Case 50: Vomiting in pregnancy

 

Case 50: Vomiting in pregnancy

CASE 50: VOMITING IN PREGNANCY

History

A 28-year-old Asian woman is referred by her GP with persistent vomiting at 7 weeks’ gestation. She is in her second pregnancy having had a normal vaginal delivery 3 years ago. She is

now vomiting up to 10 times in 24 h, and has not managed to tolerate any food for 3 days. She

can only drink small amounts of water.

She saw her GP a week ago who prescribed oral prochlorperazine but these only helped for a

few days. She feels very weak in herself and is unable to care for her son now.

On direct questioning she has upper abdominal pain that is constant, sharp and burning. She

has not opened her bowels for 5 days. She is passing small amounts of dark urine infrequently

but there is no dysuria or haematuria. There has been no vaginal bleeding.

There is no other medical or gynaecological history of note except that she suffered persistent

vomiting in her first pregnancy requiring two overnight admissions.

Examination

She is apyrexial. Lying blood pressure is 115/68 mmHg and standing blood pressure 98/55 mmHg.

Heart rate is 96/min. The mucus membranes appear dry. Abdominal examination reveals tenderness in the epigastrium but no lower abdominal tenderness. The uterus is not palpable abdominally.

INVESTIGATIONS

Normal range for

pregnancy

Haemoglobin 11.1 g/dL 11–14 g/dL

Mean cell volume 90 fL 74.4–95 fL

White cell count 8.9×109/L 6–16×109/L

Platelets 298×109/L 150–400×109/L

Sodium 131 mmol/L 130–140 mmol/L

Potassium 3.0 mmol/L 3.3–4.1 mmol/L

Urea 8.2 mmol/L 2.4–4.3 mmol/L

Creatinine 65 mmol/L 34–82 mmol/L

Alanine transaminase 30 IU/L 6–32 IU/L

Alkaline phosphatase 276 IU/L 30–300 IU/L

Gamma glutamyl transaminase 17 IU/L 5–43 IU/L

Bilirubin 12 mmol/L 3–14 mmol/L

Albumin 34 g/L 28–37 g/L

Pregnancy test: positive

Urinalysis: protein negative; blood negative; nitrites negative; leucocytes negative;

ketones ++++; glucose negative

Questions

• What is the diagnosis?

• What are the potential complications of this disorder?

• How would you further investigate and manage this patient?100 Cases in Obstetrics and Gynaecology

128

ANSWER 50

The woman is suffering from hyperemesis gravidarum. This affects only less than 2 per cent

of pregnancies, although more than 50 per cent of women report some nausea or vomiting

when pregnant.

! Definition of hyperemesis gravidarum

Severe or protracted vomiting appearing for the first time before the 20th week of pregnancy that is not associated with other coincidental conditions and is of such severity as

to require the patient’s admission to hospital.

! Differential diagnosis of vomiting in early pregnancy

• Urinary tract infection

• Gastroenteritis

• Thyrotoxicosis

• Hepatitis

The diagnosis in this case can be made because the urinalysis is negative apart from the

ketones, so urinary tract infection is very unlikely. She has not opened her bowels but this is

likely to be secondary to poor dietary intake and dehydration. Liver function is normal, so

liver disease causing vomiting is unlikely (though abnormal liver function may occur as a

result of hyperemesis itself). Thyroid function is normal, so an alternative diagnosis of hyperthyroidism causing the vomiting is unlikely.

! Complications of hyperemesis gravidarum

• Wernicke’s encephalopathy (from vitamin B deficiency)

• Korsakoff’s syndrome (from vitamin B deficiency)

• Haematemesis (from Mallory-Weiss tear)

• Psychological – resentment toward the pregnancy and expression of desire to terminate the pregnancy

The fetus is not at risk from hyperemesis and the nutritional deficiency in the mother does

not seem to affect development. The risk of miscarriage is lower in women with hyperemesis.

The risk of twins and molar pregnancy has traditionally been thought to be greater in women

with hyperemesis, but this is refuted in more recent research.

Further investigation and management

Hyperemesis is a self-limiting disease and the aim of treatments is supportive, with discharge

of the woman once she is tolerating food and drink and is no longer ketotic on urinalysis.

Fluids: 3–4 L of normal saline should be infused per day. Dextrose solutions are contraindicated as they may precipitate Wernicke’s encephaolopathy and also because the

woman is hyponatraemic and needs normal saline.

Potassium: excessive vomiting generally leads to hypokalaemia, and potassium chloride should be administered with the normal saline according to the serum electrolyte results.Case 50: Vomiting in pregnancy

129

Antiemetics: first-line antiemetics include cyclizine (antihistamine), metoclopramide

(dopamine anatagonist) or prochlorperazine (phenothiazine). In severe cases,

ondansetron may be effective. There is no evidence of teratogenicity in humans from

any of these regimes.

Thiamine and folic acid: vitamin B1 (thiamine) can prevent Wernicke’s encephalopathy

or the irreversible Korsakoff’s syndrome (amnesia, confabulation, impaired learning ability).

Antacids: for epigastric pain.

Total parenteral nutrition (TPN): TPN is rarely indicated but may be life saving where

all other management strategies have failed.

Thromboembolic stockings (TEDS) and heparin: women with hyperemesis are at risk of

thrombosis from pregnancy, immobility and dehydration, and should be considered

for low-molecular-weight heparin regime as well as TEDS.

Monitoring

Daily monitoring should be carried out, with weight measurement and urinalysis for ketones

and renal and liver function.

KEY POINTS

• Hyperemesis gravidarum is a diagnosis of exclusion.

• There is generally no adverse effect on the fetus.

• Treatment is supportive.

• Thiamine replacement prevents Wernicke’s encephalopathy and Korsakoff’s

syndrome