Paediatric surgical emergencies
Dafydd A. Davies and Jacob C. Langer
While paediatric surgery has increasingly become the domain of the subspecialist paediatric surgeon, adult general surgeons are still often faced with the challenges of assessing and managing children with surgical emergencies. The unique differences between adults and children must be taken into account when addressing every aspect of surgical management, including assessment, diagnosis, resuscitation and operative interventions. Children face a different spectrum of conditions, have different physiological responses to trauma, illness and surgical stress, and have different psychosocial needs.
This chapter will address the common abdominal paediatric surgical emergencies encountered by general surgeons. These will be categorised according to age: (i) Neonates (up to 44 weeks postgestational age), (ii) infants (1 month to 2 years of age) and (iii) children (2 years of age and older).
Routine prenatal ultrasonography has become the standard of care in many parts of the developed world, and has resulted in the detection of many congenital anomalies before birth. Common detectable anomalies relevant to the general surgeon include: abdominal wall defects, congenital diaphragmatic hernia, intestinal obstruction, and intra-abdominal masses.
Whenever possible these patients should be referred for prenatal consultation with obstetrics, neonatology and paediatric general surgery. In most cases, delivery should occur at a hospital with a neonatal intensive care unit and paediatric surgical service. If this is not possible they should be immediately transferred following delivery and resuscitation.
Intestinal obstruction is the most common abdominal emergency in the neonatal period, and is usually due to a congenital, developmental or genetic anomaly.
Assessing neonatal patients for obstruction requires a thorough history, including the nature of any vomiting and the presence or absence of abdominal distention. Since neonates are unable to verbalise, surgeons must gather as many clues as possible from the prenatal, perinatal and family historical details (Table 12.1).
Important considerations in the neonatal history
Examination of neonates with suspected intestinal obstruction should start with vital signs and an assessment of the level of resuscitation required. Certain forms of obstruction can cause severe dehydration or sepsis, which will need to be addressed early. Dysmorphic features may give clues to syndromes in which obstruction is common. The abdominal examination should make note of any discoloration, distention and signs of peritoneal inflammation, such as guarding and rigidity. It is important to look for an incarcerated inguinal hernia as the cause of obstruction (see later). A thorough evaluation of the perineum must also be carried out to ensure normal location and patency of the anus.
Routine blood tests including electrolytes and full blood count are helpful in assessing the level of dehydration as well as helping determine if electrolyte disturbances or sepsis are contributing to the presentation. It should be kept in mind that serum creatinine in the newborn reflects the mother's levels, and may not be helpful in assessing the neonate's renal function.
Abdominal radiography should be the initial imaging modality for neonates with possible intestinal obstruction. Typically, infants with duodenal obstruction have a ‘double-bubble’ appearance (Fig. 12. 1), whereas those with distal intestinal obstruction will have multiple dilated bowel loops. It is impossible to differentiate distal small-bowel obstruction from colonic obstruction based on the plain abdominal radiograph in neonates, as the haustral markings seen in adults are not visible in this age group.
FIGURE 12.1 Abdominal radiograph of an infant showing the typical ‘double-bubble’ appearance resulting from duodenal obstruction.
A contrast study is often required to definitively diagnose the aetiology of intestinal obstruction. If malrotation is suspected, an urgent upper gastrointestinal contrast study should be performed first. Once this diagnosis has been excluded a contrast enema can be done to exclude distal pathology if this is indicated. For those infants with distal obstruction on plain radiograph, a contrast enema will help to differentiate the three most common causes of distal obstruction: meconium ileus, jejuno-ileal atresia and Hirschsprung's disease (Fig. 12.2). Water-soluble contrast should always be used instead of barium, to avoid the possibility of barium leaking into the abdominal cavity should a perforation occur, and also because water-soluble contrast is more effective in relieving the obstruction in cases of meconium obstruction.
