Surgical Emergencies in the Newborn



Surgical Emergencies in the Newborn


Steven A. Ringer

Anne R. Hansen





I. POTENTIAL SURGICAL CONDITIONS PRESENTING IN THE FETUS

A. Polyhydramnios (amniotic fluid volume >2 L) occurs in 1 in 1,000 births.

1. Gastrointestinal (GI) obstruction (including esophageal atresia [EA]) is the most frequent surgical cause of polyhydramnios.

2. Other causes of polyhydramnios include abdominal wall defects (omphalocele and gastroschisis), anencephaly, diaphragmatic hernia (DH), maternal diabetes with consequent fetal hyperglycemia and glucosuria and other conditions impairing the ability of the fetus to concentrate urine, tight nuchal cord and other causes of impaired fetal swallowing, and fetal death.

3. All women with suspected polyhydramnios should have an ultrasonographic examination. In experienced hands, this is the study of choice for the diagnosis of intestinal obstruction, abdominal wall defects, DH, as well as abnormalities leading to an inability of the fetus to swallow.

4. If intestinal obstruction is diagnosed antenatally and there is no concern for dystocia, vaginal delivery is acceptable. Pediatric surgical consultation should be obtained before delivery.

B. Oligohydramnios is associated with amniotic fluid leak, intrauterine growth restriction, postmaturity, fetal distress, and renal dysgenesis or agenesis (Potter syndrome; see Chapter 28). If the duration of oligohydramnios is prolonged, it is important to anticipate respiratory compromise in these
infants, as adequate amniotic fluid volume is generally necessary for normal pulmonary development, particularly during the second trimester of gestation. Severity of pulmonary hypoplasia correlates with degree and duration of oligohydramnios.

C. Meconium peritonitis can be diagnosed prenatally by ultrasonography, typically seen as areas of calcification scattered throughout the abdomen. Postnatally, calcifications are confirmed by plain film of the abdomen. It is usually due to antenatal perforation of the intestinal tract; thus, this diagnosis should prompt an evaluation for a congenital lesion causing intestinal obstruction, either anatomic or functional (see section IV.A).

D. Fetal ascites is usually associated with urinary tract anomalies (e.g., lower urinary tract obstruction due to posterior urethral valves). Other possible causes include hemolytic disease of the newborn, any severe anemia (e.g., α-thalassemia), peritonitis, thoracic duct obstruction, cardiac disease, hepatic or portal vein obstruction, hepatitis, and congenital infection (e.g., TORCH infections; see Chapters 48, 49, 50, 51, 52, 53) as well as other causes of hydrops fetalis (see Chapter 26). After birth, ascites may be seen in congenital nephrotic syndrome. Accurate prenatal ultrasonography is important in light of the potential for fetal surgery to minimize renal parenchymal injury by decompressing either the bladder or a hydronephrotic kidney (see Chapters 1 and 28).

E. Dystocia may result from fetal hydrocephalus, intestinal obstruction, abdominal wall defect, genitourinary anomalies, or fetal ascites (see section I.D).

F. Fetal surgery. The potential for surgical intervention during fetal life continues to develop. It depends heavily on the availability of precise prenatal diagnostic techniques and experience in accurately characterizing disorders including the use of ultrasonography and fast magnetic resonance imaging (MRI).

Advances in obstetric and anesthesia management have also contributed to the feasibility of performing in utero procedures. The mother must be carefully managed through what is often a long and unpredictable anesthesia course. Medications that reduce uterine irritability have been developed that maximally ensure that the uterus can be maintained without contractions during and after the procedure. The criteria for consideration of a procedure include the following:

1. Ethical considerations are important, including balancing both the potential risk and benefit to the fetus with the potential pain or harm to the mother as well as the impact on the family as a whole.

2. Technical feasibility

3. Severity of fetal condition. Initially, most cases dealt with conditions that were life threatening either because they caused death in utero or the inability to survive postnatal life if born unrepaired. Currently, some cases are considered when a condition is not life threatening but is severe and either the condition itself is progressive (such as the growth of a large tumor partially obstructing the fetal airway) or the consequences of the condition worsen progressively (such as worsening hydrops due to a large teratoma).


