How can I differentiate between nausea and vomiting caused by gastrointestinal issues versus other underlying conditions?

Differentiating between nausea and vomiting caused by gastrointestinal (GI) issues versus other underlying conditions involves a comprehensive assessment of the person's history, a physical examination, and relevant investigations ¹.

• Gastrointestinal Causes:
  • Gastric Stasis: Features include a large volume of vomitus, infrequent vomiting, relief of symptoms after vomiting, oesophageal reflux, epigastric fullness, early satiation, and hiccups ¹. A succussion splash may be present ¹.
  • Gastric Outflow Obstruction: Symptoms are similar to gastric stasis but also involve forceful vomiting and rapid dehydration ¹.
  • 'Squashed Stomach Syndrome': This presents with symptoms similar to gastric stasis but with low-volume vomiting ¹.
  • Oesophageal Blockage: Vomiting occurs soon after eating or drinking, the vomitus comprises what has just been swallowed, and there is a sensation of food sticking ¹.
  • Bowel Obstruction: Characterised by intermittent nausea (often relieved by vomiting), worsening nausea and/or faeculent vomiting as the obstruction progresses, abdominal pain (which may be colicky), and abdominal distension (though this may be absent in high obstructions) ¹.
  • Other GI Indicators: Bile-stained (green or yellow-green) vomit may suggest intestinal obstruction ². Haematemesis (blood in vomit), excluding swallowed blood, can indicate a serious bleed from the oesophagus, stomach, or upper gut ². Blood in the stool may suggest conditions like bacterial gastroenteritis or an acute surgical condition ². Abdominal distension, tenderness, or a palpable mass can suggest intestinal obstruction or another acute surgical condition ².
  • Suspected GI Cancers: Consider oesophageal or stomach cancer if there is nausea or vomiting with weight loss, or with a raised platelet count, reflux, dyspepsia, or upper abdominal pain, especially in individuals aged 55 and over ⁴. Pancreatic cancer should be considered if nausea or vomiting occurs with weight loss in individuals aged 60 and over ⁴.
• Other Underlying Conditions:
  • Increased Intracranial Pressure: Vomiting is often effortless, occurs frequently in the morning, and may be associated with a diurnal headache and papilloedema ¹. Nausea may also be diurnal ¹. Altered responsiveness, such as lethargy or irritability, can also be a sign ².
  • Motion-Associated Emesis: Nausea and/or sudden vomiting may occur on movement, such as turning in bed ¹.
  • Anxiety-Related Nausea: Nausea presents in waves, may be triggered by a previously experienced stimulus, and can be relieved by distraction ¹.
  • Chemically Induced Nausea: This typically presents as constant nausea with variable vomiting ¹. This can be due to drugs (e.g., opioids, digoxin, antibiotics), metabolic causes (e.g., hypercalcaemia, uraemia, renal failure, tumour toxins), or intracranial disease ¹.
  • Infection: Appearing unwell or having a fever may suggest an infection ². Dysuria can indicate a urinary tract infection (UTI) ². UTIs can also be a cause of late-onset vomiting ².
• General Assessment for Differentiation:
  • History: Ask about the onset, frequency, intensity, relieving and exacerbating factors of nausea, and its relationship to vomiting ¹. For vomiting, inquire about its onset, frequency, quantity, force, colour, timing, and pattern ¹. Also, ask about other symptoms like dyspepsia, heartburn, constipation, diarrhoea, headache, or confusion ¹. Review the person's medication history, including recent changes and the use of anti-emetics ¹.
  • Examination: Perform a general examination to look for signs of dehydration, infection, confusion, drowsiness, or weakness ¹. Assess the oral cavity, examine the abdomen for tenderness, swelling, distension, or signs of intestinal obstruction, and perform a rectal examination if faecal impaction is suspected ¹. If increased intracranial pressure is a possibility, check the fundi for papilloedema ¹.
  • Investigations: Blood tests to exclude hypercalcaemia or uraemia are often useful ¹. Other helpful blood tests include liver function tests and blood glucose levels ¹. Consider tests to exclude a urinary tract infection ¹.