Notes on Nausea and Vomiting

Learning Objectives

• Understand the pathophysiology of nausea and vomiting.
• Identify common causes and risk factors of nausea and vomiting symptoms.
• Recommend non-pharmacological treatment options.
• Suggest OTC pharmacological treatment options.
• Provide effective patient education related to nausea and vomiting.

Etiology – Primary Causes

Table 1: Primary Causes of Nausea and Vomiting

• GI Tract Disorders

• Mechanical Obstruction (e.g., PUD, gastric carcinoma)

• Motility Disorders (e.g., gastroparesis, IBS)

• Peritoneal Irritation (e.g., appendicitis, pancreatitis)

• Infections (e.g., viral gastroenteritis, food poisoning)

• Topical GI Irritants (e.g., alcohol, NSAIDs)

• CNS Disorders

• Increased Intracranial Pressure (e.g., tumors, hemorrhage)

• Infections (e.g., meningitis)

• Psychogenic Causes (e.g., bulimia, anxiety)

• Other CNS Issues (e.g., migraines)

• Other Disorders

• Cardiac (e.g., myocardial infarction)

• Metabolic (e.g., diabetes, renal disease)

• Chronic Illness (e.g., cannabis hyperemesis syndrome)

Pathophysiology

• Central Pathways

• Vomiting Center (VC) in the medulla

• Chemoreceptor Trigger Zone (CTZ) affected by toxins

• Peripheral Pathways

• Vagal and splanchnic nerve afferents from the GI tract

• Vestibular system contributes to nausea and vomiting

Phases of Emesis

• Nausea: Sensation of needing to vomit
• Retching: Labored movements prior to vomiting
• Vomiting: Forceful expulsion of gastric contents

Neurotransmitters Involved

• Serotonin (5-HT3), Dopamine (DA2), Histamine (H1), Acetylcholine (M1), Neurokinin (NK1), Opiate (mu/kappa)

Clinical Presentation of N/V

Complications from Vomiting

• Dehydration
• Electrolyte imbalances
• Aspiration
• Mallory-Weiss syndrome

Symptoms of Dehydration

• General Signs: Dry mouth, dizziness, decreased urine output
• In Children: Interventions include monitoring sunken fontanelle, weight loss, and decreased skin turgor.

Treatment of Nausea and Vomiting

Treatment Goals

• Symptomatic relief
• Correct underlying causes
• Prevent complications
• Prevent recurrence

General Treatment Approach

• Evaluation to determine self-treatment eligibility
• Nonpharmacologic measures
• Over-the-counter medications
• Prescription antiemetics if necessary

Non-Pharmacological Treatments

Lifestyle and Dietary Changes

• Eat small, frequent meals (BRAT diet recommended)
• Avoid strong-smelling, fatty, or spicy foods
• Stay hydrated with clear fluids and use Oral Rehydration Solutions (ORS)

Dosing for ORS

• Children Mild to Moderate Dehydration: 50-100 mL/kg over 3-4 hours
• Severe Dehydration: Refer to ER for IV rehydration
• Adult Non-Severe Dehydration: Replace 30-50% of fluid loss in first 24 hours

Osmolarity and Sodium Content

• Acceptable osmolarity: 200-310 mOsm/L
• Recommended sodium: 70-90 mEq/L
• Household remedies generally not recommended due to low sodium content.

Pharmacological Treatment Approach

Self-Care for N/V Disorders

• Conditions include Acute Viral Gastroenteritis, Upset Stomach, Motion Sickness, and Pregnancy

Treatment for NVP (Nausea and Vomiting in Pregnancy)

• First-Line: Pyridoxine (10-25 mg)
• Consider Doxylamine as an additional option.

Special Populations

Geriatrics

• Use caution with antihistamines; medication reviews may be necessary.

Pediatrics

• Monitor for signs of dehydration and avoid Bismuth subsalicylate if recovering from chickenpox or influenza-like symptoms.

Complementary Medicine

• Ginger: 250 mg to 2 g per day may be effective with fewer side effects than standard antiemetics.
• Vitamin B6: Recommended dosing for NVP typically 10-25 mg three times a day.
• Acupressure: Effective at preventing postoperative nausea and vomiting.

Product Selection Guidelines

• Be cautious of drug interactions, particularly with antihistamines and blood thinners such as Warfarin.
• Monitor for possible side effects extensively with all medications.

Key Points

• Nausea and vomiting are symptoms indicative of underlying issues; focus on proper assessment and treatment.
• OTC antiemetics are valuable for occasional self-limiting conditions.
• Address potential complications, primarily dehydration via ORS therapy.