4. Necessary resources. The care of the mother, fetus, and potential baby during surgery, in the immediate postoperative period and after birth, must all be available in seamless proximity to the institution where the surgery is performed.

Fetal surgery has been successfully used for removal of an enlarging chest mass, such as an adenomatoid malformation of the lung or a bronchopulmonary sequestration. Mass lesions, such as sacrococcygeal teratoma, when diagnosed in utero, have been treated with excision or by fetoscopically guided laser ablation of the feeder vessels, resulting in involution, but this type of intervention is only considered when the lesion is causing life-threatening complications, such as fetal hydrops. Progressive fetal urethral obstruction has been ameliorated by the use of shunts or fulguration of posterior urethral valves. Similar fetoscopic laser ablation of connecting vessels has been used successfully in the treatment of twin-twin transfusion syndrome (TTTS) or twin reversed arterial perfusion (TRAP).

Fetal surgical correction of meningomyelocele is a rapidly evolving area of endeavor. A multicenter randomized controlled trial comparing in utero surgical correction with standard management found that performing prenatal surgery may lead to better outcomes than postnatal surgery. After 12 months, the 91 infants who had prenatal surgery were 30% less likely to die or need additional surgical procedures than the 92 infants who were treated postnatally. At 2.5-year follow-up, those treated prenatally showed improved physical development and motor function, such as unassisted walking, compared to those treated after birth. However, prenatal surgery was associated with increased risk of complications during pregnancy including premature delivery and tearing of the uterine wall from the surgical scar. Long-term effects of this approach remain uncertain. When the diagnosis of myelomeningocele is made prenatally, in utero repair is an option that parents may consider.

Successful fetal procedures that we are currently performing include ex utero intrapartum treatment (EXIT) procedures for complex airway obstructions and complex congenital DH, aortic valve dilation for critical aortic stenosis, atrial septostomy, or stent placement for intact atrial septum with hypoplastic left heart syndrome, vascular photocoagulation for TTTS or TRAP syndrome, and percutaneous bladder shunt for bladder outlet obstruction. Indications for fetal intervention continue to evolve and change.

II. POSTNATAL SURGICAL DISORDERS: DIAGNOSIS BY PRESENTING SYMPTOM

A. Respiratory distress (see sections III.B and III.C; Chapters 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39). Although most etiologies of respiratory distress are treated medically, some respiratory disorders do require surgical therapies.

1. Choanal atresia (see section III.C.1)

2. Laryngotracheal clefts (see section III.C.3)

3. Tracheal agenesis


4. EA with or without tracheoesophageal fistula (TEF) (see section III.A)

5. Congenital lobar emphysema

6. Cystic adenomatoid malformation of the lung, pulmonary sequestration

7. DH (see section III.B)

8. Biliary tracheobronchial communication (extremely rare)

B. Scaphoid abdomen

1. DH (see section III.B)

2. EA without TEF (see section III.A)

C. Excessive mucus and salivation. EA with or without TEF (see section III.A)

D. Abdominal distention can be due to ascites, pneumoperitoneum, or intestinal obstruction (mechanical or functional).

1. Pneumoperitoneum. Any perforation of the bowel may cause pneumoperitoneum (see Chapter 27).

a. Any portion of the GI tract can potentially perforate for a variety of reasons including poor bowel wall integrity (e.g., necrotizing enterocolitis or localized ischemia of the stomach or small bowel associated with some medications such as indomethacin) and excessive pressure (e.g., obstruction, TEF, or instrumentation [i.e., with a nasogastric tube]). Perforated stomach is associated with large amounts of free intra-abdominal air. Active GI air leak requires urgent surgical closure. It may be necessary to aspirate air from the abdominal cavity to relieve respiratory distress before definitive surgical repair.

b. Air from a pulmonary air leak may dissect into the peritoneal cavity of infants receiving mechanical ventilation. Treatment of pneumoperitoneum transmitted from pulmonary air leak should focus on managing the pulmonary air leak.

