C

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.