FIGURE 12.2 Water-soluble contrast enemas of infants with distal bowel obstruction. (a) Meconium ileus, showing a microcolon, dilated proximal small bowel and a soap-bubble appearance in the right lower quadrant. (b) Ileal atresia, showing a microcolon, contrast entering the distal small bowel but dilated proximal small bowel without contrast. (c) Hirschsprung's disease: lateral film showing a contracted distal rectum with dilated bowel proximally.
Neonates with suspected intestinal obstruction should be transferred in a temperature-controlled transport isolette to a specialised paediatric surgical unit for evaluation and definitive management. Resuscitation should begin as soon as the patient is assessed and should continue during transport. Nasogastric decompression with a large-calibre nasogastric tube (size 8–10 French) is important to improve ventilation, monitor resuscitation, and limit bowel distention and subsequent ischaemia.
Specific forms of intestinal obstruction
Oesophageal Atresia: This anomaly is characterised by a gap in the oesophagus, resulting in a blind-ending proximal pouch. In 90% of cases, the distal oesophagus is connected to the back of the trachea as a tracheo- oesophageal fistula. Oesophageal atresia is usually first suspected when the baby has difficulty swallowing saliva and may have coughing or respiratory distress during the first feed.1 Intubation may be needed if ventilation or respiration are significantly impaired. The diagnosis is confirmed by the inability to pass a 10–12 French nasogastric tube. This tube should be left in the proximal oesophageal pouch and placed on suction to prevent aspiration of secretions. Operative repair should only be performed by an experienced paediatric surgeon and involves division of the fistula and end-to-end anastamosis of the proximal and distal oesophagus.
Meconium Ileus: Cystic fibrosis (CF) is the most common autosomal recessive disorder in Caucasian children.2 The disease alters the regulation of chloride transport in epithelial cells, resulting in a variety of clinical manifestations. Ten to fifteen per cent of children born with CF will develop meconium ileus, in which the meconium becomes sticky and causes intraluminal obstruction. This can further lead to complications of volvulus, atresia or perforation. In addition, meconium ileus may occasionally occur in children without CF. A diagnostic work-up, including both sweat chloride determination and genetic studies, must therefore be performed on all children with meconium ileus.
Abdominal radiographs may show distal intestinal obstruction with a bubbly appearance in the right lower quadrant due to gas mixing with the viscous meconium (Fig. 12.2a).2 There may also be intraperitoneal calcification if in-utero perforation has occurred.
Following resuscitation and nasogastric decompression, a water-soluble contrast enema will reveal a microcolon (small calibre) and multiple meconium plugs in the terminal ileum (Fig. 12.2a). In approximately 50% of cases, the contrast enema will relieve the obstruction. If progress is made, but the infant remains obstructed after the initial enema and is otherwise stable, the procedure can be repeated. If the contrast enema is unsuccessful in relieving the obstruction and/or no further progress has been made, a laparotomy must be carried out. If there is no volvulus or perforation, enterotomies are made and mechanical washout is performed. Complications of volvulus, acquired atresia or perforation are managed by intestinal resection with or without a stoma, depending on the condition of the bowel and of the patient.
Intestinal Atresia/Stenosis: Atresia and stenosis can occur at any point in the alimentary canal. The two prominent aetiological theories are failure of recanalisation of the intestine during foetal development or an ischaemic event in utero.3 Early resuscitative measures should be initiated and confirmatory diagnosis can usually be made with either upper or lower gastrointestinal contrast studies. The presence of a ‘double-bubble’ sign on abdominal radiograph is considered diagnostic for duodenal atresia (Fig. 12.1), although this finding associated with distal gas may also be due to stenosis, duodenal web, or malrotation. Trisomy 21 is present in one-third of children with duodenal atresia. Patients with distal atresia will typically have multiple dilated loops of bowel on the plain abdominal radiograph. Although a diagnosis of proximal obstruction can be confidently made based on plain radiography, those with distal obstruction should always undergo water-soluble contrast enema to differentiate atresia from meconium ileus or Hirschsprung's disease.
