Galactorrhoea

Aetiology

The most common cause of galactorrhoea is hyperprolactinaemia – causes of hyperprolactinaemic galactorrhoea include:

• Idiopathic – accounts for approximately 40% of cases
• Pituitary Adenoma– benign tumours of the pituitary gland, known as prolactinomas, can secrete excessive prolactin
• Drug-Induced – medications such as SSRIs, antipsychotics, and H2-antagonists can stimulate prolactin release
• Neurological – neurogenic stimulation that inhibits dopamine, such as from varicella zoster infection or spinal cord injury
• Hypothyroidism -elevated thyrotropin-releasing hormone can increase prolactin levels
  • Other endocrine disorders such as Cushing’s disease, acromegaly, and Addison’s disease have also been linked
• Renal Failure or Liver Failure
• Damage to the pituitary stalk, leading to reduced dopamine inhibition to the pituitary, from surgical resection, multiple sclerosis, sarcoidosis, or tuberculosis

Normoprolactinaemic galactorrhoea is less common and typically idiopathic. Diagnosis is made only after excluding all other causes (e.g. normal serum markers and regular menstruation). These patients can often be safely reassured and monitored.

Clinical Features

It is important to determine the presence of true galactorrhoea* (multi-ductal milky white nipple discharge, typically bilateral), not alternative nipple discharge that could signal an alternative diagnosis.

Clarify any additional features, such as breast lumps, mastalgia, and their last menstrual period, to assess for potential underlying causes or an alternative diagnosis. Ask about features of endocrine disease and for neurological symptoms, such as headaches or visual disturbances

Ensure to take an adequate drug history, including any form of contraception, over the counter medication, or recreational drug use.

Breast examination is often unremarkable. Check for any visual changes (suggestive of compressive pituitary masses) or features of hypothyroidism.

*A Sudan IV stain for fat droplets in the discharge can be used to confirm galactorrhoea, however is rarely used in clinical practice

Investigations

Pregnancy must be excluded in all women of reproductive age as a first step in the evaluation of galactorrhoea.

Following this, patients should undergo serum prolactin testing, along with comprehensive assessments of thyroid, liver, and renal function. If the clinical history or physical examination indicates a possible endocrine disorder, additional hormonal investigations, such as IGF-1 or ACTH, may be appropriate.

In cases where a pituitary tumour or parasellar pathology is suspected, MRI imaging of the head with intravenous contrast is essential for further evaluation. Further appropriate investigations should also be considered if there are any palpable lumps or lymphadenopathy.

*Prolactin levels exceeding 1000 mU/L, in the absence of a drug-related cause, are strongly suggestive of a prolactinoma

Philippe Chanson and Sylvie Salenave [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

Figure 1
MRI scan showing a pituitary macroadenoma with suprasellar extension

Management

Effective management of galactorrhoea requires the identifying and addressing of the underlying cause.

For patients diagnosed with pituitary tumours, treatment typically begins with dopamine agonist therapy, commonly using agents such as Cabergoline or Bromocriptine. These individuals should also be referred to neurosurgery for evaluation, as trans-sphenoidal surgery may be warranted depending on the tumour’s size and impact.

Idiopathic normoprolactinaemic galactorrhoea often resolves without intervention. However, if symptoms persist, a trial of low-dose dopamine agonist therapy may be beneficial.

In cases where galactorrhoea is particularly troublesome and patients are unable to tolerate medical treatment, surgical intervention, specifically bilateral total duct excision, may be considered.