Appendicitis (GI) Flashcards
Define acute appendicitis.
Acute inflammation of the vermiform appendix, most likely due to obstruction of the lumen of the appendix (by faecolith, normal stool, infective agents, or lymphoid hyperplasia)
Describe the aetiology of acute appendicitis.
- obstruction of the lumen of the appendix caused normally by faecolith (hard mass of faecal matter), normal stool, infective agents or lymphoid hyperplasia
- lumen distal to obstruction starts to fill with mucus –> distension and increase in intraluminal and intramural Pa
- resident bacteria in appendix (Bacteroides fragilis and Escherichia coli) rapidly multiply
- Pa of lumen>venous Pa = small venules and capillaries become thrombosed but arterioles remain open –> engorgement and congestion of appendix
- inflammation progresses to involve outer serosa layer = parietal peritoneum
- anti-mesenteric border becomes ischaemic –> infarction and perforation
- bacteria leak out of infarcted wall = pus collects within and around appendix
Describe the epidemiology of acute appendicitis. (2)
- M>F
- 10-19 years old
How does appendicitis typically present?
Acute abdominal pain starting in mid-abdomen and later localising to RLQ, associated with fever, anorexia, N&V and neutrophilia
What are the signs and symptoms of acute appendicitis? (8)
- abdominal pain (starts peri-umbilical then moves to RLQ + worse on moving or coughing)
- anorexia
- nausea and vomiting
- mild pyrexia (37.5-38.5C)
- RLQ tenderness (McBurney point)
- diarrhoea / constipation
- tense, rigid abdomen (peritonitis - could indicate perforated appendix)
- hypotension and tachycardia
What might you see on examination in acute appendicitis? (8)
- palpable mass (peri-appendiceal abscess caused by perforated appendix)
- low-grade pyrexia
- flushed face and a fetor (strong, foul smell)
- reduced bowel sounds (sign of perforated appendix)
- Rovsing’s sign
- psoas sign
- obturator sign
- Blumberg sign
Where is McBurney’s point?
1/3 of the distance laterally from umbilicus towards right ASIS
What is Rovsing’s sign?
Palpation in LIF causing pain in RIF
What is the psoas sign?
- RIF pain on extending hip if retrocaecal appendix (so hip appears flexed)
- could also be a sign of psoas abscess = CT abdomen should be done
What is the obturator sign?
Pain on internal rotation of a flexed thigh
What is the Blumberg sign?
Rebound tenderness in RLQ
What could a high fever indicate instead of acute appendicitis?
Mesenteric adenitis
What type of pain can a retrocaecal appendix cause?
Flank or back pain
What type of pain can a retroileal appendix cause?
Testicular pain due to irritation of the spermatic artery or ureter
What type of pain can a pelvic appendix cause?
Suprapubic pain (possibly flexed right hip and loose mucus stool)
What are some risk factors for acute appendicitis? (4)
- M > F
- age 10-30 years
- Fx
- white
What are the first-line investigations for acute appendicitis? (4)
- FBC
- CRP
- abdominal ultrasound
- contrast-enhanced abdominal CT
What test is done to all women of childbearing age presenting with acute appendicitis?
Bedside pregnancy test to exclude pregnancy/ectopic pregnancy before any other investigations in women with LIF/RIF pain
What is the key FBC finding in acute appendicitis? (In adults vs children)
- leukocytosis (10-18 x 10^9/L) with neutrophilia is present in 80-90% of adults with appendicitis
- leukocytosis (>16 x 10^9/L) and elevated CRP level (>10mg/L) are strong predictive factors for appendicitis in children
What is CRP like in acute appendicitis?
Elevated
When is urine analysis useful for acute appendicitis?
- useful to exclude pregnancy in women, renal colic and UTI
- may show mild leukocytosis but no nitrites in appendicitis patient
What forms of imaging do we do for acute appendicitis?
- abdominal US - useful in females with suspected appendicitis to rule out ovarian pathology
- presence of free fluid should raise suspicion - first line in pregnant women
- in pregnant women if US inconclusive –> MRI
- if US inconclusive or malignancy suspected –> contrast-enhanced abdominal CT
- imaging not needed for thin, male patients with high likelihood of appendicitis - may be diagnosed clinically
What might you see on imaging for acute appendicitis?
- aperistaltic or non-compressible structure with outer diameter >6mm
- abnormal appendix (diameter >6mm) identified or calcified appendicolith seen in association with peri-appendiceal inflammation
When do we do erect CXR for acute appendicitis?
If perforation suspected
