Gastro

Question 1

How do GI conditions present in a child?

Answer 1

• vomiting,
• abdominal pain,
• diarrhoea,
• crying, etc.

Question 2

What is posseting?

What is regurgitation?

What is vomiting?

Answer 2

• Posseting: non-forceful return of small amounts of milk that often accompanies the return of swallowed air (wind) à occurs in all babies from time to time
• Regurgitation: non-forceful return of larger amounts of milk
• Vomiting: forceful ejection of gastric contents

Question 3

What are the red flag features of vomiting?

Answer 3

• Bile stained vomit (intestinal obstruction)
• Haematemesis (peptic ulcer, varices)
• Projectile vomiting in first few weeks (pyloric stenosis)
• Paroxysmal coughing (pertussis)
• Abdo tenderness (surgical abdomen)
• Hepatosplenomegaly (liver disease, inborn error of metabolism)
• Blood in stool (intussusception, bacterial gastroenteritis)
• Severe dehydration, shock (severe gastroenteritis, systemic infection, DKA)
• Bulging fontanelle or seizures (raised ICP)
• Faltering growth (GORD, coeliac)

Question 4

What are the DDx of abdo pain in a child?

Answer 4

Question 5

Why might a child be crying?

Answer 5

• Usually due to hunger and discomfort
• Sudden-onset crying:
  
  • UTI,
  • otitis media,
  • meningeal infection,
  • unrecognised fracture,
  • oesophagitis,
  • testicular torsion,
  • constipation etc.
• Infant ‘colic’:

Question 6

Summarise infant colic

Answer 6

• Paroxysmal, inconsolable crying or screaming often accompanied by drawing up of the knees and passage of flatus, which takes place several times a day
• Lasts >3hrs/day and occurs >3days/week for at least 1 week
• Occurs in 40% babies, usually in first few weeks of life, and resolves from 3-12 months
• It is benign but frustrating and worrying for parents à support and reassurance
• If severe and persistent it may be due to cows milk protein allergy or GORD

Question 7

What is appendicitis?

Answer 7

Inflammation of the appendix (a narrow blind-ended tube connected to the posteromedial end of the caecum)

Question 8

Aetiology of appendicitis in a child?

Answer 8

Inflammation is due to obstruction of the lumen of the appendix (by a faecolith, normal faecal matter or lymphoid hyperplasia due to viral infection)

• Obstruction causes a cycle of progressive inflammation and bacterial overgrowth
• Leads to ischaemia → may progress to necrosis à risk of perforation
  
  • Takes around 72hrs for perforation to occur
    
    • May occur sooner in preschool children (omentum immature so fails to surround appendix)
  • Perforation releases bacteria into abdominal cavity à peritonitis

Question 9

RFs of appendicitis in a child?

Answer 9

RFs: poor dietary fibre, prolonged bowel transit time

Question 10

Epidemiology of appendicitis in a child?

Answer 10

Most common cause of abdominal pain in childhood requiring surgical intervention

Most common in 10-19yo; uncommon in children <3yo

Question 11

Symptoms of appendicitis in child?

Answer 11

Classical presentation:

• Abdominal pain
  
  • Initially central and colicky, then localises to RIF
    
    • Umbilical initially because inflammation of visceral peritoneum is poorly localised; localises when parietal peritoneum becomes irritated (which is innervated by the same region of abdo wall that lines it)
  • Aggravated by movement (walking, bumps during car journey)
• Anorexia, nausea, vomiting, diarrhoea
• Low-grade fever (high if rupture)

Atypical presentation:

• Especially likely in young children (can’t verbalise where the pain is)
• Vomiting and diarrhoea
• Different sites of pain if abnormal appendix position, e.g. retrocaecal appendix causes pain in RUQ and absence of peritoneal irritation signs

Question 12

Signs O/E of appendicitis in a child?

Answer 12

• Tachycardia, pyrexia, reluctance to move (esp if rupture)
• Tenderness and guarding at McBurney’s point (guarding may not occur in children); percussion pain
• Rovsing’s sign: RIF pain reproduced with palpation in LIF
• Psoas and obturator sign (rarely done): pain is elicited by extending R thigh in L lateral position (psoas) and by internal rotation of flexed thigh (obturator)

Question 13

Ix for appendicitis?

