Appendicitis in Children: Fundamentals and Particularities

*Alin Villalobos Castillejos, Carlos Baeza Herrera, Miguel Alejandro Sánchez Durán, Jhonatan Mata Aranda, Miguel Ángel Minero Hibert, Ricardo Cortés García and Jorge Escorcia Dominguez*

## **Abstract**

Acute appendicitis in children under 5 years of age is a diagnostic challenge, its delay is usually dramatic and leaves serious sequelae. It is one of the main causes of surgical intervention, it is common for other diseases to be associated with it and to simulate it. Acute appendicitis is of obstructive etiology and its pathophysiology, the bacteriology involved and the evolution of the disease progresses through its phases, from the simple to the complex, is addressed in each case. The typical abdominal pain of appendicitis, in addition to vomiting and fever at a young age, is most often accompanied by an atypical clinical picture such as diarrhea. Integrating the clinical signs at this age requires the full capacity and good sense of the pediatric surgeon. For a correct and timely diagnosis, unfortunately many pediatric patients present in complicated stages of the disease, which implies decision-making regarding the type of surgical intervention and subsequent treatments.

**Keywords:** acute appendicitis, children, classification, treatment, special conditions

#### **1. Introduction**

Acute appendicitis is the main cause for abdominal surgery, and it is also one of the main diseases in pediatrics that requires surgical treatment. It is among the primary reasons for hospital care in developing countries [1]. The most frequent age of presentation is in the second decade of life; however, we must pay special attention to children under 5 years of age, as they have an atypical clinical presentation that can delay diagnosis and treatment [1]. According to our experience, based on the management of up to 1,200 appendicitis cases a year at the Surgery Unit of the Moctezuma Pediatric Hospital of the Mexico City Secretary of Health, a regional referral center in a densely populated area, we observed a predominance of males, and children under 10 years of age accounted for almost 85% of the cases. We combined a series of more than 300 children three years of age or less. Pediatric appendicitis is a common sporadic event; however, it is often associated with specific regional diseases such as Hirschsprung's disease [2]. The appendix serves as a reservoir for normal intestinal flora and has a high concentration of gut-associated lymphoid tissue [3]. A family history of appendicitis imparts a risk. Although a specific gene has not been identified, the

likelihood of appendicitis is approximately three times greater in family members with a positive history than in those with a negative history [3, 4].

### **2. Etiology**

The most frequent, almost exclusive, cause is the luminal obstruction of the proximal segment, the appendico-caecal junction, which makes practical sense as this structure is like the finger of a glove. Everything that prevents the natural drainage of mucus that normally accumulates inside, be it an appendicolith, foreign body, a vegetable seed, intestinal parasites (*Ascaris lumbricoides*), even hyperplasia and hypertrophy of lymphoid tissue, primary tumors (carcinoid, adenocarcinoma, Kaposi's sarcoma and lymphoma) or metastatic tumors will cause structural and physiological changes and depending on the time it remains occluded, the clinical and histopathological stages of the disease can be obtained [5].

#### **2.1 Fecaliths/appendicular stones**

The formation of a fecalith and a stone occurs when feces, trapped within the appendicular lumen, are continuously bathed with minerals and thickened. Like gallstones, fecaliths and appendix stones can enlarge to a critical diameter, resulting in complete lumen obstruction. The consequence is an increase in intraluminal pressure in the obstructed part of the appendix, which interferes with the circulation in the intestinal mucosa and alters venous drainage, causing a thrombosis of the terminal appendicular artery, which results in a transmural infarction and perforation [6]. The presence of fecaliths or appendicular stones is associated with a higher number of complicated acute appendicitis, with perforation in 18% of cases and appendicular abscess in 42%. Therefore, fecaliths and appendicular stones play an important role in the pathogenesis of appendicitis [6].

