|

Acute Abdominal Pain: History Taking and Differential Diagnoses

Last updated:

Overview

An acute abdomen describes the rapid-onset of severe abdominal symptoms, including pain, that may suggest a potentially life-threatening underlying cause. The causes of an acute abdomen are extremely broad, therefore a thorough history and examination are crucial to help with identifying the underlying cause.

History Taking

Presenting complaint

  • Pain:
    • Use SOCRATES to assess this – see Abdominal Pain Characteristics below
    • In many cases, the nature of the pain present can help with identifying the underlying organ involved
  • Associated symptoms – a head-to-toe approach can be helpful:
    • Any nausea and/or vomiting?
    • Any haematemesis?
    • Is it fresh red blood or digested (appears similar to coffee grounds)?
  • Have they been able to eat and drink?
    • When was the last time?
  • Any fever?
  • Any weight loss?
  • Any rash or itching?
  • Any changes in bowel habits?
    • Constipation and/or diarrhoea?
    • Ability to pass flatus?
  • Any rectal bleeding?
    • Is it fresh red blood or digested (melaena, which appears black and tarry)?
  • Any changes regarding passing urine?
  • Any features of anaemia?

In women of childbearing age, a gynaecological and obstetric history is essential. Any woman of childbearing age should be considered pregnant until proven otherwise:

  • The ‘four Ps’ can help:
  • PV bleeding?
    • Any unusual PV bleeding (e.g. intermenstrual, postcoital etc.)
  • PV discharge?
    • Any unusual PV discharge?
  • Pelvic pain?
    • Use SOCRATES
  • Pregnancy?
    • Are they pregnant?
    • When was their last menstrual period?
    • Any previous gynaecological surgery?
    • Any previous ectopic pregnancies?
  • Do they use any hormonal contraceptives?

Past medical and surgical history

Questions to ask may include:

  • Any previous conditions:
    • Inflammatory bowel disease can help narrow down the causes
    • Cardiovascular disease may predispose to an abdominal aortic aneurysm
    • Atrial fibrillation may predispose to acute mesenteric ischaemia
    • A gynaecological history may identify causes
  • Any previous trauma
  • Any previous surgery:
    • Increases the risk of adhesions forming and obstruction

Medication history

Do they take any drugs that may have contributed to this presentation:

  • Drugs that increase the risk of peptic ulcer disease:
    • Examples are: NSAIDs, aspirin, bisphosphonates, corticosteroids, and selective serotonin reuptake inhibitors (SSRIs)
  • Drugs that cause pancreatitis:
    • Examples are corticosteroids, azathioprine, thiazides, sulfonamides, furosemide, oestrogens, and tetracyclines

Family history

  • Is anyone else in the family experiencing similar symptoms?
    • May point towards infective gastroenteritis
  • Is there a family history of anything similar?
    • May point towards renal stones or inflammatory bowel disease etc.

Social history

  • Do they smoke and/or drink?
    • If so, how much and how long?
    • Excessive alcohol consumption can predispose to pancreatitis
  • Have they travelled anywhere recently?
    • May predispose patients to infections such as gastroenteritis

Abdominal Pain Characteristics

Site

Character

The character of pain may give some clues:

  • Sharp and localised pain – suggests peritoneal irritation
  • Dull and poorly-localised pain – suggests visceral pain without peritoneal irritation
  • Severe, intermittent, and/or colicky (cramping) pain – suggests renal stones or strangulated hernias
  • Tearing and severe pain – suggest aortic dissection

Radiation

Some conditions classically radiate:

  • Central abdominal pain radiating to the right lower quadrant suggests:
    • Appendicitis
  • Central abdominal pain radiating to the back – suggests:
    • Pancreatitis
    • Ruptured abdominal aortic aneurysm
    • Aortic dissection
  • RUQ pain may radiate to the back/right shoulder – suggests:
    • Hepatobiliary diseases:
      • Biliary colic
      • Cholecystitis
      • Hepatitis
    • Right lower lobe pneumonia irritating the right hemidiaphragm
  • LUQ pain may radiate to the back/left shoulder – suggests:
    • Myocardial infarction
    • Acute pancreatitis
    • Splenic disease
    • Left lower lobe pneumonia irritating the left hemidiaphragm
  • Loin-to-groin pain – suggests renal colic and renal stones

