GI Flashcards
True or false - children with encopresis feel the urge to defecate
false - they don’t
encopresis is fecal soiling: defined as the involuntary passage of decal material in an otherwise healthy and normal child
decal soiling almost always associated with severe functional constipation
treatment of chronic constipation and encopresis:
- aggressive colon clean out, with multiple enemas
- PEG to help with drawng fluid in so that the stools can leave
- should be continued for a minimum of several months (while rectum returns to size)
-
Name 4 tests that might be considered for refractory contsiptation
serum calcium TSH celiac disease Sweat test if clinically makes sense MRI of spine - r/o spina bifida occulta or tethered cord anorectal manometry (motility disorder)
Important historical questions for diarrhea
meds (Abx)
immunosuppression
sick contacts, travel, food (incl unsafe water, milk, raw shellfish, juice/fructose, daycare, pets, food prep)
In which patients can salmonella be especially scary?
in neonates or compromised host, can be life threatening
other causes of diarrhea which are life-threatening
intussusception, HUS, Hirchprung with toxic megacolon, pseudomembranous colitis, IBD with toxic megacolon
True or false - any newborn with true diarrhea should be taken very seriously and possibly referred to a tertiary centre
true - reasons why:
greater potential for dehydration
associated with major congenital intestinal defects:
- electrolyte transport (congenital sodium or chloride losing diarrhea)
- carb absorption (ie congenital lactase deficiency)
- immune-mediated defects (autoimmune enteropathy)
- villous blunting - ie microvillus inclusion disease
can get viral gastro to, bt need to think of these other causes
What is the best test for diagnosing fat malabsorption?
72 hour decal fat - gold standard
ingest high fat for 3-5 days, all stool for 72 hours
need to get dietary history also for coefficeicn of fat absorption
steatorrhea: >7% of dietary fat is malabsorbed, in normal infants, up to 15% can be malabsorbed
other tests: sudan stain, steatocrit, absorbed lipids after standardized meal
What is the best stool test to diagnose GI protein loss
fecal alpha antitrypsin measurement - most useful stool marker of protein malabsorption, also need to measure the serum to make sure that they don’t have alpha1antitrypsin (should be false-negative)
True or false - fecal leukocytes are present in secretory diarrhea
false - inflammatory diarrhea is where there are fecal leukocytes and RBCs, and is characterized by dystntry (symptoms and bloody stools)
secretory diarrhea - characterized by watery diarrhea and absence of decal leukocytes
What are the most common infectious causes of secretory diarrhea
food poisoning - toxigenic staph aureus bacillus cereus clostridium perfringens Enterotoxic e. coli vibrio cholerae giardia lamblia cryptosporidium species rotavirus norwalk-like virus
What are the common infectious causes of inflammatory diarrhea
Shigella invasive e coli salmonella species campylobacter species C. diff entamoeba histolytica yersinia enterocolitica
What percentage of infants <12 months with salmonella gastroenteritis have positive blood cultures
between 5-40% may have positive blood cultures
(vs rare in >12 months)
10% can have meningitis, osteomyelitis, pericarditis, pyelonephritis
What is the most common cause of traveler’s diarrhea
enterotoxigenic E. coli - most commonly identified cause
depending on location, other bacteria (i.e. campylobacter in soothest asia)
viruses -noroviru, rotavirus
parasites - giardia, cryptosporidium can be present
What is the treatment for traveler’s diarrhea in children
TMP/SMX
imodium for children >2 years old
consider cipro in teens
prophylactic antibiotics - do decrease frequency but not routinely recommended because of med risks
best prvention is avoiding previously peeled raw fruits and vegetables and and beverages with tap water
true or false - antibiotic therapy for shigella diarrhea eliminates organisms from feces
true - it also shortens the duration of diarrhea
true or false - antibiotic therapy for campylobacter diarrhea prevents relapse
true - it does prevent relapse and shotens duration of illness
Which children with salmonella should receive antibiotic children
age <12 months bacteremia metastatic foci enteric fever (ie typhoid) immunocompromised
Which children with yersinia should get treated with abx?
none for gastro alone
indicated if septicaemia or other localized infection
Name differential for diarrhea in newborns
congenital shot gut congenital lactose intolerance malrotation with intermittent volvulus ischemia defective sodium-hydrogen exchange congenital chloride diarrhea microvillous disease
Stool Na is 70 mmol/L and Cl is 20 mEq/L. Is this osmotic or secretory diarrhea?
osmotic diarrhea Na 135 mOsm (concentrated), pH70, Cl>40 , mOsm 6.0, no improvement with fasting
What is the osmotic gap of stool
osmolality of the decal fluid minus the sum of the concentrations of the decal electrolytes
How should you manage a child with secretory diarrhea?
