Acute Appendicitis

Appendicitis which may be defined as an inflammation of the inner lining of the vermiform appendix that later spreads to its other parts. Despite many advancements, both therapeutic and diagnostic, appendicitis remains a clinical emergency surgery department and remain one common causes of acute abdominal pain. There are different positions of appendix as shown in figure below. 

The various positions of the appendix. Photo taken from bailey and love 

Types of Appendicitis 

According to pathology of appendix it can be 

obstructive appendicitis or 

catarrhal appendicitis.

Obstructive appendicitis. 

Obstruction of the appendix lumen is essential for the development of appendiceal gangrene leading to perforation. Lymphoid hyperplasia narrows appendix lumen, causing luminal obstruction. Once obstruction occurs, continued mucus secretion and inflammatory exudation increase intraluminal pressure, which obstruct lymphatic drainage. If the condition progresses further than distension of the appendix may cause venous obstruction and ischaemia of the appendix wall. With ischaemia, bacterial invasion occurs through the muscularis propria and submucosa, producing acute appendicitis. 

Catarrhal appendicitis.

In this if bacterial infections supervene, the intraluminal pressure of appendix increases. This leads to interruption in lymphatic flow and development of appendiceal edema. This process leads to acute appedicitis characterized by distension of the appendix and vascular congestion, which is designated as catarrhal appendicitis.

Obstruction of appendix can be caused by

Foreign body 

Faecolith

Fibrotic stricture

Tumors e.g carcinoma of appendix 

Parasite (e.g Oxyuris Vermicularis). 

What is Faecolith? 

It is also known as appendicolith. It is composed of inspissated faecal materials, bacteria, calcium phosphates crystals and epithelial debris.

History of acute appendicitis 

The classical history of acute appendicitis begin with poorly localised pain which may be colicky abdominal pain. The pain is very often first noticed in the periumbilical region than transfered to right lower quadrant (RLQ). Central abdominal pain may be associated with anorexia, nausea and usually one or two episodes of vomiting. Anorexia is a useful and constant clinical feature, particularly in children and young adults. The patient mostly gives history of similar discomfort that settled spontaneously.

Abdominal pain: Most common symptom. 

Nausea: 61-92% of patients. 

Anorexia: 74-78% of patients. 

Vomiting: Nearly always follows the onset of pain; vomiting that precedes pain suggests intestinal obstruction. 

Diarrhea or constipation: As many as 18% of patients.

Symptoms of acute appendicitis

The most common symptom of acute appendicitis is the abdominal pain. Typically begins at periumbilical or epigastric region than migrating to the right lower quadrant (RLQ) of the abdomen.

Periumbilical colic pain. 

Pain shifting to the right iliac fossa. 

Anorexia.

Nausea.

Signs of acute appendicitis

The diagnosis of acute appendicitis rests mostly on thorough clinical examination of the abdomen than on any aspect of the history of the patient and laboratory and radiological investigations The cardinal features are those of an unwell patient with low-grade pyrexia, localised abdominal tenderness, muscle guarding and rebound tenderness.

Clinical signs in appendicitis

Pyrexia. 

Localised tenderness in the right iliac fossa. 

Muscle guarding. 

Rebound tenderness.

Signs to elicit in acute appendicitis. 

The following accessory signs may be present in some patients:

Rovsing sign. Right lower quadrant (RLQ) pain with palpation of the left lower quadrant (LLQ). It suggests peritoneal irritation. 

Obturator sign. Right lower quadrant (RLQ) pain with internal and external rotation of the flexed right hip). It Suggests that the inflamed appendix is located deep in the right hemipelvis

Psoas sign. Right lower quadrant (RLQ) pain with extension of the right hip or with flexion of the right hip against resistance). It suggests that an inflamed appendix is located along the course of right psoas muscle. 

Dunphy sign. sharp pain in the right lower quadrant (RLQ) elicited by a voluntary cough. It suggests localized peritonitis.

