B14. Ovarian hyperstimulation syndrome

Ovarian hyperstimulation syndrome (OHSS) is a complication of the ovarian hyperstimulation which occurs during fertility treatments.

It is characterised by enlarged ovaries, increased vascular permeability, and third spacing of fluid from the vessels to the abdominal, pleural, and pericardial cavities. This can cause hydrothorax, pericardial effusion, and haemoconcentration. These features are caused by high exogenous levels of hCG.

Patients who become pregnant from the procedure have severe course of the disease, as the addition of endogenous hCG worsens the pathophysiology.

Risk factors

• Previous OHSS
• PCOS
• High number of follicles

Clinical features

Symptoms can vary from mild symptoms and discomfort to multi organ failure and death. Possible symptoms:

• Mild
  • Nausea
  • Abdominal pain
• Moderate
  • Ascites
  • Hypoproteinaemia
• Severe
  • Hypoxia
  • Oliguria
  • Hypovolaemia
  • Thromboembolism
• Critical
  • Acute kidney injury
  • Respiratory failure
  • DIC

Diagnosis and evaluation

The diagnosis is based on typical clinical features after artificial reproduction, especially when transvaginal ultrasound shows pelvic fluid.

Treatment

The condition is self-limiting but the patient needs supportive treatment to get through the problematic period. The treatment depends on the severity.

The standard of care include intravenous fluids for hypovolaemia, aspirin and LMWH to prevent thromboembolism, and close monitoring.

Severe and critical cases require hospitalisation with fluid resuscitation, albumin administration, abdominocentesis, and ICU monitoring.

Abdominocentesis, drainage of peritoneal fluid, is simple and effective in treating symptoms, but it can worsen the condition by causing even more fluid to be lost from the intravascular space. It should be avoided when possible, and if performed we should drain less than 1,5 litres.