Appendicitis is a somewhat familiar term for everyone, even those unrelated to the medical field. In this article, we will see what appendicitis is, its epidemiology, causes, symptoms, signs, complications, and management of appendicitis.
What is appendicitis?
Appendicitis is the inflammation of the appendix. There are two types of appendicitis.
- Acute appendicitis – Develops quickly within hours in a day and requires medical treatment promptly.
- Chronic appendicitis – Inflammation lasts for a long time. Acute appendicitis is more common, and chronic appendicitis is a rare condition. Here we are mainly focusing on acute appendicitis.
What is the appendix?
The appendix is a pouch-like structure or blind muscular tube that arises from the large intestine’s posteromedial aspect of the caecum. It is situated just below the ileocecal valve, where the ileum, or the most distal part of the small intestine, joins the cecum of the large intestine.
The appendix is important in maintaining the gut microbiota and in immune function.
The appendix is short at birth but also broad at its junction. By the age of 2 years appendix get its tubular structure through the differential growth of the caecum. The length of the appendix can vary from 12mm to 22mm. The base of the appendix is constant. It is found where the three taeniae coli of the caecum fuse. Then it forms the outer longitudinal muscle layer of the appendix. The appendix consists of mucosal, submucosal, muscular, and serosal layers, the same as the typical layer structure of the gastrointestinal tract wall.
- Retrocaecal (behind the cecum) 74%
- Pelvic 21%
- Para-caecal 2%
- Sub-caecal 1.5%
- Pre-ileal 1%
- Post-ileal 0.5%
The appendix receives the vascular supply by an end-artery known as the appendicular artery. It is a branch of the ileocecal artery. A thrombosis in this artery results in necrosis of the appendix.
Epidemiology of Appendicitis
Acute appendicitis is considered the most common abdominal emergency.
Appendicitis is rare among infants and the elderly. Let’s see the reason behind this. Infants have a wide lumen of the appendix, while the elderly usually have a completely obliterated appendix. Obstruction of the appendix normally leads to appendicitis. Obstruction is rare, with a wide lumen and a completely obliterated appendix. Therefore appendicitis is also rare in the elderly and infants.
Appendicitis is common in children and early adults. Teens and early ’20s have the highest incidence.
Before puberty, the incidence of appendicitis among males and females is 1:1. Later in teenage and young adulthood, males show greater incidence than females. The male-to-female ratio of appendicitis is 3:2 at this age.
Western countries have decreased incidence, while developing countries have increased acute appendicitis in the past 30 years. Reasons behind this may be improved sanitation and increased use of antibiotics. No clear reason has been found yet.
What are the symptoms (complaints of the patient)?
The first symptom of acute appendicitis is poorly localized colicky abdominal pain. Colicky pain is a sharp pain that arises suddenly, which comes and goes like a spasm. The visceral discomfort from obstruction and inflammation leads to this type of abdominal pain.
Then the pain localized as pain around the umbilicus, known as the periumbilical region.
Then periumbilical abdominal pain shifts to the right iliac fossa. It is due to the irritation of the parietal peritoneum in the right iliac fossa with progressive inflammation of the appendix. This present as a constant, more intense, and localized somatic pain. Right iliac fossa pain usually exacerbates with coughing and sudden movements.
In the elderly, abdominal pain may be present without localization, considered an atypical presentation.
Suprapubic discomfort and tenesmus (the feeling of defecation even though the bowels are empty) may be present in inflammation of the pelvic appendix instead of somatic pain in the anterior abdominal wall. In such patients, tenderness is elicited in rectal examination. Therefore it is advised to do a rectal examination in every patient who presents with acute lower abdominal pain.
What are the signs of appendicitis? (What are the things identified by the doctor?)
Diagnosis of appendicitis is mainly based on examination rather than clinical history or investigations.
Clinical signs of appendicitis are pyrexia, localized tenderness in the right iliac fossa, muscle guarding, and rebound tenderness. Tachycardia (elevated heart rate above 100 bpm) is a typical sign.
In appendicitis, four signs are elicited. They are
- Pointing sign
- Rovsing’s sign
- Psoas sign
- Obturator sign
A low-grade pyrexia/fever is present in these patients.
The patient is asked to point to the area where the pain began and to where the pain radiated. It is known as the pointing sign. Generally, pain starts in the periumbilical region and radiates into the right iliac fossa.
The inspection may also show reduced abdominal movements in the lower abdomen.
In superficial palpation, muscle guarding over the point of maximum tenderness is detected. It is usually present in the right iliac fossa or McBurney’s point. Muscle guarding is a voluntary contraction of muscles to avoid pain.
To elicit rebound tenderness patient is asked to cough or percuss gently over the McBurney’s point or the site of maximum tenderness. Rebound tenderness arises from pain when removing the pressure rather than when applying the pressure.
In deep palpation, Pain is elicited in the left iliac fossa. It is called Rovsing’s sign.