2. Intestinal obstruction

a. EA with TEF (see section III.A) can present as abdominal distension. Obstruction of proximal bowel (e.g., complete duodenal atresia) typically results in rapid distension of the left upper quadrant. Obstruction of distal bowel causes more generalized distention, varying with location of obstruction.

b. Obstruction may be suspected when the progression of the air column through the gut is slowed or halted. Normally, when assessed by plain radiographs, air is seen 1 hour after birth at a point past the stomach and into the upper jejunum; 3 hours after birth, it is at the cecum; 8 to 12 hours after birth, it is at the rectosigmoid. This progression is slower in the premature infant.

E. Vomiting. The causes of vomiting can be differentiated by the presence or absence of bile.

1. Bilious emesis. The presence of bile-stained vomit in the newborn should be treated as a life-threatening emergency, with at least 20% of such infants requiring emergency surgical intervention after evaluation. Surgical consultation should be obtained immediately. Unless the infant is clinically unstable, a contrast study of the upper gastrointestinal (UGI) tract should be obtained as quickly as possible.


Intestinal obstruction may result from malrotation with or without midgut volvulus; duodenal, jejunal, ileal, or colonic atresias; annular pancreas; Hirschsprung disease; aberrant superior mesenteric artery; preduodenal portal vein; peritoneal bands; persistent omphalomesenteric duct; or duodenal duplication.

Bile-stained emesis is occasionally seen in infants without intestinal obstruction who have decreased motility (see section II.E.2.c). In these cases, the bile-stained vomiting will only occur one or two times and will present without abdominal distention. However, a nonsurgical condition is a diagnosis of exclusion; bilious emesis is malrotation until proven otherwise.

2. Nonbilious emesis

a. Feeding excessive volume

b. Milk (human or formula) intolerance

c. Decreased motility

i. Prematurity

ii. Antenatal exposure to MgSO4 or ante-, pre-, or postnatal exposure to narcotics

iii. Sepsis with ileus

iv. Central nervous system (CNS) lesion

d. Lesion above ampulla of Vater

i. Pyloric stenosis

ii. Upper duodenal stenosis

iii. Annular pancreas (rare)

F. Failure to pass meconium can occur in sick and/or premature babies with decreased bowel motility. It also may be the result of the following disorders:

1. Imperforate anus

2. Microcolon

3. Mucous plug

4. Other causes of intestinal obstruction

G. Failure to develop transitional stools after the passage of meconium

1. Volvulus, other intestinal obstruction

2. Malrotation

H. Hematemesis or hematochezia

1. Nonsurgical conditions. Many patients with hematemesis, and most patients with hematochezia (bloody stools), have a nonsurgical condition. Differential diagnosis includes the following:

a. Milk intolerance/allergy (usually cow’s milk protein allergy)

b. Instrumentation (e.g., nasogastric tube, endotracheal tube)

c. Swallowed maternal blood

i. Maternal blood is sometimes swallowed by the newborn during labor and delivery. This can be diagnosed by an Apt test performed on blood aspirated from the infant’s stomach (see section XI.G).

ii. In breastfed infants, either micro- or macroscopic blood noted several days after birth in either emesis or stool may be due to swallowed blood during breastfeeding in setting of cracked maternal nipples.
Inspecting the mother’s breasts or expressed milk is usually diagnostic. If not, aspirate the contents of the baby’s stomach after a feeding and send the recently swallowed milk for an Apt test.

d. Coagulation disorders including disseminated intravascular coagulation (DIC), lack of postnatal vitamin K injection (see Chapter 43)

