Paediatric Surgery SC041: The Newborn Baby Is Vomiting Repeatedly: Neonatal Intestinal Obstruction And Other GI Emergencies Flashcards
Care of neonates
- Poor temperature regulation
- Fluid intake (relatively underdeveloped kidney)
- Nutrition requirement (cannot fast for long time)
- Medication dosage (liver / renal metabolism poor)
Principles of Neonatal intestinal obstruction
Important points:
1. Bilious vomiting always pathological (Malrotation with **midgut volvulus until proven otherwise) (indicate obstruction distal to Ampulla of Vater)
- Surgical emergency
- Obstruction can be anywhere from distal to stomach down to rectum
2. Abdominal distension **NOT always present (e.g. foregut obstruction)
3. Meconium / Stool does ***NOT exclude obstruction (∵ passed into colon before defect occur)
Principles of management:
1. **NPO
2. **NG tube decompression (drip and suck)
3. ***IV fluids (replacement + maintenance) (drip and suck)
4. Investigations
- AXR +/- Contrast
- Routine bloods + pH
5. ?Surgery
***Causes of Neonatal intestinal obstruction
- Congenital anomalies
- **Intestinal atresia
—> Esophagus atresia (OA)
—> Duodenal atresia
—> SB atresia
—> Ano-rectal anomalies (Imperforate Anus +/- Fistula)
- **Malrotation - ***Meconium disease
- **Hirschsprung’s disease (Keyword: **Delay in passage of meconium >24 hours)
(Bilious vomiting DDx:
- Duodenal atresia
- SB atresia
- Malrotation (+ Bloody stools)
- Necrotising enterocolitis (NEC) (+ Bloody stools) (Keyword: ***Prematurity))
***Esophageal atresia (OA)
- Incidence ~1:3000
- M>F
- ***VACTERL associations:
—> Vertebral defects
—> Anal atresia
—> Cardiac defects
—> Tracheo-esophageal fistula (TOF)
—> Esophageal atresia
—> Renal anomalies
—> Limb anomalies - ***CHARGE syndrome:
—> Coloboma of eyelid (cleft eyelid)
—> Heart disease
—> Atresia choanae
—> Retarded development
—> Genital hypoplasia
—> Ear anomaly
Types:
- A: Pure OA with no fistula (2nd common, 15%)
- B: Proximal TOF
- C: OA + Distal TOF (most common, 80%)
- D: Proximal + Distal TOF (Double fistula)
- E: Pure TOF (3rd common) (H-type fistula: present with recurrent aspiration pneumonia)
Symptoms:
- **Polyhydramnios (indicate **foregut obstruction, baby cannot swallow / absorb amniotic fluid)
- **SGA (2.7-2.8kg)
- **Drooling of saliva
- **Unable to swallow
- **Aspiration, Respiratory distress
(- ***NO vomiting (self notes))
Diagnosis:
- Antenatal diagnosis: Polyhydramnios
- **Unable to pass NG tube
- **CXR
—> **bowel gas suggest type C / D / E —> gas pass from trachea to distal bowel
—> **no bowel gas suggest type A / B
- CT (delineate distance between 2 ends)
Surgical management:
1. Short gap (most babies) (<2 vertebral height (SpC OG))
- **Divide TOF (fistula) —> Repair esophageal atresia by **Primary anastomosis
- Long gap
- **Gastrostomy (for nutrition first for a few weeks) —> Let esophagus grow and reassess —> **Delayed primary anastomosis
- ?Esophageal replacement (uncommon)
Complications:
1. Anastomotic leak, stricture
2. Recurrent TOF
3. Tracheomalacia
4. Gastroesophageal reflux
5. Disordered peristalsis, difficulty swallowing
6. Failure to thrive
Duodenal atresia
- Associated with ***Down’s (must rule out)
- M>F
Antenatal Diagnosis:
- **Polyhydramnios
- **Double bubble sign on AXR / antenatal USG (Stomach bubble + Duodenal bubble)
S/S:
- **Post-prandial vomiting
- **Bilious / Clear vomit
Management:
- ***Duodeno-duodenostomy (join up the disconnected duodenum)
Small bowel atresia
- **Jejunum / **Ileum
- Theory: ?Vascular accident in-utero, leading to necrosis of segment of bowel —> atresia
- M>F
- Some genetic predisposition
Classification:
1. **Proximal atresia (i.e. Jejunum)
2. **Distal atresia (i.e. Ileum)
S/S:
- **Polyhydramnios (only in **high atresia)
- Proximal atresia: **Bilious vomiting on **1st day of life
