Nausea Flashcards
(50 cards)
1
Q
What are common causes of nausea in hospitalized patients?
A
- Medications (e.g., opioids, antibiotics, chemotherapy)
- Electrolyte imbalances (e.g., hyponatremia, hypercalcemia)
- Gastrointestinal obstruction or ileus
- Infections (e.g., gastroenteritis, sepsis)
- CNS causes (e.g., increased intracranial pressure)
- Postoperative state
2
Q
What is the initial approach to evaluating nausea in a hospital patient?
A
- Take a detailed history (onset, duration, frequency, associated symptoms)
- Review medication list for potential culprits
- Perform a physical exam focusing on abdomen and CNS
- Order basic labs (e.g., electrolytes, renal function)
- Consider abdominal imaging if obstruction is suspected
3
Q
Which electrolyte abnormalities commonly cause nausea?
A
- Hyponatremia
- Hypercalcemia
- Uremia (elevated urea levels)
- Hypokalemia
4
Q
What are red flag symptoms associated with nausea that warrant urgent evaluation?
A
- Severe abdominal pain
- Signs of bowel obstruction (distension, no flatus)
- Hematemesis or melena
- Altered mental status
- Headache with vision changes (possible raised ICP)
5
Q
How do you manage nausea in a patient without red flag features?
A
- Identify and treat the underlying cause (e.g., medication, electrolyte issue)
- Trial antiemetics such as ondansetron or metoclopramide
- Ensure hydration and electrolyte correction
- Monitor for improvement and adjust therapy if needed
6
Q
Which antiemetics are commonly used in hospitals?
A
- Ondansetron (5-HT3 antagonist)
- Metoclopramide (prokinetic and D2 antagonist)
- Cyclizine (antihistamine)
- Haloperidol (dopamine antagonist, used in palliative care)
- Prochlorperazine (phenothiazine)
7
Q
When is ondansetron preferred as an antiemetic?
A
- Nausea due to chemotherapy or post-operative nausea
- GI-related nausea (e.g., gastroenteritis)
- Fewer sedative effects compared to other agents
8
Q
What are the potential side effects of ondansetron?
A
- Constipation
- Headache
- QT prolongation (especially with high doses or in combination with other QT-prolonging drugs)
9
Q
What are the contraindications for using metoclopramide?
A
- Parkinson’s disease (may worsen extrapyramidal symptoms)
- Bowel obstruction (risk of perforation due to prokinetic action)
- History of tardive dyskinesia
10
Q
What are key considerations in using cyclizine?
A
- Good for vestibular nausea (e.g., motion sickness)
- Causes sedation
- Use with caution in elderly due to anticholinergic side effects
11
Q
What is the mechanism of action of metoclopramide in nausea?
A
- Dopamine D2 receptor antagonist in the chemoreceptor trigger zone (CTZ)
- Enhances gastric motility and accelerates gastric emptying (prokinetic)
12
Q
What are common side effects of metoclopramide?
A
- Extrapyramidal symptoms (e.g., dystonia, akathisia)
- Sedation
- Diarrhea
- Elevated prolactin (galactorrhea, gynecomastia)
13
Q
How does haloperidol help in managing nausea?
A
- Acts as a dopamine receptor antagonist in the CTZ
- Used particularly in palliative care or intractable nausea
- Also useful in patients with delirium or agitation
14
Q
What are NK1 receptor antagonists and when are they used?
A
- Block neurokinin-1 receptors in the CNS
- Used for chemotherapy-induced nausea and vomiting (e.g., aprepitant)
- Often combined with dexamethasone and 5-HT3 antagonists
15
Q
Which antiemetic is preferred in pregnancy?
A
- First-line: Pyridoxine (vitamin B6) with or without doxylamine
- Alternatives: Promethazine, metoclopramide, ondansetron (after first trimester)
16
Q
What is anticipatory nausea and how is it managed?
A
- Occurs before chemotherapy due to conditioning
- Managed with behavioral therapy and anxiolytics (e.g., lorazepam)
17
Q
What is gastroparesis and how does it relate to nausea?
A
- Delayed gastric emptying without mechanical obstruction
- Common in diabetics
- Symptoms: Nausea, bloating, early satiety
- Treated with dietary modification and prokinetics (e.g., metoclopramide)
18
Q
How can nausea due to increased intracranial pressure be recognized?
A
- Associated with headache, vomiting (often without nausea), blurred vision, altered mental status
- Cushing’s triad: hypertension, bradycardia, irregular respirations
- Urgent neuroimaging indicated
19
Q
What is the role of benzodiazepines in nausea?
A
- Helpful for anticipatory or anxiety-induced nausea
- Provide anxiolysis and amnesia
- Example: Lorazepam
20
Q
What non-pharmacologic measures can help reduce nausea?
A
- Fresh air, cold compresses
- Acupressure (e.g., P6 point on wrist)
- Ginger supplements
- Eating small, frequent meals
21
Q
What are signs that nausea may be due to a bowel obstruction?
A
- Crampy abdominal pain
- Abdominal distension
- Vomiting (may be feculent)
- Absent bowel movements or flatus
- High-pitched bowel sounds
22
Q
Why might prochlorperazine be used in nausea?
A
- Dopamine antagonist with antipsychotic and antiemetic properties
- Effective in migraines and vestibular disorders
- Can cause sedation and extrapyramidal symptoms
23
Q
What is cyclic vomiting syndrome?
