Abdominal pain

Notes

Introduction

Abdominal pain is a very common presenting symptom that all junior doctors should be able to appropriately investigate and manage. 

Abdominal pain can be difficult due to the wide list of differentials. It is important to consider the diagnosis in context of the patient. For example, in a young female patient with lower abdominal pain you should consider gynaecological causes high on your differential list. In an elderly person with left iliac fossa pain, diverticular disease would be a common diagnosis.

Differential diagnosis

The differential for abdominal pain should be divided by organ systems.

  1. Gastrointestinal
  2. Urinary system
  3. Gynaecological
  4. Vascular
  5. Other

Gastrointestinal

common cause of acute abdominal pain. Gastrointestinal causes can range from common benign pathologies (i.e. gastroenteritis) to life-threatening (i.e. perforation). 

Gastrointestinal causes can be further divided based on locationorgan or system affected.

  • Gastroduodenal
    • Peptic ulcer disease
    • Gastritis
    • Malignancy

  • Intestinal
    • Appendicitis
    • Small bowel obstruction
    • Large bowel obstruction
    • Diverticulitis
    • Gastroenteritis
    • Mesenteric adenitis
    • Strangulated/incarcerated hernia
    • Inflammatory bowel disease
    • Volvulus

  • Hepatobiliary & pancreatic
    • Acute cholecystitis
    • Acute cholangitis
    • Biliary colic
    • Hepatitis
    • Acute pancreatitis
    • Malignancy

Urinary system

Abdominal pain is very commonly the result of urinary pathology. 

Acute cystitis (i.e. urinary tract infection) is an extremely common cause for abdominal pain in females. Renal colic is another common cause of abdominal pain that presents with classical loin-to-groin pain.

  • Cystitis
  • Pyelonephritis
  • Ureteric/renal colic
  • Hydronephrosis
  • Malignancy
  • Acute urinary retention
  • Polycystic kidney disease

Gynaecological

Gynaecological diagnoses should always be considered in female patients.

As a general rule, pregnancy-related complications (i.e. ectopic pregnancy) always need to be excluded in young females by performing a pregnancy test. Gynaecological causes of abdominal pain include the following:

  • Ruptured ectopic pregnancy
  • Ovarian torsion
  • Ovarian cyst rupture
  • Salpingitis
  • Endometriosis
  • Mittelschmerz
  • Red degeneration of fibroid
  • Pelvic inflammatory disease

Vascular

Vascular causes are less common, but you need to have a high index of suspicion, especially in elderly patients.

Always consider vascular causes in patients with a history of cardiovascular disease (i.e. ischaemic heart disease, peripheral vascular disease)

  • Abdominal aortic aneurysm (dissection/rupture)
  • Ischaemic colitis

Other

Several alternative causes of abdominal pain should be considered, especially when more common diagnoses have been excluded.

Alternative causes of abdominal pain can include problems with the abdominal wallretroperitoneal spacepain referred from another area (i.e. myocardial infarction) or abdominal pain associated with ‘medical’ diagnoses (i.e. DKA).

  • Rectus sheath haematoma
  • Psoas abscess
  • Retroperitoneal haemorrhage
  • Acute intermittent porphyria
  • Diabetic ketoacidosis
  • Sickle cell disease
  • Addison’s disease
  • Referred pain (i.e. myocardial infarction, testicular torsion, thoracic spine disease)

History

Key aspects in the history include age, gender, pain characterisation, location and associated features.

Age & gender

You should always make a note of the patients’ age and gender. Certain diagnoses are more common in one sex (i.e. cystitis in females) and others will only occur in one sex (i.e. testicular torsion in males). Many diagnoses are more common at particular ages (i.e. vascular disease in elderly or mesenteric adenitis in children)

Characterisation of pain

Always take a full pain history in patients with abdominal pain using the SOCRATES mnemonic. It is important to determine if pain came on acutely or is chronic. Assess whether the pain persists, or comes and goes, and determine whether it radiates. Always ask whether the pain has ever occured before.

Location of pain

Location should be based on the nine regions of the abdomen or more broadly the four quadrants.

