Ovarian Hyperstimulation Syndrome Flashcards
Ovarian Hyperstimulation Syndrome
Oedema caused by ovarian stimulation during IVF treatment
Pathophysiology of ovarian hyperstimulation syndrome
Increase in vascular endothelial growth factor released by the granulosa cells of the follicles
VEGF increases vascular permeability causing fluid to move out of the capillaries into the extra vascular space
Causes oedema, ascites and hypovolaemia
What causes ovarian hyperstimulation syndrome
Gonadotropins stimulate multiple follicles to develop
HCG stimulates the release of VEGF from the follicles
When do features of ovarian hyperstimulation syndrome occur
After the trigger injection (HCG injection)
Effect on renin angiotensin system
Activates the renin angiotensin system - raised renin levels (levels correlate to severity)
Risk factors for ovarian hyperstimulation syndrome
Younger age
Lower BMI
Raised anti-Müllerian hormone
Higher antral follicle count
Polycystic ovarian syndrome
Raised oestrogen levels during ovarian stimulation
Prevention of ovarian hyperstimulation syndrome
Risk assessment
Monitoring via serum oestrogen levels and USS
If high risk:
- Use of the GnRH antagonist protocol (rather than the GnRH agonist protocol)
- Lower doses of gonadotrophins
- Lower dose of the hCG injection
- Alternatives to the hCG injection (i.e. a GnRH agonist or LH)
Monitoring for ovarian hyperstimulation syndrome
Serum oestrogen levels - higher levels indicate a higher risk
Ultrasound monitor of the follicles - higher number and larger size indicate a higher risk
Features of ovarian hyperstimulation syndrome
Abdominal pain and bloating
Nausea and vomiting
Diarrhoea
Hypotension
Hypovolaemia
Ascites
Pleural effusions
Renal failure
Peritonitis from rupturing follicles releasing blood
Prothrombotic state (risk of DVT and PE)
When does early OHSS presents
Presents within 7 days of the HCG injection
When does late ovarian hyperstimulation syndrome occur
Presents from 10 days of the HCG injection
Severity of ovarian hyperstimulation syndrome
Mild: Abdominal pain and bloating
Moderate: Nausea and vomiting with ascites seen on ultrasound
Severe: Ascites, low urine output (oliguria), low serum albumin, high potassium and raised haematocrit (>45%)
Critical: Tense ascites, no urine output (anuria), thromboembolism and acute respiratory distress syndrome (ARDS)
Management of ovarian hyperstimulation syndrome
Supportive with treatment of any complications.
This involves:
Oral fluids
Monitoring of urine output
Low molecular weight heparin (to prevent thromboembolism)
Ascitic fluid removal (paracentesis) if required
IV colloids (e.g. human albumin solution)
Management of severe OHSS
rrquire admission
Critical cases may require admission to the intensive care unit (ICU)