Exacerbating and relieving factors

Exacerbating and relieving factors may give some clues:

  • Gastric ulcers – pain classically worsened when eating
  • Duodenal ulcers – pain classically relieved with eating
  • Biliary colic – classically worse after eating a fatty meal

Investigations

Some initial tests may include:

  • Full blood count (FBC):
    • Different derangements are seen in different pathologies (e.g. leukocytosis in appendicitis)
  • Urea and electrolytes (U&Es):
    • May show electrolyte derangements or renal dysfunction
  • Urinalysis:
    • To identify pyelonephritis or renal pathology
  • Liver function tests (LFTs):
    • May be deranged with hepatobiliary disease
  • C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR):
    • May be elevated in inflammation
  • Pregnancy tests:
    • Must be performed in all women of childbearing age to rule out ectopic pregnancy

Other tests

Other tests may be performed depending on the suspected underlying cause:

  • Coagulation studies:
    • In patients with bleeding, suspected vascular pathology (e.g. abdominal aortic dissection), and if surgery is indicated
  • Serum amylase and/or lipase:
    • If acute pancreatitis is suspected
  • Serum lactate:
    • May be elevated in acute mesenteric ischaemia
  • Abdominal x-ray:
    • May reveal pathologies such as volvulus or free air in the abdomen
  • Erect chest x-ray:
    • If perforation is suspected – may show free air under the diaphragm
  • Abdominal ultrasounds, CT, and endoscopy may also be considered
  • Laparoscopy may be considered in some scenarios

Differential Diagnoses: Gastrointestinal Causes

Oesophageal perforation

  • There may be a history of vomiting/retching followed by chest/epigastric pain
  • Subcutaneous neck emphysema may be present
  • A chest x-ray may show a widened mediastinum or free mediastinal air

Mallory-Weiss tears

  • There may be a history of repeated vomiting/retching/coughing
  • Patients may have epigastric pain
  • Small streaks of bright red blood may be coughed up
  • Signs of anaemia may be present – postural hypotension, pallor, syncope, tachycardia

Perforated peptic ulcer

  • Presents as acute-onset severe epigastric pain
  • There may be a history of drugs such as NSAIDs, corticosteroids, aspirin, or selective serotonin reuptake inhibitors (SSRIs)
  • Features of upper GI bleeding such as haematemesis and melaena may be present
  • There may be a history of peptic ulcer disease:
    • Gastric ulcers – epigastric pain worse when eating
    • Duodenal ulcers – epigastric pain that improves when eating
  • Tachycardia and fever may be present
  • Abdominal rigidity, guarding, or rebound tenderness may be present
  • A chest x-ray may show free air under the diaphragm

Appendicitis

  • Acute-onset constant, severe, central abdominal pain that classically moves to the RLQ
  • Anorexia is commonly seen
  • More common in children and young adults
  • Fever and tachycardia may be present
  • Rovsing’s sign may be present – palpating the LLQ elicits pain in the RLQ
  • FBC may show leukocytosis

Acute diverticulitis

  • Acute-onset colicky LLQ pain
  • Generally seen in older patients (>50 years)
  • Diarrhoea is often seen, which may be bloody
  • There may be a long history of constipation
  • Fever may be present
  • LLQ tenderness may be present
  • FBC may show leukocytosis

Crohn’s disease

  • Patients are generally <50 years old
  • A history of chronic diarrhoea may be present
  • There may be associated fatigue, weight loss, and fever
  • An ileocaecal (right lower quadrant) mass may be present on exam
  • Oral ulcers and perianal disease (e.g. skin tags, fistulae, abscesses etc.) may be
  • present
  • Anaemia may be seen
  • ESR/CRP may be elevated
  • Faecal calprotectin may be positive

Ulcerative colitis

  • Patients are generally <50 years old
  • A history of chronic diarrhoea may be present – more commonly bloody than in Crohn’s disease
  • Faecal urgency and tenesmus may be present
  • Extra-intestinal features (e.g. joint pain) may be present
  • Anaemia may be seen
  • ESR/CRP may be elevated
  • Faecal calprotectin may be positive