  • Right upper quadrant (RUQ): Hepatobiliary pathology
  • Left upper quadrant (LUQ): Splenic pathology
  • Right lower quadrant (RLQ): appendicitis, caecal tumour, Crohn’s colitis
  • Left lower quadrant (LLQ): diverticulitis, large bowel tumour

Associated features

Associated features help you to support or refute the potential diagnosis. Important features include change in bowel habit, nausea and vomiting, urinary symptoms (i.e. dysuria, haematuria), gynaecological symptoms (i.e. PV bleeding, dysparunia), or PR bleeding

Examination

The examination should include a full abdominal assessment including checking the hernial orifices and consideration of a digital rectal exam

Examination of acute abdominal pain can be broadly divided into the general exam, abdominal exam and additional exams.

General exam

Always start by assessing the patient formally by inspection. Are they lying comfortably? Are they writhing in pain? Are they lying rigid so they do not aggrevate the pain? Does the patient appears flushed and sweaty suggesting pyrexia?

Make note of the observations. Acute pain can cause tachycardia and hypertension. Note whether the patient is febrile or has any other features of sepsis that need to be acted on swiftly. Make note of any stigmata of previous disease. Are there any abdominal scars? Are they jaundiced? Do they have a hernia?

Abdominal exam

As with all examinations, you should asess the abdomen through inspection, palpation, percussion and auscultation.

Look for any abdominal scars or hernias that may suggest bowel obstruction from adhesions or incarceration. Palpate the abdomen lightly to look for evidence of peritonitis. Is this localised to a region (i.e. RIF in appendicitis) or generalised (i.e. perforation)?. If you suspect peritonitis check percussion tenderness: exquisite pain on percussion of the abdomen associated with guarding. Palpate the abdomen deeply to assess for any masses. 

Check for any organomegaly and auscultate for bowel sounds, especially if concern regarding bowel obstruction. 

Additional exams

A digital rectal examination should always be considered as part of the abdominal examination. 

If there is concern about gynaecological pathology, a formal vaginal and speculum examination should be completed looking for any discharge, bleeding, cervical excitation due to pelvic inflammatory disease or adnexal tenderness in ectopic pregnancy. 

Investigations

Simple bedside investigations are critical in acute abdominal pain including observations, urine dip, pregnancy test, and ECG. 

Key investigations can be divided into bedside test, blood tests, imaging and special tests.

Bedside

  • Urine dip (leucytes and nitrites positive in infection, blood in renal colic)
  • Observations (fever to suggest infection)
  • ECG (referred pain from MI)
  • Capillary glucose (DKA)
  • Pregnancy test 

Blood tests

  • FBC & CRP (raised inflammatory markers if infection, drop in haemoglobin if bleeding)
  • LFT (hepatobiliary pathology)
  • U&E (renal dysfunction, electrolyte derrangement in diarrhoea & vomiting)
  • Bone profile (electrolyte derrangement, pancreatitis)
  • Amylase (pancreatitis)
  • Coagulation (Pre-op)
  • Group & Save (Pre-op)

Imaging

  • Chest x-ray (free air under the diaphragm to suggest perforation)
  • Abdominal x-ray (small or large bowel obstruction, pneumoperitoneum, air in biliary tree in gallstone ileus)
  • Ultrasound (abscesses, biliary dilatation, free fluid in pelvis, ascites, kidney masses)
  • CT (better visualisation of adominal organs, aneurysms, perforation)
  • CT KUB (renal calculi - no contrast)
  • MRCP (biliary pathology)

Special tests

  • Cultures (blood, urine)
  • Endoscopy (peptic ulcer disease, malignancy)
  • Haemoglobin electrophoresis (sickle cell)
  • Urinary porphobilinogens (acute porphyria)

Key tips

Practical recommendations to help you in the assessment and diagnosis of acute abdominal pain

  1. All females < 60 should have a pregnancy test. This is to rule out pregnancy-related complications.
  2. An amylase should be checked in all patients. This is to exclude acute pancreatitis. 
  3. Always check the hernial orifices. This is so you do not miss a strangulated hernia!
  4. Do not miss a ruptured abdominal aortic aneurysm. Have a low index of suspicion, especially in elderly patienst with cardiovascular disease. 
  5. Enurse you have a urine dip when treating UTI/Pyelonephritis. Urosepsis is an over diagnosed condition, which can then distract you from searching for another source of sepsis.

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