Appendicitis
Epidemiology
Incidence – 10% lifetime risk, with a peak incidence in the teen’s and 20’s
Children less than 7 years old account for less than 3% of cases but nearly 35% of all
mortalities.
Men:women – 2:1 until the age of 25 and then it evens out
Anatomy
The appendix is generally is a postero-medial position in relation to the caecum, is
approximately 6cm long and the surface point is McBurney’s point (1/3 of the way from
the ASIS to the umbilicus).
The base of the appendix is located at the point of convergence of the tinea coli. It’s
supplied by the appendicular artery – a branch of the posterior caecal artery.
65% are retrocaecal, 30% are pelvic and the rest are pre or post ileal
When is the appendix not in the RIF? – in pregnancy, when it’s a long appendix, in cases
of maldescent of the caecum and in situs inversus
Pathology
The mechanism of inflammation is due to obstruction. In younger patients this is
generally due to lymphoid hyperplasia, while in older patients it’s usually due to a
faecolith.
Increased intraluminal pressure leads to lymphatic congestion, venous congestion and
finally arterial compression – this will, if untreated, lead to perforation
Presentation
Symptoms:
-
Initial periumbilical referred pain, moving to RIF – up to 25% will have
no periumbilical pain
Anorexia
Nausea and minimal vomiting
Low grade pyrexia
If pelvic – diarrhoea (not profuse), nausea, vomiting and more diffuse pain
If the inflamed tip is lying against the bladder, there may be urinary
symptoms
On Examination:
- Rigidity
- Tenderness
- Guarding
- Rebound
- Mass
- Scars
- Roving’s sign - DRE
- Psoas sign – pain on active flexion of the hip
- Obturator sign – flex hip to 90o – pain on internal rotation
- Sore throat – in kids may preceed mesenteric adenitis
- Cachexia, organomegaly – neoplasm
Atypical presentations can occur in elderly patients or diabetics who may have
autonomic neurophaties, those on steroids may have masked symptoms, and in
pregnancy – the appendix is high up on the right side and may be moved away from the
peritoneum, eliminating the sharp somatic localising sign
Investigations
-
Urinalysis
FBC – raised WCC, anaemia
CRP
U&E
HCG in women
Rarely may do erect CXR – air under diaphragm?
U/S – useful in small children and in young women to rule out
gynaecological pathology
CT – very accurate but a big radiation dose and time consuming – may do
in a patient with an atypical presentation
Treatment
-
NPO
IV fluids – NS or Hartmann’s
Analgesia
Anti-emetics
Prophylactic antibiotics – 3rd generation cephalosporin and metronidazole
– pre-op antibiotics are given at induction of anaesthesia
-
DVT prophylaxis
NG if vomiting is severe
May need a urinary catheter
Post-op antibiotics – If the surgery was uncomplicated, two more doses is
sufficient. If there was perforation, 5 days of antibiotics
Surgery
May be open or laparascopic (make sure you drain the bladder) – open can be by a
gridiron incision or a lanz incision
Layers – skin, subcutaneous fat, Camper’s fascia, Scarper’s fascia, Ext. oblique, Int.
oblique, transverse oblique, transversalis fascia, peritoneum
Consent
-
Haemorrhage
Anaesthetic risks
Conversion to open procedure if patient is being consented for
laporoscopy
Wound infection
Intra-abdominal infection
Visceral damage
Fistula
Abscess
Hernia – incisional and indirect inguinal – the ilio-inguinal nerve may be
severed during surgery. This innervates the posterior wall of the inguinal
canal and damage to the nerve will increase risk of indirect inguinal hernia
Adhesions
The appendix may be found to be normal
Alternate pathology may be found that requires treatment
Keloid/hypertrophic scars