Persistent Nausea or Vomiting

The possible diagnoses for a patient presenting with persistent nausea and/or vomiting are many and varied, but in the main may be considered under five main headings:

• Pregnancy
• Visceral disease
• Metabolic/toxic
• Central nervous system disease
• Psychiatric illness

Assessment of the patient with persistent nausea and vomiting should fall into two categories:-

1. Assessment of the physical state of the patient, which has occurred as a consequence of the nausea/vomiting. Look for evidence of:
   • Poor nutritional state
   • Dehydration
   • Electrolyte imbalance
2. Assessment of the patient with regard to the potential underlying cause.¹
   Pregnancy
   80% of pregnant women experience some form of nausea and/or vomiting related to pregnancy.²
   • "Morning sickness"
   • Hyperemesis gravidarum
   • Urinary tract infection
   • Reflux oesophagitis
   • Mechanical due to gravid uterus
   Visceral disease
   • Reflux oesophagitis or GORD
   • Obstruction e.g. due to malignancy or chronic constipation
   • Cholecystitis
   • Hepatitis
   • Urinary tract infection
   Metabolic/toxic
   • Drugs e.g. cytotoxic agents, erythromycin, digoxin toxicity, theophylline
   • Alcohol
   • Hypercalcaemia
   • Uraemia
   • Diabetic ketoacidosis
   Central nervous system disease
   • Cyclical vomiting syndrome
   • Vestibular labyrinthitis and Meniere's disease
   • Raised intracranial pressure e.g. due to space occupying lesion, intracranial bleed
   Psychiatric disease
   • Bulimia nervosa
   • "Functional"
   • Rumination
   • Psychogenic

Full history with particular attention to duration, severity, aggravating and relieving factors, associated features, drug and occupational history, social history, last menstrual period, previous medical history, recent trauma.
Full examination- in particular assess hydration, nutritional state, examine abdomen, sclera and optic discs, check for nystagmus.

• Urine dipstick- for protein, blood, glucose, pH, bilirubin, urobilinogen
• Serum Urea
• Serum calcium
• Liver function tests
• Full blood count
• Pregnancy test
• Plain abdominal film
• Abdominal ultrasound
• Endoscopy
• Abdominal CT/MRI scan
• Cranial CT if suspicion of raised intracranial pressure

Non-drug

• Patients with persistent nausea and /or vomiting will require appropriate dietary advice and advice on fluid intake.
• Patients with severe dehydration may require treatment for a time with intravenous fluids.
• Psychiatric or psychology referral may be appropriate for those thought to have an underlying psychiatric/psychological cause.
• Pregnant patients should be given emotional support, advice concerning diet, adequate nutritional intake, avoiding large volume meals and tight clothing and advised to avoid taking anti-emetic preparations available over the counter. Complimentary therapies such as ginger or acupressure may be useful.l³ Pregnant women who have severe vomiting may require hospitalization, where they can receive orally or intravenously administered corticosteroid therapy, and total parenteral nutrition.
• There is some evidence for the use of acupuncture for the symptomatic relief of nausea and vomiting and this may be an option for some patients.⁴ It is particularly efficacious against nausea in post-operative patients, who had not received pre-medication.

Drugs

Once the caused of vomiting has been established, symptomatic relief may be given if appropriate, in the form of anti-emetic therapy.
Many classes of drugs exhibit anti-emetic properties such as antihistamines, phenothiazines such as prochlorperazine, anti-psychotic drugs such as haloperidol.⁵

• Metoclopramide acts directly on the gastrointestinal tract and may be the drug of choice for visceral causes.
• Medications including pyridoxine and doxylamine, have been shown to be safe and effective treatments in pregnancy.³, ⁶
• Domperidone acts at the chemoreceptor trigger zone and is especially useful for nausea and vomiting associated with chemotherapy.
• Dolasetron, granisetron, odansetron and tropisetron are specific 5HT3 antagonists and as such are particularly useful for post-operative nausea and vomiting and that associated with cytotoxic therapy.
• Dexamethasone and nabilone, a synthetic cannabinoid, may be useful for patients on cytotoxic drugs with nausea that is resistant to other therapy.

Surgical

Surgery may be required to treat some underlying causes of nausea and vomiting e.g. raised intracranial pressure and some forms of obstruction.

Recurrent vomiting may result in dehydration, electrolyte disturbance, oesophagitis/gastritis and Mallory-Weiss syndrome.