Case 3: Lower abdominal pain

19 year old female with a 24 hour history of abdominal pain. She had noticed the pain during a morning lecture and it had initially been mild and generalised. Early associated features included nausea, malaise and she had had two episodes of loose stool. She was a new student and had been living that lifestyle so she thought that it was probably due to alcohol.

However in the last couple of hours, the pain had significantly worsened. She described it as constant and sharp. She had vomited and didn’t feel like eating or drinking. She had no further diarrhoea, was passing urine although concentrated. She was advised to come to hospital by the 111 service. There was no PV bleeding, no malena or haeamtemasis and no urinary symptoms. Her last menstrual period was 6 weeks ago and normal, she has a very irregular cycle that can vary from 3-8 weeks.

She had well controlled asthma using salbutamol and beclomethasone, no other medications and no drug allergies. Interestingly she had had a couple of previous episodes of right lower abdominal pain before – although not as bad as this, this was when she was diagnosed and treated for pelvic inflammatory disease 18 months ago. She was a non-smoker, denied illicit drugs, being a new student she had been drinking more alcohol than usual.

Examination

She was alert and orientated. Her vital signs were stable but she had a HR of 104, BP 104/62, RR 16, Sp02 100% and a temperature of 37.8. The abdomen was soft but was mildly tender in the epigastrium and tender with some guarding in the right lower quadrant. Rovsings positive. Murphy’s negative. Rebound tenderness. Bowel sounds slightly increased.

Differential diagnosis

DIAGNOSIS RATIONALE
GI  
Appendicitis Likely
Cholecystitis Tender epigastrium with fever and vomiting

No jaundice

Murphy’s sign negative

Possible diagnosis however appendicitis/ectopic pregnancy more likely given location of worst tenderness

Pancreatitis Fever, tender epigastrium and tachycardic, with increased alcohol intake.

Although not classical pain

Gastritis Drinking lots – student

Some epigastric tenderness, although doesn’t explain right iliac fossa pain

Gastroenteritis Two episodes of loose stool, now resolved but patient still unwell

Vomiting is in-keeping with gastroenteritis

Severe abdominal pain is unusual and makes it less likely

GU  
UTI/Pyelonephritis No urinary symptoms

Urine dip normal

Renal Colic Pain not classical loin to groin

No haematuria (although present in only 90% cases of renal colic)

Gynae  
Ectopic Pregnancy  Likely
Ovarian torsion Possible

 

Investigations

Venous blood gas – normal, lactate 1.3

Baseline bloods (done at triage) – U&E, LFT, CRP, FBC, Amylase, WCC 11.1, CRP 43

Urinalysis: normal

Urine pregnancy test and serum BHCG negative

USS – abdomen and pelvis: Moderately inflamed and oedematous appendix, normal gynaecological anatomy

Diagnosis

Appendicitis

Treatment

Pain Management – IV paracetamol, IV morphine, IV buscopan

Screening for and treating for sepsis

NBM – IV fluid

Early involvement of the decision making surgical team for appendicectomy

Appendicitis

Royal College of Surgeons estimate 40,000 cases a year in UK. Usually a disease of the young with peak incidence within 20s and 30s.

The appendix is located at the base of the cecum and the appediceal orfiice opens into the cecum directly.

Despite being the most common surgical emergency, its aetiology is poorly understood. Appendiceal obstruction is thought to be the leading cause of appendicitis, although the cause is not always identified. The mechanism of luminal obstruction varies depending upon age. In the young, lymphoid follicular hyperplasia due to infection is thought to be the main cause. In older patients, luminal obstruction is more likely to be caused by fibrosis, fecaliths, or neoplasia. Once obstructed, the lumen becomes filled with mucus and distends, increasing luminal and intramural pressure.

The earliest change is mucosal ulceration which is thought to be caused by increased intrluminal pressure. Inflammation accompanies this. Inflammatory infiltrates spread through the appendiceal wall causing localised peritonitis. These further causes pressure in the appendix to increase. The increased pressure results in thrombosis and occlusion of the small vessels, mucous pooling and stasis of lymphatic flow. As lymphatic and vascular compromise continues the wall of the appendix becomes ischaemic and necrotic.

Bacterial overgrowth occurs within the diseased appendix.

Once significant inflammation and necrosis occur, the appendix is at risk of perforation, which leads to localized abscess formation or diffuse peritonitis.

Of note less common causes of appendices inflammation include, chrons, UC, TB

Useful links

NICE guidance – ectopic pregnancy 

NICE guidance – appendicitis

Urine vs serum pregnancy tests 

Alvarado score