what is appendicitis?
Appendicitis is the acute inflammation of the vermiform appendix, usually due to luminal obstruction, leading to bacterial overgrowth, ischemia, and possible perforation. It is the most common surgical emergency in children. In pediatrics, appendicitis is a major cause of intestinal obstruction, especially due to complications such as appendiceal mass, abscess, or perforation with peritonitis.
anatomy of the appendix
The vermiform appendix is a narrow, worm-like blind diverticulum of the cecum, arising from its posteromedial wall about 2 cm below the ileocecal junction. It is usually 2–20 cm long (average 9 cm), with a diameter of about 5–6 mm.
Situated in the right iliac fossa. Its position, however, is variable depending on the direction the tip points.
Position Frequency Clinical Importance
Retrocecal (behind cecum) ~65% Pain may be less localized; may cause psoas irritation → psoas sign positive
Pelvic ~30% May irritate bladder or rectum → tenesmus, urinary frequency
Subcecal 2% Pain localized to right iliac fossa
Pre-ileal 1% Lies in front of ileum; may cause early peritonitis
Post-ileal 1% Lies behind ileum; may mimic other causes of abdominal pain
Base is Fixed at the convergence of the three taeniae coli — an important surgical landmark. Lumen Communicates with cecum but often becomes obliterated with age.
Mesoappendix: A triangular fold of peritoneum attaching the appendix to the mesentery of the terminal ileum. Contains the appendicular artery and vein.
Arterial Supply
Appendicular artery which is a branch of the inferior division of the ileocolic artery (from the superior mesenteric artery). It runs in the free margin of the mesoappendix to reach the tip. It is an end artery, so thrombosis during appendicitis → gangrene and perforation.
Venous Drainage : Appendicular vein accompanies the artery and drains into the ileocolic vein → superior mesenteric vein → portal vein.
Lymphatic Drainage
1. Appendicular lymph node in the mesoappendix.
2. Then into ileocolic lymph nodes around the ileocolic artery.
Important because lymphoid hyperplasia (common in children) can obstruct the lumen and cause appendicitis.
Nerve Supply
Type Origin Function
Sympathetic T10 segment (via lesser splanchnic nerves → superior mesenteric plexus) Pain fibers → referred pain to umbilicus (T10 dermatome)
Parasympathetic Vagus nerve (posterior vagal trunk) Secretomotor and sensory fibers
Visceral afferents Follow sympathetic fibers Cause colicky periumbilical pain in early appendicitis
Microscopic (Histological) Structure
1. Mucosa – contains crypts of Lieberkühn and abundant lymphoid follicles, making it a gut-associated lymphoid tissue (GALT) organ.
2. Submucosa – dense with lymphoid tissue.
3. Muscularis externa – inner circular and outer longitudinal muscle layers (outer longitudinal is continuous with taeniae coli of the cecum).
4. Serosa – peritoneal covering.
Relations
Surface Related Structures
Anterior Cecum or coils of small intestine
Posterior (retrocecal) Psoas major muscle, right ureter, right gonadal vessels
Medial Terminal ileum
Lateral Parietal peritoneum of the abdominal wall
Pelvic appendix Overlies right pelvic brim, possibly contacting bladder or rectum
discuss the etology/risk factors of appendicitis
- Primary Cause: Luminal Obstruction
When the lumen of the appendix becomes obstructed, it sets off a cascade of pathological events:
The mucosa continues to secrete mucus into the closed lumen. Because the lumen is blocked, mucus and secretions cannot drain into the cecum, leading to progressive distension of the appendix. As intraluminal pressure builds up, venous and lymphatic drainage are impaired while arterial flow continues for a while leading to vascular congestion and ischemia of the appendiceal wall. The ischemic mucosa becomes more permeable and necrotic (ulceration), allowing gut bacteria (mainly E. coli, Bacteroides, Streptococcus) to invade the wall → acute suppurative inflammation. Continued ischemia and infection cause gangrenous necrosis of the wall and eventual perforation, releasing pus and fecal matter into the peritoneal cavity → localized abscess or generalized peritonitis.
