Download CM 23- Encopresis, Constipation, Hirschprungs, Megacolon

CM 23- Encopresis, Constipation, Hirschprungs, Megacolon
Objectives
• Know the classic presentation and physical exam findings consistent with Hirschsprung’s disease.
• Describe the histologic findings consistent with a diagnosis of hirschsprung’s disease.
• Name the gold standard diagnostic test for hirschsprung’s
• Define toxic megacolon, know the most commonly associated disease, symptoms, treatment for and
contraindicated diagnostic studies.
• Define constipation and encopresis
• List functional constipation/encopresis treatment options for both disimpaction and maintenance
Hirschprung Disease
• Congenital aganglionic megacolon- neurocristopathy
• Absence of ganglion cells in the submucosal and myenteric plexus
• Incidence of 1 in 5,000 live births
• Most common cause of lower intestinal obstruction in neonates
• Male:female ratio is 4 : 1 and 1:1 (short vs long segment)
• Associated with other congenital defects- Down Syndrome
• Microcephaly, mental retardation, abnormal facies, autism, cleft palate, hydrocephalus, and micrognathia.
Pathology
• Consequence of an arrest of neuroblast migration from the proximal to distal bowel
• Inadequate relaxation of the bowel wall and bowel wall hypertonicity, lead to intestinal obstruction
• Limited to the rectosigmoid in 80% of patients, 10% -5% of patients have long-segment disease
• Total bowel aganglionosis- 5%- rare
• Histologically is an absence of Meissner and Auerbach plexus and hypertrophied nerve bundles
• High concentrations of acetylcholinesterase between the muscular layers and in the submucosa
• Inheritance- sporadic, dominant and recessive patterns
Clinical manifestations
• Distended abdomen
• failure to pass meconium
• and/or bilious emesis (neonatal period)
• Failure to thrive with hypoproteinemia
• Stool  dilatation increase intraluminal pressure, decrease blood flow
• Proliferation of bacteria enterocolitis (Clostridium difficile, Staphylococcus aureus, anaerobes, coliforms)
diarrhea, abdominal tenderness
• Sepsis and signs of bowel obstruction
• Tympanitic and distended- with a large fecal mass
• Ultrashort-segment
• Ganglionic segment is limited to the internal sphincter
• Ganglion cells are present, anorectal manometry is abnormal
• Long-segment (5%)
• Involving the entire colon
• The extent determined accurately by biopsy at the time of laparotomy
Rectal Examination
• Normally placed anus- snug
• The rectum empty of feces
• Explosive discharge of foul-smelling feces and gas
• The stools can consist of small pellets, be ribbon-like, or have a fluid consistency
• Retained feces may be associated with pain and fever
• Urinary retention with enlarged balder or hydronephrosis
CM 23- Encopresis, Constipation, Hirschprungs, Megacolon
Diagnosis
• Gold standard- rectal suction biopsy
• The biopsy specimen should be stained for acetylcholinesterase to facilitate interpretation
• hypertrophied nerve bundles that stain positively for acetylcholinesterase with an absence of ganglion cells
• Unprepared contrast enema –looking for an abrupt narrow transition zone- proximal and distal colon
• Compare rectum to that of the sigmoid colon
• 10% of newborns have a normal contrast study
• Anorectal manometry (helpful for dx)
• measures the pressure of the internal anal sphincter while a balloon is distended in the rectum
• the internal anal sphincter fails to relax in response to rectal distention
• Equivocal or paradoxical response- rectal biopsy
Treatment
• Definitive treatment is operative intervention
• Primary pull-through procedure
• 3 basic surgical options
– Swenson- excise the aganglionic segment and anastomoses
– Duhamel- create a neorectum
– Soave- the endorectal pull-through procedure
• Treatment of choice laparoscopic single-stage endorectal pull-through procedures
Lateral view of a barium enema in a 3 yr old
girl with Hirschsprung disease. The
aganglionic distal segment is narrow, with
distended normal ganglionic bowel above it.
CM 23- Encopresis, Constipation, Hirschprungs, Megacolon
Constipation
Constipation: Two or fewer stools per week OR passage of hard, pellet-like stools for at least 2 weeks.
Functional Constipation: Two or fewer stools per week, voluntary withholding of stool, and infrequent passage
of large diameter, often painful, stools.
• Encopresis: Fecal Incontinence caused by leakage of retained stool
• Caused by either a defect in filling or emptying the rectum.
• It is self-perpetuating:
• Causes:
Nonorganic (Functional)
Organic
• One of the most common causes for generalized abdominal pain in children.
• PE - LLQ mass of impacted stool may be felt.