Since most infants with intestinal atresia are stable once decompressed and resuscitated, they should then be transferred to a facility with paediatric surgical expertise. Most of these anomalies are treated with a primary anastomosis. If there is significant dilatation of the proximal segment, a tapering enteroplasty should be performed as the dilated bowel tends not to have effective peristalsis.
Hirschsprung's Disease: Hirschsprung's disease (HD) is a congenital disorder characterised by a lack of ganglion cells in the distal bowel. This results in failure of peristalsis and functional obstruction. The ‘transition zone’ is usually located in the rectosigmoid region, but HD can affect the entire colon and in rare occurrences the small bowel. HD most often presents in the neonatal period with distal bowel obstruction and failure to pass meconium in the first 24 hours of life. Patients can present later in life with a history of severe constipation. Early identification and management are important to prevent complications of HD such as enterocolitis and nutritional problems.
Water-soluble contrast enema has a sensitivity and specificity of 70% and 83%, respectively, and may therefore be normal, particularly in the newborn.4 The gold standard for the diagnosis of HD is rectal biopsy, either by a suction technique at the bedside or full-thickness biopsy.
Initial management, after resuscitation and nasogastric decompression, includes digital rectal stimulation and/or rectal irrigations (10 mL/kg normal saline).
Although the historical teaching used to be routine diverting colostomy followed by a ‘pull-through’ operation several months later, the current standard of care is primary reconstructive surgery without a routine colostomy in most patients.5
Preliminary colostomy should be reserved for infants presenting with severe enterocolitis or colonic perforation.
There are a number of options for the surgical correction of HD, including the Swenson, Soave and Duhamel procedures. In recent years, laparoscopic and trans-anal approaches have been described, which have decreased morbidity and shortened hospital stay. It goes without saying that these operations should all be carried out by an experienced paediatric surgeon.
Anorectal Malformations: Anorectal malformations can be divided into low and high anomalies. Low anomalies are characterised by rectoperineal or rectovestibular fistulas in female patients. Most males with high malformations have a fistula from the rectum to the bladder neck or urethra. Females with high anomalies usually have a single channel (cloaca) formed by coalescence of the urethra, vagina, and rectum. Less commonly, there may be rectal atresia without a fistula, and some infants present with an anal membrane or anal stenosis.
Infants with these malformations usually present in the first day of life with distal bowel obstruction. Low malformations in girls with large fistulas can permit adequate evacuation of stool, and are occasionally missed. Careful examination of the perineum of all newborns for anal patency and position is therefore important. Many of these patients will suffer from associated anomalies which need to be investigated prior to proceeding with anatomical repair of the anorectal malformation.
The next consideration is to determine if the defect is amenable to primary repair or whether faecal flow should be diverted with a colostomy followed by delayed secondary anatomical repair. Children with a rectoperineal fistula can usually be managed with a local procedure from below, without a colostomy. Children with high anomalies are usually managed with a preliminary colostomy. The use of a colostomy in females with a rectovestibular fistula is controversial. The colostomy can be made using either the transverse or the sigmoid colon, and can be a loop or divided stoma. The authors favour Pena's recommendation for a divided colostomy in the proximal sigmoid colon.6 Long-term continence in these patients is determined by the level of the rectal fistula, and the presence of an absent or hypoplastic sacrum. Depending on the nature of the anomaly, repair can be carried out using a posterior sagittal approach, a laparoscopic approach, or a combination of posterior and abdominal approaches. Technical expertise is crucial to success, and again these procedures should only be performed by experienced paediatric surgeons.
Malrotation: The process of normal rotation and fixation occurs between the sixth and tenth weeks of development. If no rotation occurs, the patient is left in a position of non-rotation, which has a wide-based mesentery and does not require correction. Classic malrotation occurs when the process is interrupted part way through, leaving the caecum and the duodeno-jejunal junction (ligament of Treitz) close to each other (Fig. 12.3). Because this arrangement results in a narrow-based mesentery, the bowel is prone to midgut volvulus around the superior mesenteric vessels, which may lead to intestinal ischaemia. Malrotation with midgut volvulus is one of the true paediatric surgical emergencies and failure to recognise it early can be catastrophic, leading to loss of large portions of bowel and subsequent short-bowel syndrome or death.