Intestinal obstruction

  • Patients may have a history of previous abdominal surgery, which may predispose them to adhesions causing an obstruction. There may be a history of malignancy, which can cause obstruction
  • Patients generally have severe nausea and vomiting, which may be bilious in small bowel obstruction
  • Constipation and an inability to pass flatus may be present
  • Abdominal sounds may be faint or absent, tinkling may be seen
  • Diffuse abdominal tenderness may be seen
  • An abdominal x-ray may show dilated bowel loops or air-fluid levels

Differential Diagnoses: Hepatobiliary Causes

Biliary colic

  • Causes colicky RUQ epigastric pain that is classically provoked when eating fatty meals
  • Patients are generally stable and do not have abnormal blood tests, although some derangements may be seen
  • Abdominal ultrasound may show gallstones

Acute cholecystitis

  • Causes RUQ pain that may radiate to the right shoulder
  • Patients may have a history of biliary colic
  • Murphy’s sign may be positive – RUQ tenderness causing the arrest of inspiration during palpation
  • Fever may be present
  • FBC may show leukocytosis
  • LFTs may show derangements
  • CRP may be elevated

Acute cholangitis

  • Causes RUQ pain
  • Charcot’s triad may be present – fever, pain, and jaundice
  • Hypotension and confusion may be present – in combination with Charcot’s triad, this is known as Reynolds’ pentad
  • FBC may show leukocytosis
  • LFTs may show derangements
  • CRP may be elevated

Acute pancreatitis

  • Causes acute-onset severe epigastric or mid-abdominal pain that classically radiates to the back
  • There may be a history of specific causes such as biliary colic, alcohol misuse, or certain drugs
  • Pain may be severe on palpation
  • Flank bruising may be seen (Grey-Turner’s sign) or periumbilical bruising (Cullen’s sign)
  • FBC may show leukocytosis
  • Serum lipase/amylase is 3 times the upper limit of normal

Acute viral hepatitis

  • RUQ pain is present
  • Hepatosplenomegaly may be seen
  • Jaundice and ascites may be seen
  • Risk factors for its development may be present (e.g. unprotected sexual intercourse)
  • Liver function tests are deranged
  • Hepatitis serology and antigens are generally positive

Budd-Chiari syndrome

  • Generally seen in female patients in their 30-40s with risk factors for a hypercoagulable state, such as contraceptive use, postpartum, myeloproliferative disorders etc.
  • May present with a classic triad of ascites, abdominal pain, and hepatomegaly
  • FBC may be abnormal if a myeloproliferative disorder is present

Differential Diagnoses: Urological Causes

Renal colic

  • Acute-onset severe loin pain that radiates to the groin
  • Patients may be agitated or restless due to the pain
  • Costovertebral angle tenderness may be seen
  • A urine dipstick may be positive for blood, leukocytes, and/or nitrites
  • U&Es may be deranged

Acute pyelonephritis

  • Presents with severe loin pain that may radiate to the grain
  • There is generally fever, nausea, and vomiting
  • Dysuria may be present
  • Costovertebral angle tenderness may be seen
  • A urine dipstick is generally positive for nitrates, along with blood or leukocytes
  • Urinalysis, Gram staining, and cultures may identify the underlying pathogen

Hydronephrosis

  • May present similarly to renal stones with colicky loin-to-groin pain
  • Patients may be hypotensive and tachycardic
  • There may be a history of urinary retention and its causes
  • Costovertebral angle tenderness may be seen
  • U&Es may show derangements

Urinary retention

  • Generally presents with suprapubic tenderness
  • There may be features of an underlying cause (e.g. some drugs, such as tricyclic antidepressants, benign prostatic hyperplasia etc.)

Testicular torsion

  • Presents with sudden-onset testicular pain that may have associated nausea or vomiting
  • Typically seen in adolescents and young adult males
  • The affected testis may be retracted upwards and erythematous
  • Elevation of the testis does not ease the pain (negative Prehn’s sign)
  • The cremasteric reflex may be absent

Differential Diagnoses: Gynaecological Causes

Ectopic pregnancy

  • Severe sudden-onset unilateral pain in the LLQ or RLQ with associated vaginal bleeding
  • There is usually a 6-8-week period of amenorrhoea
  • An adnexal mass may be felt during a pelvic examination
  • Rebound tenderness may be seen if a ruptured ectopic pregnancy is seen
  • Shoulder tip pain may be seen when passing urine or opening the bowels due to peritoneal bleeding
  • Pregnancy tests are essential to rule out ectopic pregnancy

