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Obstetrics Simplified - Diaa M. EI-Mowafi

Hyperemesis Gravidarum

Definitions

  • Morning sickness: is the nausea felt by about 50% of pregnant women on getting up in the morning.
  • Emesis gravidarum: Actual vomiting in the morning.
  • These two conditions usually start between the 4th and 6th weeks of pregnancy and improves or disappears about the 12 th week.
  • Hyperemesis gravidarum: The vomiting is not confined to the morning but it is repeated throughout the day until it affects the general condition of the patient.

Incidence

1:500 pregnancies.

Aetiology

The following theories were postulated:

  • Hormonal: high human chorionic gonadotrophin (hCG) stimulates the chemoreceptor trigger zone in the brain stem including the vomiting center. This is the most accepted theory and proved by the higher frequency in the conditions where the hCG is high as in:-
    • early in pregnancy,
    • vesicular mole and
    • multiple pregnancy.
  • Allergy: to the corpus luteum or the released hormones.
  • Deficiency of:
    • adrenocortical hormone and /or,
    • vitamin B6 and B1
  • Nervous and psychological: due to
    • psychological rejection of an unwanted pregnancy,
    • fear of pregnancy or labour so it is more common in primigravidae.

Pathological Changes:

These are the same as in prolonged starvation:

  • Liver: small fatty infiltration.
  • Kidney: fatty degeneration of the convoluted tubules.
  • Heart: small subendocardial and subpericardial haemorrhages.
  • Brain: congestion and petechial haemorrhages in the brain stem resembling that of Wernicke’s encephalopathy.
  • Eye: optic neuritis and retinal haemorrhage.
  • Peripheral nerves: degeneration.
  • Blood:
    • Hypovolaemia and haemoconcentration.
    • Hyponatraemia, hypokalaemia and hypochloraemia.
    • Increased blood urea.
    • Hyperbilirubinaemia (due to liver damage).
    • Acidosis.
  • Urine:
    • Oliguria.
    • Increased specific gravity.
    • Decreased chloride.
    • Albuminuria.
    • Ketonuria.

Diagnosis

Symptoms

  • The patient cannot retain anything in her stomach, vomiting occurs through the day and night even without eating.
  • Thirst, constipation and oliguria.
  • In severe cases, vomitus is bile and/ or blood stained.
  • Finally, there is manifestations of Werniche’s encephalopathy as drowsiness, nystagmus and loss of vision then coma.

Signs

Manifestations of starvation and dehydration:

  • Loss of weight.
  • Sunken eyes.
  • Dry tongue and inelastic skin.
  • Pulse: rapid and weak.
  • Blood pressure: low.
  • Temperature: slight rise.

Differential diagnosis

Other causes of vomiting as:

  • cholecystitis,
  • appendicitis,
  • pyelonephritis,
  • gastroenteritis,
  • gall bladder diseases,
  • complicated ovarian tumours.

Management

Hospitalisation

For observation, fluid therapy and competition of neurosis.

Intravenous fluids

  • Oral feeding is prevented for 24-48 hours.
  • Three litres of glucose 5% is given by rapid infusion over 2-3 hours.
  • Maintain intravenous glucose 5% and saline therapy.
  • When vomiting is controlled frequent gradual small carbohydrate diets are started.

Drugs

  • Adrenocortical preparations.
  • Vit. B6 and Vit. B1.
  • Antihistaminics that have antiemetic effect as meclozine hydrochloride 25-50 mg twice daily. A preparation contains both meclozine hydrochloride + pyridoxine hydrochloride (vit. B6) is of good benefit.
  • Phenothiazine (chlorpromazine=largactil) 5-10 mg three times daily has a tranquilliser and antiemetic effect.

Observation for:

  • Vomiting: frequency, amount, colour and contents.
  • Vital signs: pulse, temperature and blood pressure.
  • Fluid: intake and output.
  • Urine analysis: specific gravity, albumin, ketone bodies, chloride and bile pigments.
  • Blood: urea, electrolyte and liver function tests.
  • Eye: examination of the fundus.

Termination of pregnancy

Indications:

  • Persistent severe vomiting after one week of treatment.
  • Pulse is persistently above 100/min, temperature persistently above 38oC or the systolic blood pressure is persistently below 100 mmHg.
  • Jaundice or bile in urine.
  • Anuria, absence of chloride in urine, persistent albuminuria or high blood urea.
  • Retinal haemorrhage or Wernicke’s encephalopathy .
  • Methods of termination:
  • Vaginal evacuation: if pregnancy is less than 12 weeks.
  • Abdominal hysterotomy: if pregnancy is more than 12 weeks. Use nitrous oxide + oxygen for anaesthesia but not agents that affect liver as halothane. Prostaglandins cannot be used as it will aggravate the vomiting.

N.B. mild case of hyperemesis gravidarum, i.e. without dehydration can be treated as an outpatient with the same drugs. If not responding admit to the hospital.

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