FIGURE 12.3 Schematic illustrations depicting normal intestinal rotation, non-rotation and malrotation. Bold dotted lines illustrate the width of the mesenteric base in each situation.
Rotation abnormalities are most often asymptomatic. While volvulus can occur at any time, it is most common in the first week of life.7 The most common presentation of malrotation is bilious vomiting, which may occur for two reasons: midgut volvulus with kinking of the duodenum, or compression of the duodenum by Ladd's bands. Peritonitis and shock from midgut volvulus are late symptoms and are associated with a worse prognosis. Every attempt should be made to diagnose and correct malrotation before this occurs.8 For this reason, every infant who presents with bilious vomiting should be considered to have malrotation with midgut volvulus until proven otherwise.
Any patient with suspected malrotation and volvulus needs urgent imaging and surgical consultation. Abdominal radiograph is often non-diagnostic but may show a dilated stomach, a ‘double bubble’ with distal gas or a relatively gasless abdomen. Upper gastrointestinal contrast study is the preferred examination. A nasogastric tube placed prior to the exam can not only aid in decompression of the stomach, but also the administration of the water-soluble contrast. The chief radiographic signs of malrotation are: (1) abnormal position of the duodenojejunal junction, (2) a spiral, ‘corkscrew’ or Z-shaped course of the distal duodenum and proximal jejunum, and (3) location of the proximal jejunum in the right abdomen.8Abdominal ultrasound may show abnormal orientation of the superior mesenteric artery and vein, or a ‘whirlpool sign’.9
The operation to correct malrotation involves a laparotomy, although a laparoscopic approach may be taken for children without evidence of volvulus.10 If there is volvulus, the bowel is untwisted and checked for viability. If there is ischaemia, the bowel is wrapped with warm towels and re- inspected. Grossly necrotic bowel is resected and the rest is left, with a second-look laparotomy planned for 24–48 hours later. In children who have necrosis of the entire midgut, a palliative approach should be considered.
If the intestine is viable, a Ladd procedure should be performed. This operation consists of five stages: (1) division of Ladd's bands; (2) mobilisation of the colon to the left side of the abdomen; (3) mobilisation and straightening of the duodenum; (4) dissection and widening of the small bowel mesentery; and (5) appendicectomy.
The diagnosis of peritonitis in the neonate is complicated by a number of factors, including the patient's inability to communicate with the surgeon, as well as several anatomical and physiological differences between neonates and older children/adults. The very thin abdominal wall may develop oedema and erythema as a result of underlying inflammation. Neonates breathe primarily with their diaphragms, so peritonitis results in rapid, shallow respiration, and ultimately will cause elevation in pCO2 and respiratory failure. Localised peritoneal signs can be elicited by palpation, but the examiner must be gentle, since the signs of involuntary guarding may be very subtle. In addition, the neonate does not have a well-developed omentum, so ability to localise inflammation may be impaired.
Neonates with peritonitis will often develop systemic sepsis, which may differ in its presentation from that in older children and adults. Signs of sepsis in neonates may include lethargy, temperature instability (either fever or hypothermia), increased ventilation requirements, thrombocytopenia, a high or low white blood cell count, and acidosis.
Specific forms of abdominal inflammation
Meconium Peritonitis: This condition occurs when there has been prenatal intestinal perforation, resulting in chemical peritonitis. Prenatally there may be evidence of free fluid or calcification within the abdomen. In some cases, the foetus is able to localise and wall off the perforation, which may result in a meconium cyst. The aetiology of the perforation is often distal obstruction, usually from meconium ileus or intestinal atresia, but in some cases the perforation is idiopathic.
Management of meconium peritonitis involves fluid resuscitation, nasogastric drainage and antibiotics. If there is evidence of associated intestinal obstruction, a contrast enema may be helpful preoperatively. Laparotomy should be performed, with resection of the involved bowel and either stomas or primary anastomosis, depending on the condition of the child and the bowel.