The patient will lie with the flexed right hip to relieve Pain because the inflamed appendix may lie on the psoas muscle. It is called the psoas sign.
When the hip is flexed and internally rotated, the obturator internus muscle spasms are visible. This may cause Pain in the hypogastrium when the inflamed appendix contacts with the obturator internus muscle. It is called an obturator sign.
Associated symptoms
Anorexia or loss of appetite is a constant feature usually present in children. Other symptoms include nausea (feeling of vomiting), 1-2 episodes of vomiting & abdominal bloating. Constipation or diarrhea may also occur.
These are some important factors of appendicitis related to the patient’s age.
- Infants’ diagnosis of appendicitis is delayed because they can’t give history. Therefore perforation of the inflamed appendix and post-operative complications are relatively high. As they have underdeveloped greater momentum, diffuse peritonitis can be developed rapidly.
- Almost all children with appendicitis have vomiting as a symptom. Usually, they have a strong dislike for taking food.
- Gangrene and perforation are more common among the elderly.
- The obese patient may not show local signs. Therefore to establish the diagnosis, imaging methods are used. Laparoscopy is useful in obese patients.
- In pregnancy, appendicitis is the most common extra-uterine acute abdominal condition. Diagnosis is delayed because early symptoms are also occurred due to pregnancy. In pregnancy, the main clinical feature is Pain in the right lower quadrant of the abdomen. Fetal loss can also happen in 3-5%, and if perforation occurs, it can be riskier for the fetus.
Causes for appendicitis
Bacterial multiplication within the appendix is associated with appendicitis. Generally, the mixed growth of different organisms, including aerobic and anaerobic bacteria, is responsible for appendicitis.
Luminal obstruction is the leading cause identified as the reason for bacterial proliferation in the appendix.
Obstruction of the appendix can be due to a stricture or appendicolith. Enlargement of lymphoid follicles in the appendix wall secondary to mucosal inflammation is also a cause of obstruction. Rarely due to carcinoid tumor at the base of the appendix cause obstruction.
What is an appendicolith?
Appendicolith is a calcified mass in the appendix. It may be composed of fecal matter, calcium phosphate, epithelial debris, bacteria, and rarely by a foreign body.
Other causes of obstruction in the appendicular lumen are intestinal parasites and carcinoma. Caecal carcinoma can obstruct the opening of the appendix to the caecum. This is present in middle-aged and elderly patients.
The proliferation of intestinal parasites like pinworms can occlude the lumen of the appendix.
Previous appendicitis healed without surgery can result in stricture usually.
If bacteria is not present in an obstructed appendix, mucocele results. It results from the continuous secretion of mucus from mucosal wall goblet cells.
Appendicitis doesn’t need to have an obstruction, essentially. Even a non-obstructed appendix can have appendicitis by direct infection of lymphoid follicles from the lumen or hematogenous infection. Non-obstructed appendicitis is more easily resolved than obstructed appendicitis.
Decreased dietary fiber and increased consumption of refined carbohydrates are risk factors for appendicitis
Family history with appendicitis is also important as 1/3 of children have first-degree relatives with a similar history.
Pathology Of Appendicitis
Obstruction of the appendix is the leading cause of appendicitis. In an obstruction, the appendix becomes a closed space. Bacteria in the appendix multiply in the lumen. The appendicular wall is damaged by pressure necrosis due to compression, and bacteria easily invade the appendix wall. It results in inflammation. As mentioned before, the appendix is supplied by the appendicular artery, an end artery. Occlusion of this artery results in gangrene, and perforation occurs.
Complications Of Appendicitis
The inflamed appendix becomes gangrenous. Then appendix will perforate. It results in general peritonitis and localized appendix abscess.
Investigations
Clinical diagnosis is essential in appendicitis. For that signs and symptoms mentioned above are important.
Scoring systems have been designed based on clinical and laboratory investigations to assist diagnosis of appendicitis. Alvarado (MANTRELS) scoring is mostly used.
Score
1. Symptoms
M-Migratory Right iliac fossa pain = 1
A -Anorexia =1
N -Nausea and vomiting = 1
2. Signs
T -Tenderness in right iliac fossa = 2
R -Rebound tenderness = 1
E -Elevated temperature = 1
3. Laboratory
L -Leucocytosis = 2
S -Shift to the left (presence of immature neutrophils in blood) = 1
Total = 10
A score of 7 or more is more predictive of acute appendicitis.
CECT (Contrast Enhanced Computed Tomography) scan is performed in the patients who score 5-6.
Ultrasound scan in the abdomen is performed mostly in children. Modern CT is more useful in diagnosing appendicitis. Diagnosing accuracy is high in this investigation. CECT is performed in patients with uncertain diagnoses, especially in the elderly, as there are several differential diagnoses such as acute diverticulitis, intestinal obstruction, and neoplasm.
Investigations that should be performed before surgery are full blood count and urinalysis. These two investigations are routinely performed.