Answer 13

• Clinical diagnosis (but Ix can help if in doubt)
• Bloods:
  
  • FBC: WBC (esp neutrophils) elevated in 70-90%
  • U&Es (esp if vomiting)
  • CRP and ESR
• Urine dip → rule out UTI (leukocytes may be present, but nitrite -ve)
• Pregnancy test if appropriate
• USS
  
  • May support diagnosis → thickened, non-compressible appendix with increased blood flow
  • May show complications (appendix mass, abscess, perforation)
  • Can exclude other diagnoses (ovarian torsion, ectopic pregnancy)
• CT
  
  • If diagnostic doubt; not usually done

Question 14

What score is used to assess appendicitis in a child?

Answer 14

• Paediatric appendicitis score (PAS) assesses the risk of appendicitis
  
  • <4: low likelihood of appendicitis
  • 4-6: further monitoring and clinical judgement; USS
  • >6: refer to surgical team; higher risk of appendicitis

Question 15

Mx of appendicitis in a child?

Answer 15

Initial management:

• ABCDE approach, senior help
• IV access, IV fluids, NBM
• IV antibiotics (tazocin/cefoxitin)
• Contact surgical team to discuss whether surgical intervention is needed
  
  • Sometimes conservative management (IV antibiotics and monitoring) is used for early uncomplicated appendicitis or appendix mass, with later appendicectomy (after 6wks; sooner if deterioration)

Appendicectomy:

• In uncomplicated appendicitis (no mass)
• Usually laparoscopic
• IV antibiotics for 24hrs after; discharge in 24-36hrs

If suspected perforation:

• ABCDE approach (as above)
• Appendicectomy always done

Question 16

Complications and prognosis of appendicitis in a child?

Answer 16

Complications:

• Perforation (more common in young children) à peritonitis, sepsis
• Appendix mass
  
  • Greater omentum reduces spread of infection by surrounding and adhering to the appendix
• Appendix abscess
  
  • Treat by drainage; appendicectomy after 6wks if symptoms not resolved

Prognosis is excellent with treatment

Question 17

What is gastroenteritis?

Answer 17

Infection of the GI tract, usually by a virus

Question 18

Aetiology of gastroenteritis?

Answer 18

May be viral, bacterial or protozoal

• Viral:
  
  • Most common in developed countries (80%)
  • Rotavirus is most common (esp in winter and spring)
  • Other viruses include adenovirus (type 40 and 41), norovirus, calicivirus, coronavirus, astrovirus
• Bacterial:
  
  • More common in developing countries; uncommon in developed countries
  • Campylobacter jejuni is most common in developed countries
• Protozoal:
  
  • Uncommon in developed countries
  • E.g. Giardia, Cryptosporidium

Spread is mainly by faecal-oral route (contaminated hands, utensils, food and drink)

Question 19

Name some other bacterial causes of gastroenteritis, other than the common ones

Answer 19

Question 20

What can diarrhoea and vomiting cause in gastroenteritis?

Answer 20

Diarrhoea and vomiting lead to dehydration

• Isonatraemic and hyponatraemic dehydration:
  
  • There is a total body deficit of sodium and water à these losses are usually proportional so plasma Na remains in normal range (isonatraemic dehydration)
  • When children with diarrhoea drink large quantities of water or other hypotonic solutions (cola, fruit juices), there is greater net loss of sodium than water à fall in plasma sodium (hyponatraemic dehydration)
    
    • This leads to a shift of water from extracellular to intracellular compartments
    • Increased intracellular volume leads to seizures; decreased extracellular volume leads to shock
• Hypernatraemic dehydration:
  
  • Sometimes water loss exceeds the relative sodium loss à plasma sodium increases (hypernatraemic dehydration)
    
    • Usually due to insensible water losses (high fever, hot environment) or from profuse, low sodium diarrhoea
  • The extracellular fluid becomes hypertonic compared to the intracellular fluid à shift of water into the extracellular space from the intracellular compartment
  • Signs of extracellular depletion are therefore less per unit of fluid loss (e.g. skin turgor, fontanelle depression) à harder to recognise clinically
  • It is particularly dangerous because water is drawn out of the brain à cerebral shrinkage can cause jittery movements, increased muscle tone, altered consciousness, seizures
  • Transient hyperglycaemia can occur
• Children at an increased risk of dehydration are:
  
  • <1yo (esp <6mo),
  • infants who were low BW,
  • passed 6 or more diarrhoeal stools in past 24hrs,
  • have not tolerated/been offered supplementary fluids,
  • infants who have stopped breastfeeding,
  • signs of malnutrition

Question 21

What are the RFs for dehydration e.g in gastroenteritis?

Answer 21

Children at an increased risk of dehydration are:

• <1yo (esp <6mo),
• infants who were low BW,
• passed 6 or more diarrhoeal stools in past 24hrs,
• have not tolerated/been offered supplementary fluids,
• infants who have stopped breastfeeding,
• signs of malnutrition

Question 22

Signs and symptoms of gastroenteritis?

