Appendicitis

Question 1

Name some DDx for RIF pain?

Answer 1

• Mechanical- obstruction, strictures, adhesions, volvulus
• Infectious- appendicits, diverticulitis, gastroenteritis, C diff, hepatitis, pancreatitis, cholecystitis, ischaemic colitis
• IBD- CD (terminal ileum), UC
• Genetic- Hirschsprung’s disease
• Reproductive- ectopic pregnancy, ovarian cyst torsion/rupture, endometriosis, PID
• Urinary- renal calculi, UTI, pyelonephritis, cystitis
• Neoplasia- CRC, ovarian ca, uterine ca

Question 2

What are the signs of localised peritonism?

Answer 2

• sharp, localised RIF pain,
• guarding
• rigidity
• rebound tenderness
• diminished bowel sounds

Question 3

What is McBurney’s sign?

Answer 3

Tender RIF
(esp McBurney’s point- 1/3rd distance between ASIS and umbilicus where appendix attaches to caecum)
-> sign of localised peritonism (indicated high risk rupture, need for surgery)

Question 4

What is Rovsing’s sign?

Answer 4

Compress LIF 
(stretches/compresses parietal periotenum onto inflamed appendix) -> elicits pain in RIF

Question 5

What is the Psoas sign?

Answer 5

Pt on left side, extends R thigh slowly (stretch retroperitoneal iliopsoas muscle) -> RIF worsens
Suggests retrocaecal appendix

Question 6

What is the obturator sign?

Answer 6

Internal rotation of flexed right thigh causes the obturator internus muscle to compresses 
appendix -> worsening RIF pain
Suggests pelvic appendix

Question 7

What are signs of appendiceal perforation?

Answer 7

• tense, distended abdo
• generalised guarding
• sharp, diffuse RIF pain
• absent bowel sounds
• tachycardia
• hypotension
• fever

Question 8

What are the US findings for appendicitis?

Answer 8

• enlarged appendix (>6mm)
• thickened appendix wall
• peri-appendicular fluid
• faecoliths (concentrated faeces) obstructing lumen

Note: US 60% sensitive

Question 9

What are the appendicitis CT findings?

Answer 9

• marked fat stranding in peri-appendiceal region
• peri-appendicular fluid accumulation
• lack of gas bubbles in appendix (blockage)

Question 10

Describe the pathogenesis of appendicitis?

Answer 10

• Obstructed appendix lumen (faecolith, lymphoid hyperplasia, foreign body, GIT worm, tumour)
• mucus build up, acts as bacterial growth medium
• stimulates visceral afferent stretch fibers -> visceral umbilical pain
• venous drainage blocked -> further swelling
• outer serosa inflammed (6hrs) -> parietal peritoneum inflammed -> peritonitis (localised pain)
• bowel irritation (parlaytic ileus and fluid sequestration -> hypovolaemic shock)
• arterial supply occluded -> ischaemia -> perforation
• bacterial leaks -> localised abscess -> bacterial peritonitis -> sepsis and death

Question 11

Appendicitis risk factors?

Answer 11

Non-modifiable: age (teens, late 40s), male

Modifiable: smoking, low fibre diet

Question 12

List some complications of untreated appendicitis?

Answer 12

Acute:
- perforation
- peritonitis -> septic shock
- appendicular mass (SB and omentum cover inflated appendix)
- appendicular abscess (unresolved appendicular mass enlarges)
- paralytic ileus -> fluid sequestration -> hypovolaemic shock -> death
Subacute:
- infection drains to liver -> liver abscess
Chronic:
- adhesion formation -> bowel obstruction

Question 13

How would you manage appendicitis?

Answer 13

• Fluid resuscitation
• Surgery: laparoscopic if not perforated, open if perforated
• Abx: Ampicillin + Gentamicin + Metronidazole

Question 14

Describe the surface and internal landmarks of the appendix.

Answer 14

• Surface landmark: McBurney’s point- 1/3rd distance between the ASIS and umbilicus (most common attachment point of appendix base to caecum)
• Internal landmarks:
- 2cm inferior to ileocaecal valve
- convergence point of the three taenia coli (converge to form complete longitudinal muscle coat)

Question 15

Describe the function of the appendix?

Answer 15

• vestigial structure
• contains GIT lymphoid tissue, secretes mucosal IgA
• safe haven for commensal intestinal bacteria during GIT infection (gastro), allowing later repopulation

Question 16

What are the differing appendix positions? How do these present differently?

Answer 16

1) Retrocecal (43%)- behind caecum or lower ascending colon
Clinical: flank or back pain, worsened by psoas sign
2) Pelvic (9%)- descending into pelvis and suspended over pelvic brim
Clinical: suprapubic pain, dysuria, tenesmus, rectal mass, worse with obturator sign, LLQ (if long)
3) Subcecal- below cecum and pointing to inguinal canal
4) Paracecal
5) Pre-ileal
6) Post-ileal
Clinical: testicular pain (irritates spermatic a. or ureter)

Question 17

Describe the vascular supply and drainage of the appendix?

Answer 17

Arterial supply:
Ileocolic artery -> appendicular artery (terminal branch)
Venous drainage:
Appendicular vein -> ileocolic vein -> superior mesenteric vein -> portal vein -> sinusoids in liver -> hepatic veins -> IVC

Question 18

Why does appendicitis pain migrate from the umbilicus to the RIF?

Answer 18

Visceral: appendix and umbilicus innervated by T10 sympathetic fibres
-> appendiceal stretching felt in umbilical region (T10 dermatome)
Parietal: inflammation spreads to outer serosa -> spreads to parietal peritoneum -> local nociceptive fibres stimulated -> localised RIF pain

Question 19

Describe L1 innervation?

Answer 19

• partial innervation of psoas major and quadratus lumborum

- part of lumbar plexus -> iliohypogastric (T12-L1), ilioinguinal (L1) and genitofemoral (L1-2) nerves

Question 20

Describe the lumbar plexus?

Answer 20

Lumbar plexus:

1. Iliohypogastric (T12-L1):
   - Motor: interval and transverse abdominis muscles
   - Sensory: lateral gluteal region
2. Ilioinguinal (L1):
   - Motor: internal oblique, transverses abdominis muscles
   - Sensory: upper and medial thigh, scrotum and root of penis (males), mos pubis and labia majora (females)
3. Genitofemoral (L1-2):
   - Motor: cremasteric muscle
   - Sensory: upper anterior thigh, scrotum (males), mons pubis (females)