Acute appendicitis
Objectives
To guide the investigation and management of acute appendicitis in the deployed environment.
Scope
This guideline describes the management of patients with acute appendicitis in a forward medical context or deployed Emergency Department.
Definitive diagnosis and treatment are in the domain of Role 2 Enhanced facilities and above. Therefore, the scope of this guideline is to assist in the initial management and appropriate contextual decisions.
Audience
This guideline is intended for the use of registered healthcare professionals fulfilling a general role in a forward medical location or in an Emergency Department on deployed operations.
Initial Assessment & Management
Background
The Appendix is a small, narrow blind ended tube (about 6-10cm long) that is connected to the caecum (the proximal part of the large intestine, just before the colon). Its precise function is not fully understood but is thought to have a minor role in immunity and as a reservoir for normal gut flora.
Appendicitis is acute inflammation of the appendix, thought to be initiated by luminal obstruction in up to 50% of cases. There may be underlying infection, or in rare cases (0.5 – 1.5%), malignancy. This obstruction leads to appendix distension and subsequent bacterial overgrowth and inflammation, with eventual ischaemia, necrosis and perforation.
The main risk factors include family history, age (most common 15-19) and male sex. It is the most common abdominal surgical emergency in the world and one of the most common causes of abdominal pain in children and adults with a lifetime incidence of 8.6% in men and 6.7% in women.
Diagnosis is based on clinical features on history and examination but can be challenging due to atypical presentations so should be considered in most presentations of acute abdominal pain.
Initial Assessment & Management
History: Abdominal pain which typically begins centrally then migrates to the right iliac fossa. It tends to be worsened by movement by this stage and it should be noted that a sudden relief of this pain can indicate perforation. Other symptoms can include malaise, pyrexia, nausea, GI upset or urinary symptoms (from bladder irritation).
Examination: Assess for tenderness in the right lower quadrant. The site of maximal tenderness is typically over ‘McBurney’s point’, 2/3 of the way along a line drawn from the umbilicus to the anterior superior iliac spine. Guarding (muscular rigidity) and rebound tenderness can suggest local peritoneal irritation (peritonitis) while more generalise peritonitis can be the result of perforation. Be wary of different presentations which can present with right loin pain and reduced tenderness due to overlying caecal ‘protection’. A palpable abdominal mass may suggest an appendix mass or abscess.
Alert Danger: Ensure a groin and scrotal examination is performed to exclude incarcerated hernia and testicular torsion. Include a pelvic examination, when appropriate, if a gynaecological cause is part of your differential. Routine PR examination is not required. A pregnancy test is essential when available.
Analgesia: analgesic requirements can be significant in patients with acute appendicitis and may require opioids. Pain should be managed in accordance with CGOs. LINK Appropriate analgesia will not ‘mask’ signs and the ability to monitor clinical progression.
Anti-emetics: nausea and vomiting can be present. Anti-emetics should be used routinely to reduce these symptoms.
Antibiotics: In the unwell patient with suspected acute appendicitis, IV antibiotics should be administered in accordance with deployed antimicrobial guidance. LINK Suspected cases at the lower end of the spectrum in terms of severity can be treated with oral antibiotics initially with response assessed and treatment escalated as required. Early antibiotic initiation can halt disease progression completely, avoid perforation, and therefore reduce morbidity.
Fluid resuscitation: Hartmann’s or other balanced crystalloid can be used if required for resuscitation of the shocked patient or for maintenance if the patient is NBM.
Nutrition: the patient is likely to have anorexia (not hungry) and a desire to eat is actually a good indicator of clinical improvement. Clear oral fluids should be allowed if tolerated as this will not impact on the ability to proceed to urgent surgery.
Evacuation: Patients may respond quickly to antibiotic treatment but evacuation should still be considered early to the potential for deterioration, the possibility of another diagnosis, and chance of recurrent symptoms.
Advanced Assessment & Management
Urine Dipstick: to exclude ectopic pregnancy or pregnancy associated complication. Can also help exclude a Urinary Tract Infection (UTI) but bladder irritation from the appendix can lead to urinary leucocytes.
Bloods: FBC and CRP are raised in the majority of cases, but can be normal, especially if the patient presents early. See Reference materials and Toolbox for ranges.
Imaging: Trans-abdominal ultrasound can be utilised but has a low specificity. Utility is likely low in the deployed skillset. CT can be utilised at level R2E or above if the attending surgeon deems appropriate.
Prolonged Casualty Care
Fluid balance: if evacuation is delayed, intravenous fluids can be utilised to support oral intake. A urine output of >0.5ml/kg/hour can be targeted in the unwell patient.
Analgesia: as above.
Antibiotics: These should be continued if evacuation is delayed, even if there is clinical improvement.
Nutrition: as above. Can be reintroduced as tolerated if clinical condition improves.