15.4.5.1 Appendicitis And Distal Bowel Obstruction

Question 1

Appendicitis
Epidemiology

Answer 1

• Appendicitis is the most common surgical emergency in childhood and presents more commonly in males.
• The peak incidence is between 10 – 11 years of age.
• Incidence rate is variable from 7% life-time risk in Western Europe to 0.5% in Sub-Saharan Africa.
• Although diagnostic methods and treatment have improved, appendicitis is still associated with a substantial morbidity and although rare, mortality still occurs.

Question 2

Appendicitis
Pathophysiology

Answer 2

• Luminal obstruction followed by bacterial infection.
• Various reasons for luminal obstruction are faecaloma, lymphoid hyperplasia secondary to Yersinia, Shigella or Salmonella, cystic fibrosis, foreign body or carcinoid tumour.
• Increased luminal pressure leads to vascular compromise and perforation.
• The appendix has one artery and occlusion of this artery will cause necrosis of the appendix that will lead to perforation. (Reason why it perforates easily)

Question 3

Appendicitis
Signs and Symptoms

Answer 3

Symptoms include:
- loss of appetite
- fever
- vomiting
- lower abdominal pain.
➡️Abdominal pain starts peri-umbilical (visceral nerve with its origin in 8-10th thoracic dorsal ganglia), and spreads to right lower quadrant when peritonism develops due to somatic sensation.
- Diarrhoea can develop with a pelvic appendix and renal colic like pain can be present in a retro-caecal appendix.

• Patients present with different levels of dehydration, tachycardia, pyrexia and according to duration of symptoms.
• Before palpation of the abdomen, ask the child to point to the area of maximal pain {this is alway appendicitis!!}, flexing the hips to relax abdominal muscles also helps prior to palpation. Abdominal distension with local or generalized tenderness or a palpable mass over McBurny’s point can be present on physical examination. McBurny, an American surgeon, mapped out the approximate location of appendix base relative to umbilicus and anterior superior iliac crest by dividing this distance to 3 equal distances (McBurney’s point is 1/3 closer to iliac crest).
• Children younger than 5 years are usually unable to verbalize pain, clinically difficult to examine and hence present late with perforated appendicitis.

Question 4

Define anorectal malformation

Answer 4

Anorectal malformations are abnormalities of the anus and rectum. They include a range of abnormalities from an absent anus (imperforate anus) to a rectal fistula which can appear on the perineum and look like an anal opening in an abnormal place.

Question 5

Anorectal malformations (ARM)
Epidemiology

Answer 5

• 1 in 4000 - 5000 live births
• More common in males

Question 6

ARM classification

Answer 6

According to the level of the fistula (where does the rectum connect)

Only know which is most common

Boys
- Imperforate anus with a rectal fistula:
➡️Perineal fistula (opening in perineum)
➡️Recto-urethral fistula: rectum connects to the urethra (most common in males)
➡️Recto-vesical fistula (rectum inserts at bladder neck)
- Imperforate anus without rectal fistula (rare and associated with T21)

Girls
- Imperforate anus with a rectal fistula:
➡️Perineal fistula (opening in the perineum)
➡️Recto-vestibular fistula (most common type of anorectal malformation in girls)
➡️Recto-vaginal fistula (exceptionally rare)
- Cloacal malformation (1 opening instead of 3)
urethra, vagina, and rectum all drain into single common channel with a single perineal opening instead of three
- Imperforate anus without rectal fistula
If girls only have 2 openings = most likely a rectal fistula

The higher the fistula, the less developed the muscles will be and the more severe the life long complications will be {incontinence}

Question 7

ARM signs and symptoms

Answer 7

Antenatal ultrasound: (only much later in pregnancy)
- Polyhydramnios
- May see thickened dilated bowel loops.
- May detect associated VACTERL anomalies

At birth:
- No anus (imperforate anus) or an abnormal anus on inspection of the perineum
- Signs of bowel obstruction:
➡️abdominal distension
➡️vomiting (feeds± bile-stained vomitus)
- Failure to pass meconium (the black stool passed normally within the first 24-48 hours after birth) NB!
- Associated anomalies

Need to examine the anus of every single baby, this is easily missed!!

Question 8

ARM abnormalities

Answer 8

• Trisomy 21
• Genito-urinary abnormalities
• Any of the VACTERL {know what stands for} anomalies (VERY COMMON)
  o Vertebralabnormalities:abnormalspineorvertebra
  o Anorectal abnormalities: born without an anus or with anus in abnormal place.
  o Cardiac abnormalities (Most common associated abnormality): Heart abnormalities
  o Trachea-oEsophagealfistula
  o Renalabnormalities:kidneys,ureter, or bladder
  o Limb abnormalities (Radial dysplasia, polydactyly

Question 9

Define Hirschprung’s disease

Answer 9

All muscle, but no brain
- Is a congenital functional large bowel obstruction.
- Characterized by the absence of ganglion cells (aganglionosis) in the myenteric and submucosal plexuses of the intestine
- The affected distal aganglionic bowel is contracted and unable to relax to let faeces pass.
- HD is an abnormal innervation of unknown aetiology affecting the distal
- Bowel leading to inability to pass stool normally, causing distal bowel obstruction.

Question 10

Hirschprungs’s disease pathophysiology

Answer 10

• Incidence: 1: 5000
  Anatomical distribution:
• 80% rectosigmoid HD (M:F = 4:1)
• 10% long segment HD (up to transverse colon; M:F = 2:1)
• 5 – 10% total colonic HD (M:F = 1:1)

Question 11

Hirschprung’s disease

Answer 11

Antenatal US:
- May see dilated bowel loops of bowel and mom may present with polyhydramnios

Postnatal:
- Clinical features of neonatal distal bowel obstruction (usually within first few days post-delivery)
- Vomiting
- Milky vomits increasingly becoming bile stained
- Failure to pass meconium within 24 hours
- Abdominal examination
o Abdominaldistention
o Abdominal redness +/- oedema o Tenderness
o Visible bowel peristalsis
- Rectal examination (gentle and only by surgeon)
o Urgent rectal exam is therapeutic!
- Normal patent anus
- 90% of normal new-born’s pass meconium within 24 hours (black, tarry sticky stool) Babies with HD typically fail to pass meconium within first 48 hours
- Dehydration, metabolic & biochemical derangements (Due to ongoing vomiting of lower gastrointestinal contents)
- If enterocolitis is present = sepsis with fever, tachycardia and potential septic shock with high mortality

Late presentation:
- Around 50% of patients with HD present beyond the neonatal period (>28 days old) and can present with:
- History of delayed passages of meconium at birth
- Chronic constipation
- Abdominal distension
- Malnutrition and failure to thrive
- Rectum often empty with explosive evacuation of loose stool

Important questions: When did your baby pass meconium? If it was passed late; could be Hir Disease!

Question 12

Hirschprung’s disease associated abnormalities

Answer 12

• Trisomy 21 (Down’s syndrome)
• Other rare neurocristopathy syndromes
• Isolated congenital anomalies e.g., congenital heart disease
• MEN type 2
• Malrotation
• Urinary tract anomalies