GI and Liver Flashcards
What age is soiling most common?
Age 5-10 years
What % of school children suffer from constipation?
5-30%
What general terms are used to describe constipation?
Infrequent defecation, painful dedication, or both
What is chronic constipation?
Two or more of the following in the preceding 8 weeks:
1) Fewer than 3 bowel movements / week
2) More than 1 episode of faecal incontinence / week
3) Either palpable stools in abdo, or large stools palpable rectally
4) Passing stools so large they block the toilet
5) Retentive posturing and withholding behaviours
6) Painful defecation
What is faecal incontinence? How can it broadly be split?
Passage of stool in inappropriate places:
1) Organic faecal incontinence = from organic disease
2) Functional = without organic disease, either:
- Constipation-associated faecal incontinence
- Non-retentive faecal incontinence (no constipation associated) = passage of stools in inappropriate places in children >4yrs with no evidence of constipation
What is faecal impaction?
Large faecal mass (abdo or rectal assessed by abdo, rectal or other methods of examination) unlikely to be passed on demand
What is pelvic floor dyssynergia?
Inability to relax pelvic floor when attempting to defecate
What is the pathophysiology of constipation?
Begins as constipation leading to faecal retention. This leads to a vicious cycle as hard stools inhibit defecation and increases constipation. The rectum becomes distended with faecal impaction
In extreme cases, only liquid matter can escape = overflow diarrhoea
What psychosocial factors may be associated with constipation in children?
1) Psychological problems
2) Major life events eg parental divorce, bullying, sexual abuse
3) Neurodevelopmental disorders
4) Autism
5) Issues toilet training
What features are important to ask about in a constipation hx?
1) Frequency of defecation
2) Consistency of stools
- Can include Bristol Stool Chart
3) Episodes of faecal incontinence
4) Pain on defecation
5) Whether stools block toilet
6) Any associated behaviour
In an infant aged <6 months, what causes straining and crying for 10 minutes before passage of stools?
Dyschezia = painful or difficult defecation which resolves spontaneously
Often mistaken for constipation
What is pain on defecation likely to lead to? Does this resolve?
Withholding
Toddlers and older children get better at withholding
What should examination of a child with constipation include? (3)
1) Palpation of the abdo for faecal mass
2) Inspection for anal stenosis or anal ectopia
3) Checking for sacral abnormalities
NB rectal examination is not routinely required nor is routine radiology recommended
What are some organic causes of constipation? (9)
1) Anorectal malformation
2) Anal fissure
3) Rectal prolapse
4) Hirschsprung’s disease
5) Neurenteric problems
6) Spinal cord problems
7) Pelvic floor dyssynergia
8) Metabolic or systemic disorders
9) Toxic
10) Cow’s milk allergy
When do most of the organic causes of constipation present?
First few weeks of life
How should anorectal malformations be investigated?
Physical examination - inspecting the perineum in any baby with constipation
Checking if the anus is in the correct position relative to the vulva or scrotum
Digital exam (with little finger) occasionally - assess volume and hardness of rectal stool
How common is anal fissure? What is it associated with?
Common
Associated with painful defecation
Passage of blood and sentinel pile on anterior anus = characteristic
What may cause rectal prolapse? (4)
1) Chronic straining
2) Constipation
3) Disorders of sacral nerve innervation
4) Chronic diarrhoea
What is Hirschsprung’s disease?
Absence of parasympathetic ganglion cells in the myenteric and submucosal plexus of the rectum, possibly extending to the colon
Leads to an aganglionic segment which is unable to relax = functional colonic obstruction
How does Hirschsprung’s disease present in neonates? (3)
1) Abdo distention
2) Failure to pass meconium within first 48hrs of life
3) Repeated vomiting
NB delayed passage of meconium is very important - nearly half of all infants with Hirschsprung’s disease do not pass meconium within 36hrs and nearly half of all infants with delayed first passage of meconium have Hirschsprung’s disease
How does Hirschsprung’s disease present older infants and children?
Can present with chronic constipation that is resistant to usual treatments and a daily enema may be required
Rarely soiling and overflow incontinence which is in contrast to children with functional constipation
Causes early satiety, abdo discomfort, distention and poor nutrition and eightgian
What can develop in children with Hirschsprung’s disease?
Enterocolitis = at any age
How may enterocolitis present?
Abdo pain
Fever
Foul smelling and possibly bloody diarrhoea
Vomiting
What may happen in enterocolitis if not spotted early?
