Appendicitis

Introduction: Appendicitis is a medical emergency that requires prompt surgery to remove the appendix. It is one of the most common acute surgical problem in children and is most commonly misdiagnosed. Left untreated, an inflamed appendix will eventually perforate leading to peritonitis.

 

Epidemiology: The lifetime risk for appendicitis is 9% in men and 7% for women. About one third of patients with appendicitis are younger than 18 years of age. The incidence of appendicitis varies worldwide. In India more than 2,70,000 cases are reported annually. Although it can strike at any age, appendicitis is rare under age 2 and most common between ages 10 and 30.

 

Etiology: Appendicitis may be a result of luminal obstruction followed by infection due to Yersinia, Salmonella, and Shigella. The cause of luminal obstruction may be an inspissated and calcified fecal mater called fecalith (Fig.1). Appendiceal lymphoid hyperplasia may cause luminal obstruction leading to appendicitis. Parasitic infection such as Entamoeba, Strongyloides, Enterobius vermicularis, Schistosoma or Ascaris can cause appendicitis. Enteric and systemic viral infection can lead to appendicitis. Patients with cystic fibrosis are more prone for appendicitis due to alterations in the mucus secreting glands. Carcinoid tumors can be a source of appendicitis, if they are obstructing the appendiceal lumen.

 

Pathogenesis/ pathophysiology:

Spectrum of appendicitis involves from a simple infection to perforation. The varying stages of appendicitis include acute appendicitis, suppurative appendicitis, gangrenous appendicitis and perforated appendicitis.

The continuous inflammation of the appendix will cause distention of the appendiceal wall leading to nausea and vomiting. As the pressure inside the inflamed appendix increases, the lymphatics get obstructed, leading to further edema and swelling. Further increase in pressure leads to venous congestion and results in ischemia, infarction and gangrene. This leads to bacterial transmigration of the wall of appendix. As a result of mediators released by ischemic tissue, white blood cells and bacteria, it leads to fever, tachycardia and leucocytosis.

Further increase in intraluminal pressure will lead to perforation, localized abscess formation, if omentum conceals the perforation or it may lead to generalized peritonitis.

 

Clinical features

The child may complain of gastrointestinal symptoms before full fledged appendicitis sets in. There may be anorexia, indigestion or change in bowel habits. A hungry child may rarely have appendicitis.

Initially the child may complain of pain around the umbilicus, gradually the pain gets localized to the right iliac fossa. Nausea is common but vomiting is rare until and unless the appendix is perforated leading to features of intestinal obstruction.

After few hours of nausea and vomiting the pain sets in. It will be followed by fever and tachycardia.

An inflamed appendix coming in contact with the parietal wall triggers off pain localized in the right iliac fossa or the McBurney’s point.

Signs of Acute appendicitis are, fever more than 101degree F, high leucocyte count, tachycardia with tenderness in the McBurney’s point.

A pelvic abscess due to perforated appendix may lead to Diarrhea, or tenesmus.

Younger children usually present with a complicated appendicitis because of inability to give proper history and low index of suspicion by the clinician. The most common presenting symptoms for these children will be vomiting, followed by fever and abdominal pain.

 

Differential diagnoses: Appendicitis can mimic a variety of intra abdominal conditions. The differential diagnosis of acute appendicitis is listed in table 1.

The clinical diagnosis of appendicitis is challenging as many times the presentations can be variable and symptoms may be non specific.

Most common gastro intestinal conditions which may mimic appendicitis includes acute gastroenteritis, viral mesenteric adenitis and constipation. Meckel’s diverticulitis and Chron’s disease may be other rare causes in the abdomen.

Extra-abdominal causes like pleurisy and pneumonia can mimic acute appendicitis and failure to diagnose may be life threatening as anesthetizing under in the presence of lower respiratory infection will be hazardous.

 

Approach to diagnosis:

PHYSICAL EXAMINATION: Clinically a child with appendicitis will be quite and lie in bed with minimal movement. An older child may limp while walking with a grumpy face. They will give history of pain with every jerk while walking, coughing or while being in the car.

Before examining the patient if the child is asked to show the area of pain, they will usually point to the McBurney’s point.

Palpation should be started away from the site of tenderness and progressed towards the site of pain. This will help in elicitng the Rovsing’s sign  which indicates peritoneal irritation due to referred pain.

A classical McBurney’s point tenderness is diagnostic of acute appendicitis in conjunction with an elevated total leucocyte count, tachycardia and fever. Tenderness may be mild during the initial stages and can be elicited by palpation or percussion. The pain of retrocecal appendix may be elicited midway between the 12th rib and posterior superior iliac spine. Rectal tenderness will suggest a pelvic appendicitis.

A perforated appendicitis may present in the form of local or generalized guarding and rigidity, depending on the severity of the disease. A rebound tenderness may indicate localized peritonitis. Diffuse peritonitis is more commonly seen in infants as the omentum is short and not able to seal of the pus. Older children have a contained infection in the form of localized pus.

If the diagnosis is in doubt, serial abdominal examination at intervals of 6-12 hours can help in eliciting if the signs are progressing or reducing in intensity.

LABORATORY INVESTIGATIONS:  In  the routine blood investigation, complete blood count will suggest an increase in the total leucocyte count above the normal range for the concerned laboratory. The Neutrophil count also is increased in most of the cases of appendicitis. Though the leucocyte count maybe an adjunct in diagnosing acute appendicitis but may not always be sensitive and specific. C reactive protein may be done by some physicians but not mandatory in the diagnosis of appendicitis.

