Merck Manual

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Some Autoimmune Disorders

Some Autoimmune Disorders


Main Tissues Affected


Red blood cells

Anemia (decreased number of red blood cells) develops, causing fatigue, weakness, and light-headedness.

The spleen may enlarge.

The anemia can be severe and even fatal.


Large blisters, surrounded by red, swollen areas, form on the skin. Itching is common.

The disorder affects mainly older people and can be life threatening, especially in older people who have other disorders.

Beta cells of the pancreas (which produce insulin)

Symptoms may include excessive thirst, urination, and appetite, as well as various long-term complications.

Lifelong treatment with insulin is needed, even if the destruction of pancreatic cells stops, because not enough pancreatic cells remain to produce enough insulin.

The prognosis varies greatly and tends to be worse when the disease is severe and lasts a long time.

Lungs and kidneys

Symptoms, such as shortness of breath, coughing up blood, fatigue, and swelling, may develop.

The prognosis is good if treatment begins before severe lung or kidney damage occurs.

Thyroid gland

The thyroid gland is stimulated and enlarged, resulting in high levels of thyroid hormones (hyperthyroidism).

Symptoms may include a rapid heart rate, intolerance of heat, tremor, weight loss, and nervousness.

With treatment, the prognosis is good.

Thyroid gland

The thyroid gland is inflamed and damaged, resulting in low levels of thyroid hormones (hypothyroidism).

Symptoms may include weight gain, coarse skin, intolerance of cold, and drowsiness.

Lifelong treatment with thyroid hormone is necessary and usually relieves the symptoms completely.

Brain and spinal cord

The covering of affected nerve cells is damaged. As a result, the cells cannot conduct nerve signals normally.

Symptoms may include weakness, abnormal sensations, vertigo, problems with vision, muscle spasms, and incontinence. Symptoms vary over time and may come and go.

The prognosis varies.

The connection between nerves and muscles (neuromuscular junction)

Muscles, particularly those of the eyes, weaken and tire easily, but the weakness varies in intensity. The pattern of progression varies widely.

Drugs can usually control the symptoms.


Large blisters form on the skin and mucous membranes (such as those lining of the mouth).

The disorder can be life threatening if untreated.

Certain cells in the stomach's lining

Damage to cells in the stomach's lining makes absorbing vitamin B12 difficult. (Vitamin B12 is necessary for the production of mature blood cells and the maintenance of nerve cells.) Anemia results, often causing fatigue, weakness, and light-headedness. Nerves can be damaged, resulting in weakness and loss of sensation.

Without treatment, the spinal cord may be damaged, eventually contributing to loss of sensation, weakness, and incontinence.

The risk of stomach cancer is increased. Otherwise, with treatment, the prognosis is good.

Joints or other tissues, such as lung, nerve, skin, and heart tissue

Many symptoms are possible. They include fever, fatigue, joint pain, joint stiffness, deformed joints, shortness of breath, loss of sensation, weakness, rashes, chest pain, and swollen joints and tendons.

The prognosis varies.

Joints, kidneys, skin, lungs, heart, brain, and blood cells

The joints, although inflamed, do not become deformed.

Symptoms of anemia, such as fatigue, weakness, and light-headedness, and those of kidney, lung, or heart disorders, such as fatigue, shortness of breath, itching, and chest pain, may occur.

A rash may develop.

Hair loss is common.

The prognosis varies widely, but most people can lead an active life despite occasional flare-ups of lupus.

Blood vessels

Vasculitis can affect blood vessels in one part of the body (such as the nerves, head, skin, kidneys, lungs, or intestine) or several parts. There are several types.

Symptoms (such as rashes, abdominal pain, weight loss, difficulty breathing, cough, chest pain, headache, loss of vision, and symptoms of nerve damage or kidney failure) depend on which part of the body is affected.

The prognosis depends on the cause and how much tissue is damaged. Usually, the prognosis is much better with treatment.