NOT PREGNANT OR BREASTFEEDING BUT MILK COMES OUT OF THE NIPPLE
The most common known nipple discharge is the breast milk, however, not all discharge of breast milk is normal, this depends on whether the woman is breastfeeding or not. Nipple discharge varies in volume, colour or number of ducts involved and these depends on the cause of the discharge. The discharge could also involve one or both breasts, it could be persistent or intermittent, spontaneous or expressive, it may or may not be associated with a breast mass.
BRIEF ANATOMY OF THE BREAST
The breast is a modified sebaceous gland located on the chest of both males and females. It is underdeveloped and has no function in the males. In the females it is well developed and serves the major function of milk production and might be an erogenous zone for some females. The breast is largely made up of fat, connective tissues, glands meant for milk production, ducts that drain the milk into a widened area called the lactiferous sinuses. The areola is the circular pigmented area at the tip of the breast, its colour depends on the skin colour of the woman. The areola also has some small elevations called the glands of Montgomery which are more prominent during pregnancy. These glands help to lubricate the breast to prevent cracks during breastfeeding. The lactiferous sinuses are located beneath the areola. The nipple is the small conical structure located at the tip of the breast and the ducts continue from the lactiferous sinuses and terminate at the nipple which is seen as the small punctate openings on the nipple.
CATEGORIES OF NIPPLE DISCHARGE
Nipple discharge can either be normal lactation, benign physiologic discharge or pathologic nipple discharge. Physical breast examination gives a lot of details used in categorising nipple discharge. The characteristics and causes of the various categories of nipple discharges are described below.
Lactation is the production, secretion and ejection of milk from the breast for the purpose of feeding babies. This might begin in early second trimester for some while for others, it might take more than 24 hours after delivery to begin. It involves both breasts, the colour of the breast milk is initially yellow then later it becomes whitish, it comes out from multiple ducts on the nipple, the volume is initially small but later increases in volume and becomes spontaneous even when the baby is not suckling. It may be associated with a swelling called galactocele; this develops during lactation due to blockage and subsequent dilatation of the lactiferous duct. The galactocele mass is soft, painless located around the areola. It resolves with message or can be aspirated by your doctor or excised if the mass persists. Breastfeeding should continue with the affected breast. The spontaneity of lactation has to do with the frequency of breastfeeding; if you feed your baby every 2 hours, the breast milk might start coming out spontaneously when it is time for another feeding. This is why you might hear breastfeeding mothers say ‘’my baby is crying’’ when their breast milk starts flowing and they are not around their babies. The act of suckling by the baby programs the brain to release hormones needed for milk production and let down. Discharge of breast milk might continue 6 months after cessation of breastfeeding.
BENIGN PHYSIOLOGIC NIPPLE DISCHARGE
This is also known as galactorrhoea, it is a milky discharge from the breast. It occurs in non-pregnant and non-breastfeeding females. It involves multiple ducts in both breasts and might be expressive or spontaneous. This is due to the increase in the level of the hormone called prolactin. This hormone is under the control of dopamine released by the hypothalamus which suppresses it. Certain physical activities, medications and medical conditions can increase the prolactin level above the normal range (20ng/ml) which might result in galactorrhoea.
CAUSES OF BENIGN PHYSIOLOGIC NIPPLE DISCHARGE
The following are possible causes of benign physiologic nipple discharge
- Chest wall stimulation; from breast examination, suckling the breast, nipple piercing, chest wall surgery, chest herpes zoster infection.
- Medications; some of which are phenothiazine, chlorpromazine, haloperidol, risperidone metoclopramide antidepressant, cimetidine, ranitidine, opiate, methyldopa.
- Medical conditions; chronic renal failure, hypothyroidism, liver cirrhosis, seizures.
- Tumours or radiation of the pituitary gland or hypothalamus
- Diseases that infiltrates the pituitary gland or hypothalamus; tuberculosis, sarcoidosis
High prolactin level may result in loss of ovulation, menstrual abnormalities and even infertility.
PATHOLOGIC NIPPLE DISCHARGES
They are usually unilateral, involving a single duct, spontaneous, pale yellow, pale yellow with tinge of blood, black or bloody with or without a mass. There may also be changes around the nipple-areola complex.
CAUSES OF PATHOLOGIC NIPPLE DISCHARGES
Below are the possible causes of pathologic nipple discharges
INTRADUCTAL PAPILLOMA; This arises from a lactiferous duct near the nipple, it is associated with a blood stained nipple discharge from a solitary duct and a lump might be absent. It can transform into a breast cancer.
DUCTAL ECTASIA; may arise from multiple ducts involving one or both breasts, the discharge may be persistent or intermittent, scanty or copious with a yellowish, brownish, greenish or blackish nipple discharge. A mass might be felt on the affected breast around the areola with associated pain and nipple retraction.
BENIGN MAMMARY DYSPLASIA; Also known as fibrocystic disease of the breast. It is common in women who have not given birth. Its aetiology is not clear however; it is believed to be due to the hypersensitivity of the breast epithelium to oestrogen. It is associated with a pale yellow or greenish nipple discharge, breast lump, a cyclical or non-cyclical breast pain.
DUCTAL CARCINOMA; Occurs when cancer cells fill up the breast ductal system. It is associated with a pale yellow or bloody nipple discharge and breast mass.
BREAST ABSCESS; is common during breastfeeding when bacteria infect the breast however, non-lactating females may have breast abscess through bacteria already in the blood circulation. It is associated with nipple discharge of pus, breast pain, fever and change in colour of the skin over the site of the abscess.
TREATMENT OF NIPPLE DISCHARGE
The treatment of nipple discharge depends on the type and cause of the discharge. Before adopting a treatment modality for you, your doctor will take detailed history from you and perform a physical breasts examination. Some investigation will also be carried out which will involve pregnancy test, thyroid function test, renal function test, prolactin level. Imaging tests such as ultrasound scan, mammography, ductography. Other tests include, fine needle aspiration under ultrasound guidance for cytology. These help to confirm the diagnosis and guide the definitive treatment modality which could be medical, surgical or both. It is very important to do a regular self-breasts examination as some of these conditions might be noticed early when the chance of complete recovery is high.
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