Autoimmune hypophysitis (AH or lymphocytic hypophysotis) is chronic inflammation of the pituitary gland. This causes the gland to become larger in size and less effective. AH is rare, and the course of the disease can take multiple routes. Over time:
- the gland can get bigger (enlarge);
- it can influence other glands in the endocrine and immune system (infiltration);
- it may become progressive and destructive (gland atrophy and fibrosis);
- or AH can resolve completely on its own.
In all cases, antibodies that target the pituitary gland can be detected and appear to be the cause of the condition. Patients with AH often have a family history of autoimmunity or active autoimmune diseases such as lupus.
It is rare to see AH alongside SLE. It can happen and the two appear to be related and can occur in the same person. In this case study, it was a 66-year-old man, but AH, like SLE, occurs most frequently in women. Both conditions also respond well to the same treatments and are affected by the same factors, especially pregnancy.
What is the Pituitary Gland?
The pituitary gland is an organ that acts as a sort of regulator for the other hormone-producing glands in the body. It is located at the base of the brain just behind the bridge of the nose. In healthy individuals, it is about the size of a pea.
Hormones are chemical messengers that the body uses to communicate between its cells. Which allow for the cooperation and coordination that the body needs to live. The hormones secreted by the pituitary gland control the thyroid, adrenal glands, ovaries and testis, among others. Read more about the thyroid and lupus, here.
The pituitary gland is managed by the hypothalamus, the part of the brain that detects and helps to balance out the basics of life, such as temperature regulation, hunger and thirst, sleep and wake. When the hypothalamus detects an imbalance (such as a lack of available energy, a chill, or a need for hydration) it sends signals to the pituitary gland. The pituitary gland then sends out hormonal messages to other organs in the body to get them to act in a way that resolves the issue. This can include encouraging food-seeking behavior and digestion or drinking water, sweating, or narrowing blood vessels in contact with the surface of the skin, depending on the issue. These all happen without conscious thought, but are essential to life.
Because it is so central to how these organs function, when something happens to the pituitary gland, as in AH, a whole range of basic life needs and behaviors can be affected. This includes sleep, energy levels, and appetite.
Autoimmune Hypophysitis, Lupus, and Pregnancy
Autoimmune hypophysitis is heavily associated with pregnancy, both before birth and postpartum. However, it does not seem to cause complications, or lead to issues with future pregnancies. The reason behind this association with pregnancy might have something to do with changes that the pituitary gland goes through during pregnancy. Because it increases in size and takes in more blood, it may be more vulnerable to or more likely to be exposed to attacks by the immune system.
Other changes also happen with the immune system during pregnancy. However, with SLE, these can be unpredictable and unique to each individual. Whether a person with SLE experiences a pregnancy-related symptom flare, reduced symptoms, or no change seems to be up to luck
Symptoms of Autoimmune Hypophysitis
Autoimmune hypophysitis has a range of symptoms caused by different aspects of the condition, both the physical and the chemical.
- As the pituitary gland swells in this condition, the pressure causes some of the classic symptoms, including headaches and Vision Problems, usually lessened sight. Headache and visual field alterations (the physical symptoms) are the most frequent symptoms. AH is usually diagnosed through pituitary biopsy, which is a small sample taken from the organ and assessed in the lab. Usually, this is done by going in through the nostril and is generally a safe procedure.
- As the pituitary gland comes under attack, it cannot produce enough pituitary hormones. Which regulate other hormone-producing organs in the body. These symptoms mimic hypoadrenalism, hypothyroidism, and hypogonadism. A part of this is that, postpartum, the new mother may be unable to lactate, a very visible symptom. Nausea, however, can be mistaken for morning sickness, a symptom or side effect of pregnancy.
Diabetes insipidus is another consequence of the reduced pituitary hormones. Diabetes insipidus is a fluid imbalance unrelated to diabetes mellitus (the one usually referred to as ‘diabetes.’) The kidneys do not filter the blood properly, and the body does not sense its water levels appropriately. This leads to frequent and diluted urination and hard-to-quench thirst. It must be managed to prevent dehydration and inappropriate urination and relieve uncomfortable thirst. Because the pituitary gland influences water balance and regulation, AH can lead to diabetes insipidus.
When AH resolves either on its own or through treatment, diabetes insipidus and the other symptoms may also resolve as hormone regulation returns to normal.
Treating Autoimmune Hypophysitis
Iilimumab is a monoclonal antibody that stimulates the immune system to attack T-lymphocyte antigen 4. This turns the immune system against tumors, making it an effective anticancer therapy. However, this also can lead to increased immune activity, increased immune sensitivity, and potentially autoimmune disease as the immune system ramps up its activity and what it chooses to attack. People taking monoclonals should keep an eye out for AH. Read more about monoclonal antibodies and lupus, here.
Glucocorticoids can be effective for treating AH, both because they are anti-inflammatory and because they make up for the reduced adrenal function. Azathioprine and methotrexate are also effective, especially for people who cannot safely use glucocorticoids.
In some cases, it resolves itself (or enters remission) without treatment.
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