Pointing sign.

The patient is asked to point where there is maximum pain. Mostly it's at McBurney's point which is a point that lies one-third of the distance laterally on a line drawn from the umbilicus to the right anterior superior iliac spine(ASIS).

Signs to elicit in acute appendicitis 

Scoring system for diagnosis of acute appendicitis. 

The Alvarado score is for the diagnosis of acute appendicitis which may be remembered as (MANTRELS) score. A score of 7 or more than 7 is strongly predictive of acute appendicitis 

The Alvarado (MANTRELS) score for acute appendicitis 

Investigations for the diagnosis of acute appendicitis.

CBC

WBC >10,500 cells/µL. In 80-85% of adults with appendicitis. 

Neutrophilia >75-78% of the patients

C-reactive protein. 

CRP level >1 mg/dL is common in patients with appendicitis. 

Very high levels of CRP may indicate gangrenous evolution of the disease. 

Urinalysis. 

Urinary 5-HIAA increase significantly in acute appendicitis and decrease when the inflammation shifts to necrosis of the appendix. 

Ultrasonography.

Because of minimally invasive investigation is easy to perform and can be repeated. A normal appendix is usually not visualized by ultrasonography. Followings positive findings may be present on ultrasonography for the diagnosis of acute appendicitis

1. Probe tenderness

2. Noncompressible tubular structure of 7-9 mm in diameter.

3. The periappendiceal accumulation of fluid or abscess.

4. The acoustic shadow of Faecolith

5. The indistinct layered structure which indicates Phlegmonous appendicitis. 

Vaginal ultrasonography alone or in combination with transabdominal ultrasonography may be useful to determine the diagnosis of acute appendicitis in women of childbearing age. 

CT scanning. 

Its the gold standard for diagnosis of acute appendicitis. 

CT scanning with oral contrast or rectal Gastrografin enema has become the most important imaging study in the evaluation of patients with atypical presentations of acute appendicitis. 

MRI. 

Its Useful in pregnant patients if graded and compression ultrasonography is nondiagnostic.

What are Differential diagnosis(DDs) of acute appendicitis.? 

Although acute appendicitis remains the most common abdominal surgical emergency, the diagnosis of acute appendicitis can be extremely difficult at times. There are some common conditions that it is wise to consider carefully and, if possible, exclude.

DDs of acute appendicitis in Children. 

Gastroenteritis. 

Mesenteric adenitis. 

Meckel's diverticulitis. 

Intussusception. 

Henoch–Schönlein purpura. 

Lobar pneumonia

DDs of acute appendicitis in Adults. 

Adult Regional enteritis. 

Ureteric colic. 

Perforated peptic ulcer.

Torsion of testis Pancreatitis. 

Rectus sheath haematoma. 

DDs of acute appendicitis in Adult female.

Mittelschmerz. 

Pelvic inflammatory disease. 

Pyelonephritis. 

Ectopic pregnancy. 

Torsion/rupture of ovarian cyst. 

Endometriosis. 

DDs of acute appendicitis in Elderly Diverticulitis.

Intestinal obstruction. 

Colonic carcinoma. 

Torsion appendix epiploicae. 

Mesenteric infarction. 

Leaking aortic aneurysm.

Management of acute appendicitis

Establish IV access. 

Administer aggressive crystalloid therapy with clinical signs of dehydration or septicemia. 

Keep patients with suspected appendicitis NPO

Administer parenteral analgesic. 

Antiemetic if needed. 

Bowel rest and Intravenous antibiotics, often metronidazole and 3rd generation cephalosprin.

Surgery (appendectomy) remains the standard teaching and curative treatment for acute appendicitis. Appendectomy may be performed by

1. Open appendectomy

2. Laproscopic appendectomy

3. Natural Orifice Transluminal Endoscopic Surgery (NOTES). This is known as scar less surgery. This is performed through natural orifices like Trans vaginal (in married woman) through rectum and mouth.