A properly taken history, with adequate physical findings and corroborative laboratory test will point towards making a correct diagnosis of Acute appendicitis. The diagnosis of acute appendicitis may at times be challenging. This has lead to several scoring system in pursuit of making a correct diagnosis, but non have proved to be 100% specific and sensitive.

RADIOLOGICAL STUDIES:

A plain x ray may suggest fecaliths in 10-20% of cases but rarely done to diagnose appendicitis. A chest x ray to rule out pneumonia may be needed.

An ultrasound may suggest a non compressible appendix with an AP diameter of more than 7mm. Presence of an appendicolith, with periappendiceal fluid may be confirmatory in the hands of a skilled sinologist .Most studies demonstrate a sensitivity greater than 85% and specificity greater than 90%.

Most often the clinician resorts to Computer assisted tomography for the diagnosis when all means have failed to arrive at a correct diagnosis. CT scan may show an enlarged appendix with thickening of the appendiceal wall, periappendiceal fat stranding and enhancement of appendiceal wall.  It may help in the diagnosis due to anatomical abnormality such as malrotation or situs inversus (Fig 3).  The sensitivity of CT scan is over 90% and its specificity is over 80%.

Serial examination by the same examiner is the safest and the most accurate diagnostic tool.

 

Management:

The treatment of acute appendicitis is appendectomy. The management options in the peri-operative period may vary. The choice of antibiotics and its length of use may vary from surgeon to surgeon.

In early non complicated appendicitis only perioperative antibiotics are required. The recommended dose is from a single dose to 48 hours. In complicated appendicitis, it has been suggested that as little as 48 hours of coverage is adequate. Standard antibiotic therapy at our institution is 3rd generation cephalosporin for early appendicitis and 3rd generation cephalosporin, amikacin and metronidazole for complicated appendicitis. Continuation of antibiotics is decided depending on the presence of fever and elevated leukocyte count and not as a fixed protocol.

SURGERY- The gold standard treatment for appendicitis is prompt surgery. Though some cases of early appendicitis can resolve spontaneously but the future risk of developing complicated appendicitis cannot be ruled out. Majority of the appendicitis today are operated by laparoscopic methods. Open appendicectomy is becoming rarer in surgical practice though the trainee should be aware of while having problems in performing laparoscopic appendicectomy. The advantages of laparoscopic appendicectomy are many fold  including shorter hospitalizations, decreased post operative pain, decreased wound complications, increased ability to diagnose co-existing conditions or other pathological conditions, surgical ease in obese patients and faster post operative recovery. Laparoscopic appendicectomy for complicated appendicitis is gaining much popularity than before.

Opinion regarding irrigation and drainage varies from surgeon to surgeon. We usually perform a laparoscopic appendicectomy with suction of the pus and drainage of the peritoneal cavity by a tube drain for complicated appendicitis.

Evidence based clinical pathways are being widely used in the management of appendicitis leading to better patient treatment and outcome.

If not treated in time acute appendicitis may lead to complications like perforation and peritonitis. With the advent of higher antibiotics and awareness there is a decline in the incidence of complications. Complications of appendicitis are listed in table 2. Acute appendicitis in females should be treated with a low threshold for surgery as complicated appendicitis may lead to fertility problems in the future.

In recent years due to broad spectrum antibiotics the mortality due to complicated appendicitis is almost nil.  Antibiotics have markedly decreased the incidence of various complications listed in table 2. Although the length of hospitalization and morbidity due to complicated appendicitis still far exceeds those with simple appendicitis, the overall morbidity in children with complicated appendicitis is less than 10%.

 

Prevention: the consequences of complicated appendicitis may be prevented through both public and medical education leading to early and prompt treatment before perforation.

 

 

  1. Key points:

 

  • Appendicitis remains the most common acute surgical condition of the abdomen in children.
  • Luminal obstruction due to fecalith remains the commonest cause of acute
  • Salient clinical features of acute appendicitis are- right iliac fossa pain, nausea and vomiting, fever associated with tachycardia and elevated leucocyte count.
  • Radiological investigations like ultrasound and CT scan may aid in the diagnosis of appendicitis.
  • The gold standard treatment for appendicitis is laparoscopic appendisectomy.
  • The combination of surgical evaluation, prompt observation, a period of observation if the diagnosis is equivocal followed by imaging if necessary and care provided by experienced clinicians and institutions will lead to the best outcome for children with appendicitis.
  1. Suggested readings/ Bibliography

James.C.Y.Dunn. Appendicitis.In: J.L.grosfeld, J.A.O’Neill, Arnold.G. Coran, E.W.Fonkalsrud. Editors. Pediatric Surgery. 6th edition, Chapter 98,Vol1, Mosby INC, 2006.

FIGURE AND LEGEND:

Figure 1:

CT Scan suggestive of appendicitis in a case of Situs inversus.

Appendicitis in Situs inversus

TABLE 1:

Differential diagnosis of Acute appendicitis

Gastro intestinal system Acute gastroenteritisAcute viral mesenteric adenitisConstipation

Meckel’s diverticulitis

Chron’s disease

Typhoid

Appendiceal tumor, carcinoid tumor.

Hepatobiliary HepatitisCholecystitis
Urinary System HydronephrosisPyelonephritisUreteral or renal calculus
Uterus, ovary Ovarian torsionRuptured ovarian cyst
Others Primary peritonitisHenoch-Schonlein purpuraPancreatitis

Pleuritis

Pneumonia

Psoas abscess

Torsion of appendix epiploica

TABLE 2

COMPLICATIONS IN ACTUTE APPENDICITIS

Wound infection
Intra abdominal abscess formation
Post operative intestinal obstruction
Prolonged ileus
Entero cutaneous fistula

View Full text article on Appendicitis: Appendicitis

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