Congenital abnormalities - Paediatrics

Congenital abnormalities

Tongue Tie

·        Short lingual fraenulum

·        Rarely interferes with eating or speech

·        Generally requires no treatment

Oesophageal Atresia

·        Happens early in embryonic life:

o  Lots else happening then too – look for associations as well

o  Cardia, Renal, Anus, Vertebral, Oesophagus, Trachea: CRAVET

·        Symptoms: dribbles all the time

·        Usually distal oesophagus attached to trachea (fistula) ® air in stomach

·        Urgent neonatal repair

Pyloric Stenosis

·        = Hypertrophic pyloric stenosis

·        4:1 boys to girls.  Males 1/200 – 1/400

·        Family history: in 15% of siblings or previous generation 

·        Pathophysiology: circular muscle hypertrophy ® progressive narrowing of pyloric stenosis 

·        Presentation: 3 – 6 weeks, initial spilling ® progressive dysfunction ® several days of non-bilious high volume projectile vomiting with or between feeds. Dryish nappies (from dehydration) 

·        Exam: peristaltic waves of exaggerated gastric peristalsis + palpable lump in RUQ (= pyloric tumour) when hips flexed and relaxed (eg immediately after a feed)

·        Differential:

o  Gastro-oesophageal reflux – but baby well and growing

o  Exclude infection: UTI, meningitis, gastroenteritis, chest infection 

·        Investigations: usually clinical diagnosis. Check electrolytes and blood gases for hypochloraemic hypokalaemic alkalosis

·        Treatment:

o  Rehydration: IV saline + KCL + glucose

o  Surgery: pyloromyotomy

Duodenal Atresia

·        Present in first 24 hours with green vomiting after feed

·        Xray shows double-bubble sign: gas in stomach

·        Associations: 1/3^rd have Down syndrome, 10% of Downs have duodenal atresia

Small Bowel Atresia

·        Due to loss of blood supply to that part of the gut in utero. Infarcts and heals (as opposed to after birth when bacteria ® gangrene)

·        Bowel distal to the obstruction may be malformed

Malrotation

·        In 80% of cases, diagnosed in first month of life. Usually presents after 2 –3 days with bilious vomiting 

·        Exclude: strangulated hernias, bowel obstruction secondary to adhesions, intussusception and sepsis 

·        Investigations: barium meal ® duodenal jejunal junction hasn‟t ascended to level of pylorus and is not to the left of the midline 

·        Pathogenesis: Dates from time when the midgut is in the umbilical chord. Failure of fusion (sygosis) of the small bowel mesentery to the posterior abdominal wall ® narrow “universal mesentery” with the superior mesenteric artery supplying the whole mid-gut ® torsion leads to mid-gut ischaemia

·        Surgical emergency

Meckel’s Diverticulum

·        Most frequent congenital abnormality of the gut (2% of autopsied adults). Due to persistence of omphalomesenteric duct

·        Illness of 2‟s: incidence 2%, 2 feet from ileocaecal valve, symptomatic from 2 years onwards 

·        Wide mouthed diverticulum (approx 5 cm), on antimesenteric border of the ileum, usually within 100 cm of ileocaecal valve. 30% of the time ectopic tissue is opposite the diverticular 

·        50% have normal ileal mucosa, rest have duodenal, pancreatic, colonic or gastric (not subject to feedback ® ulcers) mucosa

·        Symptoms:

o   40% of GI bleeds

o   Maroon not melaena

o   Intermittent 

o   ¯HB but no shock 

o   30% present with intussusception or band, 20% with diverticulitis like appendicitis, 5% with umbilical mass 

o   Meckel‟s diverticulitis: blocked, inflamed ® enlarged ® burst

·        Rarely symptomatic after age 5, but may ®

o   Haemorrhage, before age 10, due to peptic ulceration of surrounding ileal mucosa,

o   Inflammation, may mimic acute appendicitis 

o   Obstruction in kids/teenagers: intussusception into lumen of bowel, or twist on fibrous remnant of the omphalomesenteric duct extending from bowel to abdominal wall (remnant of the yoke sac)

·        Diagnosis and treatment:

o   Pertechnetate scan: looking for hot spot

o   Diagnostic Laproscopy

o   Treatment with laparotomy and end to end anastamosis

Meconium Ileus

·        Tenacious meconium won‟t shift, gets colonised and ­gas

·        Þ Cystic fibrosis.

Hirschsprung’s Disease (Aganglionic Megacolon)

·        = Aganglionic Megacolon

·        1^st described by Hirshsprung in 1886

·        Incidence: 1 in 3 – 5,000 live births.  Boys four times girls.  Familial tendency

·        Aetiology: ?arrest in migration of ganglion cells from neural crest down GI tract

·        Pathology: 

o   Absent GI ganglion cells (co-ordinate motility of bowel – Meissner‟s and Auerbach‟s plexuses). Always includes internal anal sphincter and spreads proximally a variable length:

§  50% to recto-sigmoid junction, through to

§  10% including total colon 

o   Affected colon can‟t relax ® greatly dilated proximal segment 

o   Macroscopic: affected segment may look normal, proximal segment damaged mucosa, possible perforation, thickened wall 

o   Microscopic: absence of normal ganglion cells (visible with acetyl cholinesterase stain) and hypertrophy of nerve fibres (non-specific – can occur with other conditions)

·        Clinical presentation: 

o   Age of presentation unrelated to length of affected segment. Eg someone with their total colon affected can present after years

o   3 groups of kids:

§  Neonate: acute lower GI obstruction, abdominal distension, bilious vomiting, maybe fulminant

§  diarrhoea, maybe perforation.  Clue: no gas in rectum on x-ray 

§  Infancy: constipation, abdominal distension, possibly precipitated by change in bacterial flora on introducing other foods after exclusive breast-feeding (may ®massive diarrhoea) 

§  Older: severe constipation, chronic abdominal distension, scybala (hard mass of faecal matter), failure to thrive, never soil pants

·        Diagnosis: 

o   Barium enema: narrow rectum, enlarged proximally. Usually rectum lumen twice the diameter of the colon. Don‟t do an enema if risk of perforation (barium in the peritoneum®serious peritonitis) 

o   Rectal manometry: inflate balloon in rectum, distal rectum and internal anal sphincter should normally relax, this won‟t 

o   Rectal biopsy: But finding ganglion cells is hard even in a normal specimen. Histochemistry – test for ­Ach (preganglionic nerve cells looking for ganglion cells)

·        Treatment: Two stage surgery:

o  Stage 1: Disobstruct: ostomy in lowest portion of bowel with ganglia

o  Stage 2: Later, bring ganglionated bowel to anus

Imperforate anus

·        In girls, often attaches into the posterior wall of the vagina 

·        Adequacy of the levator sling depends on how high the lesion is. If low, only a superficial problem. If high (growth arrested above levator sling), then reconstruction is more difficult

·        Look for other developmental abnormality: eg GU, vertebral, etc

 Other

·        Gastroschisis: paraumbilical defect with evisceration (extrusion of viscera) of abdominal contents. Incidence 1.6/10,000. No covering. Usually only bowel hanging out. Usually no other defect. Corrective surgery has good outcome. Delivery in tertiary centre 

·        Exomphalos: Herniation of abdominal contents (may include liver) into the base of the umbilical chord. Covered with peritoneum. Incidence 4.3/10,000. Other abnormalities often present