Common Obstructing Agents
a. Fecaliths (inspissated fecal material): Most common cause in children and adults. A hard mass of dehydrated fecal matter forms in the lumen. This physically blocks the appendiceal opening. It often arises from slow colonic transit, dehydration, or constipation. Fecaliths also serve as a nidus for bacterial growth, accelerating inflammation once obstruction occurs.
b. Lymphoid hyperplasia : Most common cause in children specifically. The appendix contains abundant lymphoid follicles, which can enlarge (hyperplasia) in response to viral infections such as:
* Adenovirus
* Epstein–Barr virus
* Measles
* Cytomegalovirus
* Upper respiratory tract infections or gastroenteritis
This lymphoid enlargement compresses or obstructs the lumen from within. This explains why appendicitis often follows or coincides with a recent cold or GI infection in children.
c. Parasites : Enterobius vermicularis (pinworm) can physically block the lumen or cause mucosal irritation and inflammation. Ascaris lumbricoides worms can enter and obstruct the lumen. Parasites also trigger eosinophilic and lymphocytic inflammation, which may further narrow the lumen.
d. Foreign bodies (rare): Ingested materials such as seeds, bones, or beads can get trapped in the narrow lumen. They act as a physical obstruction and/or irritant → mucus retention → bacterial overgrowth → appendicitis.
2.Male sex (Age 10–20 years) : Males have slightly higher rates, possibly due to hormonal or anatomic factors influencing lymphoid tissue reactivity. Peak period of lymphoid tissue development; higher chance of hyperplasia causing obstruction. This may explain the increased rate in teenagers, as the submucosal lymphoid tissue reaches its peak number in the adolescent followed by a gradual decrease after age of 30.
4.Bacteria such as Yersinia, Salmonella, and Shigella
explain how bacteria can cause appendicitis
4.Bacteria such as Yersinia, Salmonella, and Shigella
A. Yersinia enterocolitica / Yersinia pseudotuberculosis
Yersinia is an enteroinvasive Gram-negative bacillus that targets lymphoid tissue (especially Peyer’s patches and appendiceal lymphoid follicles). It invades the ileal mucosa via M cells overlying Peyer’s patches. The bacteria multiply in mesenteric lymph nodes and appendiceal lymphoid follicles, causing:
Lymphoid hyperplasia of the appendix. The enlarged lymphoid tissue narrows or obstructs the appendiceal lumen, mimicking classical appendicitis.
Clinically, it can present almost identically to acute appendicitis (right lower quadrant pain, fever, leukocytosis), but sometimes the appendix itself is only mildly inflamed — the real culprit is mesenteric adenitis.
B. Salmonella species (especially Salmonella typhi and non-typhoidal strains)
Salmonella invades intestinal mucosa through M cells and is taken up by macrophages. It causes bacteremia and localized infection in gut-associated lymphoid tissue (including the appendix). The infection induces acute inflammation and necrosis in the appendiceal wall, even without complete obstruction. In some cases, typhoid ulcers in the appendix can form, which may lead to perforation. Direct bacterial invasion of appendiceal mucosa → neutrophilic infiltration, edema, and necrosis → appendicitis-like picture. It may coexist with typhoid enteritis or bacteremia.
C. Shigella species
Shigella primarily causes invasive colitis, but it can extend into the ileocecal and appendiceal regions. It invades and destroys colonic and appendiceal epithelial cells → ulceration and mucosal necrosis. This triggers acute suppurative inflammation of the appendix, with or without true luminal obstruction. Results in Appendicitis caused by direct mucosal invasion and inflammation, not by mechanical blockage.
classififcation of appendicitis
By progression and pathology
Early/Simple (catarrhal): Initial inflammation without complications. An obstruction causes mucosal edema and fluid accumulation, leading to distention and increased pressure.
Suppurative: The inflammation spreads through the entire wall of the appendix, resulting in pus formation (neutrophil infiltration) and ulceration.
Gangrenous: Tissue death occurs due to the severe inflammation and lack of blood supply.
Perforated: The appendix ruptures, which can be limited to surrounding tissue (phlegmon or abscess) or spread throughout the abdomen (diffuse peritonitis).
pathophysiology of appendicitis
In children: Appendix lumen is narrower → obstruction occurs more easily. Omentum is less developed → perforation and diffuse peritonitis occur earlier and more severely.
