Chapter 60: Nausea and vomiting

Vomiting or emesis is a rather dramatic event with a diverse number of causes. It is usually preceded by nausea.

History

A careful history is essential with an emphasis on drug intake, possible psychogenic factors, including self-induced emesis, weight loss, other GIT symptoms or symptoms suggestive of systemic disease.

Examination

If fever is present possible sources of infection (e.g. middle ear, meninges and urinary tract) should be checked.

A careful abdominal examination is appropriate in most instances and this includes urinalysis. Look particularly for scars indicating previous surgery. Look for a succussion splash—this indicates pyloric obstruction.

A neurological examination needs to be considered, including ophthalmoloscopy. Consider raised intracranial pressure.

No examination is complete without assessment of the patient’s physical fitness, including the level of hydration, especially in infants and the very old. In these age groups the history may be difficult to obtain and the consequences of fluid loss are more complicated. Always be mindful of the possibility of pregnancy in the female patient. Look for acid dental erosion as a marker of bulimia.

Investigations

These should consider the underlying cause and also biochemical abnormalities resulting from fluid and electrolyte loss.

The following need to be considered:

• pregnancy test (all females of child-bearing age)

• microscopy and culture of stools

• radiology of GIT

• endoscopy

• oesophageal motility studies

• neurological investigation for suspected intracranial pressure (e.g. CT scan, MRI)

• drug toxicity studies

• biochemistry

• cortisol/short synacthen test

• Surgical GIT causes are unlikely in the absence of abdominal pain.

• Vomiting without bile-stained vomitus = pyloric obstruction.

• Vomiting of bile = obstruction below duodenal ampulla.

• Vomiting of ingested food = oesophageal obstruction.

• Vomiting without nausea and possibly projectile = ↑ intracranial pressure.

A summary of the diagnostic strategy model is presented in TABLE 60.1.

Common causes in infants

• feeding problems

• food intolerance

• physiological, e.g. posseting, simple reflux

• gastro-oesophageal reflux

• gastroenteritis

• viral respiratory infections

Is the vomiting bile-stained?

• Green vomiting = urgent surgical referral for possible intestinal malrotation with volvulus (6 hours leeway before gangrene of bowel)² Other causes: meconium ileus, small bowel atresia

• Non bile-stained vomitus (curdled milk): consider pyloric stenosis, GORD, feeding problems, concealed infection (e.g. UTI, meningitis). Both pyloric stenosis and GORD cause projectile vomiting.

Important warning signs in neonates

• Excessive drooling of frothy secretions from mouth

• Bile-stained vomitus—always abnormal

• Delayed passage of meconium (beyond 24 hours)

• Inguinal hernias

Refer to surgical emergencies in children (CHAPTER 96).

Specific conditions

Oesophageal atresia

• Vomiting occurs with the first feeding.

• There is excessive drooling of frothy secretions from the mouth.

• Pass a French gauge 10 catheter through the mouth to aid diagnosis.

Congenital hypertrophic pyloric stenosis

• Usually sudden onset 3rd–6th week

• Projectile vomitus

• Failure to thrive

• Male:female = 5:1

• Gastric peristalsis during test feeding (L → R):

  • – feel for pyloric tumour either during test feeding or immediately after vomiting (deep in right epigastrium)—see FIGURE 60.1; once felt, further investigation is not necessary

• Biochemistry:

  • – metabolic alkalosis: sodium usually <130 mmol/L, chloride <100 mmol/L

• Special investigations (if necessary):

  • – barium meal (string sign)—concern about aspiration

  • – abdominal ultrasound

• Treatment:

  • – correct fluid and electrolyte deficiency (hypochloraemic alkalosis) before surgery

  • – appropriate fluid is $N2$ (half normal) saline with 5% dextrose

  • – surgical management (longitudinal pyloromyotomy)

Acute gastroenteritis

See CHAPTER 44.

Intussusception

See CHAPTER 34.

Vomiting in the older child

Common causes

• acute gastroenteritis

• acute viral infections

• other common infections, e.g. otitis media

• travel/motion sickness

• migraine/cyclical vomiting

• drugs and toxins, e.g. snake bite

Not to be missed

• acute appendicitis/peritonitis

• strangulated inguinal hernia

• other surgical emergencies

• raised intracranial pressure, e.g. head injury

• serious infection, e.g. pneumonia, meningitis, sepsis

• diabetes/ketoacidosis

• haemolytic uraemic syndrome

• eating disorders: binging/purging

Cyclical vomiting⁷

Features:

• severe, unexplained vomiting or nausea occurring at varying intervals in a healthy person

• lasts hours to days

• most common in children (mean age 5 years)

• ± severe abdominal pain, photophobia, headache

• regarded as a migraine variant

• usually remits in adulthood—may persist

• treated with antimigraine therapy

Gastroparesis (adults)³

Gastroparesis (gastropathy) or severely delayed gastric emptying is a moderately common condition, which is a cause of nausea and vomiting.

