: perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti-Saccharomyces cerevisiae antibody (ASCA):
positive pANCA
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Crohn disease
crampy abdominal pain, intermittent diarrhea, bloody diarrhea if colitis a feature (blood less common in CD than in ulcerative colitis), weight loss, fatigue, FHx of inflammatory bowel disease
aphthous ulcers, evidence of weight loss, pallor, abdominal tenderness, abdominal mass, perianal fistula, perirectal abscess, anal fissure, perianal skin tags; extraintestinal manifestations including iritis, arthritis, sacroiliitis, erythema nodosum, pyoderma gangrenosum
- plain abdominal x-rays:
small bowel or colonic dilatation; calcification; intra-abdominal abscesses
More - upper GI series with small bowel follow-through:
edema and ulceration of the mucosa with luminal narrowing and strictures
More - CT scan abdomen and pelvis:
skip lesions, bowel wall thickening, surrounding inflammation, abscess, fistulas
More - serologic markers: perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti-Saccharomyces cerevisiae antibody (ASCA):
positive ASCA
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Small bowel obstruction
intolerant of feeding, with nausea and/or vomiting; abdominal pain may or may not be a feature; hx of previous abdominal surgery; hx of cystic fibrosis may be present
limited abdominal distension (with proximal obstructions in the duodenum or early jejunum); abdominal tenderness may or may not be present; rebound tenderness and guarding may occur if perforation, ischemia, and peritonitis; hyperactive bowel sounds (early finding), hypoactive or absent bowel sounds (late finding); incarcerated femoral, obturator, umbilical or ventral hernia may be present
- abdominal x-ray:
dilated small bowel loops, air-fluid levels throughout abdomen
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- abdominal ultrasound:
may demonstrate focal area causing obstruction
More - upper GI contrast study:
dilated small intestine; may demonstrate a transition zone of obstruction
More - lower GI contrast study:
dilated small intestine; may demonstrate a transition zone of obstruction
More - CT scan abdomen:
dilated small intestine; may demonstrate a transition zone of obstruction, mass, tumor, abscess
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Volvulus
infant age group; hx of bilious vomiting; pain usually manifests as notable transition to an inconsolable state
often diffuse abdominal distension and tenderness; faint or no bowel sounds, rigid abdomen, guarding, rebound tenderness, fever, or hematochezia
- abdominal x-ray:
partial or complete obstruction; dilated bowel loops; air-fluid levels; abdominal free air with perforation
More - CBC:
elevated WBC (suggests intestinal ischemia)
Large bowel obstruction
hx of risk factors: mental illness, inflammatory bowel disease, diabetes, poor diet, previous colorectal resection, laxative abuse, megacolon, or previous abdominal surgery; change in bowel habit with partial or complete obstruction, or change in caliber of stool; colicky abdominal pain becoming more constant and worse with movement, coughing or deep breathing as bowel approaches perforation; intolerant of feeding, with nausea or vomiting
tympanic, distended abdomen; hyperactive bowel sounds that become absent in advanced stages; abdominal rebound, guarding, and/or rigidity if perforation or close to perforation; empty rectum; incarcerated femoral, obturator, umbilical, or ventral hernia may be present
- abdominal x-ray:
gaseous distension of large bowel; volvulus suggested by kidney-bean-shape bowel loop
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- abdominal ultrasound:
may demonstrate focal area causing obstruction (e.g., intussusception)
- lower GI contrast study:
may indicate site of obstruction
More - CT scan abdomen and pelvis:
gaseous distension of large bowel; may demonstrate a transition zone of obstruction
More - flexible/rigid sigmoidoscopy:
flood of stool and mucus upon passing and decompressing apex of volvulus
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Necrotizing enterocolitis
premature neonate weighing less than 1500 g; feeding intolerance, apnea, lethargy, bloody stools
abdominal distension, tenderness, abdominal wall erythema, hematochezia, bradycardia
- abdominal ultrasound:
fluid collections, ascites
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Peptic ulcer disease
FHx of peptic ulcer disease; weight loss, vomiting, anorexia, and intermittent epigastric pain, usually related to eating meals; pain often nocturnal and usually relieved by antacids; melena and/or hematemesis if blood vessel perforated
unremarkable or epigastric tenderness; melena may be present on rectal exam or occult bleeding on stool hemoccult test
- CBC:
normal or leukocystosis; anemia present if sustained blood loss
- erect chest x-ray:
usually normal
More - upper GI series with water-soluble contrast:
mucosal defect(s) consistent with ulcer or free intraperitoneal contrast consistent with perforation
More - upper GI endoscopy:
mucosal inflammation, ulceration, and hemorrhage
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- Helicobacter pylori breath test or stool antigen test:
positive result if H pylori present
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Viral hepatitis
multiple sexual partners, sexual intercourse with infected individuals (hepatitis B and/or C), travel to developing countries, pregnant (hepatitis E); early disease: malaise, muscle and joint aches, fever, nausea, vomiting, diarrhea, headache, anorexia, dark urine, pale stool, abdominal pain; late disease: weight loss, easy bruising and bleeding tendencies
jaundice; early disease: tender hepatosplenomegaly, lymphadenopathy; late disease: generalized wasting, cachexia, gynecomastia, ascites, altered sensorium, asterixis, or decreased deep tendon reflexes, caput medusa, ascites, hepatosplenomegaly, congestion secondary to right heart failure
- serum LFTs:
high direct bilirubin, AST, ALT, alk phos and gamma-GT