The appendix serves as a reservoir for normal intestinal flora and has the highest concentration of gut-associated lymphoid tissue (GALT) in the intestine. It has been suggested that only half the cases arise from luminal obstruction from stool, fecaliths, lymphoid hyperplasia, or neoplasm. Although the natural history of untreated appendicitis may be perforation and abscess development, this course is not ensured and may not be linear. Resolution without treatment can occur as is seen in cases of relapsing or chronic appendicitis.
The cause of appendicitis is intraluminal obstruction caused by lymphoid hyperplasia, parasite-infected fecal matter, and ingested foreign bodies. Once the lumen is obstructed, mucus and bacterial proliferation result in venous congestion, which in turn will cause arterial flow obstruction, ischemia, necrosis, and free perforation into the peritoneal cavity. The human defense system of omentum often wraps itself around the organ and limits the free perforation and results in appendix “mass” formation.
clinical features of appendicitis
a)Migratory Pain – visceral pain starts around the umbilicus due to distension of appendix, later after few hours, somatic pain occurs in RIF due to irritation of parietal peritoneum due to inflamed appendix
1. **Visceral pain: Dull, poorly localized periumbilical/epigastric pain (T10 innervation).
2. **Somatic pain: Shifts to right iliac fossa (McBurney’s point) as parietal peritoneum becomes inflamed.
Typically any abdominal movement causes exacerbation of the pain, which is described as sharp in nature. This pain is of visceral nerve origin and is referred to the common dermatome of the 8th–10th thoracic dorsal ganglia, which results in the sensation of periumbilical pain. It is important to remember that inflammation of any midgut derivative will cause this same symptom. Some children may confuse this sensation with hunger. The pain is classically described as migrating to the right lower quadrant. The pain becomes localized to the right lower abdomen when the inflammation on the appendix irritates the local peritoneum, which has potent somatic sensation. This tenderness is exhibited by objective demonstration of pain such as wincing, moving, or flexing when gentle pressure is applied in the right lower quadrant (RLQ) near the McBurney point.
b) Anorexia- if good appetite not appendicitis (very common, early) anorexia without vomiting
c) Malaise
d) Fever (low grade) unless perforation has occurred, in which case there is generalized peritonitis and high fever. High fever is more common after appendiceal rupture due to the inflammatory response from the peritoneal contamination.
e) Abdomen pain caused by coughing
f) Nausea and reflex vomiting- due to reflex pylorospasm
g) Other features: Foetor oris,
constipation is usual feature but diarrhoae can occur if appendix is in postileal or pelvic postion. Diarrhea is often seen with perforated appendicitis, but is also more common in infants and toddlers, which may lead to the diagnosis of gastroenteritis. In general, gastroenteritis is more likely with a history of repeated episodes of vomiting and diarrhea starting at a similar time or preceding the onset of the pain. This is especially true when the abdominal pain is the minor symptom, it is not localized, and there is no focal tenderness.
urinary frequency: inflamed appendix may be in contact with bladder and cause bladder irritation
Tenderness in right lower quadrant (McBurney’s point).
Guarding, rebound tenderness (signs of peritonitis) which is best elicited with gentle tapping over the right iliac fossa. However, in obese children and patients with retrocecal appendicitis, these signs are often absent or equivocal in nature.
In children: presentation is often atypical → diagnostic challenge, high perforation rate. If the patient is under the influence of narcotic analgesia at the time of examination, demonstration of tenderness by any of these means is considerably more concerning for appendicitis.
what special signs may be elicited in appendicits?
Special signs:
* Rovsing’s sign: Pain in RLQ with palpation of LLQ. If the patient has rebound tenderness, gentle pressure to the left side of the abdomen (Rovsing sign) or placing a hand in the center of the patient’s abdomen with mild shaking of the abdomen will elicit tenderness in the setting of peritonitis. RLQ pain with these maneuvers is concerning for appendicitis.
* Psoas sign is RLQ pain when the patient is in the left decubitus position and the right leg is extended. A positive psoas sign is often suggestive of a retrocecal appendicitis.
* Obturator sign: Pain on internal rotation of flexed right thigh → pelvic appendix. The obturator sign is RLQ pain with flexion and internal rotation of the right hip.
