Post-partum hyponatraemia

Question 1

A 28 year old female delivered her second baby 7 days ago, and returns with headache, confusion and a seizure. The plasma sodium is 117 mol/L. How would you investigate and manage her?

Answer 1

Impression
This is symptomatic postpartum hyponatraemia and given the severity of this presentation this warrants admission for urgent treatment and management, likely ICU disposition.

Concerned about this being due to Sheehan’s syndrome; is hypopituitarism in the context of pituitary necrosis secondary to ischaemia and hypovolaemic shock due to blood loss in the peri-partum period.

DDx
Hyponatraemia:
- Hypervolaemic: CCF, liver disease, renal disease, nephrotic syndrome
- Euvolaemic: SIADH, beer potomania, hypothyroidism
- Hypovolaemia: diuretics, mineralocorticoid deficiency, 3rd space losses

Seizures:

• eclampsia
• SOL
• other electrolyte derangement, BSL
• Drugs

Question 2

Sheehan’s syndrome - Assessment

Answer 2

Assessment

• ensure HD stability
• status pathway if non-remitting seizures

Question 3

Sheehan’s Syndrome - History

Answer 3

History

• Seizure: before, during, after (semiology)
• Sx: LOC, fever, abdo pain
• Sheehan Sx: difficulties breast feeding, altered mental status, cold intolerance, weakness, constipation
• O&G history: blood loss, complications, pregnancy details, type of delivery

Question 4

Sheehan’s Syndrome - Examination

Answer 4

Examination

• General inspection + vitals (hypotension)
• Neuro examination: seizures
• Hydration status

Question 5

Sheehan’s Syndrome - Investigations

Answer 5

Investigations
Key/diagnostic
- MRI for partial/complete pituitary loss
- Other SOL in consideration of ?seizure aetiology

Bedside: ECG, BSL, UA, urine sodium and urine osmolality
Bloods: FBC, UEC, LFT, TFT, pituitary panel; GH level (given growth hormone secreting cells are on the periphery of the AP, thereby most susceptible to ischaemia), serum osmolality, serum sodium
Imaging: MRI brain for empty sella

Question 6

Sheehan’s Syndrome - Management

Answer 6

Management
- Inpatient management with MDT (O&G, ICU, Surg)

Acute
- Seizure prevention/management
o Magnesium sulphate; status pathway if relevant
o diuresis if hypervolaemia
o fluid resus if hypovolaemic
o senior colleague discussion re appropriate re-hydration and administration of sodium to prevent complications (de-myelination and irreversible neurological injury)
- electrolyte replacement, careful administration of NS +/- hypertonic saline (risk of pontine demyelination with rapid correction)

Longterm
- endocrine referral for longterm hormonal replacement in view of ?Sheehan's syndrome);
   o Thyroid
   o Cortisol
   o Growth hormone