What is the workup and treatment of hyperemesis gravidarum?

Workup and Treatment of Hyperemesis Gravidarum

Hyperemesis gravidarum requires prompt management with rehydration, electrolyte correction, thiamine supplementation, and a stepwise antiemetic approach to prevent maternal morbidity and adverse pregnancy outcomes. 1

Definition and Epidemiology

• Hyperemesis gravidarum (HG) is an intractable form of nausea and vomiting in pregnancy characterized by persistent vomiting, weight loss ≥5% of pre-pregnancy weight, dehydration, and ketonuria 1
• Affects 0.3-2% of pregnancies 1, 2
• Usually starts before week 22 of gestation, with symptoms resolving by week 16 in >50% of patients and by week 20 in 80%, though 10% may experience symptoms throughout pregnancy 1

Risk Factors

• Prior history of hyperemesis gravidarum 1
• Hyperthyroid disorders 1
• Elevated human chorionic gonadotropin and estrogen levels 1
• Previous molar pregnancy 1
• Psychiatric illness 1
• Pre-existing conditions such as diabetes mellitus and asthma 1
• Singleton female pregnancies or pregnancies with multiple male fetuses 1
• Elevated growth or differentiation factor-15 levels in maternal blood 1

Clinical Presentation and Diagnostic Workup

Clinical Assessment

• Comprehensive history including previous pregnancies and pre-existing conditions 1
• Physical examination focusing on signs of dehydration (orthostatic hypotension, decreased skin turgor, dry mucous membranes) 1
• Evaluation for malnutrition (weight loss and muscle wasting) 1
• Neurologic examination for neuropathy or vitamin deficiency 1
• Severity assessment using the Motherisk Pregnancy-Unique Quantification of Emesis (PUQE) score 1

Laboratory Evaluation

• Electrolyte panel to assess dehydration and imbalances 1
• Liver function tests (elevated in 40-50% of HG patients) 1
• Urinalysis for ketonuria 1
• Thyroid function tests to rule out hyperthyroidism 3
• Nutritional and vitamin deficiency screening 4

Imaging

• Abdominal ultrasonography to:
  • Detect multiple or molar pregnancies 1
  • Assess fetal growth 1
  • Rule out hepatobiliary, vascular, or renal causes of symptoms 1

Treatment Algorithm

Step 1: Non-pharmacological Interventions

• Diet modifications:
  • Small, frequent, bland meals 1
  • BRAT diet (bananas, rice, applesauce, toast) 1
  • High-protein, low-fat meals 1
  • Identify and avoid specific food triggers and strong odors 1

Step 2: Initial Pharmacological Management

• Vitamin B6 (pyridoxine) 10-25 mg every 8 hours 1
• Ginger 250 mg capsule 4 times daily 1
• H1-receptor antagonists (first-line therapy):
  • Doxylamine 10-20 mg (available in combination with pyridoxine) 1
  • Promethazine 1
  • Dimenhydrinate 1

Step 3: Management of Moderate to Severe Cases

• Intravenous fluid resuscitation to correct dehydration 1, 2
• Electrolyte replacement 1, 2
• Thiamine supplementation to prevent Wernicke's encephalopathy 1, 4
• Additional antiemetics:
  • Metoclopramide 1, 3
  • Ondansetron 1

Step 4: Refractory Cases

• Intravenous corticosteroids for severe disease 1
• Alternative pharmacotherapeutics:
  • Mirtazapine 2
  • Olanzapine 2
  • Gabapentin 2
• Nutritional support:
  • Enteral nutrition if oral intake remains inadequate 2, 5
  • Parenteral nutrition for severe cases with ongoing weight loss 2, 5

Monitoring and Follow-up

• Regular assessment of hydration status and electrolyte balance 1
• Weight monitoring to ensure adequate nutrition 4
• Evaluation of symptom control using PUQE score 1
• Fetal growth monitoring 1

Prognosis and Complications

• With proper treatment, pregnancy outcomes are generally favorable 4
• Untreated HG is associated with:
  • Low birth weight 1
  • Small for gestational age infants 1
  • Premature delivery 1
  • Decreased maternal quality of life 3
  • Secondary depression 3

Important Considerations and Pitfalls

• Early intervention is crucial to prevent progression from mild nausea and vomiting to hyperemesis gravidarum 1
• Always rule out other causes of nausea and vomiting (urinary tract infection, thyrotoxicosis) 3
• Persistent liver chemistry abnormalities despite symptom resolution should prompt investigation for alternative etiologies 1
• Recurrence risk is high with subsequent pregnancies 1
• Multidisciplinary care involving obstetricians, gastroenterologists, and nutritionists may be required for severe cases 1