- Distal atresia: Present after a **few days, **abdominal distension
- **Abdominal distension
- **Meconium may be passed (if atresia occurs late in gestation, meconium already passed into colon)
Investigations:
- AXR —> absent distal bowel gas
- GI contrast ***enema (Small colon (microcolon))
(Management:
- Join up proximal and distal end)
Ano-rectal anomalies
~ Reverse of esophageal atresia
- **Imperforate Anus +/- **Fistula
—> Boys: **Recto-vesical fistula (more common) / Recto-prostatic fistula (more common) / Recto-urethral fistula / Recto-perineal fistula
—> Girls: **Recto-vaginal fistula (usually come out in introitus (aka vestibular anus)) / Recto-perineal fistula
- ***VACTERL association
Diagnosis:
1. Presentation **clear-cut at birth (sometimes suspected antenatally with **dilated rectum on USG)
2. ***Invertogram (Plain X-ray: bottom up, head down so air float to rectum) (to delineate distance from rectum to perineum for surgical planning)
3. CT scan
Surgical management:
- Short gap (<1.5cm): Simple **1 stage anoplasty (create an anus)
- Long gap: **3 stage procedure: **Stoma (diverting descending colostomy) —> **Pullthrough (anoplasty) —> ***Closure of stoma
Pullthrough:
- **Posterior sagittal anorectoplasty (PSARP) (i.e. Open)
- **Laparoscopic-assisted anorectoplasty (LAR)
***Malrotation
- Physiological rotation in 1st trimester, normal 270o rotation, subsequent fixation
- Malrotation —> result in ***Short mesentery
- Predispose to **midgut volvulus + **duodenal compression
Normal person:
- SB mesentery start at LUQ, end at RLQ
Malrotation:
- **DJ flexure on right side (very near to Caecum) —> short base —> easily twisted
- Large bowel not attached to lateral abdominal wall —> peritoneal attachment (Ladd’s bands: attach caecum to retroperitoneum in RLQ) compress on duodenum —> duodenal obstruction —> **Bilious vomiting
S/S:
- **Bilious vomiting
- **Bloody stools (indicate midgut volvulus —> bowel ischaemia)
(- Initially ***scaphoid abdomen (∵ distal gut collapse) —> after a complete obstruction —> rapid expansion of volvulus —> abdominal mass / distended abdomen)
- Abdominal pain
- Ill-looking
Diagnosis:
- AXR (**DJ flexure sitting on / right of spine)
- Upper GI contrast **meal + **follow through (if in doubt —> but should first go in OT anyway) (corkscrew appearance)
- **Time is essence
Management:
1. **Laparotomy
2. Midgut volvulus: **Detorting of volvulus + Assess viability + Resection if needed
3. Malrotation: ***Ladd’s procedure for malrotation
- Meconium disease
Pathophysiology:
- **In-utero perforation of gut
—> **Meconium leaks into peritoneal cavity
—> Calcified (∵ not in lumen) + trigger inflammation
—> Peritonitis
—> ***Meconium ileus
—> Absent bowel gas
Causes of In-utero perforation:
1. **Small bowel atresia
2. **Hirschsprung’s disease
3. ***Cystic fibrosis (sweat test after operation)
4. Accident
S/S:
- Present as Simple obstruction / in-utero perforation (Meconium peritonitis)
Diagnosis:
- Contrast enema for diagnosis in suspected cases
Meconium ileus vs Meconium plug
Meconium plug:
- Transient hypomotility, self-limiting
- Contrast enema shows colonic obstruction
- Improves after contrast flushing
- Surgery rarely needed
- Hirschsprung’s disease
- Incidence of 1:5000
- Genetic association: ***RET
Pathophysiology:
- Failure of migration of ganglion from proximal to distal GI tract
—> No ganglion cells in distal GI tract (rectum always affected)
—> **Aganglionic segment from rectum up
—> No peristalsis (~ paralytic ileus)
—> **Absent rectal gas (High pressure zone)
Classification (according to where ganglion cells stop):
- Short segment (75%) (only rectum / sigmoid involved)
- Long segment (20%) (beyond sigmoid colon involved)
- Total colonic (SpC Revision)
S/S:
- Abdominal distension
- **Delay in passage of meconium >24 hours (Keyword in exam!!!)