A
- Recurrent episodes of severe nausea and vomiting
- Seen in children and some adults
- May be associated with migraine or stress
- Treated with antiemetics and migraine prophylaxis
24
Q
Which antiemetic is helpful for vestibular causes of nausea?
A
- Antihistamines such as cyclizine or promethazine
- Anticholinergics like scopolamine patch
25
When should nausea be considered drug-induced?
- Onset corresponds with new medication
- Common culprits: opioids, antibiotics, chemotherapy, iron supplements
- Resolution after stopping the offending agent
26
What is the benefit of using dexamethasone for nausea?
- Anti-inflammatory and antiemetic effects
- Often used in chemotherapy or post-surgical settings
- Can enhance effectiveness of 5-HT3 antagonists
27
How do you evaluate nausea in a patient with chronic kidney disease?
- Consider uremia as a cause
- Check BUN and creatinine
- Review dialysis schedule and adequacy
- Consider antiemetics and address underlying metabolic derangement
28
What are features of serotonin syndrome that may overlap with nausea?
- Nausea, vomiting, diarrhea
- Mental status changes (agitation, confusion)
- Hyperreflexia, clonus
- Autonomic instability (fever, tachycardia)
29
Why should you monitor QTc when using antiemetics?
- Drugs like ondansetron and haloperidol can prolong QT interval
- Risk of torsades de pointes
- Check baseline ECG in high-risk patients or when using multiple QT-prolonging drugs
30
What is the preferred route of antiemetics in patients with active vomiting?
- Parenteral (IV or IM)
- Rectal or sublingual options can be used if IV not available
31
What role does serotonin play in nausea and vomiting?
- Serotonin (5-HT) is released from enterochromaffin cells in the GI tract in response to toxins or distension
- It activates 5-HT3 receptors on vagal afferents leading to stimulation of the vomiting center
32
What is the chemoreceptor trigger zone (CTZ) and why is it important?
- Located in the area postrema of the medulla oblongata
- Detects emetogenic substances in blood/CSF
- Rich in dopamine, serotonin, and NK1 receptors
33
How does motion sickness lead to nausea?
- Caused by mismatch between visual and vestibular inputs
- Activates the vestibular nuclei, which project to the vomiting center
- Mediated by histamine and muscarinic receptors
34
Which receptors are involved in the central vomiting pathway?
- Dopamine (D2)
- Serotonin (5-HT3)
- Histamine (H1)
- Muscarinic (M1)
- Neurokinin (NK1)
35
Why is it important to assess hydration in patients with nausea?
- Prolonged nausea can lead to dehydration and electrolyte loss
- Signs include dry mucous membranes, tachycardia, hypotension
- IV fluids may be needed to stabilize the patient
36
What medications can cause nausea as a side effect?
- Opioids
- Antibiotics (e.g., erythromycin, doxycycline)
- NSAIDs
- Chemotherapy agents
- Oral iron or potassium
37
How does scopolamine treat nausea?
- Anticholinergic that blocks muscarinic receptors in the CNS
- Particularly effective for motion sickness
- Available as a transdermal patch
38
What is cannabinoid hyperemesis syndrome?
- Recurrent nausea and vomiting in chronic cannabis users
- Often relieved by hot showers
- Treated with cannabis cessation and supportive care
39
How is nausea managed in patients receiving chemotherapy?
- Prophylactic antiemetics: 5-HT3 antagonists, NK1 antagonists, corticosteroids
- Tailored based on emetogenic potential of the chemo regimen
- Scheduled dosing often more effective than PRN
40
What is the significance of early vs late onset postoperative nausea?
- Early: often related to anesthetics or opioids
- Late: may be due to ileus or surgical complications
- Treatment varies depending on timing and likely cause
41
How can GERD cause nausea?
- Acid reflux irritates the esophageal lining and vagus nerve
- Can produce nausea, especially in supine position
- Treated with PPIs, lifestyle changes
42
Why are elderly patients more sensitive to antiemetic side effects?
- Increased risk of sedation, confusion, and falls
- Greater sensitivity to anticholinergic effects
- Need for lower doses and careful monitoring
43
When is a CT abdomen indicated in a nauseated patient?
- If bowel obstruction, volvulus, or ischemia is suspected
- Associated with abdominal pain, distension, or peritonitis
- Helps identify surgical emergencies
44
How does uremia cause nausea?
- Accumulation of nitrogenous waste products irritates the CTZ
- Common in advanced chronic kidney disease
- Managed with dialysis and antiemetics
45
What is the vomiting center in the brain and where is it located?
- Located in the medulla oblongata
- Coordinates input from CTZ, GI tract, vestibular system, and higher centers
- Initiates vomiting reflex
46
What is the role of dietary advice in managing chronic nausea?
- Small, frequent meals
- Avoid fatty, spicy, or strong-smelling foods
- Cold meals may be better tolerated than hot ones
47
How do you differentiate between nausea of central vs GI origin?
- Central: associated with headache, dizziness, neuro symptoms
- GI: often linked to food intake, abdominal pain, bowel habit changes
48
When should you consider endoscopy in a patient with nausea?
- Persistent or unexplained nausea
- Associated with weight loss, dysphagia, or anemia
- To rule out gastric ulcers, malignancy, or motility disorders
49
What is the best antiemetic option for nausea in palliative care?
- Haloperidol: effective for chemical or central causes
- Metoclopramide: good if gastric stasis suspected
- Cyclizine: useful for vestibular causes
50
Why might nausea worsen at night in hospitalized patients?
- Circadian rhythm changes
- Supine position aggravates reflux
- Slower gut motility in inactivity
- Missed antiemetic dosing schedule