Answer 22

• Vomiting
• Diarrhoea
  
  • Bloody stools suggests bacterial cause
  • Mucous suggests bacterial cause or rotavirus
• Fever
  
  • Low-grade seen in 50% children with viral gastroenteritis
  • >39⁰C suggests bacterial
• Abdo cramps
• Anorexia
• Signs of dehydration
  
  • Suspect hypernatraemic dehydration if jittery movements, increased muscle tone, hyperreflexia, convulsions, drowsiness/coma

Question 23

What are the clinical signs of dehydration (e.g. in gastroenteritis)?

Answer 23

Question 24

Ix for gastroenteritis?

Answer 24

• Clinical assessment of dehydration:
  
  • Most accurate measure is weight loss (recent weight is not always available)
• History and examination are used to assess the degree of dehydration
  
  • No clinically detectable dehydration (usually <5% loss of body weight)
  • Clinical dehydration (usually 5-10% loss)
  • Shock (usually >10% loss)
• Clinical diagnosis (usually no Ix needed)
• Stool microscopy and culture
  
  • Indications: appears septic, blood/mucous in stool, immunocompromised, recent foreign travel, diarrhoea not improved by day 7
• Bloods:
  
  • U&Es, creatinine, glucose, FBC: if IV fluids are needed or suspecting hypernatraemia

Blood culture: if antibiotics are started

Question 25

Mx of gastroenteritis?

Answer 25

If no clinical dehydration:

• Aim is to prevent dehydration
• Continue breastfeeding and other milk feeds/age-appropriate diet
• Encourage fluid intake to compensate for increased GI losses
• Discourage fruit juices and carbonated drinks
• Give oral rehydration solution (ORS) as supplemental fluid if at increased risk of dehydration (see aetiology)

If there is clinical dehydration:

• Mainstay of therapy is oral rehydration
  
  • ORS works by giving Na and glucose à these are absorbed which also causes water to be absorbed from intestine à absorption of solutes and water exceeds secretion à keeps the child hydrated until the infective organism is eradicated
• Give fluid deficit replacement (50ml/kg) over 4hrs as well as maintenance fluid requirement; give ORS often and in small amounts
• Continue breastfeeding/age-appropriate diet
• Consider supplementing ORS with usual fluids if inadequate intake of ORS
• If inadequate intake of fluid or vomits persistently, consider giving ORS via NG tube
• If deterioration or persistent vomiting à give IV fluids

If in shock:

• 20ml/kg 0.9% NaCl solution, repeat if necessary
• Then give IV fluids

IV fluids:

• Replace fluid deficit over 24hrs and give maintenance fluids
• 0.9% NaCl solution +/- 5% glucose
• Monitor plasma electrolytes, urea, creatinine and glucose; consider IV K supplementation
• Continue breastfeeding if possible

After rehydration:

• Reintroduce normal food
• Avoid fruit juices and carbonated drinks
• Advise parents: diligent hand washing, towels infected by child should not be shared, do not return to school until 48hrs after last episode

Medication:

• Do not give antidiarrhoeal drugs and antiemetics → ineffective and may prolong excretion of bacteria
• Antibiotics are not routinely given, even if there is a bacterial cause
  
  • Only give for suspected/confirmed sepsis, extraintestinal spread of bacterial infection, salmonella gastroenteritis in children <6 months, malnourished or immunocompromised children or for specific infections (e.g. C. diff with pseudomembranous colitis, cholera, shigellosis, giardiasis)

Hypernatraemic dehydration:

• Management can be difficult
• Use oral rehydration to rehydrate hypernatraemic children with clinical dehydration
• If IV fluids are needed they should be given slowly
  
  • If given too quickly a rapid reduction in plasma Na conc and osmolality leads to a shift of water into cerebral cells à seizures and cerebral oedema
  • Give 0.9% saline +/- 5% glucose over at least 48hrs to replace fluid deficit, measuring plasma Na regularly (aiming to reduce it at less than 0.5mmol/l/hr)

Question 26

What is Crohn’s disease?

Answer 26

Chronic granulomatous inflammatory disease that can affect any part of the GI tract from mouth to anus

Question 27

Aetiology of Crohn’s disease?