#### **2.2 Bacterial infection**

Most opponents of the obstruction theory advocate an infectious pathogenesis for acute appendicitis. The lack of increased bacterial counts in acute inflammation suggests that the environment for bacterial growth is unfavorable and that the number of organisms invading the wall is low compared to those in the lumen or associated with the mucosa [6].

#### **2.3 Hiperplasia linfoide**

Since the cecal appendix is rich in lymphatic follicles, lymphoid hyperplasia can lead to obstruction of the lumen of the appendix. In a pathology analysis of 405 appendages, Babekir and Devi found significant lymphoid hyperplasia in 25% of acutely inflamed appendixes. Although this could be partly a secondary phenomenon during the inflammatory process, a typical viral illness with symptoms of gastroenteritis could probably trigger an acute appendicitis after a few days [6].

#### **3. Pathophysiology**

The obstruction of the appendicular lumen causes inflammation, increased intraluminal pressure and ultimately ischemia. Subsequently, the appendix enlarges and incites inflammatory changes in the surrounding tissues, such as the pericecal fat *Appendicitis in Children: Fundamentals and Particularities DOI: http://dx.doi.org/10.5772/intechopen.97295*

**Figure 1.**

*Showing the anatomy of the cecal appendix and the fecalith obstructing the lumen.*

and the peritoneum. Rapid distention of the appendix occurs due to its small luminal capacity, and intraluminal pressures can reach 50 to 65 mm Hg (**Figure 1**) [7]. This appendicular condition leads to an enlargement of the cecum, the cecal content is stored and does not advance towards the right colon. The presence of fecal load within a large cecum can be identified on plain abdominal radiography as a specific sign of acute appendicitis [7]. Once the luminal pressure exceeds 85 mm Hg, thrombosis of the venules draining the appendix occurs, and in the setting of continuous arteriolar flow, vascular congestion and congestion of the appendix develop [5, 7]. Lymphatic and venous drainage is impaired and ischemia develops. The mucosa becomes hypoxic and begins to ulcerate, resulting in compromise of the mucosal barrier and leading to invasion of the appendicular wall by intraluminal bacteria. Most bacteria are gramnegative, mainly *Escherichia coli* (76%), followed by *Enterococcus* (30%), *Bacteroides* (24%), and *Pseudomonas* (20%) [8].

The inflammation spreads to the serosa, parietal peritoneum, and adjacent organs and as a result, visceral afferent nerve fibers entering the spinal cord at T8-T10 are stimulated, causing epigastric and periumbilical pain referred by the corresponding dermatomes. At this stage, somatic pain replaces early referred pain, and patients generally experience a shift at the site of maximum pain towards the right lower

**Table 1.** *Pathophysiology of appendicitis.*

quadrant. If this continues, arterial blood flow is eventually compromised and a heart attack occurs, resulting in gangrene and perforation (**Table 1**) [9].

### **4. Classification of appendicitis**

After a few hours, sometimes less than 24 hours or a little longer, the appendix is observed, (describing it from the inside out) with a large accumulation of mucus in which a significant variety of bacteria, especially anaerobes, are immersed. Being usual inhabitants in normal conditions, they find the ideal means to proliferate. The mucous lining, following the natural history of the disease, responds with the migration of specific inflammatory cells in response to the situation. Therefore, arterial and venous circulation also alter their dynamics and the flow slows down, causing what that observed when the disease is in the initial phase, simple acute appendicitis. There may or may not be a generally small amount of peri-appendicular fluid, rich in bacteria, but transparent in appearance. As time passes, from 24 to 36 hours after symptoms begin and in an average of 3.2 days, that process worsens and the name of the following stages basically obeys the appearance of the structure. Thus, if the appendix is seen intact, with or without a large fecalith inside, but with a blackish coloration of its wall and dark purulent fluid in its environment, it is gangrenous (**Figure 2**) [10].

