Diagnosis of OHSS

Question 1

Early OHSS

Answer 1

Within 7 days of the hCG injection and is

usually associated with an excessive ovarian response

Question 2

Late OHSS

Answer 2

Typically presents 10 or more days after the hCG injection and is usually the result of endogenous hCG derived from an early pregnancy

Question 3

Initial investigations in OHSS

Answer 3

• Full blood count
• Haematocrit (haemoconcentration)
• C-reactive protein (severity)
• Urea and electrolytes (hyponatraemia and hyperkalaemia)
• Serum osmolality (hypo-osmolality)
• Liver function tests (elevated enzymes and reduced albumin)
• Coagulation profile (elevated fibrinogen and reduced antithrombin)
• hCG (to determine outcome of treatment cycle) if appropriate
• Ultrasound scan: ovarian size, pelvic and abdominal free fluid
• Consider ovarian Doppler if torsion suspected

Question 4

Differential diagnoses of OHSS

Answer 4

• Pelvic infection
• Pelvic abscess
• Appendicitis
• Ovarian torsion or cyst rupture
• Bowel perforation
• Ectopic pregnancy
  It is not commonly associated with severe pain, pyrexia or signs of peritonism

Question 5

Relevant history for OHSS

Answer 5

• Time of onset of symptoms relative to trigger
• Medication used for trigger (hCG or GnRH agonist)
• Number of follicles on final monitoring scan
• Number of eggs collected
• Were embryos replaced and how many?
• Polycystic ovary syndrome diagnosis?

Question 6

Relevant symptoms for OHSS

Answer 6

• Abdominal bloating
• Abdominal discomfort/pain, need for analgesia
• Nausea and vomiting
• Breathlessness, inability to lie flat or talk in full sentences
• Reduced urine output
• Leg swelling
• Vulval swelling
• Associated comorbidities such as thrombosis

Question 7

Examination in OHSS: General

Answer 7

• Assess for dehydration
• Oedema (pedal, vulval and sacral)
• Record heart rate, respiratory rate, blood pressure, body weight

Question 8

Examination in OHSS: Abdominal

Answer 8

• Assess for ascites, palpable mass, peritonism

- Measure girth

Question 9

Examination in OHSS: Respiratory

Answer 9

• Assess for pleural effusion, pneumonia, pulmonary oedema

Question 10

Extra investigation which may be required in OHSS

Answer 10

• Arterial blood gases
• D-dimers
• Electrocardiogram (ECG)/echocardiogram
• Chest X-ray
• Computerised tomography pulmonary angiogram (CTPA) or ventilation/perfusion (V/Q) scan