Necrotising Enterocolitis: Necrotising enterocolitis (NEC) is most commonly seen in low-birth-weight and small-for-gestational-age infants.11 The aetiology of NEC is unknown, but a combination of bacterial colonisation, intraluminal substrate and intestinal ischaemia/hypoxia all appear to be important.12
NEC should be suspected in neonates with sepsis, increased abdominal girth, feeding intolerance, abdominal wall discoloration or bloody stools. Abdominal radiograph may show pneumatosis intestinalis, portal venous gas or free intra-abdominal air (Fig. 12.4). It is convenient to classify the severity of NEC using the Bell classification (Table 12.2), which helps to guide treatment and may assist the surgeon in decision-making about operative intervention.13
Bell stages of necrotising enterocolitis (NEC)
Reprinted from Bell MJ, Ternberg JL, Feigin RD et al. Neonatal necrotizing enterocolitis. Therapeutic decisions based upon clinical staging. Ann Surg 1978; 187(1):1–7. With permission from Wolters Kluwer Health.
FIGURE 12.4 Abdominal radiographs of infants with necrotising enterocolitis. (a) Pneumatosis intestinalis. (b) ‘Football sign’ on supine film depicting intra-abdominal free air. (c) Free intra-abdominal air on lateral film.
Initial management of NEC includes bowel rest, nasogastric decompression, broad-spectrum antibiotics, parenteral nutrition, and supportive measures to optimise perfusion and oxygenation of the bowel. Persistent clinical deterioration and signs of necrosis or perforation are generally considered indications for operative intervention. Options include bedside peritoneal drainage, or laparotomy with resection of grossly necrotic bowel and either primary anastomosis or stomas, depending on the status of the child and the bowel.11,14
A recent randomised control trial in neonates less than 1500 g with perforation found no significant difference in outcomes between peritoneal drainage and laparotomy.15
Before laparotomy parents should always be informed of the possibility of a long segment of necrosis requiring massive resection that would leave the child with short-bowel syndrome. Palliative management should then be considered in these infants.
Isolated Ileal Perforation: This condition resembles NEC, in that it primarily affects preterm and small-for-gestational-age infants. However, infants with isolated ileal perforation do not have any abnormalities of the intestine other than localised perforation, usually in the distal ileum. It is unclear whether this represents a very localised form of NEC or a distinct entity. Clinically, these infants present with sudden deterioration, sepsis and free air without any evidence of pneumatosis seen on the abdominal radiograph. In general, the same principles of treatment are applied to ileal perforation and NEC.
Other Neonatal Conditions
Incarcerated inguinal hernia
Inguinal hernias are very common throughout childhood. Hernias in children almost always arise from persistence of the processus vaginalis. If the processus contains only fluid, it is known as a hydrocele; the hydrocele is communicating if the processus remains open and non-communicating if the processus has become obliterated proximal to the fluid. Communicating hydroceles should be repaired electively if they have not closed by 1 year of age.
In most cases, inguinal hernias are asymptomatic and can be repaired electively. Incarceration of bowel may result in complete bowel obstruction, and represents a surgical emergency since both the bowel and the testis may become ischaemic. The risk of incarceration is greatest in newborns and is approximately 30% in the first 2 years of life. Premature infants are at highest risk.
Neonates and infants presenting with an incarcerated hernia should be resuscitated if necessary, and an immediate attempt should be made to reduce the hernia. In contrast to the adult with an incarcerated hernia, testicular ischaemia is far more common than intestinal ischaemia, and it is appropriate to be aggressive about reducing the hernia. Multiple attempts and the use of sedation may be necessary. Ice should not be applied to the hernia, since it may induce hypothermia. Surgical repair of an incarcerated hernia in an infant is a formidable undertaking. The sac is often thin and oedematous, and the risks of injury to the cord structures and recurrence of the hernia are very high. Therefore, if a general surgeon is unable to reduce the hernia and a paediatric surgeon is accessible, the patient should be referred immediately.
