Hyperemesis gravidarum

Question 1

Which of these electrolyte abnormalities is seen in severe cases of hyperemesis gravidarum?

1. Hyperchloraemic, hypernatraemia with normal urea and normal ketones
2. Hyperkalaemia with hyponatraemia, elevated urea and raised ketones
3. Hypochloraemic, hyponatraemia with elevated urea and raised ketones
4. Hypochloraemic, hyponatraemia with normal urea and ketones
5. Normal sodium, hyperchloraemia with elevated urea and normal ketones

Answer 1

3

Admission should be considered in cases of ketonuria and/or weight loss despite use of oral anitemetics

Question 2

What is the RCOG term used for problematic ‘morning sickness’ in pregnancy? How common is it?

Answer 2

NVP - nausea and vomiting of pregnancy

NVP affects 75% of pregnant women

Question 3

What is the extreme form of NVP?

Answer 3

Hyperemesis gravidarum

Question 4

How common is HG?

Answer 4

Affects 1% of pregnancies

Question 5

What is the aetiology of HG?

Answer 5

Thought to be linked to raised beta hCG levels, oestrogen and thyroxine. Likely cause is multifactorial.

Question 6

When is HG most common in pregnancy?

Answer 6

Between 8 -12 weeks but may persist up to 20 weeks (and very rarely beyond)

BMJ best practice: NVP typically begins at 4-7 weeks and resolves by second trimester.

Question 7

What are the risk factors for HG? What is a protective factor?

Answer 7

• multiple pregnancies
• trophoblastic disease
• triploidy, trisomy 21, and hydrops fetalis
• hyperthyroidism
• nulliparity
• obesity

Smoking is associated with decreased incidence of hyperemesis.

Question 8

What are the clinical features of hyperemesis gravidarum?

Answer 8

Dehydration - dry mucous membranes, increased HR, decreased cap refill time

Check for signs of hyperthyroidism.

Question 9

What investigations should be done in HG to guide management?

Answer 9

• Urinalysis
• U&Es
• Blood gas
• Weight measurement

Consider pelvic US if >5% weight loss to evaluate for the presence of multiple gestation, gestational trophoblastic disease, and hydrops fetalis.

Question 10

What is the RCOG triad of hyperemesis gravidarum?

Answer 10

• 5% pre-pregnancy weight loss
• dehydration
• electrolyte imbalance

Question 11

How can you classify the severity of HG?

Answer 11

Validated scoring systems such as the Pregnancy-Unique Quantification of Emesis (PUQE)

Question 12

What is the 1st line management of hyperemesis gravidarum?

Answer 12

Antihistamines e.g. oral cyclizine, promethazine or prochlorperazine

Question 13

What are the 2nd line options for hyperemesis gravidarum and what are the cautions with their use?

Answer 13

2nd line - ondansetron or metoclopramide

Cautions:

• Metoclopramide - do not use for >5 days as EPSEs may occur
• Ondansetron - small risk of cleft lip/palate if used in the first trimester; must discuss risks with patient.

Question 14

What are the final line treatments for hyperemesis gravidarum?

Answer 14

• Hydrocortisone 100mg BD IV - convert to oral prednisolone 40-50mg daily once tolerated, then taper the dose gradually until lowest maintenance dose is reached.
• Most severe cases: TOP

Question 15

What are some alternative therapies that may be tried (but have little evidence for use)?

Answer 15

Ginger and P6 (wrist) acupressure: CKS suggest these can be tried but there is little evidence of benefit

Question 16

What is given on admission to hospital in hyperemesis gravidarum?

Answer 16

• IV fluids -plasmalyte/0.9% sodium chloride solution; first give 1L stat then over extended periods.
• Pabrinex - thiamine replacement

Question 17

What are the complications of hyperemesis gravidarum?

Answer 17

To mother:

• Wernicke’s encephalopathy - due to malnutrition and vitamin deficiencies
• Mallory-Weiss tear - due to retching
• Central pontine myelinolysis
• Acute tubular necrosis

To fetus:

• Small for gestational age
• Pre-term birth