There are some investigations that should be done selectively according to the patient. They are pregnancy tests, urea and electrolytes, supine abdominal radiograph, ultrasound scan of abdomen or pelvis, and contrast-enhanced computed tomography (CECT) scan of abdomen and pelvis.
Treatments for Appendicitis
Two types of treatment methods are present. They are operative and non-operative.
Non-operative method
The non-operative method is not commonly used. It is a conservative method that can be performed in uncomplicated appendicitis. The absence of appendicolith, perforation, or abscess is considered here.
Resting of the bowel and intravenous antibiotic is the treatment. Metronidazole and 3rd generation cephalosporin are used.
About 25% of patients initially treated with a conservative method require surgical management within one year for recurrent appendicitis.
Operative method
The operative method is commonly used and is considered the standard treatment. Surgical removal of the appendix/appendectomy is performed without unnecessary delay. Sufficient intravenous fluid and appropriate antibiotics should be given preoperatively.
Appendectomy /appendicectomy
Both terms indicate the surgical removal of the appendix. It is considered the most commonly performed urgent abdominal procedure. Usually, it is the first major procedure of a training surgeon. Appendectomy is performed under general anesthesia. It is done by an open or laparoscopic approach.
i. The laparoscopic approach to appendicectomy
The laparoscopic approach is more beneficial if the equipment and expertise are available. The first laparoscopy is done to confirm the diagnosis. The advantages of the laparoscopic approach are quick recovery, lower risk of wound infection, and minimally invasive procedures. To perform a laparoscopic procedure bladder should be empty.
ii. Open appendicectomy
In an open appendectomy, a gridiron incision is normally used. If better access is needed, Rutherford Morison incision is used. It is much helpful in para-caecal, retrocausal, and fixed appendix. Lanz incision is also used because it gives better exposure and makes it easy to extend the incision if needed. If the diagnosis is doubtful lower abdominal midline incision is performed.
Post-operative complications of appendicitis
Post-operative complications are not common after an appendectomy. The complications include wound infection, intra-abdominal abscess, ileus, respiratory, venous thrombosis, venous embolism, pylephlebitis, fecal fistula, and adhesive intestinal obstruction.
After an appendectomy, a few examinations should be performed on an unwell patient to identify the complication.
- A wound examination is done for wound infection.
- An abdominal examination is performed to detect an abscess.
- A rectal examination is performed to detect pelvic abscess.
- Lungs are examined to find out pneumonitis or collapse.
- Legs are examined, considering venous thrombosis.
1. Wound Infection
Wound infection is present 4-5 days after appendicectomy. Presentations are pain and red skin around the wound, known as erythema. It is the commonest complication after surgery. Causative organisms include a mixture of gram-negative bacilli and anaerobic bacteria. Treatment for this is wound drainage. Antibiotics are also given when needed.
2. Intra-abdominal abscess
An intra-abdominal abscess can be presented with spiking fever, malaise and, loss of appetite, or anorexia. It develops within 5-7 days after the appendectomy. Before discharge, the patient should be advised about the symptoms and to take medical advice soon if any symptoms present.
Computed tomography (CT) is helpful for the diagnosis and helps percutaneous drainage. If imaging doesn’t show intra-abdominal collection or patients who are suspected of having intra-abdominal sepsis, a laparotomy is considered.
3. Ileus
Painful obstruction in the small intestine is known as ileus. Following appendectomy, ileus may be present for several days. If it presents for more than 4-5 days with fever, it is highly suggestive of intra-abdominal sepsis. Prompt investigations should be performed.
4. Respiratory complications
Respiratory complications are present when the patient has a pulmonary disease. Otherwise, respiratory complications are rare after an appendicectomy. To avoid the occurrence of complications, adequate analgesics and appropriate physiotherapy is indicated.
5. Venous thrombosis and venous embolism
Venous thrombosis and venous embolism have been identified as rare complications unless the patient is elderly or a woman on oral contraceptive pills (OCP).
6. Pylephlebitis or portal pyemia
Inflamed thrombosis of the portal vein is known as pylephlebitis or portal pyemia. It is a serious complication that arises from gangrenous appendicitis. It is presented with high fever, rigors (shivering), and jaundice (yellowish discoloration of skin, sclera, and mucous membranes). This condition results from septicemia in the portal venous system. It can be severe up to the development of intrahepatic abscesses. Percutaneous drainage and systemic antibiotic is the treatment.
7. Fecal fistula
Patients with Crohn’s disease are prone to develop fecal fistula following appendicectomy. If the caecal wall becomes edematous or inflamed, encircling stitches that have been put in too deeply may be causative.
8. Adhesive intestinal obstruction
Adhesive intestinal obstruction is considered the most common late complication of appendicectomy. It is presented with prolonged pain in the right iliac fossa. For the confirmation purpose and to divide laparoscopic adhesion method is used.