Gastrointestinal Emergencies of the term and preterm infant

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Gastrointestinal Emergencies of the term and
preterm infant

• Curry Bordelon, PNP-AC, MBA
• Pediatrix Medical Group

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Objectives

• Overview of basic GI anatomy
• Overview of GI function
• Discussion of open abdominal wall defects and
  their treatment
• Discussion of closed abdominal wall defects and
  their treatment

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Overview of the GI tract

• Stomach
• hollow muscular organ.
• second phase of digestion, following mastication.
  
• highly acidic environment due to gastric acid
  production and secretion
• pH range usually between 1 and 4, depending
  onfood intake, time of the day, drug use, and
  other factors.
• Combined with digestive enzymes, able to break
  down large molecules to smaller ones so that they
  can eventually be absorbed from the small
  intestine.

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Overview of the GI tract

• Stomach
• produces and secretes about 2 to 3 liters of
  gastric acid per day (highest in the evening).
• Absorption of vitamin B12 from the small
  intestine is dependent on conjugation to a
  glycoprotein called intrinsic factor which is
  produced by parietal cells of the stomach.

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Overview of the GI tract

• Deuodenal
• hollow jointed tube (25-30 cm) connecting the
  stomach to the jejunum.
• first and shortest part of the small intestine
  and it is where most chemical digestion takes
  place.
• begins with the duodenal bulb and ends at the
  ligament of Treitz.
• largely responsible for the breakdown of food in
  the small intestine.
• Brunner's glands, which secrete mucus, are found
  in the duodenum.

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Overview of the GI tract

• Deuodenal
• Regulates the rate of emptying of the stomach via
  hormonal pathways.
• Secretin and cholecystokinin are released from
  cells in the duodenal epithelium in response to
  acidic and fatty stimuli present there when the
  pyloris opens and releases gastric chyme into the
  duodenum for further digestion. These cause the
  liver and gall bladder to release bile, and the
  pancreas to release bicarbonate and digestive
  enzymes such as trypsin, lipase and amylase into
  the duodenum as they are needed.

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Overview of the GI tract

• Jejunal
• central of the three divisions of the small
  intestine (between duodenum and ileum).
• small intestine is usually between 5.5-6m long in
  adults (2.5m is the jejunum).
• pH in the jejunum is usually between 7 and 8
  (neutral or slightly alkaline).
• specialized lining for the absorption of
  carbohydrates and amino acids (proteins broken
  down in the stomach by pepsin and acid).

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Overview of the GI tract

• Jejunal
• carbohydrates are broken down in the duodenum by
  enzymes from the pancreas and liver into sugars.
• Fats are broken down in the duodenum by "lipase"
  from the pancreas into fatty acids.
• Amino acid, sugar, fatty acid particles,
  vitamins, minerals, electrolytes and water are
  small enough to soak into the villi of the
  jejunum and drop into the blood stream.

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Overview of the GI tract

• Ileum
• last portion of the small intestine (responsible
  for absorption of fats, and bile salts).
• pores in the ileum are slightly bigger than those
  in the jejunum and allow vitamin B12, vitamins
  dissolved in fatty liquids, electrolytes, bile
  salts and water to be reabsorbed.
• ileum joins the colon at the ileocecal valve
  (prevents the back flow of materials into the
  small intestine).

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Overview of the GI tract

• Colon.
• Its function is to move the waste from the small
  intestine on to the rectum.
• material first passes through the ascending colon
  and then through the transverse colon absorbing
  more water and potassium.
• The sigmoid colon is designed to slow down this
  movement of the waste until it is ready to be
  eliminated.

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Types of defects

• open abd wall (all or some of the abdominal
  contents noted outside the infant)
• closed abd wall (normal appearance outside the
  infant)

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Open abdominal wall defects

• gastroschisis
• omphalocele

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Gastroschisis

• Full-thickness defect of the abd wall exposing
  intestinal contents.
• Generally a small defect (3-6 cm).
• Right lateral to the umbilicus.
• 1 in 40,000 births.
• Malegt female
• Infants are generally preterm or SGA
• Malrotation affects nearly all infants
• Survival rates are higher than omphalocele, 95

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Gastroschisis

• Treatment involves
• Gastric decompression
• Gut rest
• Antibiotics
• Silo suspension (sealed plastic device surgically
  attached to infant and suspended above infant.
• allows the bowel to return to normal size.
• commonly have underdeveloped abd capacity thus
  not allowing for primary closure.
• Daily decompression allow for stretching of the
  abd tissue and minimizes intestinal damage.
• Primary closure- generally for small defects or
  those term infants with adequate abd tissue.