- take off feeds
- rehydrate and fix lytes
- investigation for:
- enteric pathogens
- baseline malabsorption w/u
- proximal small bowel damage
**if suspect problems with the mucosa, do a small bowel biopsy , if abnormal, give parenteral alimentation and refeeding
electron microscopy - may reveal congenital abnormalities of the microvillus membrane and brush border
What are some hormonal causes of secretory diarrhea?
- VIP oma
- hypergastrinoma
- carcinoid syndrome
consider this if initial studies are negative
What is the most common cause of bloody diarrhea in infants <1 year?
allergic or non-specific colitis
usually attributed to cow’s milk protein formula, can occur in breastfed from transmission of maternal dietary antigens
How can you make a definitive diagnosis of C. diff
sigmoidoscopy
pseudomembranous plaques or nodules
How helpful is eosinophilia as a diagnostic sign of parasite disease?
normally total eosinophil count is not >500/mm3
screening tool: poor PPV (15-55%), negative predictive value is better (73-96^) especially if eosinophil count remains normal
What are the most common presentations of giardiasis?
- asymptomatic carrier
- chronic malbsorption with steatorrhea and FTT
- acute gastro
Gold standard for diagnosis of giardia? best non invasive test
gold standard: duodenal biopsy (close to 100%)
single-stool exam and stool ELISA for Giardia >95%
other tests: single stool exam for trophozoites or cysts, 3 stool exams, duodenal aspirate, string test
Name some groups of patients at particular risk of giardiasis
1 CF
- Chronic pancreatitis
- Achlorhydia
- agammaglobulinemia
- hypogammaglobinemia
Potential complications of amebiasis - most common organ it goes to
Entamoeba histolytica - to LVR in 10% of patients, to other organs less commonly:
- liver abscess, pericarditis, cerebral abscess, empyema
What is the triad of findings in acrodermatitis enteropathica
diarrhea
hair loss
dermatitis
What is the inheritance of acrodermatitis enteropathica
autosomal recessve
Which is the other main differential for the clinical presentation of acrodermatitis hepatica
dietary zinc deficiency -zinc deficiency can give the same clinical presentation
- found in kids with long-term TPN
- also in perms with decreased stores and increased requirements
What age of kids most commonly presents with toddler diarrhea?
6-40 months
often after enteritis and abx treatment
DO NOT HAVE: fever, pain or growth failure
don’t usually have malabsorption
What are some possible causes of toddler diarrhea
- too much fruit juice
- intestinal hypermotility
- increased bile acids and sodium
- prostaglandin abnormalities of the intestine
DIAGNOSIS OF EXCLUSION
possible investigations should include: disaccharide intolerance, protein hypersensitivity, parasitic infestation, IBD
Which ethnicity is most likely to have late onset lactase deficiency?
Vietnamise - 100% (?)
in US: Native American 90%
Black 75%
Hispanic 50%
White 20%
in World:
Filipino 55%, French 32%, Dutch 0%
True or false - lactase levels are high in infancy
yes they are, and then they decline progressively, after age 5, lower levels (so deficiency a bit of a misnomer) ->essentially if they take too much lactose, get symptoms
see chart for differential of secondary lactose deficiency
How is lactose intolerance diagnosed
most common test - hydrogen breath test - feed them lactose after fasting, collect air (fermentation of carb by bacteria leads to hydrogen after lactose ingestion); peak hydrogen >20 ppm is considered positive test
need colonic bacteria - therefore recent antibiotics not a good idea
direct measure of lctse levels - biopsy of duodenum or jejunum during scope
What is the classical clinical presentation of celiac disease
9-24 month old child
FTT, diarrhea, abdo distention, muscle wasting and hypotonia
weight decreases before height
can get irritable and despressed, vomiting less common
can also get edema, rickets and clubbing
can be more subtle also
What are possible non GI manifestations of celiac disease?