- Enterocolitis
- Gush of air come out (explode) during DRE (~吉穿氣球)
- May present later in life: **Chronic constipation, Failure to thrive
Diagnosis:
1. **Rectal biopsy (to look for absence of ganglion cells, increased hypertrophic nerve fibres (ACE stain))
2. **Contrast enema (look for “narrow” rectum + dilated proximal colon)
3. ***Anorectal manometry
Treatment:
1. **Resect aganglionic segment —> **Pull down normal ganglionic segment (anastomose just above dentate line)
- **Transanal endorectal pullthrough
- **Duhamel operation (Retro-rectal tunnel with end to side anastomosis)
- Swenson (Rectosigmoidectomy and circumferential anastomosis)
- Soave (Normal bowel pulled through the aganglionic muscular cuff)
Complications:
1. ***Persistent constipation
- Retained aganglionosis / transitional zone pullthrough
- Anal achalasia
- Intestinal obstruction
- ***Soiling
- Injury to sphincter / nerve fibre - ***Post-op Enterocolitis
- Surgical emergency
- IO, vomiting, bloody diarrhoea, fever, sepsis
—> NPO + IV fluid + Antibiotic + Colonic irrigation
—> Laparotomy +/- Stoma
Other neonatal emergencies
- Congenital diaphragmatic hernia (CDH)
- Necrotising enterocolitis (NEC)
- Abdominal wall defects
- Omphalocele
- Gastroschisis
- Congenital diaphragmatic hernia (CDH)
- ***Posterolateral most common (1:4000)
- ***L side > R side (R side can be acquired after liver surgery)
Pathophysiology:
- Herniated abdominal contents prevents **lung growth —> **Pulmonary hypoplasia + **Pulmonary hypertension
- **Non-rotation of intestines (∵ intestine sit within thoracic cavity instead of going back to abdominal cavity for rotation —> did not rotate at all)
Diagnosis:
- Prenatal diagnosis (worse prognosis with earlier diagnosis (i.e. earlier defect —> earlier herniation to compress developing lung —> higher mortality))
Treatment:
1. Surgery
- repair hernia
- prevent long term complications only (e.g. bowel strangulation) (X improve survival, which depend on lung maturity)
- open / thoracoscopic
- only do surgery after stabilisation of baby by medical therapies
- Medical therapies (prevent **pulmonary hypertension —> can improve outcome)
- **HFOV (high-frequency oscillatory ventilation)
- **ECMO
- **Nitric oxide
- **Steroids (help to mature lung)
- **Surfactant
Prognosis:
- Survival depends on lung maturity (surgery not improve survival)
- Necrotising enterocolitis (NEC)
- Associated with Prematurity (Keyword in exam!!!)
- Exact mechanism unknown (Food seem to be triggering factor (not feed —> no NEC))
Multifactorial cause:
- Reduced intestinal protection
- Intestinal ischaemia
- Infection
S/S (~**Midgut volvulus except abdominal wall erythema):
- Abdominal wall **erythema / ecchymosis (∵ inflammation)
- Abdominal **distension (∵ accumulation of gas from bacterial metabolism from web)
- **Bloody stools
- Palpable abdominal mass
(- ***Bilious vomiting (∵ accumulation of gas from bacterial metabolism from web))
Investigations:
- Fever
- High WBC
- Low BP (∵ sepsis)
- AXR:
—> **Pneumatosis intestinalis (air within bowel wall ∵ gas forming organisms go through cracks of mucosa)
—> **Portal venous gas (very severe)
—> **Perforation (Pneumoperitoneum: Football sign)
(—> **Ground glass appearance)
Treatment:
1. NPO, **TPN
2. **IV Antibiotic
3. **Surgery (minority)
- **Resection + **Stoma / **Primary anastomosis
- Indications:
—> **Pneumoperitoneum (Football sign)
—> **Bowel ischaemia (signs of sepsis: metabolic acidosis, thrombocytopenia (platelets usually biphasic in sepsis: initially penia then cytosis after a few days))
—> Clinical deterioration
—> Failure of medical treatment
Prognosis:
- Mortality increases with disease extent + prematurity
- Abdominal wall defects
- Omphalocele
- Hole in **Umbilicus
- Cord inserts in sac
- **Sac present (covering exposed abdominal content)
- Bowel normal
- Bowel function: **Normal
- **Associated anomalies common —> suggest chromosomal testing / advise abortion (mostly **trisomy —> incompatible with long term survival)
(From SpC PP:
—> **Beckwith-Wiedemann syndrome
—> ***Chromosomal aneuploidies: Down’s, Edwards’, Patau’s, Turner’s)
—> CHARGE syndrome
—> Carpenter syndrome
—> Goltz syndrome)
- Hole usually big enough —> no bowel strangulation - Gastroschisis
- Hole in **Lateral to umbilicus (usually R side)
- Normal cord
- **Sac absent
- Bowel matted (thickened bowel wall, rigidity, adherent bowel loops)
- Bowel function: **Ileus
- Associated anomalies rare
- Hole usually small —> can cause **bowel strangulation
Diagnosis:
- Prenatal USG
- Clinical
Management:
1. **Cling film (prevent fluid loss)
2. **Antibiotics (prevent infection)
3. **Rule out associated anomalies
4. Surgery
- **Reduction + **Primary closure
- **Silo bag formation —> **Gentle traction / reduction for 7-10 days —> **Secondary closure
- Complications: ***Malrotation
SpC Interactive tutorial: Neonatal surgery
Pyloric stenosis
- Onset of **non-bilious vomiting at **2-8 weeks of age
- ***Unknown etiology
- Vomiting occurring at nearly ***every feeding
- ***Projectile vomiting
- Patients usually ***not ill-looking
- Baby in the early stage remains hungry —> ***sucks vigorously after episodes of vomiting
- Prolonged delay in diagnosis can lead to:
1. Dehydration
2. Metabolic alterations (Hypokalaemic hypochloraemic metabolic alkalosis)
3. Lethargy
Diagnosis:
- Clinical (Bulging of epigastric region: hypertrophied pyloric muscles)
- Contrast meal
- ***USG (Gold standard, measure thickness + length of pylorus)
Treatment:
- ***Ramstedt pyloromyotomy (Laparoscopic)