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Omphalocele

• failure of the intestines to return from the
  umbilical cord into the abd cavity resulting in a
  transparent membrane that encapsulates
  intestinal tissue.
• 1 in 5,500 births
• Male gt female
• Frequently associated (50 - 77) with other
  syndromes such as trisomies, CHD, CDH
• Ranges from 2-15 cm on average. Smaller defects
  may be overlooked
• Larger defects may include spleen and liver also

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Omphalocele

• Survival rates are high (75 - 95).
• Due to associative chromosomal issues, surgery is
  the second choice of treatment. First line
  treatment involves abdominal wrapping or painting
  the defect with silver nitrate or silvadine to
  promote eschar formation and epitheal tissue
  growth.
• Abd decompression and delayed feedings are
  important to allow the inflamed intestinal lumen
  to return to normal size. Antibiotics may also
  be used.
• Surgical repair is generally reserved for the
  most severe cases and involves using gortex flaps
  to cover the transparent sack.
• An unfortunate result of non-surgical closure is
  malrotation.

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Closed abdominal wall defects

• Atresias
• Stenosis
• TE fistula and/or EA
• NEC
• Perforation
• Diaphragmatic hernia

• Hirshsprungs
• Imperforate anus
• Meconium plug syndrome
• Meconium ileus syndrome

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Atresias/stenosis

• Bilary
• Duodenal
• Jeunoileal
• Stenosis

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Bilary Atresias

• complete obstruction of the bile flow of the
  extrahepatic ducts.
• Most common form of ductal cholestasis
• 1 in 10,000 births
• Prevents bile from entering the duodenum
• Cause unknown (malformed or inflammatory process)
• Digestion and absorption of fat soluble vitamins
  (A,D,E,K) is impaired.
• Leads to cirrhosis symptoms and death if
  untreated.
• Associated congenital defects found in 15 (CHD,
  Splenic issues, small bowel atresias, trisomies)

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Bilary Atresias

• Normal appearing infant with normal stools
• Symptoms usually begin with persistent jaundice
  after the first week of life
• Direct bili levels begin to climb
• Green bronze color to skin
• Gradually stools become clay-colored
• Differential diagnosis (hepatitis, HIV, CMV, HSV
  errors of metabolism)
• Survival untreated is less than 2 yrs.
• Nearly all pts have long term liver issues
  (elevated enzymes ALT, AST, GGT, CRP, chronic
  fatigue, poor weight gain, ascites)
• Treatment involves hepatic portoenterostomy
  (Kasai procedure) which is the dissection and
  resection of the extrahepatic duct.

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Duodenal Atresia

• Incomplete recanalization of the lumen.
• Transverse diaphragm of the tissue completely
  obstructing the lumen
• 1 in 7,500 births.
• 25 of all duodenal atresias are related to Downs
• Polyhydramnios is the 1 first sign on prenatal
  US
• 60-70 of DA pts also have trisomies, Imperf A,
  TE anomilies, CHD, VATER, VACTERL, renal issues,
  annular pancreas
• Bilious Emesis is the 1 presenting symptom after
  delivery

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Duodenal Atresia

• Proximal atresias/obstruction generally results
  in vomiting within the first few hours of life.
• Distal atresias/obstruction results in emesis
  longer after delivery.
• Classic double bubble on xray. Gasless pattern
  after the atresias
• 65-84 survival rate with early intervention.
• Treatment involves decompression of the stomach
  by continuous suctioning followed by surgical
  removal of the atresia area with a side to side
  anastomosis.

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Jejunoileal Atresia

• obstruction of the distal segment of the small
  intestine.
• Most commonly near the ileo-cecal valve
• 1 in 20,000 births
• Polyhydramnios is not as common of a risk factor
  (only ¼ of the presenting infants).
• Classic triple bubble and microcolon on xray
• 84-95 survival rate.
• Treatment involves decompression of the stomach
  by continuous suctioning followed by surgical
  removal of the atresia area with a side to side
  or end to end anastomosis

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Stenosis

• Far less common than atresias/obstructions.
• Generally from excessively narrow areas of the
  small intestine (duodenum or the ileo-cecal
  valve).
• Most common cause is by webbed areas of the inner
  lumen.
• Occurs most often following other GI surgeries

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TE fistula and/or EA

• Failure of the trachea to differentiate from the
  esophagus
• There are different types of disorder
• 85 have EA and a TE fistula
• 8 have EA without any connection to the trachea
• 1 have esophageal fistula and no connection to
  the stomach
• 4 are an H type fistula
• 1 in 4,500 births

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TE fistula and/or EA

• VATER and VACERL association is common
• 20-30 are preterm
• Signs are excessive oral secretions (from an
  inability to swallow), inability to pass OG/NG
  tubes, aspiration, chronic pneumonias.
• 97 survival rates
• Mortality is associated with associative
  disorders
• Surgery depends on the type of disorder.

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NEC

• Necrosis of the mucosal and submucosal layer of
  intestine.
• Any portion of the GI tract can be affected.
• Causes are still a debate (most common causes are
  selective bowel ischemia, infection or
  delayed/improper feedings.
• Osmolarity of certain formulas/meds increase risk
  of NEC.
• Feeding of EBM decreases the risk of NEC by 65
  in the preterm infant.
• Most common disease affecting hospitalized
  infants, 8 of all inpatient infants.