If the hernia is reduced, repair should be undertaken 24–48 hours later, allowing some of the oedema to settle, but hopefully before re-incarceration.16
Abdominal wall defects
Gastroschisis is characterised by an abdominal wall defect to the right of the umbilicus, through which most of the intestinal tract protrudes.17 Omphalocele (also called exomphalos) is characterised by herniation of bowel with or without solid organs, into the umbilical cord. Gastroschisis tends to be an isolated anomaly, whereas omphalocele is often associated with chromosomal, cardiac, renal, limb and facial anomalies.
If the diagnosis is made prenatally, delivery should occur at a centre with paediatric surgical support. Resuscitation and nasogastric decompression should begin in the delivery room. The bowel or sac should be wrapped in warm, saline-soaked, sterile gauze and covered with sterile plastic wrap to minimise heat and evaporative fluid loss.
Repair of both conditions should be undertaken by an experienced paediatric surgeon. Options include primary closure, or staged closure using a Silastic® silo that allows the bowel to be reduced gradually into the abdomen over 1–6 days.18
Hypertrophic Pyloric Stenosis
Hypertrophic pyloric stenosis (HPS) is an acquired condition in which the pylorus becomes abnormally thickened, causing gastric outlet obstruction. This occurs in infants during the first 2–12 weeks of life and is characterised by projectile, non-bilious vomiting usually occurring after feeds. HPS occurs in approximately 1:400 children, with a significant male predominance.19
Diagnosis is suspected based on a history of progressive, forceful, non-bilious vomiting in a child of the appropriate age. Physical examination usually reveals some level of dehydration. The presence of a palpable ‘olive’ in the epigastrium has a 99% positive predictive value for the disease.20 Vomiting of gastric contents leads to depletion of sodium, potassium and hydrochloric acid, resulting in the typical hypochloraemic, hypokalaemic metabolic alkalosis. The kidneys attempt to conserve sodium at the expense of hydrogen ions, often leading to paradoxical aciduria.21 The level of dehydration can be estimated by clinical examination, urine output, and serum chloride and bicarbonate levels. If the pyloric olive is not palpable, the diagnosis can be confirmed by ultrasound (pyloric length > 16 mm and single wall thickness > 3 mm). If an experienced sonographer is not available, the diagnosis can be made using a barium swallow (Fig. 12.5).
FIGURE 12.5 Images of hypertrophic pyloric stenosis. (a) Abdominal ultrasound. (b) Upper gastrointestinal contrast study.
Surgery should be deferred until the infant is fully resuscitated. This is accomplished by using normal saline or Ringer's lactate with potassium. Most children should receive a bolus of 20 mL/kg, and then an infusion consisting of 1.5 times the maintenance requirement (i.e. 6 mL/kg/h for this age group) until the urine output and electrolytes have been normalised.
Surgical management of HPS consists of extramucosal longitudinal splitting of the pyloric muscle. The original procedure described by Ramstedt in 1912 was performed through a transverse right upper quadrant incision. This technique has been modified in many institutions to utilise circumumbilical incisions and, more recently, laparoscopic techniques.22Following pyloromyotomy, many infants will experience continued vomiting for 24–48 hours, although the majority will eventually tolerate feeds and be discharged. Postoperative complications are rare but include wound infection, duodenal or gastric perforation and incomplete pyloromyotomy.
Intussusception, or ‘telescoping of the bowel’, occurs when one portion of bowel invaginates into a more distant portion. This results in venous congestion, bowel wall oedema, intestinal obstruction and ultimately full-thickness necrosis of the intussusceptum. The peak incidence of intussusception is seen at 6–9 months of age.23 The majority are ileocolic with hyperplastic lymphoid tissue in Peyer's patches acting as a lead point.24 These are often referred to as ‘idiopathic’. Asymptomatic small-bowel to small-bowel intussusception may be seen incidentally on abdominal ultrasound, or sometimes may be associated with Henoch–Schonlein purpura or cystic fibrosis. Less than 5% of intussuceptions are due to a pathological lead point such as a Meckel diverticulum, polyp or small-bowel tumour such as lymphoma or leiomyoma. Intussusception occurring outside of the usual age range, or those that recur, should raise suspicion for a pathological lead point.