* The Dunphy sign is increased RLQ pain with coughing and a positive Markle (heel jar) test is pain with dorsiflexion of the right foot.
clinical features of complicated appendicitis
Complicated appendicitis occurs as a result of perforated appendix with or without abscess formation. Physical findings may reveal diffuse peritonitis or a tender right lower quadrant mass, which is due to an organized abscess. It is more common to have diffuse peritonitis in young children because they have less omental tissue to isolate the infection. In contrast, older children are more likely to have an appendiceal abscess.
* Perforation: High fever, diffuse abdominal pain, peritonitis.
* Appendiceal abscess/mass: Localized tender mass, late presentation.
However, simple appendicitis may not always be differentiated from complicated cases prior to surgery. Diagnostic laparoscopy and appendectomy can be employed when the preoperative diagnosis of appendicitis is uncertain
laboratory diagnosis of appendicitis
Laboratory
Most surgeons request blood tests and expect to find an elevated white cell count (leukocytosis), with a disproportionately elevated neutrophil percentage and a high Capsularreactive protein (CRP). A urine dipstick (urinalysis) is also done, which, in the case of appendicitis, should show no or a few red cells and white cells (due to irritation of ureter/bladder).
radiologic diagnosis of appendicitis
Imaging
Ultrasound (preferred in children):
Graded compression US is performed by placing pressure on the transducer to displace bowel loops in order
to identify the appendix. The pressure is adequate if the psoas muscle and iliac vessels are identified, which ensures
the range of view is posterior to the appendix. The common US signs of appendicitis include a fluid-filled, noncompressible appendix, a diameter >6 mm, an appendicolith, periappendiceal or pericecal fluid, and increased periappendiceal echogenicity caused by inflammation
US reports should have a description of the findings, and the findings should be categorized as:
category 1—appendix visualized and normal,
category 2—appendix nonvisualized without secondary signs of appendicitis,
category 3—appendix nonvisualized with secondary signs, and
category 4—appendicitis with or without abscess.
* Useful for ruling out ovarian/testicular pathology.
CT scan (if ultrasound inconclusive): High sensitivity/specificity, but avoided in children due to radiation. Computed tomography (CT) provides a three-dimensional image of the entire abdomen and pelvis; and is generally accurate (found CT to be significantly more accurate) Thus, CT has become the most widely accepted and utilized imaging for abdominal pain in adult patients. Radiation risk too high in kids.
how to categorize ultrasound findings in appendicitis
US reports should have a description of the findings, and the findings should be categorized as:
category 1—appendix visualized and normal,
category 2—appendix nonvisualized without secondary signs of appendicitis,
category 3—appendix nonvisualized with secondary signs, and
category 4—appendicitis with or without abscess.
detail the alvarado scoring system for appendicitis
Alvarado scoring for appendicitis (1986):
-Migrating pain 1
-Anorexia 1
-Nausea and vomiting 1
-Tenderness in right iliac fossa 2
-Rebound tenderness 1
-Elevated temperature 1
-Leukocytosis with count more than 10,000 2
-Shift to left with neutrophilia in peripheral smear 1
Total score 10
Score less than 5: Not sure.
Score between 5-6: Compatible.
Score between 6-9: Probable.
Score more than 9: Confirmed.
detail the pediatric appendicitis score (PAS) system
Pediatric Appendicitis Score (PAS)
PAS modifies Alvarado for pediatrics To quantify the likelihood of acute appendicitis in children based on history, physical examination, and basic laboratory findings.
Clinical Feature Finding Score
1. Migration of pain From periumbilical → right lower quadrant (RLQ) 1
2. Anorexia Loss of appetite 1
3. Nausea or vomiting Present 1
4. Tenderness in RLQ Localized tenderness on palpation 2
5. Cough/percussion/hopping tenderness (peritoneal irritation) Pain elicited when child coughs, jumps, or is percussed in RLQ 2
6. Elevated temperature (fever) ≥ 38°C 1
7. Leukocytosis WBC count > 10,000/mm³ 1
8. Neutrophilia Neutrophils (PMNs) > 75% 1
Maximum total score = 10
Total PAS Interpretation Recommended Action
1–3 Low probability of appendicitis Observe / consider alternative diagnoses; no immediate imaging required.