May progress to sepsis, transmural intestinal necrosis and perforation
What is the mortality of enterocolitis?
30-35%
Accounts for most of the mortality associated with Hirschsprung’s disease
When does Hirschsprung’s disease usually present?
Early - well inside first month
What investigations are done for Hirshsprung’s disease?
Rectal biopsy = test of choice
NOT anorectal manometry
What investigations are done for neurenteric problems?
Colonic motility = test of choice
Colonic transit
+/- rectal biopsy
What investigations are done for spinal cord problems?
MRI = investigation of choice
Physical examination
+/- anorectal manometry
What is anorectal manometry?
Measures pressures of anal sphincter muscles, sensation in the rectum and neural reflexes that are needed for normal bowel movements
What metabolic / systemic disorders may cause constipation and what investigations are done for them?
Hypothyroidism
- TFTs
Coeliac disease
- Total IgA and IgA tTG (tissue transglutaminase)
- Consider IgG EMA (endomysial antibodies), IgG GDP (gliadin peptides) or IgG tTG if IgA is deficient
Hypocalcaemia
- Calcium test
CF
- Sweat test
What toxicity may cause constipation and what should be investigation should be performed?
Lead levels
Toxicity screen
What investigations may be performed for cow’s milk allergy?
Elimination diet
Allergy testing
What investigations are done for functional / idiopathic constipation?
Hx and examination are most important and further tests are rarely necessary
Further investigations are recommended occasionally in chronic constipation and always in non-retentive faecal incontinence, specifically:
- Radiology (kidneys, ureter, bladder
- Colonic transit
What is features are needed to confirm constipation is present in a child <1 yr?
What about an older child?
At least 2 of the following:
1) <3 complete stools / week (unless exclusively BF when infrequent stools can be normal
2) Large hard stool or ‘rabbit droppings’
3) Sx associate with defecation: distress on passing stool, bleeding with hard school or straining
4) Past hx of constipation
5) Prev or current anal fissure
An older child may have the above, plus:
6) Overflow soiling = the child may be unaware of passing loose, smelly stools, which may be thick and sticky, or dry and flaky
7) Large stools big enough to block the toilet
8) Poor appetite that improve with the passage of a large stool
9) Retentive posturing eg tiptoes, straight legged with an arched back
10) Staining, painful bowel movements and/or anal pain
What features make a diagnosis of idiopathic constipation likely? (5)
1) Hx of meconium being passed within 48hrs of birth (in a full-term baby)
2) Constipation begins at least a few weeks after birth
3) Precipitating factors present eg weaning, poor fluid intake
4) Abdo is soft and not distended, normal appearance of anus (rectal examination not required)
5) General health, growth and development are normal with normal gait, tone, and power in lower limbs
What are some red flags for constipation in children?
1) Symptoms commence from birth or in first few weeks
2) Failure or delay (>first 48hrs at term) in passing meconium
3) Ribbon stools
4) Leg weakness or locomotor delay
5) Abdo distension with vomiting
6) Abnormal examination findings:
- Abnormal appearance of anus
- Gross abdo distension
- Abnormal gluteal muscles, scoliosis, sacral agenesis etc
- Limb deformity including talipes
- Abnormal reflexes
What is the management of functional / idiopathic constipation?
1) Disimpaction
2) Maintenance therapy
3) Modification of behaviour
- eg regular toileting / reward systems
4) Incontinence
- Explain involuntary nature to parents / school nurse
- Regular toileting
What does disimpaction involve in the management of functional / idiopathic constipation?
- Initially osmotic laxative eg polyethylene glycol (PEG) 3350 + electrolyte eg Movicol
- May increase symptoms eg soiling at first
- If not tolerated, substitute for stimulant laxative either on its own or with lactulose (osmotic laxative) or faecal softener (decussate) if stools are hard
- If not effective after 2 weeks:
Add stimulant laxative eg sodium picosulfate or Senna if >1 month
OR Decussate (softener and weak stimulant laxative) from 6mnths
OR bisacodyl suppositories from 2yrs
Rectal treatments eg enemas should be avoided but may be needed in extreme cases under specialist supervision
What does maintenance therapy involve in the management of functional / idiopathic constipation?
- Dietary advice
- Stool charts
- Regular laxatives over months / years (preferably osmotic PEG 3350 or lactulose) titrated to maintain soft formed stool
- Avoid stopping and starting treatment causing intermittent impaction
- Avoid prolonged use of stimulant laxatives, only use intermittently to avoid impaction