Nausea

Gastrointestinal Causes

Gastroenteritis: Acute onset of nausea often accompanied by vomiting, diarrhea, and abdominal cramps; usually viral but can be bacterial.
Peptic Ulcer Disease: Nausea associated with epigastric pain, often relieved by antacids or food; may be accompanied by hematemesis or melena.
Gastroesophageal Reflux Disease (GERD): Chronic nausea with a burning sensation in the chest (heartburn), regurgitation, and dyspepsia.
Biliary Colic: Nausea associated with episodic, severe right upper quadrant pain; often triggered by fatty meals; consider gallstones.
Bowel Obstruction: Severe nausea and vomiting associated with abdominal distension, constipation, and absence of bowel movements.
Pancreatitis: Nausea with severe epigastric pain radiating to the back; may be associated with vomiting and alcohol use or gallstones.

Central Nervous System Causes

Migraine: Nausea often accompanies unilateral throbbing headache, photophobia, and phonophobia; may also present with aura.
Increased Intracranial Pressure: Persistent nausea with morning headaches, vomiting, and papilledema; consider space-occupying lesions.
Vestibular Neuritis: Acute onset of severe vertigo with nausea and vomiting; often following a viral infection.
Meningitis: Nausea with severe headache, neck stiffness, photophobia, and fever; requires urgent evaluation.
Cerebral Hemorrhage: Sudden onset of severe headache with nausea, vomiting, and neurological deficits; consider in hypertensive patients or those with trauma.

Cardiovascular Causes

Myocardial Infarction: Nausea and vomiting, particularly in the context of chest pain, shortness of breath, and diaphoresis; more common in inferior MI.
Heart Failure: Chronic nausea associated with abdominal discomfort, swelling, and fatigue; often worsened by lying flat.
Hypertensive Crisis: Severe nausea with headache, visual disturbances, and chest pain; may be associated with end-organ damage.
Aortic Dissection: Sudden onset of severe tearing chest or back pain with nausea; often associated with hypertension and syncope.

Metabolic and Endocrine Causes

Diabetic Ketoacidosis: Nausea and vomiting with polyuria, polydipsia, abdominal pain, and altered mental status; associated with hyperglycemia and ketonuria.
Uremia: Nausea associated with chronic kidney disease; may be accompanied by anorexia, fatigue, and pruritus.
Hypercalcemia: Nausea with polyuria, polydipsia, constipation, and confusion; consider malignancy or primary hyperparathyroidism.
Addison’s Disease: Chronic nausea, vomiting, and abdominal pain with hyperpigmentation and hypotension; associated with adrenal insufficiency.
Thyrotoxicosis: Nausea with weight loss, heat intolerance, tremor, and palpitations; associated with hyperthyroidism.

Other Causes

Pregnancy: Common cause of nausea, particularly in the first trimester; associated with morning sickness and hyperemesis gravidarum.
Medications: Many drugs, including opioids, antibiotics, and chemotherapy agents, can cause nausea as a side effect.
Psychogenic: Nausea related to anxiety, stress, or eating disorders; may be associated with panic attacks or phobias.
Substance Use: Nausea can be caused by alcohol, recreational drugs, or withdrawal from substances such as opiates or benzodiazepines.

Symptomatology

Onset and Duration: Acute onset may suggest gastroenteritis, myocardial infarction, or vestibular causes; chronic nausea may be due to metabolic, endocrine, or psychogenic causes.
Associated Symptoms: Vomiting, abdominal pain, headache, dizziness, or chest pain can help narrow the differential diagnosis; for example, vomiting and headache may suggest migraine.
Exacerbating and Relieving Factors: Ask about triggers such as food intake, movement, or stress; relief with vomiting may suggest a gastrointestinal cause.
Severity and Impact: Assess how the nausea affects daily activities, appetite, and hydration status; severe or persistent nausea may require more urgent investigation.

Background

Past Medical History: Important to note any history of gastrointestinal disorders, migraines, cardiovascular disease, or metabolic conditions.
Drug History: Review current and recent medications, including over-the-counter and herbal remedies; ask about any recent changes in medication.
Family History: Consider family history of conditions like migraines, peptic ulcer disease, or heart disease, which may predispose the patient to similar issues.
Social History: Assess lifestyle factors such as diet, alcohol use, smoking, and recreational drug use that might contribute to nausea.
Travel History: Recent travel can suggest infectious causes, particularly gastroenteritis or parasitic infections.

Laboratory Tests

Full Blood Count: To assess for anemia or infection, particularly if gastrointestinal bleeding or sepsis is suspected.
Electrolyte Panel: Check for electrolyte imbalances, especially in patients with vomiting or metabolic disorders.
Liver Function Tests: Useful if liver disease or biliary colic is suspected as a cause of nausea.
Renal Function Tests: To assess for uremia, particularly in patients with known chronic kidney disease or symptoms suggestive of renal failure.
Amylase/Lipase: Elevated in pancreatitis, which often presents with nausea and abdominal pain.
Thyroid Function Tests: To rule out hyperthyroidism as a cause of nausea.
Pregnancy Test: Should be performed in all women of childbearing age presenting with nausea to rule out pregnancy.

Imaging and Specialist Tests

Abdominal Ultrasound: First-line imaging for biliary colic, pancreatitis, or other abdominal causes of nausea.
CT Abdomen: Useful for diagnosing bowel obstruction, appendicitis, or other intra-abdominal pathologies.
CT or MRI Brain: Consider if central causes such as increased intracranial pressure or stroke are suspected, particularly in patients with neurological symptoms.
Upper GI Endoscopy: Indicated if peptic ulcer disease, gastritis, or other upper gastrointestinal pathology is suspected.
ECG and Cardiac Enzymes: Important in assessing for myocardial infarction in patients presenting with nausea and chest pain.

Endocrine & metabolic