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Hyperemesis gravidarum - Dr Deac Pimp

Definition

  • Significant nausea and vomiting in pregnancy leading to:
    • Electrolyte disturbance
    • Dehydration
    • Ketonuria (3+ or over)
    • Nutritional deficiency
    • Weight loss

 

Risk factors

  • Previous hyperemesis
  • Motion sickness
  • First pregnancy
  • Multiple pregnancy
  • Female pregnancy
  • Obesity
  • H. pylori positive
  • Migraine
  • Hyperthyroidism
  • Diabetes
  • Age <30
  • Low BMI
  • Non-white ethnicity
  • Molar pregnancy

 

Differential diagnoses

  • Molar pregnancy
  • Pre-eclampsia
  • Gestational trophoblastic disease
  • GI disorder:
    • Gastroenteritis
    • Gastritis
    • Peptic ulcer
    • Appendicitis
    • Pancreatitis
    • Hepatitis
    • Bowel obstruction
  • Neurological:
    • Migraine
    • Raised ICP
  • Endocrine:
    • Diabetes
    • Thyrotoxicosis
    • Hypercalcaemia
    • AKI
    • CKD
  • Medication side effect

 

Epidemiology

  • Affects around 2% of pregnancies
  • Admission rate = 1% of pregnancies
  • Up to 90% experience some nausea and vomiting, and up to 35% experience some clinical symptoms
  • More common in Western cultures
  • Onset normally 4-7 weeks
  • Peak prevalence between 8 and 12 weeks gestation, but often persists into middle of pregnancy and beyond

 

Aetiology

  • Pregnancy

 

Clinical features

  • Onset in 1st trimester, if onset is after this, alternative diagnoses are likely
  • Nausea and vomiting:
    • Constant and severe nausea
    • Frequent vomiting
    • Unable to keep food and drink down (in morning sickness, should still be able to have some fluids and/or food)
    • May have haematemesis (from continued irritation/vomiting, may be from Mallory-Weiss tear in oesophagus as result of continued vomiting)
    • May have bile
  • Electrolyte imbalance
  • Dehydration
  • Significant ketonuria (3+ or 4+)
  • Weight loss of >5% of patient’s pre-pregnancy weight (sometimes 10% or 15% are used, depending on trust guidelines)
  • Often present with:
    • Tachycardia
    • Hypotension
    • Postural hypotension
    • Insomnia
    • Mood changes
  • Improvement normally occurs in middle of pregnancy, some nausea and vomiting likely throughout (morning sickness generally resolves after first trimester)
  • Impact on working and self-care

 

Pathophysiology

  • Not well understood, likely a result of circulating hormone levels, especially HCG and oestrogens
  • Positive correlation between peak levels of these hormones and HG
  • More female babies and multiple pregnancies in patients with HG, which supports this theory

 

Investigations

  • Is a diagnosis of exclusion – must ensure that there is not another pathology causing nausea and vomiting
    • FBC
    • U&Es
    • LFT
    • TFT
    • Blood glucose
  • Urinalysis
    • Ketones
    • Exclusion of infection
    • Indication of diabetes
    • Increased specific gravity (dehydration)
  • Pelvic ultrasound:
    • Multiple pregnancy
    • Molar pregnancy
    • Gestational trophoblastic disease
    • Ovarian cyst
    • Other gynaecological pathology
  • Weight

 

Management

  • Try initial non-medical treatment to reduce need to medicate in mild cases
    • Small, high-carb, low-fat meals
    • Ginger
    • Avoid smells and tastes that induce nausea
    • Dry biscuit on waking
    • Rest
  • Anti-emetic medication when dietary advice doesn’t work/established HG
    • First line = promethazine or cyclizine
    • Second line = metoclopramide (not if age <20), prochlorperazine or ondansetron
  • PPI and/or H2 receptor antagonists if dyspepsia also present
  • Rehydration with fluids (saline or Hartmann’s/plasmalyte, NOT dextrose, as may worsen hyponatremia and increase risk of encephalopathy)
  • Control of electrolytes, including potassium replacement
  • Thiamine supplementation
    • Oral 25-50mg TDS if tolerable
    • Multivitamin IM
    • IV infusion 100mg thiamine in 100ml saline
  • Nutritional support if necessary
  • Thromboprophylaxis
  • Corticosteroids for intractable HG
    • 100mg hydrocortisone BD
    • Then prednisolone 40mg daily
    • Aim to stop by 20 weeks
  • Criteria for admission include:
    • Vomiting despite oral anti-emetics, with ketonuria and weight loss
    • Inability to tolerate any food or fluid orally
    • Comorbidities

 

Prognosis

  • Normal morning sickness is not associated with any adverse outcomes for mother or baby
  • HG can lead to maternal death in rare cases
  • Complications include:
    • Wernicke’s encephalopathy
    • Oesophageal rupture or Mallory-Weiss tears
    • Central pontine myelinolysis
    • Retinal haemorrhage
    • Pneumothorax
    • Hyponatremia:
      • Confusion
      • Headache
      • Seizures
      • Respiratory arrest
    • Hypokalemia:
      • Muscle weakness
      • Cardiac arrhythmia
  • Post-partum complications include:
    • Continued nausea and aversion to food
    • PTSD
    • Gallbladder dysfunction
  • Fetal complications include:
    • Higher incidence of low birth weight and prematurity
    • Long terms effects are unknown
  • Risk of HG in subsequent pregnancies is increase 29x to 16-19%
Hyperemesis Gravidarum.docx
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