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NEC

• 65-92 of infants affected with NEC are preterm
  infants.
• Most commonly seen in infants 3-21 days post
  delivery.
• Xray shows tiny lucent bubbles.
• Generally infants present with abd distention,
  increased emesis, bloody stools or feeding
  intolerance.
• Treatment involves 3 basic principles
• Bowel restNPO for 10-14 days
• Prevention of progressive injuryNPO, Fluid
  management, antibiotics
• Placement of abd drains.

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Perforation

• Spontaneous rupture of the intestine/colon
  allowing for leakage of air into the abd cavity.
• Most commonly associated with NEC and ischemic
  bowel
• Most common risk factors are NEC, sepsis,
  mechanical ventilation, prematurity, long term
  steroid usage and postoperative abd
  complications.
• Survival is directly related to how quickly the
  staff is able to identify clinical changes.
• Pneumoperitoneum (free air in the abd cavity) is
  the most common radiographic sign of perforation
  (football or sail sign in the most lateral abd on
  a left lateral decub).

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Perforation

• INTESTINAL PERFORATION IS AN EMERGENCY!!!!
• Surgical removal of the damaged and perforated
  area is almost always required.
• Treatment also involves preventing additional
  bowel injury by
• Bowel restNPO for 10-14 days
• Gastric decompression
• Fluid management, antibiotics
• Placement of abd drains may not be needed.

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Diaphragmatic hernia

• Herniation of intestinal contents into the
  thoracic cavity resulting in underdeveloped lung
  tissue leading to respiratory distress.
• 1 in 4,000 births
• Usually present with cyanosis, respiratory
  distress and scaphoid abd.
• Usually seen during routine prenatal US.

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Diaphragmatic hernia

• Post delivery xray reveals intestinal loops in
  the chest cavity
• Immediate intubation and gastric decompression is
  essential to higher survival rates.
• Treatment also involves surgical placement of abd
  tissue back into abd cavity once the infant has
  become stable.

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Hirshprungs

• Also known as megacolon or aganglionic colon
• Congenital absence of ganglionic cells in the
  distal colon and rectum.
• Failure of the neural crest cells to migrate
  properly to caudal region.
• Local failure of the colon to relax thus causing
  a restrictive, narrowed area.
• Zone between the ganglionic and the tapered
  aganglionic area of the distal colon is called
  the transitional zone.
• The rectum is always involved.
• 1 in 5,000 births.
• Males gt females

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Hirshprungs

• Most infants are chromosomally normal
• Primary symptoms are bilious vomiting, failure to
  pass stools and abdominal distention. All infant
  should pass first stool within 48 hrs of birth.
• A significantly dilated colon proximal to the
  transitional zone on xray.
• Survival rates are high at 80-95 with early
  intervention
• Diagnosis is only definitive by performing a
  rectal biopsy
• Treatment involves a standard rectal pull
  trough which involves a complete removal of the
  affected aganglionic zone, allowing for 7-10 days
  of bowel rest and slow reintroduction of feeds.

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Imperforate anus

• The abnormal or incomplete partitioning of the
  cloacae resulting in anal stenosis or atresia.
• Rectourethral and rectovaginal fistulas are
  common.
• Cause is unknown
• 1 in 5,000 births
• 20 - 75 have associated anomalies.
• VATER and VACTERAL syndromes are common

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Imperforate anus

• Atresias are the most obvious types.
• Stenosis is less obvious and usually present as
  stooling from the penis/vagina or meconium
  stained urine.
• Spinal anomalies occur in 50 of patients.
• Overall mortality (20) depends on the type if
  defect and the associated anomalies.
• Treatment for stenotic anal openings involves
  daily progressive dilation of the anus.
• For more involved complete atresia, surgical
  opening and pull through is essential.

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Meconium plug syndrome

• Intestinal obstruction of the lower distal colon
  and rectum
• Most commonly associated with decreased colonic
  motility and hyptonicity (CF).
• Different from hirschprungs (no aganglionic cell
  regions).
• Risk factors include prematurity, diabetic
  mothers, neurologically devastated infants and
  mothers treated with magnesium sulfate.

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Meconium plug syndrome

• Primary symptoms are bilious vomiting, failure to
  pass stools and abdominal distention.
• Mortality is very low once the stool is passed.
• Surgical intervention is rare.
• Small saline enemas are the preferred treatment.

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Meconium ileus

• Obstruction of the distal colon due to abnormally
  thick meconium
• Generally a result of meconium plug syndrome.
• 95 of the infants with meconium ileus have CF.
• 1 in 2,000 births
• Primary symptoms are progressive abdominal
  distention within the first 12-24 hours of life
  followed by bilious vomiting and a failure to
  pass stools.

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Meconium ileus

• On xray the infant will have dilation proximal to
  the obstruction and a soap-bubble appearance at
  the point of obstruction (due to the trapped air
  in the dense meconium).
• Non operative therapy is generally successful in
  15-25 of infants and involves regular
  hyperosmolar enemas to evacuate the thickened
  stool. Medication therapy also should be
  implemented.
• A temporary ostomy to decompress the obstructed
  area may be necessary until fluid status is
  stabilized.

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Questions?