2. Surgical conditions resulting in hematemesis and bloody stool

a. Necrotizing enterocolitis (most frequent cause of hematemesis and bloody stool in premature infants; see Chapter 27)

b. Gastric or duodenal ulcers (due to stress, steroid therapy)

c. GI obstruction: late sign, concerning for threatened or necrotic bowel

d. Volvulus

e. Intussusception

f. Polyps, hemangiomas

g. Meckel diverticulum

h. Duplications of the small intestine

i. Cirsoid aneurysm

I. Abdominal masses (see section VIII)

1. Genitourinary anomalies including distended bladder (see section VII and Chapter 28)

2. Hepatosplenomegaly: may be confused with other masses; requires medical evaluation

3. Tumors (see section VII)

J. Birth trauma (see Chapter 6)

1. Fractured clavicle/humerus (see Chapter 58)

2. Intracranial hemorrhage (see Chapter 54)

3. Lacerated solid organs—liver, spleen

4. Spinal cord transection with quadriplegia

III. LESIONS CAUSING RESPIRATORY DISTRESS

A. EA and TEF. At least 85% of infants with EA also have TEF. Pure EA and TEF with proximal TEF may be suspected on prenatal ultrasonography by the absence of a stomach bubble.

1. Postnatal presentation depends on the presence or absence as well as location of a TEF.

a. Infants often present with excessive salivation and vomiting soon after feedings. They may develop respiratory distress due to the following:

i. Airway obstruction by excess secretions

ii. Aspiration of saliva and milk

iii. Compromised pulmonary capacity due to diaphragmatic elevation secondary to abdominal distension

iv. Reflux of gastric contents up the distal esophagus into the lungs through the fistula

b. If there is no fistula, or if it connects the trachea to the esophagus proximal to the atresia, no GI gas will be seen on x-ray examination, and the abdomen will be scaphoid.


c. TEF without EA (H-type fistula) is extremely rare and usually presents after the neonatal period. The diagnosis is suggested by a history of frequent pneumonias or respiratory distress temporally related to meals.

2. Diagnosis

a. EA itself is diagnosed by the inability to pass a catheter from the mouth or nose into the stomach. The catheter is inserted into the esophagus until resistance is met. Air is then injected into the catheter while listening (for lack of air) over the stomach. The diagnosis is confirmed by x-ray studies showing the catheter coiled in the upper esophageal pouch. Plain x-ray films may demonstrate a distended blind upper esophageal pouch filled with air that is unable to progress into the stomach. (The plain films may also show associated cardiac or vertebral anomalies of the cervical or upper thoracic region of the spine.)

b. H-type fistula. This disorder can often be demonstrated with administration of nonionic water-soluble contrast medium (Omnipaque) during cinefluoroscopy. The definitive examination is combined fiberoptic bronchoscopy and esophagoscopy with passage of a fine balloon catheter from the trachea into the esophagus. The H-type fistula is usually high in the trachea (cervical area).

3. Associated issues and anomalies. Babies with TEF and EA are often of low birth weight. Approximately 20% of these babies are premature (five times the normal incidence), and another 20% are small for gestational age (eight times the normal incidence). Other anomalies may be present, including chromosomal abnormalities and the VACTERL association: Vertebral defects, imperforate Anus, Cardiac defects, TEF with EA, Renal dysplasia or defects and Limb anomalies.

4. Management. Preoperative management focuses on minimizing the risk of aspiration and avoiding gaseous distension of the GI tract with positive pressure crossing from the trachea into the esophagus.

a. A multiple end-hole suction catheter (Replogle or Vygon) should be placed in the proximal pouch and put to continuous suction immediately after the diagnosis is made.

b. The head of the bed should be elevated 30 degrees to diminish reflux of gastric contents into the fistula and aspiration of oral secretions that may accumulate in the proximal esophageal pouch.

c. If possible, mechanical ventilation of these babies should be avoided until the fistula is controlled because the positive pressure may cause severe abdominal distension compromising respiratory function. If intubation is required, the case should be considered an emergency. Guidelines for intubation are the same as for other types of respiratory distress. The endotracheal tube should be advanced to just above the carina in the hopes of obstructing airflow through the fistula. Most commonly, the fistula connects to the trachea near the carina. Care must be taken to avoid accidental intubation of the fistula. Optimally, if mechanical ventilation is required, it should be done using a relatively high rate and low pressure to minimize GI distention. Heavy sedation should be avoided because it compromises patient’s spontaneous respiratory effort which generates negative intrathoracic pressure, minimizing passage of air through the fistula into the esophagus.

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Oct 27, 2018 | Posted by in PEDIATRICS | Comments Off on Surgical Emergencies in the Newborn
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