Causes of Organic Constipation
Anatomic
- Anal Stenosis
- Imperforate Anus
- Anteriorly Displaced Anus
- Intestinal Stricture
Abnormal Musculature
- Prune Belly Syndrome
- Gastroschisis
- Down Syndrome
Intestinal Nerve or Muscle abnormalities
• Hirschprung
• Visceral Myopathy or Neuropathy
• Intestinal Neuronal Dysplasia
Spinal Cord Defects
• Tethered Cord
• Spinal Cord Trauma
• Spina Bifida
• Drugs (Narcotics, Anticholinergics, Lead)
• Metabolic Disorders
• Hypokalemia
• Hypercalcemia
• Hypothyroid
• Diabetes
• Intestinal Disorders
• Celiac Disease
• Cow’s Milk Protein Intolerance
• Cystic Fibrosis (Meconium Illeus)
• IBD (stricture)
• Tumor
• Connective Tissue Disorders
• SLE
• Scleroderma
• Psychiatric
• Anorexia
•
•
CM 23- Encopresis, Constipation, Hirschprungs, Megacolon
Long term effects:
- Patient anxiety and family stress.
- Enuresis
- Accompanying Urinary tract stasis – UTIs
- Encopresis – watery stool from the proximal colon leaks around hard retained stool and may pass unnoticed
by the child.
5-10 year olds typically effected.
Often mistaken for diarrhea.
Children typically present with soiling
• Recurrent Urinary Tract Infections
– detrusor instability, which can lead to
– urinary incontinence,
– large bladder capacity, and
– dyscoordinated voiding
• 30% of chronically constipated- urinary incontinence, 11% urinary tract infection
• 13% of urinary retention had functional constipation
Functional Constipation/Encopresis Treatment
• Disimpaction – Enemas, Glycerin suppositories or oral laxatives.
- Polyethylene glycol (PEG) 1.5g/kg/day
• Maintenance
- Diet modification – water, fiber, fruit juices
- Behavioral Therapy – scheduled toilet times
- Laxatives - Polyethylene glycol 1g/kg/day, Lactulose 1-3 ml/kg/day, Glycerin suppositories
• Long treatment course with frequent relapses
Oral Medications
• Osmotic agents- lactulose (a synthetic disaccharide), sorbitol, and polyethylene glycol (PEG 3350)
• Lubricants- mineral oil
• Stimulants- promote enhanced colonic transit (eg, senna, bisacodyl) avoided as long-term therapy
CM 23- Encopresis, Constipation, Hirschprungs, Megacolon
•
•
•
•
Megacolon
Toxic Megacolon- complication of inflammatory bowel disease
– total or segmental nonobstructive colonic dilatation plus systemic toxicity
congenital megacolon (Hirschsprung's disease)
idiopathic or acquired megacolon
– chronic constipation of any etiology
– intestinal pseudoobstruction
lack of systemic toxicity distinguishes these presentations from true toxic megacolon
Case 1- Constipation
• 11 yo male admitted to PICU with Severe Dehydration, abdominal distension, and Altered Mental Status
• Last bowel movement > 1 month ago
• Born premature at 35 weeks to a drug-addict mother, adopted at birth
• VSD closed spontaneously, ADHD, severe developmental delay; he functions at level 4-5 years old
• Chronic constipation (functional), rectal biopsy at age 8 yrs ruled out Hirshsprung disease
•
Rx with laxatives and purgatives all his life (frequent “Fleet Phoshpo-Soda” Enema)
Labs:
• Na+ 144 (133-143)
• K+ 5.7 (3.4-4.7)
• Ca++ 6 (8.9-10.3)
• Mg++ 4.1 (1.7-2.4)
• PO4- 26 (3.3-6.2)
• PH+ 7.16 (7.34-7.44)
• HCO3- 15 (22-26)
Abd X-ray:
• Fecal Impaction
• Distended loops of colon
ECHO:
• LVSF 6% (NR >30%)
• [It was 38% at age 8]
What happened
• 10pm >> ER
• 2am >> PICU
• 12:30pm >> Cardiac Arrest and Asystole > Vtach>Sinus Rhythm
• 7pm >> C. Arrest and Asystole> VTach> PEA (Echo poor contractility)
• 7:49pm >> Resuscitation Stopped & Pronounced Death
Dx: Chronic Constipation >>> Toxic Megacolon
Severe Electrolyte Imbalance >>> Severe Myocardial Depression and Cardiac Arrhythmias
Key points (Board Exam Favorites)
• Hirschprung: The rectum empty of feces and Explosive discharge of foul-smelling feces and gas
• Gold standard for Hirschsprung disease- rectal biopsy
• Down Syndrome- Hirschprung disaease- association
• Definition of constipation: 2 or fewer stools/wk OR passage of hard, pellet-like stool for at least 2 wks
• First line of therapy of constipation-beside diet modificatiob- osmotic agents-polyethylene glycol
• Encopresis could be mistaken for diarrhea (encopresis is constipation that finally expels as water when
disimpacted, uncontrollable)