1. Acute Abdomen + The Appendix
Kingdom of Bahrain Arabian Gulf University College of Medicine and Medical Sciences
General Surgery
Acute Abdomen + The Appendix
Ali Jassim Alhashli

2. Definition: it is a sudden onset of abdominal pain which is associated with ≥ 1 peritoneal signs (rigidity, guarding or rebound tenderness) and Patients seeks medical attention.
What is the difference between guarding and rigidity?
Guarding: attempt by the patient to prevent painful palpation.
Rigidity: abdominal muscles are firm and do not allow examiner’s hand to enter.
Classic position of a patient with peritonitis: motionless with knees flexed.
What is the difference between visceral and parietal pain?
Visceral pain: diffuse (poorly localized), dull/aching, triggered by: distention, ischemia or chemical irritation.
Mid-epigastrium: stomach, duodenum, hepatobiliary system or pancreas.
Mid-abdomen: jejunum or ileum.
Lower-abdomen: colon and internal reproductive organs.
Parietal pain: well-localized, sharp, triggered by irritation to parietal peritoneum (example: inflamed appendix causing sharp RLQ pain due to irritation of nearby peritoneum).
When assessing pain, you have to ask about the following (SOCRATES):
S: Site.
O: Onset.
C: Character.
R:Radiation.
A: Associated symptoms.
T: Time/duration.
E: Exacerbating/ relieving factors.
S: Severity.
Acute Abdomen

3. Acute Abdomen
What is the difference between radiating and referred pain?
Radiating pain: means that your pain begins in one place and travels to another location along the path of the nerve.
Biliary tract pain: radiating to right shoulder due to irritation of right hemidiaphragm.
Splenic rupture: radiating to left shoulder due to irritation of left hemidiaphragm (Kehr’s sign).
Kidney pain: from flank to groin and genitalia (loin-to-groin).
Pancreas pain: to the back.
Referred pain: pain felt at a site distant from a disease process.
What are the investigations which you will usually ask for a patient presenting with acute abdomen?
Labs: CBC (looking for leujocytosis), amylase/lipase, BUN/creatinine and electrolytes, LFT and bilirubin, β-hCG (in all females of reproductive age group).
ECG: because inferior wall myocardial infarction can present with pain in epigastric area.
CXR + AXR: pay attention for air under diaphragm which indicated the presence of perforation (a surgical emergency).
CT-scan of the abdomen (especially done if you did not reach a final diagnosis with all of the above).

4. Differential diagnoses
Acute Abdomen
What are the surgical causes of abdominal pain?
Location of pain
Differential diagnoses
RUQ
Acute cholecystitis
Hepatic abscess.
Perforated duodenal ulcer.
Appendicitis in a pregnant female.
RLQ
Appendicitis.
Cecal diverticulitis.
Meckel’s diverticulitis.
Intussusception.
Ovarian pathology (torsion, tubo-ovarian abscess or ectopic pregnancy).
LUQ
Splenic abscess.
Splenic rupture.
LLQ
Sigmoid diverticulitis.
Volvulus.
Periumbilical
Pain in (EARLY) appendicitis.
Pain from Small Bowel Obstruction (SBO)

5. Paracentesis findings
Mention some of the important NON-SURGICAL causes of abdominal pain.
Inferior wall MI.
Lower lobe pneumonia.
Sickle cell crisis.
Diabetic ketoacidosis (DKA).
Psychological (hysteria).
What are the indications for urgent operation in patients with acute abdomen?
Physical findings
Involuntary guarding or rigidity.
Increasing or localized severe tenderness.
Tense or progressive distention.
Tender abdominal or rectal mass with high fever or hypotension.
Rectal bleeding with shock or acidosis.
Radiologic findings
Pneumoperitoneum.
Free extravasation of contrast material.
Mesenteric occlusion on angiography.
Space-occupying lesion on scan with fever.
Endoscopic findings
Perforated or uncontrollably bleeding lesion.
Paracentesis findings
Pus, blood, bile, bowel contents or urine.
Acute Abdomen

6. Appendix – Anatomy and Embryology
Appendix buds off from the cecum at 6th week. Notice that the base of the appendix is fixed to the cecum while the tip can end in different positions.
Anatomy:
Mesoappendix: it is the mesentery which suspends the appendix from terminal ileum.
Arterial supply: superior mesenteric artery → ileocolic artery → appendicular artery (contained within mesoappendix).
Histological layers of the wall of appendix: mucosa, submucosa, inner circular muscle, outer longitudinal muscle and serosa.
Function: immunological organ which secretes IgA (but it is not essential and can be removed).
Length: 6-9 cm.
Lumen capacity > 1 ml.