More - serum IgM anti-HAV:
positive if acute hepatitis A infection
- serum hepatitis B surface antigen (HBsAg):
positive if hepatitis B infection
More - serum hepatitis B core antigen (HBcAg):
positive if hepatitis B infection
More - serum hepatitis B e antigen (HBeAg):
positive if hepatitis B infection
More - serum HCV RNA:
positive if hepatitis C infection
More - serum total (IgM and IgG) anti-HDV antibodies:
positive if hepatitis D infection
More - serum anti-HEV IgM antibodies:
positive if acute hepatitis E infection
Biliary dyskinesia
hx of previous negative workup for cholelithiasis common; recurrent RUQ pain; nausea and vomiting; symptoms may or may not be associated with eating
may be equivocal; RUQ tenderness
- LFTs:
normal AST, ALT, alk phos, and bilirubin
- RUQ ultrasound:
normal
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- hepatobiliary iminodiacetic acid (HIDA) scan:
decreased (<35%) gallbladder ejection fraction
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Acute pancreatitis
nausea, vomiting, epigastric pain radiating to back; acute-onset abdominal pain
epigastric or upper abdominal tenderness; tachycardia and hypotension in severe cases; discoloration around the umbilicus (positive Cullen sign) or flanks (positive Grey-Turner sign) in cases of hemorrhagic pancreatitis; small children may demonstrate increased irritability and abdominal distension only
Splenic infarction/cysts
varied; may be hx of trauma; cysts either asymptomatic or dull, left-sided abdominal pain; infarction typically causes fever as well as pain, but occasionally asymptomatic; left-sided shoulder and/or chest pain; presence of risk factors for splenic infarction (sickle cell disease, high altitude)
may be vague LUQ tenderness
- Doppler ultrasound:
infarction or cyst on spleen
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- CT scan abdomen with intravenous contrast:
infarction or cyst on spleen
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Nephrolithiasis
FHx of nephrolithiasis and/or gout; intermittent, severe, colicky flank and/or abdominal pain; nausea and vomiting; gross or microscopic hematuria; urinary frequency/urgency; atypical presentation common in younger children
ipsilateral costovertebral angle and flank tenderness; tachycardia and hypotension in pain-controlled patient may suggest concurrent urosepsis
Testicular torsion
acute-onset testicular pain; nausea, and vomiting; hx of recurrent episodes suggests repeated episodes of testicular torsion followed by spontaneous detorsion; hx of trauma may be present
tender, edematous testicle; affected testicle may appear higher than unaffected testicle with horizontal lie; associated scrotal erythema and edema; absent cremasteric reflex; usually no pain relief with elevation of the scrotum
- gray-scale ultrasound:
presence of fluid and the whirlpool sign (the swirling appearance of the spermatic cord from torsion as the ultrasound probe scans downward perpendicular to the spermatic cord)
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- power Doppler ultrasound:
absent or decreased blood flow in the affected testicle; decreased flow velocity in the intratesticular arteries, increased resistive indices in the intratesticular arteries
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Ovarian torsion
acute onset of one-sided lower abdominal or pelvic pain; nausea and vomiting common; hx of frequent, similar episodes; fever rare
tender pelvic mass (adnexal); in patients old enough to undergo pelvic exam, cervical motion tenderness may be elicited; typically no vaginal discharge, but may be some mild to moderate vaginal bleeding
- pelvic ultrasound:
solid appearance of the ovary, unilateral ovarian enlargement, ovarian peripheral cystic structures, marked stromal edema, fluid in the pouch of Douglas
Ruptured ovarian cyst
rupture usually spontaneous, can follow history of trauma or sexual intercourse; mild chronic lower abdominal discomfort may suddenly intensify
adnexal tenderness; adnexal size unremarkable due to collapsed cyst; peritonism may be present in lower abdomen and pelvis
- pelvic ultrasound:
complex mass appearance; fluid in the pouch of Douglas
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Pelvic inflammatory disease
sexually active; multiple partners; hx may be suggestive of sexual abuse (particularly if young child); pain worse with sexual intercourse; dull, aching lower abdominal pain with or without dysuria; vaginal discharge, low-grade fever
temperature >101°F (38.3°C); cervical motion tenderness, adnexal or uterine tenderness, vaginal or cervical mucopurulent discharge
- genetic probe or culture of vaginal secretions for Neisseria gonorrhoeae and Chlamydia trachomatis:
positive result indicates presence of organisms
More - HIV serology:
positive or negative
More - hepatitis studies:
positive or negative
More - rapid plasma reagin (RPR):
positive or negative
More - laparoscopy:
normal or may demonstrate endometritis, hydrosalpinx, pyosalpinx, tubo-ovarian abscess
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Pregnancy complications
hx of previous ectopic pregnancy or miscarriage, fallopian tube or pelvic surgery, pelvic inflammatory disease (PID); lower abdominal pain, amenorrhea, and vaginal bleeding
minimal abdominal tenderness and/or vaginal bleeding; pelvic exam may reveal a mass, eliciting cervical motion tenderness if hemoperitoneum is present; tubal rupture can cause hemodynamic instability
- type and screen:
variable
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Empyema
recent pneumonia, fever, cough, chest pain; malaise, anorexia, weight loss, or fatigue may occur; presence of risk factors (immunocompromise, comorbidities predisposing to the development of pneumonia, pre-existing lung disease, iatrogenic interventions in the pleural space, male sex)
febrile, toxic patient, dullness on percussion, absence of breath sounds over affected area; abdominal tenderness and distension without guarding or rebound
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