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hyperemesis_gravidarum

hyperemesis gravidarum

Introduction

  • nausea and vomiting effect up to 85% of pregnant women
    • usually mild and self-limiting, frequently resolving before 14wks gestation
    • it is thought to be an evolutionary function to avoid eating foods which may be high risk to either the foetus (teratogenic or abortifacient such as plant toxins, alcohol, caffeine) or to the immunosuppressed mother who is at risk of food-borne pathogens which are more likely in meats, fish and eggs, while safer foods such as fruit, grains and sweets are craved 1)
    • it tends to be associated with a positive pregnancy outcome (50-75% lower miscarriage rates)2)
  • more severe cases with significant dehydration and ketonuria are a frequent presentation to ED
    • ~13% of these patients have symptoms beyond 20wks gestation 3)

Differential diagnosis of persistent vomiting in pregnancy

relatively common causes

less common causes

unusual causes

ED Mx of hyperemesis

dehydrated or ketonuric

  • IV thiamine supplementation to prevent the complication of Wernicke’s encephalopathy should be administered to all women with hyperemesis gravidarum severe enough to warrant admission. Thiamine dose is 100mg daily for 2-3 days. This will normally need to be given parenterally, 100mg thiamine in 100mL 0.9% sodium chloride IV over 30-60 minutes.
  • consider VTE prophylaxis if requiring admission

  • these patients usually do well with iv rehydration Rx (eg. N Saline 1L over 2hrs then 1L over 2-4hrs then 3L/day of Hartmann's with 5% glucose - do not use 5% glucose alone!) + anti-emetics (see below)
  • often these patients can be directly admitted from triage to a ED short stay observation unit using a care plan pathway
  • send bloods for FBE, U&E, and, TSH if thyroid testing has not been done
  • check urinalysis and send MSU m/c/s if suspicious of UTI
  • exclude other conditions such as a surgical abdomen
  • ensure an USS has be done or will be done within a week or so to exclude multiple pregnancies and molar pregnancy.
  • repeated vomiting usually causes some oesophagitis and may even cause Mallory-Weiss tear resulting in small amounts of blood in vomit.
    • this does not usually need Ix but Mx with antacids or ranitidine may be useful.

not significantly dehydrated and not ketonuric

  • these patients can usually be managed as an outpatient
  • check urine, USS as above
  • non-pharmacologic measures
    • small frequent meals and snacks aiming for food/fluid every 1-2 hours
    • avoid foods that may trigger symptoms including spicy, odourous, very sweet or acidic foods
    • chew foods slowly
    • eliminate other non-dietary triggers
    • during the first trimester avoid multivitamins that contain high levels of iron (>27mg iron per tablet), re-start after 12wks
    • adequate sleep
    • sea-sickness P6 acupressure wristbands
    • ginger (orally as a tablet or syrup) to a maximum of 1g daily
  • oral agents to consider (as per WH guideline 2019):
    • first line:
      • pyridoxine (vitamin B6) 25mg o tds (this medication is optional as effectiveness is limited)
    • second line:
      • add doxylamine (Restavit, a H1 antagonist) 12.5mg o nocte, increase to 25mg nocte, then add 12.5mg mane and afternoon if needed
    • third line, add either ONE of the following:
    • fourth line, add a sedating antihistamine:
      • promethazine 10-25mg tds/qid
    • fifth line if severe, persistent or resistant vomiting:
      • ondansetron (Zofran) 4-8mg o (tablet or wafer) bd/tds max 24mg/day
    • sixth line - consider parenteral administration of ONE of the following:
    • seventh line:
      • prednisolone 50mg o daily for 3 days, then 25mg o daily for 3 days, then reduce by 5mg as tolerated
        • may need initial IV hydrocortisone 100mg 12hrly un til oral pred is tolerated
        • monitor glucose levels and consider prophylactic ranitidine 300mg o nocte to prevent gastritis
  • don't forget to remind patient to take folate supplements as well to reduce probability of neural tube defects
  • patients with > 10% LOW with persistent symptoms or a pre-pregnancy BMI < 18 should be referred to dietitian
3)
Sheehan P. Hyperemesis gravidarum. Assessment and management. Aust. Fam. Physician 2007; 36: 698-701
4)
Ting. Case report - incarcerated diaphragmatic hernia EMA 2008 20:441-443
hyperemesis_gravidarum.txt · Last modified: 2019/08/18 03:09 by wh