4.2.1 Evaluation

A thorough history and examination is essential in elucidating the cause of nausea and/or vomiting. In over two-thirds of seriously ill patients, one or more causes will be determined [2]. History should focus on onset, frequency, and severity of nausea, recent medications, underlying medical illnesses, and associated symptoms. Ask about recent initiation or titration of opioids as commonly associated with nausea. Inquire about gastritis, reflux disease, and constipation as appropriate treatment may relieve symptoms. For cancer patients, find out the type of cancer, location of tumor(s), and any recent chemotherapy or radiotherapy. Key questions can help lead to determining the activated pathway. Early satiety, bloating, and relief of nausea with small-volume emesis are suggestive of gastric stasis. Alternatively, gastric obstruction is associated with colicky abdominal pain and large-volume bilious emesis. Nausea associated with certain smells or the sight of food suggests activation of the CTZ in the brain. Motion-induced nausea, often associated with vertigo indicates vestibular activation. Increased intracranial pressure typically causes early morning nausea and is associated with headaches and impaired cognition. Finally, anxiety or emotionally induced nausea suggests a cortical component [2, 7].

Physical examination should be attuned to confirming the pathway identified in the history. GI causes can be confirmed by evidence of ascites, enlarged liver, palpable abdominal mass, or impacted stool on rectal exam. Look for fever, confusion, asterixis, or neurological signs. Evidence of dehydration or weight loss may suggest symptom severity.

Laboratory tests may not be necessary on all patients with nausea and vomiting. A basic metabolic panel may show evidence of a reversible cause as detailed in Table 4.2 requiring appropriate medical management. A plain abdominal radiograph can help distinguish between constipation and obstruction. For patients near the end of life, it may be appropriate to treat symptomatically without additional laboratory or radiological testing depending on the goals of care.

4.2.2 Treatment

According to a mechanism-based model, initial antiemetic should be effective against the most likely neuroreceptor involved. In the hospital setting, severe nausea and vomiting require initiation of an IV antiemetic. The chosen antiemetic should be prescribed around the clock and titrated to the maximum recommended dose until relief is achieved. If symptoms persist, add another agent directed against a different receptor [1, 3, 8]. Once nausea is controlled, transition patients to an oral formulation. Many patients will require antiemetics on discharge for chronic symptoms.

4.2.3 Alternative Treatments

Nonpharmacological approaches to nausea and vomiting may be of benefit in addition to antiemetics. For chemotherapy-induced nausea, acupuncture and acupressure are beneficial [9]. More feasible options in the hospital setting include small meals, carbonated drinks, and avoidance of strong odors [8].