Ovarian torsion

  • Severe sudden-onset unilateral pain in the LLQ or RLQ
  • There may be a history of trauma or exercise
  • Nausea and vomiting may be seen
  • Unilateral severe adnexal tenderness may be seen during a pelvic examination
  • In severe cases, there may be abdominal rigidity, guarding, or rebound tenderness
  • A pregnancy test is negative

Ovarian cyst rupture

  • May present similarly to ovarian torsion with sudden-onset severe unilateral pain in the LLQ or RLQ
  • There may be a history of trauma or exercise
  • Light vaginal bleeding may be seen

Pelvic inflammatory disease

  • May be seen in patients who have or have risk factors of sexually-transmitted infection (e.g. Chlamydia or gonorrhoea)
  • May also occur following the insertion of an intrauterine device
  • Menstrual irregularities, abnormal vaginal discharge, and fever may be seen
  • Cervical excitation or adnexal tenderness may be present on examination

Differential Diagnoses: Vascular Causes

Ruptured abdominal aortic aneurysm

  • Severe central abdominal pain that may radiate to the back
  • Patients may be haemodynamically unstable and be hypotensive/tachycardic and may have reduced consciousness
  • There may be a history of cardiovascular disease
  • An expansile and pulsative mass may be felt on abdominal palpation, however, this may be limited due to severe pain

Mesenteric ischaemia

  • Presents with acute-onset central abdominal pain
  • Patients classically have atrial fibrillation or other cardiovascular diseases
  • There may be a history of post-prandial abdominal pain (intestinal angina)
  • Pain is generally out of proportion to examination findings
  • Hypotension and tachycardia may be present
  • An abdominal x-ray may show free air, dilated bowel loops, or bowel wall thickening
  • A chest x-ray may show free air under the diaphragm
  • Serum lactate may be elevated, and an arterial blood gas may show metabolic acidosis

Differential Diagnoses: Other Important Causes

Infective gastroenteritis

  • There may be a history of travelling and carrying out activities that may predispose them to infection (e.g. eating street food or staying in places with unsanitary conditions)
  • Other family members may be affected
  • Patients may be dehydrated
  • FBC may show leukocytosis
  • Increased urea in proportion to creatinine suggests dehydration
  • Stool cultures may identify the underlying pathogen

Strangulated hernia

  • There may be a history of an intermittently painful abdominal lump
  • Pain, fever, increased size, or localised tenderness may be seen
  • Features of bowel obstruction or features of bowel ischaemia (e.g. bloody diarrhoea) may be seen

Psoas abscess

  • Presents with flank pain and patients may limp
  • Fever, nausea, and vomiting may be seen
  • There may be risk factors present, such as Crohn’s disease, diverticulitis, endocarditis, or intravenous drug use
  • Pain with active hip flexion and passive extension may be seen
  • FBC may show leukocytosis
  • CRP may be elevated

Spontaneous bacterial peritonitis

  • Presents with acute-onset abdominal pain and fever in patients with a history of ascites
  • Nausea and vomiting may be seen
  • Paracentesis analysis may show increased neutrophil counts and may identify the underlying causative organism

Diabetic ketoacidosis

  • Features are generally acute and patients may have abdominal pain
  • There may be associated nausea and vomiting, and reduced consciousness
  • There may be a history of polyuria and polydipsia
  • A triggering stressor may precede the event, such as pneumonia and urinary tract infections
  • Kussmaul’s breathing may be seen (deep and gasping hyperventilation)
  • Signs of hypovolaemia may be seen such as tachycardia, hypotension, delayed capillary refill time
  • The patient’s breath may smell like acetone
  • Serum glucose is elevated
  • U&Es may show low sodium and high potassium
  • Urinalysis is positive for glucose and ketones and may be positive for nitrites if an infection is present
  • Arterial blood gases show metabolic acidosis

Addisonian crisis

  • There may be general abdominal pain, nausea, vomiting, and weight loss
  • Postural hypotension, dizziness, and syncope may be present
  • Skin hyperpigmentation may be seen
  • Fevers may be present
  • Hyponatraemia and hyperkalaemia may be seen

Author