Answer 27

There is transmural, patchy inflammation affecting one or several segments of the GI tract

• Initially, there are areas of acutely inflamed, thickened bowel
• Leads to strictures of the bowel and fistulae (between adjacent loops of bowel, between bowel and skin, or to other organs (e.g. bladder, vagina)

Aetiology unknown; likely to be due to environmental factors (infections, medications) triggering a response in genetically susceptible patients (multiple genes identified)

Question 28

Epidemiology of Crohn’s disease?

Answer 28

Bimodal peak of onset: 15-30yo, 60-80yo

More common than UC in children

Question 29

Signs and symptoms of Crohn’s disease?

Answer 29

• Classical presentation (25%):
  
  • Abdominal pain
  • Diarrhoea (may be bloody but not always)
  • Weight loss
• Extra-intestinal manifestations:
  
  • Oral lesions or perianal skin tags/fistulae/abscesses
  • Uveitis
  • Arthralgia
  • Erythema nodosum
• General ill health
  
  • May be the presenting features, esp in older children
  • Fever, lethargy, anorexia, weight loss
  • Growth failure, delayed puberty

Question 30

Ix for Crohn’s disease?

Answer 30

• Bloods:
  
  • FBC (low Hb, high WCC)
  • Look for deficiencies due to malabsorption: iron, B12/folate
  • High ESR/CRP
  • Albumin (low)
  • U&Es, LFTs
  • pANCA negative (perinuclear antineutrophil cytoplasmic antibody)
• Stool sample
  
  • Culture (exclude infection)
  • Faecal calprotectin (raised in inflammation – non-specific)
• Upper GI endoscopy and ileocolonoscopy and biopsy
  
  • Histological hallmark is presence of non-caseating granulomas (not seen in 30% at presentation)
  • Cobblestone mucosa, transmural colonic inflammation with infiltration of macrophages/lymphocytes/plasma cells
• Imaging:
  
  • CT/MRI (may be used to assess extent of disease)
  • AXR, barium enema (strictures (string sign of Kantor), deep ulceration (rose thorn)

NB endoscopy/colonoscopy and barium enema may be dangerous in acute exacerbation (perforation risk)

Question 31

Mx of Crohn’s disease?

Answer 31

Specialist MDT

Inducing remission:

• Basic obs, fluid resuscitation, analgesia, TPN if necessary
• Monitor markers of disease activity (fluid balance, ESR/CRP, platelets, stool frequency, Hb, albumin)
• Polymeric diet (liquid diet consisting of hydrolysed nutrients)
  
  • For 6-8wks in mild exacerbation; induces remission in 75%
• Oral budesonide (glucocorticoid)
  
  • If polymeric diet ineffective or more severe exacerbation
  • Fewer SEs than systemic corticosteroids
• Aminosalicylates (5-ASA), e.g. mesalazine
  
  • If not controlled (add to budesonide or replace)
• Oral corticosteroid, e.g. prednisolone
  
  • If still not controlled
  • IV if severe disease
• Infliximab or surgery (if very severe and unresponsive)

Maintaining remission:

• Immunosuppressant therapy
  
  • Azathioprine, mercaptopurine, methotrexate
• Anti-TNF agents if immunosuppressants failed
  
  • Infliximab, adalimumab
  • Very effective in maintaining remission

Long-term supplemental enteral nutrition

• May be needed to correct growth failure
• Overnight nasogastric or gastrostomy feeds

Surgery for complications

• Resection of affected bowel and stoma formation
• Risk of recurrence

Question 32

Complications & prognosis of Crohn’s disease?

Answer 32

Complications:

• Malabsorption, growth faltering
• Bowel strictures
• Perforation
• Fistulae (between bowel, bladder, vagina, skin)
• Perianal fistulae and abscesses
• Toxic megacolon (more common in UC)

Generally good prognosis à most patients lead normal lives with occasional relapses

2/3 require surgery at some stage

Question 33

Prognosis and complications of gastroenteritis?

Answer 33

Complications:

• Dehydration → shock, electrolyte abnormalities, AKI, metabolic acidosis
• Metabolic acidosis (due to faecal loss of bicarbonate and impaired renal H+ excretion)
• Postgastroenteritis syndrome:
  
  • Following gastroenteritis, the introduction of a normal diet may result in return of watery diarrhoea
  • Treat by restarting oral rehydration therapy

Usually self-limiting in UK; 1% mortality in developing countries

Question 34

What is ulcerative colitis?

Answer 34

Chronic relapsing inflammatory disease involving the rectum, and extending proximally to affect a variable length of colon

Question 35

Aetiology of ulcerative colitis?

Answer 35

There is diffuse inflammation of the rectal mucosa and submucosa, extending proximally

• Classified according to location (proctitis, proctosigmoiditis, L-sided colitis, extensive colitis)

Aetiology unknown; likely due to environmental factors triggering a response in genetically susceptible patients

Question 36

Epidemiology of ulcerative colitis?