- dermatitis herptiformis
- iron deficiency anemia - unresponsive to supplement therapy
- arthritis and arthralgia
- dental enamel hypoplasia
- chronic hepatitis
- osteopenia and osteoporosis
- delayed puberty
- short stature
- hepatitis
Screening test for celiac disease
anti TTG and IgA and anti-endomysial antibodies - highly sensitive and specific for celiac
because low code - initial screen should be TTG
antigliadin antibodies: NOT as sensitive or specific so not recommended as first-line screening ; check IgA since selective IgA deficiency most common primary immunodeficiency in western countries, more common in patients with celiac disease
How do you do definitive diagnosis of celiac disease?
small bowel biopsies -
1st one on gluten: villous atrophy, increased crypt mitoses and disorganization and flattening of the columnar epithelium (villous blunting)->after gluten free diet, these findings should reverse completely
Name common conditions with increased risk of celiac disease
- DM1
- autoimmune thyroiditis
- Down syndrome
- Turner syndrome
- William syndrome
- selective IgA deficiency
- 1st degree relative with celiac disease
How can you investigate for pancreatic insufficiency?
measure decal pancreatic elastase
pancreatic insufficiency - can cause fat malabsorption (i.e. in CF)
decreased measure is associated with pancreatic insufficiency
False positive (i.e. decreased measurement): when sample from diarrhea
How much body fluid is lost with mild dehydration, moderate dehydration, severe dehydration?
mil: 100 ml/kg fluid loss with >10% weight loss
What 3 characteristic are most accurate to predict 5% dehydration?
- cap refil
- skin turgor
- abnormal resps
true or case - the BUN is a good way to measure dehydration in a kid
not very reliable - doesn’t increase until GFR falls to 1/2 normal, then rises by about 1% each hour
may rise even less in a fasting child with disease, 80% of patients with 5-10% dehydration my have a normal BUN
What two substances are transported (coupled) at the intestinal brush border
sodium and glucose
coupled transport, facilitated by sodium glucose cotranspoter
ORT - enough sodium, glucose, osmolarity to maximize cotransportation and avoid problems of excessive sodium intake/additional osmotic diarrhea
one problem with ORT - not enough calories, however how, making more with cereal or polymers to help
A child presents with diarrhea and mild dehydration. How should you rehydrate him?
ORT should be used
rapidly - 50-100 ml/kg over 3-4 hours PLU should replace ongoing losses (from the diarrhea)
as soon as rehydrated, should start an age-appropriate unrestricted diet, continue nursing
formula fed - don’t need to dilute, usually don’t need special formula
don’t need labs or meds
Which of the following interventions are recommended still for diarrhea?
a) switch to lactose-free formula
b) clear liquids such as ginger ale
c) avoid fatty foods
d) BRAT diet
e) avoid food for 24 hours
f) none of the above
f) none of the above
we shouldn’t do any of the things listed anymore
why:
lactose free - usually unnecessary in infants, only in severe malnutrition and dehydration MAY have a small role
clear liquids - lots of these have lots of sugar, increase osmotic diarrhea
fat might reduce intestinal motility
bananas, rice and applesauce and toast diet - unnecessarily restrictive, poor nutrition
don’t need to avoid food - early feeding decreases the intestinal permeability of infection, reduces illness duration and improves nutritional outcome
Name 3 benefits of oral ondansetron for gastroenteritis?
decreases risk of persistent vomiting
reduces need for IV in ER department
reduces hospitalization (also CPS statement on this); ORT after ondansetron
other meds for anti emetics (i.e. domperidone, metoclopramide, prochlorperazine and promethazine) not supported by guidelines
What are some possible side effects of anti motility agents?
