A closer look at breast inflammation and fever

Inflammation is a vital part of your immune system's healthy function

Inflammation is the way our immune system cares for our body, keeping the myriad different elements of our immune system in balance in ways that are invisible to us, so that our tissues remain healthy and resilient.

Inflammation is our body’s protective response. Inflammation both responds to, and is triggered by, many down-regulating or up-regulating feedback loops. These feedback loops apply to the various kinds of immune cells and clotting proteins, as well as to networks of signalling molecules.

• Normal healthy inflammation inside our body cleans up debri from our own cells or macromolecules, often because they are damaged, such as in an arthritis, or in a lactating breast when a milk gland breaks down.

• Normal healthy inflammation removes random stray cells which might go rogue if they were to remain in our tissues.

• Inflammation also heals wounds in, or damage to the integrity of, our skin and organs.

• An inflammatory response is launched in response to something coming in from outside our body, such as a foreign body or microbes.

Inflammation needs to be in balance and not overactive if we are to remain well

Consistent over-activity of the inflammatory response can create disease in our bodies. Inflammation is like the engine of the immune system, which needs to keep purring along, homeostatically stable through a myriad feedback loops. But if elements of the inflammation get out of control and start to dominante, disease can result.

A very concerning kind of inflammation known as an auto-immune disease occurs as an out-of-balance reaction to the body's own living cells.

Once an inflammatory response has intensified in a localised part of the body, it will emerge somewhere on a spectrum from acute to chronic.

The five signs of acute inflammation

1. Pain, which results when a build-up of fluid leads to swelling, and swollen tissues push against sensitive nerve endings.

2. Redness, which occurs when there is an increased blood flow to the area, which is the inflammatory response bringing in immune factors.

3. Heat, which is another result of this increased blood flow.

4. Swelling, which results from both the dilation of the tiny blood vessels in your tissues (capillaries and venules). Swelling is also a result of inflammatory factors defusing out through leaky walls of the capillaries into the surrounding tissue.

5. Loss of function, which occurs because of the impact of pain, redness, heat and swelling on bodily tissues. In the breast, this is the way inflammation causes worsening cycles of tissue breakdown.

Sometimes these signs aren’t present yet even though your body has begun to launch an inflammatory response. At other times, inflammation causes tiredness, unwell feelings, or fever. Inflammation also results in increased levels of biomarkers including C-reactive protein (CRP).

Inflammation can become severe and end-stage

• An area of focussed inflammation which doesn’t resolve might result in an abscess, which is the body’s way of walling off the area of infection and broken down tissue, and attempting to ensure it doesn’t continue to affect the rest of the body. The relationship between inflammation and infection is complex. An infection results when elements of the microbiome or an external organism overwhelm our immune system's healing inflammatory response.

• An abscess, if left untreated, gradually acts upon the overlying skin to damage it. 'Pointing' of the abscess results, and when the skin breaks down completely, pus from the abscess leaks to the outside world through a fistula.

Sometimes, acute inflammation can develop into a septicaemia, which is infection spreading throughout the whole of the body via the blood stream. Septicaemia was often fatal before the advent of antibiotics.

Fever

The high body temperatures of fever make certain proteins more active, which then switch on the genes which activate the white cells, your immune system's powerful healing cells.

Too much use of medications which dial down fever can actually get in the way of your fever activating your immune system. Fever is an ancient part of your immune response, and it's doing good. That's not to say that you won't use paracetamol sometimes, but you don't need to be taking medication every four hours to try to stop the fever.

When do the normal inflammatory processes of a lactating breast become problematic?

The lactating breast is in a state of dynamic homeostasis. This means that the environment of your breasts are constantly changing. Your breasts' immune system has multiple feedback loops operainge to keep it stable, constantly downregulating or upregulating small imbalances. Breast inflammation emerges when one or various feedback loops become out of balance.

Inflammation itself is a set of feedback loops designed to address the disruption and re-assert equilibrium.

• Neutrophils and macrophages are the first rapidly induced defense strategy.

• Chemical messengers such as cytokines and chemokines secreted by neutrophils and macrophages lead to the eradication of antigens. 1

Two main mechanisms interact together to cause a cascade of worsening inflammation: ductal occlusion, and worsening positive pressure within the glandular and ductal systems. Here are things it helps to know.

• Two-thirds of the glandular tissue of the lactating breast is found within a three-centimetre radius of the nipple base, and ultrasound imaging has shown that milk ducts are very easily compressed by light pressure, similar to the way light touch compresses the veins on the back of your hand.20-22 These ducts which are visible in a woman's breast tissue with imaging are the largest possible milk ducts. Imagine how easily the tiny branches are pressed shut, deeper within the breast!

• Ducts are not storage vessels. They lie empty and even squashed shut for some time after milk has been removed.

• Lactocytes constantly secrete milk into the alveolar lumens. A small amount of milk might also flow into and accumulate in the ducts, under the slightly positive pressure of milk secretion within the alveoli.

• Milk is removed from the breasts by the intermittent negative pressure of suckling and the intermittent positive pressure of milk ejection in the ductal system, working in tandem. Sometimes breasts leak milk in the absence of suckling, due to positive pressure of milk ejection, although in the absence of suckling some backflow of the milk in the ducts is also evident with milk ejection.

• Milk ejection results in contraction of alveoli and dilation of the ducts.

• Occlusion of the ducts in response to mechanical pressure from the outside interferes with the capacity of milk to be removed from areas of the breast because the duct is compressed, even when exposed to the negative pressure of suckling.

• If milk can’t be extracted from a duct, the cavity inside the gland into which the lactocytes secrete milk fills and become very dilated. This places the junctions between the lactocytes under severe mechanical stress, causing the release of inflammatory factors.2 An inflammatory cascade in the connective tissue or stroma surrounding the glandular tissue is triggered.

• The resultant dilated capillaries and swelling caused by the inflammation then further worsens ductal occlusion, which worsens milk back pressure and inflammation.

The fever of breast inflammation

Fever is an important part of our breasts' immune response to stress. When there is enough inflammation happening in your breasts, fever is activated. This doesn't mean you have an infection, although it does mean that you have active and acute inflammation, which requires a lot of attention and care from both others and yourself, so that it heals and doesn't keep worsening.

Stopping the fever doesn't help heal a visible, painful inflammation in the breast, despite what you might have heard. Stopping the fever too much with anti-inflammatories or paracetamol might even slow down healing.