7. Appendix – Anatomy and Embryology

8. Appendix – Anatomy and Embryology

9. Appendix – Acute Appendicitis
It is the acute inflammation of the appendix in which the following sequence of events occurs:
Obstruction of the lumen:
Young patients: lymphoid tissue hyperplasia.
Older patients: fecalith (hard, stony mass of feces).
Distention: which initially produces visceral pain that it dull and diffuse. This pain is felt around the umbilicus (T10 distribution). Then, as distention progresses and appendix starts to irritate parietal peritoneum adjacent to it → pain changes to become well-localized (in RLQ) and sharp (parietal pain).
Venous congestion.
Impaired blood supply increases the risk of mucosal ischemia and bacterial invasion.
Inflammation and ischemia progressing to serosal surface of appendix.
Signs and symptoms:
Signs:
Direct rebound tenderness at McBurney’s point (one third distance between right anterior superior iliac spine and umbilicus).
Rosving’s sign: palpation of LLQ causes pain in RLQ.
Obturator sign: flex knee and hip + internal rotation. If there is pain, this mostly indicates pelvic appendicitis.
Iliopsoas sign: pain on extension of the right hip.
Symptoms:
Pain which starts initially around the umbilicus and then localize in RLQ.
Fever.
Nausea and vomiting.
Loss of appetite.
Appendix – Acute Appendicitis

10. Appendix – Acute Appendicitis

11. Appendix – Acute Appendicitis
What are your differential diagnoses for patient presenting with similar picture?
GI: gastroenteritis, primary peritonitis, mesenteric adenitis (Yersinia enterolytica causes inflammation of mesenteric lymph nodes, their swelling and thus abdominal pain), Meckel’s diverticulum and intussusception (especially in pediatric age group).
Genitourinary:
Pyelonephritis or ureteral stone.
Female: ectopic pregnancy or ovarian torsion/cyst.
Male: testicular torsion.
Diagnosis:
Notice that If you are sure clinically that the patients has appendicitis, imaging is not necessary. Take him immediately to OT.
Labs: CBC (usually < 10,000 with predominance of neutrophils… suspect perforation/abscess when < 18,000), amylase/lipase, BUN/creatinine/electrloytes and urinalysis (to rule out genitourinary causes).
Imaging:
Ultrasound (useful in pregnancy): ↑ diameter (< 6 mm) + appendix non-compressible (due to presence of fecalith).
Abdominal CT-scan (best): it shows
Thickened wall of the appendix.
Increased diameter (< 6 mm).
Presence of fecalith.
Periappendiceal streaking.
Appendix – Acute Appendicitis

12. Appendix – Acute Appendicitis

13. Appendix – Acute Appendicitis
Treatment:
Pre-operative:
NPO.
IV fluids.
Analgesia.
Antibiotics.
Recommended: appendectomy… open or laparoscopic (preferred).
If there is perforation of the appendix (usually occurring at the tip of the appendix) → open appendectomy with peritoneal washout and antibiotics.
If patient presents ≥ 5 days after onset of symptoms, don’t do appendectomy unless there is failure to manage him medically with antibiotics or appendicitis recurs.
Appendicitis in special populations:
Pregnant females:
It is the most common surgical emergency in pregnant females.
Risk of fetal mortality:
3-8% with appendicitis.
30% with perforation.
Presentation: RUQ pain (because appendix is pushed by the distended uterus).
Treatment: surgery!
Elderly patients:
The main problem in this age group is that they present atypically leading to later diagnosis.
They have less pain and clinical picture might resemble that of SBO.
Therefore, their risk for perforation and mortality is higher than young patients.
Appendix – Acute Appendicitis

14. Appendix – Appendiceal Neoplasms
Carcinoid:
Definition: it is a low-grade neuroendocrine tumor which secretes serotonin. It is the most common type of appendiceal tumors. Most common location is in the appendix followed by small bowel followed by the rectum.
Signs and symptoms:
Usually it is asymptomatic and found incidentally.
If it is symptomatic, it will produce abdominal pain and carcinoid syndrome (because it secretes: serotonin, bradykinin and tryptophan). Carcinoid syndrome is characterized by:
Flushing, sweating, watery diarrhea, dyspnea and wheezing.
Patients might also have pellagra-like symptoms (3 D’s: Dermatitis, Diarrhea and Dementia) due to niacin deficiency.
Diagnosis:
Most are found incidentally when appendectomy is done or with radiographic studies.
If patient has carcinoid syndrome:
24-hour urinary collection for 5-HIAA (elevated in 50% of patients).
Elevated urine and blood serotonin.
Treatment:
Medical: serotonin antagonists (such as cyproheptadine) to relieve symptoms.
Surgical:
Appendiceal carcinoid > 2cm: appendectomy.
Appendiceal carcinoid < 2cm: right hemicolectomy (it is a procedure which involves the removal of: cecum, ascending colon, hepatic flexure and first 1/3 of transverse colon).

15. Appendix – Appendiceal Neoplasms (Carcinoid tumor: gross and microscopic)

16. Appendix – Appendiceal Abscess
Signs and symptoms (HINT: suspect appendiceal abscess in a patient who presents with features of appendicitis and has RLQ mass):
Increasing RLQ pain.
RLQ mass (which is felt on rectal examination).
Fever.
Leukocytosis (usually < 18,000).
Nausea/vomiting/anorexia.
Diagnosis: CT-scan.
Treatment: percutaneous/open drainage + antibiotics.