Ovarian hyperstimulation syndrome (OHSS)

Question 1

What is the incidence of OHSS?

Answer 1

0.6-33%

Question 2

What are some differential diagnoses for OHSS?

Answer 2

• Ovarian torsion
• Ovarian cyst accident
• Ectopic pregnancy
• Bowel perforation
• Pelvic infection and abscess
• Appendicitis

Question 3

Discuss the examination you would perform for a woman you suspect has OHSS:

Answer 3

General:

• Volume status
• Oedema
• Observations
• Body weight

Abdomen:

• Shifting dullness
• Distension/girth
• Mass
• Peritonism

Respiratory:

• Pleural effusion
• Pneumonia
• Pulmonary oedema

Pelvic:

• Palpable masses / ovaries
• Adnexal tenderness

Question 4

Discuss the investigations you would order for a woman you suspect has OHSS:

Answer 4

Bloods:

• FBC: haemoconcentration, elevated WCC
• U&Es: elevated Cr, electrolyte disturbance (hyponatremia, hyperkalaemia)
• LFTs: low albumin, abnormal enzymes
• Coags: elevated fibrinogen, reduced antithrombin
• CRP (severity)
• hCG (to determine if pregnant)

Imaging:
- Pelvic USS: ascities, ovarian size, other adnexal masses/collections, ?pregnancy

Adjuncts depending on clinical findings:

• ABG
• D-dimer
• ECG / ECHO
• CXR: pleural effusions, pulmonary oedema
• CTPA or V/Q Scan: PE

Question 5

Discuss your management of a woman with mild-moderate OHSS only:

Answer 5

• Outpatient management with review every 2-3 days.
• Review acutely if worsening.
• Prophylactic clexane.
• Drink at least 1L/day and measure urine output (at least 1L/day)
• Avoid NSAIDs (renal impairment)

Question 6

Discuss your management of a woman requiring inpatient management of OHSS:

Answer 6

MDT input: gynaecology, anaesthetic, ICU/HDU, renal physician, haematology, respiratory physician.

Monitoring:

• Regular obs Q4H at least: HR, BP, RR, O2 sats, temp.
• Strict fluid balance including measured voided urine or IDC for urine output.
• May require invasive monitoring in HDU/ICU if persistent haemoconcentration despite IVF replacement

Symptom relief:

• Analgesia; avoid NSAIDs.
• Drainage of tense ascites.

Prevent/correct haemoconcentration:

• Drink to thirst if possible.
• IVFs
• Avoid diuretics; may be indicated if persistent oliguria after adequate fluid replacement and drainage of ascites.

VTE prevention: prophylactic clexane.

Maintain cardiorespiratory and renal function:

• Drainage of pleural and pericardial effusions.
• Replacement albumin 25% 50-100g infused over 4 hours and repeated 4-12 hrly if large volume ascites drained.