**usually not for children < 3 year old
examples: imodium (loperamide), diphenoxylate and atropine (lomotil), tincture of opium (Paregoric): can case drowsiness, ileum and nausea, potentiate the effects of certain bacterial enteritises (Shigella, Salmonella) or accelerate the course of antibiotic-associated colitis
also limited evidence in kids
What is the big concern with pepto-bismol?
can get salicylate overdose
What are some adsorbent meds
ie attapulgite, kaolin-pectin can cause abdo fullness and interfere with other meds
true or false - probiotics can help decrease Ab associated diarrhea in children
true, does this by replenishing the good bacteria in the gut
examples include :
lactobacillus GG, bifidobacterium bifidum, streptococcus thermophilus
also CPS statement about this
What percentage of children may outgrow a peanut allergy
only 20%
food allergies after age 3 also less likely to be outgrown
What is Heiner syndrome
is it IgE mediated
hematemesis and hemoptysis with failure to thrive
NOT ige mediated, causes chronic pulmonary disease
associated with milk allergy
Are heated apples a common cause of oral allergy syndrome?
is oral allergy syndrome IgE mediated
nope, usually the allergens are heat labile, so heated (i.e. cooked apple)should be fine
oral allergy syndrome - is IgE mediated
get swelling of oral cavity after having certain fresh fruits/veggies, cross-reactivity to proteins in pollen
True or false - skin-prick allergy testing is very sensitive for food allergies
true - negative test (<3mm wheal) can exclude IgE mediated food allergy
but low specificity (positive test is less meaningful)
True or false - serum allergen-specific IgE levels have good positive predictive value
false - lots of false-positive values screening for lots of foods can result in unnecessary food avoidance , lots of variability
atopic patch testing - cell mediated resonse, likely better for late-phase allergens, but not well studied
What is the gold standard diagnostic test for food allergy
dobule blind, placebo-controlled, food challenge - gold standard
fastint patient without recent antihistamine use, small quantities of the food are given, waiting for the reaction
true or false - exclusive breast feeding decreases atopic dermatitis and cow milk allergy
true - it does for the first 2 years of life
hydrolysed formulas may delay or prevent atopic dermatitis
(again CPS statement on this topic)
When does GER resolve?
almost all by 18 months of age (95-98%)
by 12 months - 75-85% resolve
by 6 months - 25-50% resolve
When does GER become GERD
when physiologic GER - with feeding refusal, poor weight gain, painful emesis, chronic respiratory problems and other
Which is the 24 hour pH probe
traditionally, 24 hour pH probe most reliable test for the diagnosis of GER, doesn’t detect nonacid reflux
multichannel luminal impednac e- a new test with pH probe to assess nonacid reflux
What does a milk scan show?
can see postprandial flux and delay in gastric emptying, but can’t distinguish between physiologic and pathologic reflux
True or false - upper GI study can indicated reflux?
nope, but it can detect anatomic abnormalities such as malrotation which might contribute
What finding on endoscopy suggests possible reflux?
endoscope - histologic esophagitis suggestive but not diagnostic of reflux - absence of esophagitis does not rule out reflux
What finding is often associated with Sandifer syndrome?
typically , an esophageal hiatal hernia is also present
Sandifer syndrome: paroxysmal dystonic posturing with opisthotonus and unusual twisting of the head and neck in associated with GER (secrets)
True or case - milk-thickening agents improve the results of pH monitoring
false -
they DO reduce regurg and vomiting and help with weight gain, but don’t decrease episodes of GER and no effect on reflux index (with pH monitoring)
Which pro motility agent has demonstrated efficacy in GERD?
cisapride - only pro motility medication with demonstrated efficacy in GERD (but other ones haven’t shown effectiveness)
only liited access because of increased prolonged QT and dysrhythmias
What are some indications for fundoplication?
- recurrent aspiration
- refractory or Barrett esophagitis
- reflux associated apnea
- reflux associated failure to thrive (refractory to medical therapy)
- wrap the gastric funds around eh distal esophagus, tighten the gastroesophageal junction
What are the most common complications of fundoplication?
- dysphagia
- small bowel obstruction
- paraesophageal hernia
- gas-bloat syndrome: gagging, retching, nausea, abdo distention
- post fundo dumping
What is the most common symptom of primary peptic ulcer disease?
abdo pain - 90% of patients
classically - related to meals - in children this association on half the time
nocturnal pain - 60% of patients (helps distinguish organic)
melena (1/3 of patients)
UNCOMMON features: vomiting, hematemesis, perforation
What are the secondary causes of ulcers?