4–6 Equivocal (intermediate probability) Obtain abdominal ultrasound or serial exams to confirm diagnosis.
7–10 High probability of appendicitis Surgical consultation; likely appendicitis → consider appendectomy or confirm by imaging.
initial management of appendicitis
Initial stabilization
* NPO (nil per os).
* IV fluids for hydration.
* IV broad-spectrum antibiotics (cover gram-negatives and anaerobes).
* Analgesia.
Intravenous antibiotics such as ampicillin, cephalosporin, aminoglycosides, and metronidazole are given before surgery. The choice and duration of antibiotic therapy is determined by the operating surgeon based on the severity of the disease and perforation, and it can last from 1 to 10days.
non operative management of appendicitis
- Non-operative management (selected cases)
This can be attempted in two clinical manifestations: (a) early or suspected appendicitis by absence of peritonism or low-grade fever in otherwise well child who can tolerate oral fluid/feed and (b) in a subgroup of patients, also clinical well, with delayed presentation who are considered as having an “appendix mass.”
In both situations, intravenous antibiotics alone ± percutaneous drainage usually resolve pain, and the child can be discharged 7–10days later. In both situations, follow-up is necessary and frequently, in cases of appendix mass, the child is readmitted 6–8weeks later and an interval appendectomy is performed, which can be done open or laparoscopically
indications and contraindications of non-operative management of non-perforated appendicitis
Indications:
* Mild uncomplicated appendicitis (no perforation, abscess, or fecalith)
* Stable patient
* Imaging confirms non-complicated disease
Contraindications / Predictors of Failure:
* Appendicolith (strong predictor of recurrence)
* Symptoms >48 hours
* Marked leukocytosis (>18,000) or CRP >4 mg/dL
* Signs of bowel obstruction or abscess
* Toxic appearance
detail the steps of an open appendectomy
B.Operative Management — Gold standard
Open (Conventional) Appendectomy
a. Indications:
* Most cases of acute appendicitis (especially with localized peritonitis)
* Perforation or abscess not suitable for laparoscopy
Preparation:
* IV fluids, antibiotics, and analgesia
* Nasogastric tube if vomiting or distension
* Foley catheter for bladder decompression (in complicated cases)
Step 1: McBurney’s (gridiron) incision - oblique or transverse right lower quadrant incision at the McBurney’s point. Lanz incision (transverse right lower quadrant) may be used (more cosmetic). In delayed or perforated cases → extend incision laterally for better exposure.
Step 2: Incise skin and subcutaneous tissue. Split the external oblique aponeurosis along its fibers. Split internal oblique and transversus abdominis in the direction of their fibers (muscle-splitting, not cutting). Open transversalis fascia and peritoneum carefully.
Step 3: Identify the Cecum and Follow taeniae coli of the cecum — they converge at the base of the appendix.
Step 4: Gently deliver appendix into the wound. If retrocecal, mobilize the cecum medially or extend the incision laterally to expose it.
Step 5: Divide mesoappendix between clamps or with bipolar diathermy. Ligate appendiceal artery to prevent bleeding.
Step 6: Apply a crushing clamp near the base. Ligate the base with absorbable suture (e.g. 2-0 Vicryl). Appendectomy is done close to the cecal base without injuring it.
Step 7: Stump Management using Various methods:
* Simple ligation (common, safe)
* Ligation + inversion with purse-string suture
* Inversion only (without ligature)
* Surgeon’s preference; inversion not mandatory.
Step 8: Wash peritoneal cavity with warm saline, in cases of contamination or perforation suspected.
Step 9: Peritoneum and muscle layers closed (usually with continuous absorbable sutures). Drain placement if perforation, abscess, or contamination. Skin closure: interrupted nonabsorbable sutures (or delayed closure if infection risk).
detail the non-operative management of non-perforated appendicitis
Protocol:
* IV broad-spectrum antibiotics for 24–48 h (e.g. ceftriaxone + metronidazole or ampicillin + gentamicin + clindamycin)
* Switch to oral antibiotics once afebrile and improved
* Close clinical monitoring and repeat imaging
* If deterioration → surgical appendectomy
detail the steps of a laparascopic appendectomy
Laparoscopic Appendectomy
a. Advantages:
* Better visualization (especially in females or atypical appendix)
* Less wound infection, faster recovery
* Shorter hospital stay
Port Placement:
1. Umbilical port (5–10 mm) – camera + extraction site
2. Left lower quadrant port (5 mm) – working port
3. Right upper quadrant port (5 mm) – retraction and dissection
- Insert telescope via umbilical port.