Answer 36

Common; peak onset 15-30yrs

Less common than Crohn’s in childhood

Question 37

Signs and symptoms of ulcerative colitis?

Answer 37

• Rectal bleeding
• Diarrhoea (with blood and mucus)
• Colicky abdo pain
• Weight loss and growth failure (less frequent than Crohn’s)
• Extra-intestinal manifestations: erythema nodosum, arthritis, uveitis

Question 38

Ix for ulcerative colitis?

Answer 38

• Bloods:
  
  • FBC (low Hb, high WCC)
  • Look for deficiencies due to malabsorption: iron, B12/folate
  • High ESR/CRP
  • Albumin (low)
  • U&Es, LFTs
  • pANCA positive (perinuclear antineutrophil cytoplasmic antibody)
• Stool sample
  
  • Culture (exclude infection)
  • Faecal calprotectin (raised in inflammation – non-specific)
• Upper GI endoscopy and ileocolonoscopy and biopsy
  
  • Confluent colitis extending from the rectum proximally (variable length)
    
    • 90% children have pancolitis (usually confined to distal colon in adults)
  • Histology shows mucosal inflammation with granular appearance (pseudopolyps), crypt damage (cryptitis, architectural distortion, abscess, crypt loss) and ulceration
• Imaging:
  
  • CT/MRI (may be used to assess extent of disease)
  • AXR, barium enema
• NB endoscopy/colonoscopy and barium enema may be dangerous in acute exacerbation (perforation risk

Question 39

Mx of ulcerative colitis?

Answer 39

Inducing remission:

• Basic obs, monitor fluid balance
• Aminosalicylates (5-ASA), e.g. mesalazine
  
  • Topical if mild, oral if severe/extensive
• Corticosteroids
  
  • Topical if mild (rectal hydrocortisone), oral if severe/extensive (prednisolone)
• Severe fulminating disease:
  
  • Medical emergency
  • IV fluids
  • IV corticosteroids
  • Ciclosporin or infliximab (if needed)
  • Surgery (if no response)

Maintaining remission:

• Aminosalicylates
• If aggressive/extensive: immunomodulatory therapy (e.g. azathioprine) +/- low-dose corticosteroids
• In resistant disease biological therapies (e.g. infliximab) can be tried

Surgery

• Colectomy with ileostomy or ileorectal pouch
• For severe fulminating disease or chronic poorly controlled disease

Regular colonoscopic screening after 10yrs from diagnosis

Question 40

Complications and prognosis of ulcerative colitis?

Answer 40

Complications:

• Toxic megacolon
• Perforation
• Colonic adenocarcinoma in adults
• Primary sclerosing cholangitis
• Ankylosing spondylitis

Generally good prognosis à most patients lead normal lives with occasional relapses

Question 41

What is Meckel’s diverticulum?

Answer 41

Question 42

Aetiology of Meckel’s diverticulum?

Answer 42

During embryogenesis the vitelline duct runs between the terminal ileum, the umbilicus and the yolk sac

• It usually regresses by the 5^th week of development
• A Meckel’s diverticulum forms if it fails to regress
  
  • It is a true diverticulum containing all 3 layers of the intestinal wall, and has its own blood supply

Symptoms arise from ectopic tissue within the diverticulum, or from residual bands that connect the apex of the diverticulum to the abdominal wall

Aetiology is unknown; no known RFs

Question 43

Epidemiology of Meckel’s diverticulum?

Answer 43

Rule of 2s:

• Affects 2% people (common)
• 2% are symptomatic
• Usually presents in <2yo
• M:F 2:1

Question 44

Signs and symptoms of Meckel’s diverticulum?

Answer 44

• Usually asymptomatic
• Intermittent painless rectal bleeding
  
  • Bright red blood
  • Due to ulceration of ileal mucosa by acid production (from ectopic gastric cells)
  • May cause anaemia

O/E:

• normal abdo exam

Meckel diverticulitis

• Peritoneal irritation which may localise to RIF (mimics appendicitis)

Question 45

Ix for Meckel’s diverticulum?

Answer 45

• FBC (anaemia)
• Meckel’s scan
  
  • Radionucleotide scan with IV technetium-99 pertechnetate
  • Shows increased uptake by ectopic gastric mucosa in 70% cases
  • Diagnostic (but negative scan doesn’t exclude diagnosis)
• AXR (if obstruction suspected)

Question 46

Mx of Meckel’s diverticulum?