Causes include:

• diabetic gastroparesis

• postsurgical gastroparesis, e.g. vagotomy (complete or partial), fundoplication

• trauma

• idiopathic (de novo)

Less common causes include:

• connective tissue disorders (e.g. scleroderma)

• vasculitides

• myopathic disorders (e.g. muscular dystrophy)

• thyroid dysfunction

• hypokalaemia

• pancreatitis

Symptoms

• Upper abdominal discomfort/bloating

• Early satiety

• Nausea

• Postprandial vomiting (1–3 hours after meals)

• Abdominal pain

Diagnosis

• Endoscopy → significant gastric residue

• Barium swallow with follow through

• Nuclear medicine gastric emptying test (gastric retention of 60% after 2 hours is abnormal)

Special problems

• Malnutrition

• Dehydration

Management

• Advise patients to eat small, frequent meals, with careful chewing of food.

• Avoid large pieces of bread especially doughy bread (encourage toasting).

• Avoid fat, especially French fries, raw fruit and vegetables.

• Refer diabetic patients to a dietitian for advice.

• domperidone 10–20 mg (o) tds, 15–30 minutes before meals

• or

• metoclopramide 5–10 mg (o) tds, 30 minutes before meals

• or

• erythromycin (has prokinetic properties) 125 mg (o) tds, 15 minutes before meals (rapidly develops tolerance)

• consider cisapride 10 mg (o) tds before meals (with caution)

• Injection of botulinum toxin into the pylorus

• Gastric pacing with internally implanted neurostimulators⁶

Chronic idiopathic nausea and vomiting⁴

This term is applicable to those patients who experience chronic nausea and vomiting without an identifiable cause or precipitant.

Dietary modification with CBT is recommended. Anti-emetic or antidepressant medication can be considered.

These include dehydration, metabolic alkalosis, hypokalaemia, aspiration, mucosal tear of gastro-oesophageal junction, rupture of the oesophagus (Boerhaave syndrome).

The first-line management is to ensure that any fluid and electrolyte imbalance is corrected and that any underlying cause is identified and treated. Various anti-emetics can give symptomatic relief.

Note: Avoid the use of centrally acting dopamine antagonist drugs (DADS, e.g. metoclopramide and prochlorperazine) in children because of risk of extrapyramidal side effects (EPSE), usually acute dystonic reactions. Elderly also at risk. EPSE rare with domperidone because it does not cross the blood–brain barrier. Other DADS include haloperidol and droperidol (limited use).

Serotonin 5-HT₃ antagonists

These include ondansetron, granisetron, dolasetron, palonosetron and tropisetron and are effective at preventing chemotherapy- and radiotherapy-induced emesis when initiated prior to treatment. Dexamethasone enhances the effect of 5-HT₃ agents. Ondansetron can be used in children with gastroenteritis, preferably in wafer format.

Drug-induced nausea and vomiting⁴

• metoclopramide 10 mg (o) or IM 8-hourly prn

• For cytotoxic drugs (e.g. cisplatin) and radiotherapy:

• metoclopramide 10 mg (o) or IM 1–2 hours prior to therapy then 8-hourly (if mild)

• For severe cases:

• ondansetron 8 mg (o) or IV prior to therapy then two doses 6-hourly

• plus

• dexamethasone 8 mg IV 30 minutes prior to therapy, then two doses 6-hourly

Note: Restrict ondansetron to 8 mg daily for those with hepatic dysfunction.

A list of some drugs that can cause nausea and vomiting is presented in TABLE 60.2.

Motion sickness

Refer to CHAPTER 14.

• promethazine theoclate 25 mg (o) 60 minutes prior to travel

• or

• dimenhydrinate 50 mg (o) 60 minutes prior to travel

• or

• hyoscine 300–600 mcg (o) 30 minutes prior to travel

• or

• hyoscine 1.5 mg dermal disc: applied to dry hairless skin behind the ear 5–6 hours before travel (effective for 72 hours)⁴

For treatment: repeat oral presentations 4–6-hourly during trip (max. 4 doses in 24 hours).

Vestibular disturbances⁴

The phenothiazine derivatives are the most effective, while the dopamine D2-receptor antagonists are relatively ineffective. Refer to CHAPTER 46.

• prochlorperazine 5–10 mg (o) or 10 mg rectally, SC or IM 4 times daily prn

• or

• promethazine theoclate 25 mg (o) or IM 4-hourly prn (max. 100–150 mg per 24 hours)

Note: Beware of tardive dyskinesia with prolonged use.

Gastroenteritis

For severe cases in adults:

• metoclopramide 10 mg (o) or IM 8-hourly prn

Pregnancy

• pyridoxine hydrochloride 25 mg (o) tds

• plus

• doxylamine 25 mg (o) nocte

• if still ineffective add

• metoclopramide 10 mg (o) tds or IM (if oral intolerance)

• if response still unsatisfactory

• ondansetron tablet or wafer 4–8 mg (o) bd to tds

Postoperative vomiting⁴

• metoclopramide 10 mg IM or IV (slowly), 8-hourly prn

• or

• prochlorperazine 12.5 mg IM, 8-hourly prn

Chemotherapy and radiotherapy

• ondansetron 4 mg (o or SL) bd

• plus

• dexamethasone 4 mg (o) daily