Systemic disease: sepsis, acidosis, sickle cell, CF, SLE, renal failure, severe hypoglycaemia
traumatic injury: head trauma, burns, major surgery
drugs and toxins: steroids, NSAIDS, theophylline, tolazoline (nonselective alpha antagonist)), aspirin
What is the first line therapy for H. pylori infection
most effective treatment remains uncle
current first line: amox, PPI and clarithromycin or metronidazole
What is the cause of most peptic ulcer disease in adults?
H pylori
in kids, the relationship between gastric ulcera/recurrent abdo pain is more weaker , although stron relationship between astral gastric it and primary duodenal ulcer disease
in adults, most duodenal ulcers (90%) is caused by H pylori, gastric ulceration in 70%
How can we detect H pylori?
non invasive: 1. urea breat test 2. serology - doesn't distinguish between past and present infection (and lots of people are colonized with H pylori) 3. stool antigen test Invasive tests: 1. culture of gastric biopsy specimen 2. PCR of biopsy specimen 3. ID of histologic gastritis 4. special stains for H pylori
how much blood volume is likely lost if there is hypotension and resting tachycardia in a bleeding patient?
likely 30% loss
remember that the Hg takes 12-72hours to equilibrate so should use vital signs instead to estimate blood loss
What’s the best way to distinguish upper and lower GI bleed?
nasogastric lavage - bright red coffee ground - positive, (not pink tinged)
upper GI - proximal to ligament of Treitz
if negative - can rule out gastric esophageal or nasal sources, but still can be duodenal
initial NG insertion very important (because blood can increase the intestinal transit time, make it harder to determine the site)
Causes of melena:
melena - denatured blood (by acid) usually before ligament of Treitz, can be seen in patients with Meckel diverticulum (as a result of denaturation by anomalous gastric mucosa even though it is a small intestine problem)
Which of the following does not cause a false positive tat for blood in stool (i.e. hem occult)
a) red meat
b) ingestion of broccoli
c) iron
d) cantaloupes
c) iron does not cause false positive results
other causes of false positive: recent ingestion of red meat or peroxidase-containing fruits and veggies (i.e. broccoli, radishes, cauliflower, cantaloupes, turnips)
how it works: hemoglobin and its derivatives are catalysies for oxidation of guiac (hem occult) and produces a colour change
What are some causes of false negative hem occult?
- ascorbic acid ingestion
2. delayed transit time/bacterial overgrowth (bacteria degrades the hemoglobin)
What are some causes of lower GI bleeding in newborn and infants?
mucosal causes:
peptic ulcer disease, NEC, infectious colitis, eosinophilic/allergic colitis, Hirschprung
Structural causes:
intestinal duplication, meckel diverticulum, intussusseption
A previusly asymptomatic 18 month old child has large amounts of painless rectal bleeding? (red but mixed with darker clots)
Meckel diverticulum - failure of the intestinal end of the omphalomesenteric duct to obliterate, 2% of the population, about 1/2 have gastric mucosa , 2x more in males, usually in 1st 2 years of life, most common presentation is massive pin less bleeding that is red or maroon in colour
tarry stool in 10% of cases , may have other minor episodes
presentation can vary from shock, intussusception with obstruction, volvulus or torsion
(the other big differential for painless rectal bleeding is juvenile polyps (although in thos age group more likely Meckel)
What are two polyposis syndromes associated with increased risk of aenocarcinoma
- Peutz-Jeghers
- Juvenile polyposis coli
as much as 30% increase
Worldwide, what is the most common cause of GI blood loss in children?
Hookworm infection - caused by parasites nectar americanus, ancylostoma duodenal (often asymptomatic)
progressive microscopic blood loss, often leads to anemia as a result of iron deficiency
Treatment of variceal bleeding?
massive bleed - always start with ABCs, CBC, LFTs, coats, crossmatch; for vatical bleeding specifically - diagnostic endoscopy, therapeutic endoscopy, vasopressin, octreotide
Name the six most common causes of massive GI bleed in children
- esophageal varices
- Meckel
- hemorrhagic gastritis
- Crohn disease with ileal ulcer
- peptic ulcer (mainly duodenal)
- AVM