Answer 46

If asymptomatic:

• No treatment if discovered incidentally on imaging
• Prophylactic excision if discovered intraoperatively in a child/young adult

If symptomatic:

• Excision of diverticulum and any bleeding section of ileum; lysis of any adhesions causing obstruction
• Blood transfusion if necessary
• IV antibiotics if perforation and peritonitis

Question 47

Complications and prognosis of Meckel’s diverticulum?

Answer 47

Complications:

• Anaemia
• Intussusception → obstruction
• Postoperative complications: intestinal leakage (from suture line at site of excision), infection, adhesions

Excellent prognosis with treatment of symptomatic patients

Question 48

What is Hirschsprung’s disease?

Answer 48

Congenital condition where there is absence of ganglion cells in the myenteric (Auerbach) and submucosal (Meissner) plexuses of part of the large bowel, resulting in a narrow, contracted segment

Question 49

Aetiology of Hirschsprung’s disease?

Answer 49

Affects the anus and extends for a variable distance proximally, ending in a normally innervated, dilated colon

• Confined to rectosigmoid colon in 75%; entire colon involved in 10%

Due to failure of the neural crest-derived ganglion cells to migrate from the proximal to distal bowel during embryonic development

• Leads to part of the rectum/colon with no parasympathetic nerve innervation
• The affected bowel has only sympathetic innervation à hypertonicity and lack of appropriate relaxation in response to proximal distension à narrow/contracted segment of bowel à functional obstruction

Question 50

RFs for Hirschsprung’s disease?

Answer 50

RFs:

• Down’s,
• MEN IIA,
• male,
• gene mutations (ch 10 and 21),
• FHx

Question 51

Epidemiology of Hirschsprung’s disease?

Answer 51

Uncommon à 1/5000 live births; 20% of all neonatal obstruction

M>F

90% present in neonatal period; 95% present in 1^st year

Question 52

Signs and symptoms of Hirschsprung’s disease?

Answer 52

• Neonatal presentation (most common):
  
  • Failure to pass meconium in first 24-48hrs of life
  • Signs of intestinal obstruction: abdominal distension, bilious vomiting
  • Hirschsprung enterocolitis (rare, but life-threatening)
  • DRE: may reveal narrowed segment; withdrawal of finger often releases gush of flatus and stool
• If presents in later childhood:
  
  • Chronic constipation (usually profound) usually without soiling
    
    • Associated abdo distension and pain
  • Failure to thrive

Question 53

Ix for Hirschsprung’s disease?

Answer 53

• AXR
  
  • Dilated colon with absent air in rectum
  • Non-specific (difficult to differentiate between colon and small bowel in young children)
• Contrast enema
  
  • The most valuable initial screening diagnostic test
  • Shows contracted distal bowel and dilated proximal bowel
• Suction rectal biopsy
  
  • Definitive diagnosis
  • Must be taken at least 1.5cm above the pectinate line
  • Shows absence of ganglion cells
• Anorectal manometry
  
  • Usually not needed for diagnosis
  • Normally when rectum is distended with a balloon, pressure in anal canal falls (due to sphincter relaxation) à this reflex is absent in Hirschsprung’s

Question 54

Mx of Hirschsprung’s disease?

Answer 54

Initial management:

• If enterocolitis: ABCDE approach, IV fluids, IV metronidazole
• Bowel irrigation
  
  • Saline flushed into rectum through tube
  • Used to manage the abdominal distension before surgery

Surgical:

• Initial colostomy, followed by anastomosing normally innervated bowel to the anus
• Usually in first week of life

Short-segment disease with only mild constipation in older children:

• Manage with stimulant laxatives alone (senna)

Question 55

Complications and prognosis of Hirschsprung’s disease?

Answer 55

Complications:

• Hirschsprung’s enterocolitis
  
  • Ischaemic à necrosis and perforation proximal to the aganglionic segment
  • 50% mortality
• Postoperative enterocolitis (enterocolitis can occur after a successful operation; usually disappears in <1yr)
• Postoperative constipation
• Postoperative diarrhoea (esp if aganglionic segment is long)

Outcome is generally good à surgery works

Question 56

What is intussusception?

Answer 56

Invagination (telescoping) of a portion of proximal bowel into the lumen of the adjoining distal segment

Question 57

Aetiology of intussusception?