The most advanced phase is labeled as abscess appendicitis when the evolution time has been days or sometimes weeks, with a tendency for pus to spread to the entire peritoneal cavity. The appendix is usually ruptured or destroyed, and there is a great liquefaction of periappendicular tissue with a quantity of liquid greater than 10 ml, sometimes reaching more than two liters, depending on the age of the child (**Figure 3**) [10].

**Figure 2.** *Appendix in gangrenous phase with dilated bowel loops.*

*Appendicitis in Children: Fundamentals and Particularities DOI: http://dx.doi.org/10.5772/intechopen.97295*

**Figure 3.** *Appendix with fecalith.*

#### **Figure 4.** *Appendix with perforation in the middle third.*

In all cases clinical behavior is unpredictable, although it can be stated with certainty that the patient's condition will worsen as the hours go by. Although this category obeys somewhat arbitrary rules, in accord with our experience, we believe there is a strong relationship with the response of each phase to the antimicrobial management schemes that are established, and in the same sense, it coincides with the prognosis. A concern of some academics is when the cecal appendix is perforated. According to a study published by the National Institute of Pediatrics of Mexico, micro-perforations can be observed even in the earliest stage of the disease, so that for each stage we add the perforated phase at the margin if it is minimally or grotesquely broken or destroyed (**Figures 3** and **4**) [11].

According to the findings found during surgery, appendicitis is initially staged as simple or uncomplicated and complicated; this staging sets the course for postoperative treatment. Simple and gangrenous appendicitises are considered uncomplicated and have a good prognosis; perforated and abscessed appendicitises are classified as complicated (**Table 2**) [11].

#### **Simple appendicitis**


#### **Complicated appendicitis**


**Table 2.** *Classification of appendicitis.*

#### **5. Clinical picture**

The symptoms and signs that accompany the disease are typically three, which almost always appear in this order: pain of sudden onset, progressive intensity and periumbilical location, as the appendix is innervated by the splanchnic nerves that emerge of the lower thoracic ganglia, ganglion 10, one of the structures that conducts the painful stimulus to the dorsal nerve root along the dorsal spinothalamic tract. With the appearance of pain and the vagal stimulus, vomiting, anorexia and occasionally diarrhea are added. At the end of the process fever appears, which almost never exceeds 38.5° C, and when it does, the disease has been treated with antibiotics and is in advanced stage, or is not appendicitis. These symptoms can occur in less than 50% of patients and be nonspecific in children under 5 years of age. Children under 3 years of age have perforated appendicitis in more than 80% of cases compared to 20% of children between 10 and 17 years of age [12].

The complementary support resources to prepare the diagnosis in a timely manner, hematic cytology and the radiological study, are almost always useful, but above all is the skill of the surgeon, with the subtlety that a good physical exam requires, who collects the most important data: right quadrant muscle stiffness in the location of the appendix and exquisite pain located around no more than three square centimeters on the same anatomical site. This rule is not carved in stone. If the order is different, it has the same usefulness and validity. Palpation of the lower left quadrant and referred pain in the lower right quadrant, the obturator sign (internal rotation of the right lower limb) and the psoas sign may be nonspecific for appendicitis and only rebound has a greater clinical correlation with appendicitis [12]. With regard to digital rectal examination, we are convinced that it does not provide data to substitute for a good physical study of McBurney's point, so we do not recommend performing it. For a child, the maneuver, in addition to being unnecessary and annoying, requires the informed consent of the parents. The abdominal maneuvers and signs referred to in the literature are useful and should be sought [12].

The support provided by cytology is important, since the increase in the leukocyte count has been mentioned as having a significant relationship of 60–90% with perforated appendicitis. It is advisable to carry out the band count, since in our experience, they are almost always very high, even without leukocytosis. If more than 15,000 are found, it may not be appendicitis or it is complicated. Finally, the total leukocyte count, absolute neutrophils and C-reactive protein have been shown to have a greater sensitivity and specificity for appendicitis when the three are used in addition to the clinical history and evaluation of the patient [12].