Few children with ileocolic intussusception will demonstrate the classic triad of intermittent severe abdominal pain with drawing up of the legs, palpable abdominal mass and ‘redcurrant jelly’ stool. Physicians must therefore have a high index of suspicion due to the variability of symptoms. Patients may present with irritability, lethargy, abdominal pain, vomiting, diarrhoea or constipation, haematochezia, fever, dehydration or shock. Management should initially focus on diagnosis and resuscitation.
Following fluid resuscitation, imaging should be performed to confirm the diagnosis of intussusception. Abdominal radiograph may show air-fluid levels and distention of the small bowel and there may be a characteristic lack of air in the right lower quadrant. Ultrasonography has a high sensitivity and is currently the investigation of choice.24
Traditionally, the treatment of intussusception has been barium enema. More recently, pneumatic reduction using air or CO2 has been associated with an 80–95% success rate.24
If the intussusception is partially but not completely reduced it is worth trying again a few hours later, since some of the oedema may have been eliminated by the first attempt and a second attempt may be associated with a 50% chance of success.25 Pneumatic pressures of 60–100 mmHg are recommended.26
Surgical intervention is reserved for those patients who fail hydrostatic or pneumatic reduction, or who have signs of infarcted or perforated bowel such as peritonitis or free air on abdominal radiograph at the time of presentation. At laparotomy, the intussusception is manually reduced if possible. If the intussusception is not reducible, the bowel appears necrotic or a pathological lead point is identified, a segmental resection should be performed with primary anastamosis. Recently some authors have documented excellent results using a laparoscopic approach to this condition.27
Appendicitis is the most frequent abdominal surgical emergency in children.28 As in adults, the classic presentation is mid-abdominal pain moving to the right lower quadrant, anorexia, vomiting, low-grade fever and localised tenderness with peritoneal signs in the right lower quadrant (see also Chapter 9). Presentation in children may be atypical, particularly in those under 5 years of age. Some authors have attempted to quantify the usefulness of specific findings in children using scoring systems. Clinical scoring systems such as the Alvarado Score and the Paediatric Appendicitis Score have been shown to be both sensitive and specific (Table 12.3).29–31
Paediatric Appendicitis Score: a score of 6 or more has been shown to be associated with a high likelihood of the child having acute appendicitis
Paediatric Appendicitis Score
Nausea or vomiting
Leucocytosis (WBC > 10 000/μL)
Neutrophilia (‘left shift’)
Migration of pain to RLQ
RLQ, right lower quadrant; WBC, white blood cell count.
Reprinted from Samuel M. Pediatric Appendicitis Score. J Pediatr Surg 2002; 37(6):877–81. With permission from Elsevier.
In the otherwise well, stable patient with an equivocal presentation, the diagnostic options include observation with serial examinations, or imaging with ultrasound or computed tomography (CT) (Fig. 12.6). There is a great deal of controversy as to which technique is more appropriate (see also Chapter 5). Ultrasound is clearly more operator dependent, but recent analyses have suggested that CT scans in childhood may be associated with an increased risk of radiation-induced malignancy later in life.32 Both have excellent accuracy.
FIGURE 12.6 Ultrasound (a) and computed tomography (b) images of children with acute appendicitis. A faecolith is visible at the base of the inflamed appendix in both images.
Increasingly, surgeons are using a laparoscopic approach to appendicectomy in children. As in adults, the benefits of the laparoscopic approach include reduced postoperative pain and length of stay, in addition to a decrease in wound infection rate. There is some evidence that the rate of intra-abdominal abscess may be higher after laparoscopic appendicectomy in children with perforated appendicitis.33 The laparoscopic approach may also be beneficial in children who are muscular or obese, and in adolescent females, where the incidence of ovarian pathology as a cause for the symptoms is higher.
