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Nausea and Vomiting
(Nausea and vomiting in infants and children is discussed elsewhere.)
Nausea, the unpleasant feeling of needing to vomit, represents awareness of afferent stimuli (including increased parasympathetic tone) to the medullary vomiting center. Vomiting is the forceful expulsion of gastric contents caused by involuntary contraction of the abdominal musculature when the gastric fundus and lower esophageal sphincter are relaxed.
Vomiting should be distinguished from regurgitation, the spitting up of gastric contents without associated nausea or forceful abdominal muscular contractions. Patients with achalasia or rumination syndrome or a Zenker diverticulum may regurgitate undigested food without nausea.
Severe vomiting can lead to symptomatic dehydration and electrolyte abnormalities (typically a metabolic alkalosis with hypokalemia) or rarely to an esophageal tear, either partial (Mallory-Weiss) or complete (Boerhaave syndrome). Chronic vomiting can result in undernutrition, weight loss, and metabolic abnormalities.
Nausea and vomiting occur in response to conditions that affect the vomiting center. Causes may originate in the GI tract or CNS or may result from a number of systemic conditions (see Table: Some Causes of Nausea and Vomiting).
The most common causes of nausea and vomiting are the following:
Cyclic vomiting syndrome (CVS) is an uncommon disorder characterized by severe, discrete attacks of vomiting or sometimes only nausea that occur at varying intervals, with normal health between episodes and no demonstrable structural abnormalities. It is most common in childhood (mean age of onset 5 yr) and tends to remit with adulthood. CVS in adults is often due to chronic marijuana (cannabis) use.
Some Causes of Nausea and Vomiting
History of present illness should elicit frequency and duration of vomiting; its relation to possible precipitants such as drug or toxin ingestion, head injury, and motion (eg, car, plane, boat, amusement rides); and whether vomitus contained bile (bitter, yellow-green) or blood (red or “coffee ground” material). Important associated symptoms include presence of abdominal pain and diarrhea; the last passage of stool and flatus; and presence of headache, vertigo, or both.
Review of systems seeks symptoms of causative disorders such as amenorrhea and breast swelling (pregnancy), polyuria and polydipsia (diabetes), and hematuria and flank pain (kidney stones).
Past medical history should ascertain known causes such as pregnancy, diabetes, migraine, hepatic or renal disease, cancer (including timing of any chemotherapy or radiation therapy), and previous abdominal surgery (which may cause bowel obstruction due to adhesions). All drugs and substances ingested recently should be ascertained; certain substances may not manifest toxicity until several days after ingestion (eg, acetaminophen, some mushrooms).
Family history of recurrent vomiting should be noted.
Vital signs should particularly note presence of fever and signs of hypovolemia (eg, tachycardia, hypotension, or both).
General examination should seek presence of jaundice and rash.
On abdominal examination, the clinician should look for distention and surgical scars; listen for presence and quality of bowel sounds (eg, normal, high-pitched); percuss for tympany; and palpate for tenderness, peritoneal findings (eg, guarding, rigidity, rebound), and any masses, organomegaly, or hernias. Rectal examination and (in women) pelvic examination to locate tenderness, masses, and blood are essential.
Neurologic examination should particularly note mental status, nystagmus, meningismus (eg, stiff neck, Kernig sign or Brudzinski sign), and ocular signs of increased intracranial pressure (eg, papilledema, absence of venous pulsations, 3rd cranial nerve palsy) or subarachnoid hemorrhage (retinal hemorrhage).
Many findings are suggestive of a cause or group of causes (see Table: Some Causes of Nausea and Vomiting).
Vomiting occurring shortly after drug or toxin ingestion or exposure to motion in a patient with an unremarkable neurologic and abdominal examination can confidently be ascribed to those causes, as may vomiting in a woman with a known pregnancy and a benign examination. Acute vomiting accompanied by diarrhea in an otherwise healthy patient with a benign examination is highly likely to be infectious gastroenteritis; further assessment may be deferred.
Vomiting that occurs at the thought of food or that is not temporally related to eating suggests a psychogenic cause, as does personal or family history of functional nausea and vomiting. Patients should be questioned about the relationship between vomiting and stressful events because they may not recognize the association or even admit to feeling distress at those times.
All females of childbearing age should have a urine pregnancy test. Patients with severe vomiting, vomiting lasting over 1 day, or signs of dehydration on examination should have other laboratory tests (eg, electrolytes, BUN, creatinine, glucose, urinalysis, sometimes liver tests). Patients with red flag findings should have testing appropriate to the symptoms (see Table: Some Causes of Nausea and Vomiting).
The assessment of chronic vomiting usually includes the previously listed laboratory tests plus upper GI endoscopy, small-bowel x-rays, and tests to assess gastric emptying and antral-duodenal motility.
Specific conditions, including dehydration, are treated. Even without significant dehydration, IV fluid therapy (0.9% saline 1 L, or 20 mL/kg in children) often leads to reduction of symptoms. In adults, various antiemetics are effective (see Table: Some Drugs for Vomiting). Choice of agent varies somewhat with the cause and severity of symptoms. Typical use is the following:
Obviously, only parenteral agents should be used in actively vomiting patients.
For psychogenic vomiting, reassurance indicates awareness of the patient’s discomfort and a desire to work toward relief of symptoms, regardless of cause. Comments such as “nothing is wrong” or “the problem is emotional” should be avoided. Brief symptomatic treatment with antiemetics can be tried. If long-term management is necessary, supportive, regular office visits may help resolve the underlying problem.
Some Drugs for Vomiting
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