Ovarian hyperstimulation syndrome (Complete)

Question 1

Define OHSS

Answer 1

Exaggerated response to hormone therapies used in procedures such as IVF to induce ovulation

Question 2

How common is OHS in IVF procedures?

Answer 2

Occurs in 1/3rd of IVF cycles

3-8% present with moderate/severe presentations

Question 3

What is the aetiology of OHSS?

Answer 3

Exccessive response to hormonal therapies in IVF procedure

Causes multiple follicles to mature and enlarge

Results in multiple corpus luteums which secrete excess:

• Oestrogen
• Progestogen
• Local cytokines (especially VEGF)

Question 4

What fertility treatments are most associated with OHSS?

Answer 4

IVF

GnRH agonsists

hCG treatment

Clomifene less associated with OHSS

Question 5

What are the main risk factors fpr OHSS?

Answer 5

Young age

Lean

PCOS

History of multiple pregnancies

History of OHSS

Question 6

What are the main clinical featues of OHSS?

Answer 6

Demographic: Woman on fertility treatments (e.g. IVF)

Compression of nearby structures:

Bloating

Abdominal discomfort

Nausea and vomitting

VEGF:

Oedema

Pleural effusions

Ascites

Weight gain

Increased risk of thromboembolism

• DVT
• PE
• Stroke

Question 7

What are mild presentations of OHSS?

Answer 7

Abdominal discomfort

Bloating

Question 8

What are considered moderate presentations of OHSS?

Answer 8

As mild plus:

Nausea and vomitting

Ascites on US

Question 9

What are considered severe presentations of OHSS?

Answer 9

As mild/moderate plus:

Clinical ascites

Oliguria

Haematocrit >45%

Hypoproteinaemia

Question 10

What are considered critical presentations of OHSS?

Answer 10

Thromboembolism

ARDS

Tense ascites

Anuria

Question 11

What investigations should be conducted in woman presenting with OHSS?

Answer 11

Bedside:

Abdominal/bimanual examination: Feel for masses

Basic obs

Weight

Bloods:

FBC: Check for low haematocrit

U&Es: Check renal function

LFTs: Check for alternativ cause of ascites

Serum albumin: Check underlying cause of ascites (low albumin in OHSS)

Coagulation profile: Assess clotting risk

D-dimer: If thromboembolism suspected

Imaging:

CXR: Check for pleural effusion

Mainly routine bloods to check for organ dysfunction

Question 12

How are patients with OHSS managed?

Answer 12

Mainly conservative

Conservative:

Ongoing monitoring and supportive care

Analgesia (avoid NSAIDs due to impact on renal function)

Medicine:

Anti-emetics (e.g. cyclizine) if requred

LMWH: Reduce risk of thromboembolism