Approximately 40% of children present with perforation, and the incidence is over 65% in those aged 0–4 years old.28 In contrast to non-perforated appendicitis, these children usually present with prolonged symptoms, higher fever, higher white blood cell count and more diffuse peritoneal signs. Some children present with frank sepsis and diffuse peritoneal contamination; these children benefit from resuscitation, followed by immediate appendicectomy and peritoneal washout. Many children with perforated appendicitis present with a prolonged history and a localised abscess or phlegmon on imaging. This condition can be managed either by early operation or by non-operative management consisting of broad-spectrum antibiotics and image-guided drainage of any purulent collections. As in adults (see also Chapter 9), the need for a subsequent interval appendectomy several months later is controversial. The authors reserve the use of interval appendectomy for those with an appendicolith on imaging, since their risk of recurrent appendicitis is over 50%.34
Fluid Resuscitation Of The Child With A Surgical Emergency
Fluid and electrolyte management in children are made challenging by differences in total body water and compensatory mechanisms, as well as changes in physiology throughout childhood. Total body water is as high as 80% of body weight in neonates, and decreases to the adult level of approximately 60% by 1 year. Degree of dehydration can be estimated from the history and physical examination. Children with mild dehydration (1–5% of body fluid volume) show few clinical signs but frequently have a history of 12–24 hours of vomiting or diarrhoea. Those with moderate dehydration (6–10%) are often lethargic, have low urine output (usually evident as fewer wet nappies/diapers), weight loss, loss of skin turgor, sunken eyes or fontanel, dry mucus membranes and crying without tears. If severe dehydration (11–15%) is reached the child may develop cardiovascular or neurological instability. Children have very active peripheral vasoconstriction, so that blood pressure will be maintained until advanced intravascular volume depletion is reached with onset of hypotension, irritability or coma. However, tachycardia is an early sign that should be recognised and treated.21
The urgency of fluid replacement depends on the degree of dehydration and the cause of the fluid loss. The goals of treatment are the restoration and preservation of cardiovascular, neurological and renal perfusion. In the event of dehydration resulting from an inflammatory condition that will require urgent surgical intervention, such as appendicitis, isotonic fluid (normal saline or Ringer's lactate solution) should be given in 20 mL/kg boluses until signs of cardiovascular compromise subside. For situations in which there is no urgency to do an operation, such as pyloric stenosis, the fluid deficit can be replaced more slowly. This has the advantage of avoiding sudden fluid shifts, and the possibility of cerebral oedema and seizures, which are particularly likely in neonates and infants. The commonly used protocol is to calculate the fluid deficit, and replace half over the first 8 hours and the other half over the subsequent 16 hours.
The principles of trauma management are the same for children as they are for adults (see also Chapter 13). Securing the airway and ensuring adequate ventilation are paramount prior to treating bleeding and circulatory collapse. Fluid resuscitation is based on the patient's size, keeping in mind the differences in physiological response to hypovolaemia mentioned in the previous section. As with adults, two boluses of crystalloid (20 mL/kg) should be given through large-bore intravenous lines as quickly as possible. If there is still suspicion for ongoing bleeding, blood products are administered in 20 mL/kg boluses.
The principles of managing penetrating trauma in children are also the same as in adults (see Chapter 13). However, children sustaining blunt abdominal trauma are more prone to solid-organ injury due to the low-lying nature of these organs with respect to the paediatric ribcage and the relative laxity of the abdominal wall. In general, injuries to the spleen, liver and kidney can be managed non-operatively regardless of the grade of injury and operations are rare for blunt abdominal trauma in children. The indications for laparotomy in a child with blunt abdominal trauma include: evidence of peritonitis on abdominal examination; free intra-abdominal air on imaging; inability to normalise haemodynamic status despite resuscitation efforts; a rapidly expanding abdomen associated with persistent hypotension; and the need for transfusion of more than one-half of a blood volume over 24 hours.