Answer 57

Usually involves the ileum passing into the caecum through the ileocaecal valve

• Leads to intestinal obstruction and mesenteric constriction à venous return obstruction à engorgement and oedema à bleeding à prevention of arterial perfusion à intestinal infarction and perforation

Aetiology is unclear; 90% idiopathic

• May be due to viral infection leading to enlargement of Peyer’s patches (lymphoid follicles in lamina propria) à act as lead point
• In older children there is usually a pathological lead point (e.g. Meckel diverticulum, polyp, tumours)

Question 58

RFs for intussusception?

Answer 58

• adenovirus,
• HSP,
• FAP

Question 59

epidemiology of intussusception?

Answer 59

Most common cause of intestinal obstruction in infants; rare in neonates

Question 60

Signs and symptoms of intussusception?

Answer 60

• Usually presents at 3 months – 2yrs (can occur at any age)
• Triad:
  
  • Severe colicky pain
    
    • Episodes last 1-3mins; child become pale and draws up the legs
    • There is recovery between the painful episodes
    • Child may become increasingly lethargic
  • Vomiting
    
    • Initially non-bilious; becomes bilious as intussusception becomes more established
  • PR bleeding
    
    • Redcurrant jelly stools à late sign due to mucosal necrosis and sloughing
• On examination:
  
  • Abdominal distension
  • ‘Sausage shaped’ mass palpable in abdomen
  • Signs of dehydration and shock (if severe)

Question 61

Ix for intussusception?

Answer 61

• AXR
  
  • Initial investigation when perforation or obstruction is suspected
  • ‘Crescent sign’: curvilinear mass on R (esp in transverse colon distal to hepatic flexure) is pathognomonic
• Abdo USS
  
  • To confirm diagnosis and check response to treatment
  • ‘Donut’ or ‘target’ sign

Question 62

Mx of intussusception?

Answer 62

Initial management:

• ABCDE approach
• IV fluid resuscitation (often hypovolaemia due to pooling of fluid in gut)
• NGT decompression
• IV antibiotics (e.g. gentamycin)

Therapeutic enema:

• Within 24hrs
• Air, water or contrast enema given for reduction of intussusception, by radiologist
• Usually 3 attempts (as risk of perforation)

Surgical reduction:

• If therapeutic enema fails or if there are signs of peritonitis

Laparoscopic or open

Question 63

Complications and prognosis of intussusception?

Answer 63

Complications:

• Intestinal perforation à peritonitis, sepsis, shock
• Recurrence

Therapeutic enema has 75% success; recurrence rate is 10%

Surgery has 2-5% recurrence rate

Question 64

What is malrotation and volvulus?

Answer 64

Malrotation is a spectrum of rotational and fixation disturbances that can occur during embryonic development

Volvulus is twisting of the intestine

Question 65

aetiology of malrotation and volvulus?

Answer 65

In normal embryological development, the small bowel rotates around the superior mesenteric artery

• This happens in 3 stages: (I) herniation, (II) return to the abdomen with 270⁰ counter-clockwise rotation, (III) fixation
• If the rotation does not occur properly, fixation of the bowel is abnormal
  
  • Non-rotation: midgut only rotates 180⁰; incomplete rotation (malrotation): duodenal loop lacks 90⁰ and caecocolic loop 180⁰ of the normal 270⁰ turn
  • The most common form of malrotation is when the caecum remains high and fixed to the posterior abdominal wall
• Malrotation predisposes the patient to volvulus
  
  • Usually when there is lack of fixation to the retroperitoneum and a narrow midgut mesenteric base à allows twisting of the intestine (volvulus)
    
    • May obstruct the blood supply and lead to intestinal necrosis
• There may be abnormal peritoneal bands that cross the duodenum (Ladd’s bands)
  
  • These create low-grade duodenal obstruction

Question 66

RFs for malrotation and volvulus?

Answer 66

embryological abnormalities that disrupt rotation and fixation (gastroschisis, omphalocele, congenital diaphragmatic hernia, jejunoileal atresia)

Question 67

signs and symptoms of malrotation and volvulus?

Answer 67

• Usually presents in first 1-3d of life with intestinal obstruction (from Ladd bands) or volvulus, but can present later (with obstruction/volvulus)
• Acute mid-gut volvulus:
  
  • Usually presents <1yo
  • Sudden onset bilious vomiting
  • Abdo distension
  • Severe pain
• Acute duodenal obstruction:
  
  • Usually presents in infancy
  • Forceful vomiting
  • Abdo distension
  • Gastric waves
  • Diarrhoea, constipation, GOR
• Chronic mid-gut volvulus:
  
  • Recurrent abdo pain
  • Malabsorption
  • May appear normal between volvulus episodes
• Chronic duodenal obstruction:
  
  • Usually presents in infancy-preschool
  • Bilious vomiting
  • Failure to thrive
  • May have intermittent abdo pain
• On examination:
  
  • Acute obstruction: tachycardia, tachypnoea, abdo distension, tinkling bowel sounds
  • Infarction/necrosis: tachycardia, pallor, pyrexia, signs of peritonitis

Question 68

Ix for malrotation and volvulus?

