When you are on call, you will often get a bleep about a patient with abdominal pain. Abdominal pain can be a bit of a minefield and it is easy to get bogged down with all the possibilities. The key is to be systematic and take a clear history and thorough examination so that you can whittle down the possibilities.

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Initial Assessment

To begin, it is important to ask key questions to prioritise:

• Are the observations abnormal? If they are unstable, they need urgent review & you need to call assistance
  • ABCDE!
• Could the patient be given some analgesia whilst pending review? I have frequently given analgesia, then found a patient whose pain has resolved by the time of review
• Has something changed? Stable, long term abdominal pain is less worrying than acute severe abdominal pain

When reviewing a patient, focus your assessment to rule out the common & dangerous differentials. These include:

• Surgical abdomen (peritonism, signs of infection – could be due to an infection of any structure)
• Bowel obstruction
• Ischaemic bowel
• Acute coronary syndrome
• UTI
• Constipation
• Urinary retention
• Dyspepsia
• Functional abdominal pain

History

• Site: where is the pain? Know your anatomy and which structures are in each abdominal region.
  • RIF pain – could it be appendicitis?
  • RUQ pain – could it be cholecystitis?
• Onset: chronic pain? New? Trigger?
• Character: Colicky pain that comes and goes? Constant? Dull ache? Burning?
• Radiation: does the pain radiate anywhere else? For example, in appendicitis, this characteristically starts in the umbilical region and then localises to the RIF.
  • In pancreatitis, pain characteristically radiates from the epigastric region to the back.
  • Other causes that may radiate to the back: pyelonephritis/renal stones
• Associated symptoms:
  • Related to meals? (Biliary colic/cholecystitis)
  • Constipation? Passing wind? (bowel obstruction, constipation)
  • Vomiting? (pancreatitis/obstruction/infection)
  • Diarrhoea? (gastroenteritis/diverticulitis/other infective causes/IBD)
  • Urinary symptoms? (UTI/pyelonephritis/renal stones)
  • Melaena? vomiting blood? (upper GI bleed)
  • Any chance of pregnancy? Gynae symptoms?
• Timing: when is the pain worst?
• Exacerbating/relieving factors – worsened by fatty meals? (biliary colic/cholecystitis/peptic ulcer disease)
• Severity: is the patient super unwell with the worst pain they have ever had? – consider surgical abdomen (particularly ischaemia, obstruction)
• Alcohol – ask about units per week: liver disease, peptic ulcer disease, pancreatitis

Examination

• Inspection from the end of the bed – do they look unwell?
• Are they jaundiced? – think biliary pathology related to gallstones for example pancreatitis, cholecystitis, biliary colic.
• Any masses? Ensure that you also inspect hernia orifices if lower abdominal pain
• Palpation –
  • Are they peritonitic or guarding? – most likely they will need urgent surgical assessment +/- urgent CT
  • Do they have a palpable bladder?
  • Elicit Murphy’s sign for RUQ pain
  • Remember to ballot the kidneys and feel for AAA
• Auscultation – are there bowel sounds present? Are they overactive i.e. indicative of obstruction?
• Hernias – cough impulse? Is it reducible? Is the overlying skin red/tender? Are they opening bowels? Is the abdomen distended? How bad is the pain? Is it constant?
• Do a PR exam if PR bleed, not opening bowels etc

Investigations

What investigations you do will depend on what you are suspecting and where the pain is.

• VBG (or ABG) can be very valuable. You can quickly identify the very unwell patient who is acidotic, raised lactate & check a blood glucose (DKA). Raised lactate is very useful when considering bowel obstruction or ischaemic bowel
• FBC/CRP to look for raised inflammatory markers/signs of infection
• Amylase – to rule out pancreatitis
• Electrolytes – hypokalaemia can cause pseudo-obstruction
• LFTs – look for obstructive patterns – may be indicative of gallstones
• ECG (+/- troponin if necessary) – don’t forget an acute MI can also be mistaken for epigastric pain
• Urine dip – if positive for blood and colicky pain think renal stones
• AXR – can be used if suspecting obstruction but there is uncertainty. CT is the gold standard but that should be discussed with a senior
• Always ensure a pregnancy test has been carried out

Further imaging (following discussion with seniors!)

• USS – especially useful in young females for ovarian pathology, can be used if suspecting gallstones, cholecystitis, appendicitis, can visualise urinary tract, can be used to further evaluate hernias
• CT abdomen – especially in older patients. Remember appendicitis in older patients can be due to caecal malignancy. Can also see appendicitis, cholecystitis, diverticulitis, bowel obstruction, colitis. Sometimes can see pancreatitis if after 2-3 days of onset. Can be used to further evaluate hernias
• CT KUB – if suspecting renal stones
• MRCP – to further visualise biliary tree. Normally done to look for CBD stones, for example before cholecystectomy or if USS normal and obstructive LFTs.
• Colonoscopy/flexible sigmoidoscopy – PR bleed/change in bowel habit/colitis

A few examples

Remember – not every patient is a textbook case. Be aware that often we do not get to the bottom of abdominal pain and so sometimes it may be non-specific.

• Constipation (especially if on opioids)
• UTI
  • Urine dip, inflammatory markers might be raised. Check the trust guidelines to treat
• Urinary retention (Catheterisation advised!)
• Dyspepsia
  • Gaviscon/PPI/ranitidine are of value
• Functional
  • Longstanding pain that may or may not improve with analgesia. These patients may request morphine if they’ve been in hospital multiple times with it and have recurrently used morphine in the past

Those that need escalation

• Bowel obstruction – distended abdomen, may be guarding. Not opening bowels or passing flatus. May be vomiting (faeculant). Bowel sounds tinkling (hyperactive)
  • Conservative management involves nil by mouth, Ryles tube for drainage and IV fluids ‘drip & suck’
  • VBG advised to check the lactate
• Appendicitis – pain starts in the umbilical region, then localises to RIF. Tender on palpation. Rosving’s sign positive. Raised inflammatory markers and signs of infection. Can be confirmed on USS/CT.
  • If septic or looking unwell, they may need to urgently go to theatre
• Cholecystitis – RUQ pain, Murphy’s sign positive. Often 4 F’s – fat, fertile, female, forty as risk factors. May have known history of gallstones. Raised inflammatory markers. Can be seen on USS
  • They need urgent antibiotics
  • Differential includes:
    • biliary colic, where the pain comes & goes with typically normal bloods
    • ascending cholangitis where there is jaundice also (Charcot’s triad) due to CBD obstruction. These patients are usually very unwell and need urgent escalation
• Pancreatitis – epigastric pain radiating to back +/- jaundice. Significantly raised amylase (3x normal), think alcohol/gallstones as an initial cause. May be chronic in alcoholics.
• Acute coronary syndrome – make sure you look for this in the high-risk patient. An ECG is very important!
• Diverticulitis – LIF pain, raised inflammatory markers, diarrhoea +/- blood. These patients need to be observed as diverticulae can perforate.
• Renal colic – colicky pain, comes in waves, radiates to back. Urine dipstick is positive for blood. May have urinary symptoms.
• Upper GI bleed – vomiting blood or melaena. Smoking and NSAID use are risk factors. These patients quickly deteriorate so need urgent escalation

Again, as a foundation doctor, the most important thing to do is to rule out sinister causes that will need immediate treatment. If you can also order relevant investigations to give you clues for the cause of the abdominal pain, you are doing great.

Written by Dr Christa Brew (FY2)