- Identify appendix.
- Use unipolar/bipolar diathermy or energy device to divide mesoappendix (close to appendix to avoid bleeding).
- Ligate base:
- Endoloops
- Intracorporeal suture
Or secure extracorporeally through small stab incision.
- Divide the appendix near the base.
- Retrieve appendix via umbilical port to avoid direct contact with the wound. If the appendix is too thick, it should then be placed in a retrieval bag, which is withdrawn through the port site. A cheap sterile retrieval bag can be made by cutting one of the “fingers” of a surgical glove.
- Wash peritoneum if perforated.
- Remove trocars and close port sites.
outline the management of perforated appendicitis
Three general strategies are applied for the treatment of perforated appendicitis: antibiotics only, antibiotics followed by interval appendectomy, and appendectomy on presentation. The rationale for treating initially with antibiotics is to avoid a difficult operation during the peak of the inflammatory process, which can make the operation more difficult. Principles:
* Source control (remove appendix, drain pus)
* Broad-spectrum IV antibiotics
* Adequate fluid resuscitation
* Peritoneal lavage with warm saline
Antibiotic regimen: Traditional “Triple therapy”: ampicillin + gentamicin + clindamycin. Alternatives: ceftriaxone + metronidazole, or piperacillin–tazobactam
Postoperative Care:
* Continue antibiotics until afebrile, WBC normalized, and tolerating oral intake.
* Monitor for intra-abdominal abscess.
management of appendicular abscess
B. Appendicular Abscess
Presentation:
* Localized abscess seen on imaging (ultrasound/CT)
* Fever, leukocytosis, tenderness, sometimes fluctuation or palpable mass
Management:
1. Percutaneous drainage:
Under US or CT guidance. Drain placed and flushed with saline once or twice daily to maintain patency. Continue IV antibiotics
2. Interval appendectomy: Performed 6–8 weeks later after inflammation resolves, to prevent recurrence.
3. If abscess ruptures or generalized peritonitis develops→ Proceed to emergency appendectomy + peritoneal washout.
prognosis of appendicitis
Prognosis
* Early uncomplicated appendicitis: Excellent prognosis after surgery.
* Delayed or perforated cases: Higher morbidity, longer hospital stay, increased risk of adhesive obstruction.
* Children <5 years have highest risk of perforation due to atypical presentation and delayed diagnosis.
management of appendicular mass
A. Appendicular Mass (Phlegmon)
Presentation:
* RLQ palpable tender mass, usually after 3–5 days of symptoms
* Low-grade fever, mild leukocytosis
Imaging: heterogeneous mass with inflamed appendix, omentum, and bowel
Management:
Conservative (Ochsner–Sherren regimen):
1. Nil per mouth
2. IV fluids and broad-spectrum antibiotics
3. Close observation
4. If mass resolves → discharge with oral antibiotics
5. Interval appendectomy after 6–8 weeks (to prevent recurrence)
If condition worsens (fever, abscess formation, or peritonitis) → proceed to surgery or drainage.
-
GASTROSCHISIS & OMPHALOCELE66
-
INGUINAL HERNIAS59
-
ANORECTAL MALFORMATIONS47
-
TEF/OA42
-
HIRSCHSPRUNG DISEASE37
-
PEDIATRIC BURNS (SURGERY)34
-
PEDIATRIC INTUSSUSCEPTION35
-
APPENDICITIS30
-
NECROTIZING ENTEROCOLITIS26
-
PEDIATRIC TRAUMA24
-
UNDESCENDED TESTICLE24
-
MALROTATION23
-
PYLORIC STENOSIS18
-
NEONATAL INTESTINAL OBSTRUCTION16
-
STOMA15
-
Wilms Tumor0
-
FB INGESTION/INHALATION0
-
GI ATRESIAS0