Answer 68

• Bloods: FBC, U&E, blood gas (metabolic acidosis with resp alkalosis)
• AXR
  
  • Dilated loops of bowel or gasless abdominal fluid
• Urgent upper GI contrast study
  
  • Diagnostic standard; should be performed on all infants with bilious vomiting
  • Cork-screw appearance with volvulus, or duodenal-jejunal flexure to the R of the midline with malrotations
• If signs of vascular compromise or rupture à urgent laparotomy
  
  • (Don’t do UGI)

Question 69

Mx for malrotation and volvulus?

Answer 69

Initial management (en route to theatre):

• ABCDE approach, senior help
• IV access, IV fluids
• NG tube decompression
• IV broad spectrum antibiotics
• UGI contrast study

Surgery:

• Open laparotomy and Ladd procedure
  
  • Volvulus is untwisted, Ladd bands divided, placement of small bowel on R and large bowel on L (to broaden mesentery), appendicectomy (to avoid diagnostic confusion in the future)
• If non-acute presentation:
  
  • Intermittent/partial volvulus or partial obstruction: timely (i.e. next day) open/laparoscopic Ladd procedure
  • Asymptomatic finding of malrotation: elective open/laparoscopic Ladd procedure

Question 70

Complications and prognosis of malrotation and volvulus?

Answer 70

Complications:

• Bowel strangulation, necrosis and perforation à septic shock
• Short gut syndrome (if large amount of bowel removed due to ischaemia/necrosis) à malabsorption
• Recurrence of volvulus (because malrotation cannot be completely corrected)
• Adhesions

10% mortality in volvulus; volvulus survivors have 10% risk of recurrence

Question 71

What is necrotising enterocolitis?

Answer 71

Severe gastrointestinal illness usually seen in preterm babies, characterised by intestinal epithelial destruction

Question 72

What is the aetiology of necrotising enterocolitis?

Answer 72

• Caused by impaired intestinal barrier function
  
  • This allows spread of commensal organisms into the mucosa, and potential colonisation by pathological organisms (E. coli, Klebsiella)
  • This leads to inflammation (from immune response) → more cell damage → more bacterial invasion (cycle)
  • Eventually leads to intestinal necrosis, perforation and sepsis
• The exact cause of impaired barrier function is unknown
  
  • Thought to be due to a combination of immature intestinal epithelial barrier and immature mucosal immune system (leading to bacterial invasion)

Question 73

What are the RFs for necrotising enterocolitis?

Answer 73

• prematurity,
• low BW,
• formula feeding (breastmilk is protective)

Question 74

What are the signs and symptoms of necrotising enterocolitis?

Answer 74

Presents in the first few weeks of life

• Feed intolerance & vomiting (may be bile stained)
  
  • Early signs
  • May be a history of initially making progress on feeding
• Fresh blood in stool

Signs:

• Decreased bowel sounds
• Distended abdomen +/- visible intestinal loops
• Temperature instability, bradycardia, lethargy, respiratory distress
• Signs of shock (if severe)

Question 75

What are the Ix for ?necrotising enterocolitis?

Answer 75

Question 76

What is the Mx of necrotising enterocolitis?

Answer 76

Initial management:

• ABCDE approach
• Mechanical ventilation, IV fluids, circulatory support if needed
• Stop oral feeding (NBM)
  
  • NG tube to decompress bowel (with suction)
• Broad spectrum antibiotics
  
  • To cover aerobic and anaerobic organisms
  • E.g. ampicillin/gentamycin + metronidazole/clindamycin

Surgery:

• For bowel perforation or if deteriorating; if extensive weigh up risks of short gut syndrome
• Needed in 20-40%
• Resection of necrotic bowel with formation of a stoma/anastomosis

Oral feeds can be restarted 7-10d after gas in the bowel wall (pneumatosis) clears

• TPN is always needed until then

Question 77

What are the complications of necrotising enterocolitis?

Answer 77

• Immediate:
  
  • Bowel perforation
  • Sepsis, shock, DIC
• Long-term:
  
  • Strictures, fistulas
  • Short gut syndrome (malabsorption due to extensive bowel resection)

Question 78

What is the prognosis of necrotising enterocolitis?

Answer 78

20% mortality (varies according to BW)