To find out, discover more about autoimmune diseases here. After the birth of her second child, Sapna found it unusually difficult to lose the body weight, despite starting a rigorous diet and exercise program. She also found herself forgetting important things, like where she put her car keys, pediatrician appointments, or a scheduled lunch with friends.

Says the usually slim and organized Ritu mother of two, now 41, "I was mystified. I had to write everything down on a calendar in my kitchen, or I would immediately forget it. I was feeling moody. I was eating well, exercising, and not losing a pound. And I slept 10 hours a night. But every afternoon, I had to take a long nap just to get enough energy to get up off the couch and make dinner." According to Sapna, "Most nights, I fell into bed exhausted as soon as the kids were tucked in."

After a doctor dismissed her symptoms as fatigue normal for a busy mother, Sapna sought a second opinion. The second doctor ran blood tests, including thyroid antibody tests, and diagnosed her with Hashimoto's Thyroiditis, an autoimmune form of hypothyroidism, an underactive thyroid. The doctor prescribed thyroid hormone replacement.

"After a few weeks," says Sapna, "I noticed the difference in my energy and mood, started losing weight again, stopped napping, wasn't forgetting every single appointment. I felt so much better. It was a shock that this gland I barely knew existed could have such an impact on my life!"

Sapna's problem, Hashimoto's Thyroiditis, is one of the most common autoimmune diseases.

"Autoimmune disease" refers to a category of more than 80 chronic illnesses, each very different in nature, that can affect everything from the endocrine glands -- like the thyroid -- to organs like the kidneys, to the digestive system. Underlying all autoimmune conditions is the concept of autoimmunity.

The immune system provides protection against a variety of potentially damaging substances that can invade the body. These substances include disease-causing organisms, such as bacteria, fungi, parasites, and viruses. The body's ability to resist these invaders is called immunity. A key feature of the immune system is its ability to destroy foreign invaders while leaving the body's own healthy tissues alone. Sometimes, however, the immune system attacks and damages these healthy tissues. This reaction is called an autoimmune response or autoimmunity. In the nutshell, Autoimmunity refers to the process by which the immune system gets confused, and rather than protecting organs and cells, turns around and actually attacks those same organs and cells, producing inflammatory reactions and other serious symptoms and diseases.

Autoimmune diseases predominantly strike women, suffering about 75 percent of all autoimmune diseases according to the research conducted worldwide. Autoimmune diseases are more common during childbearing years, and frequently appear in women who have just had a baby, after periods of high emotional or physical stress or accidents, during periods of hormonal change such as pre-menopause, and after starting the Pill or hormone replacement therapy.

Autoimmune diseases also can run in families. If a close family member has an autoimmune disease, then the risk of developing an autoimmune disease is also somewhat increased. Having one autoimmune disease increases the risk slightly of developing another autoimmune condition.

The following is a partial checklist of frequently noticed symptoms of the most common autoimmune conditions. This list is by no means exhaustive, but it covers many of the common autoimmune symptoms and conditions. Carefully filling out this checklist and taking it to your doctor can be an important first step in getting appropriate testing and the right medical diagnosis.

The brief description of the symptoms common to autoimmune diseases are:

Fatigue: It's not a good fatigue, from working hard, but an anxious, uncomfortable fatigue related to lack of sleep. Or a disruption of the energy production mechanism in cells, either from lack of oxygen, increased toxicity, infections or a malfunction of the cells.

Sleep Disturbance: About 80 percent of affected people may wake up three or four times a night or in some cases don't wake up, but in the morning you still feel like a truck ran over you.

Short Term Memory Loss: Because of the low thyroid and heart complications typical in autoimmune diseases, there is a decrease in blood flow to the left lobe of the brain causing an oxygen deficiency in the brain. This can lead to the memory loss and forgetfulness that is common in autoimmune diseases.

Emotional Liability: Someone may cry more easily, be more anxious and fearful. This is caused by the illness, and is not a psychological reaction! Irritability, anxiety and depression

Depression: As with the emotional symptoms, the hypothalamus is involved. This is not clinical depression, but literally has a physical cause that is sometimes experienced as a deep depression right in the heart.

Low Thyroid Function: About 85% of people affected have this symptom, but only about 10% of the time does it show up on a typical thyroid test. About 10% have excessive hair loss.

Gastrointestinal Problems: About 75% have this symptom. It can be anything from gas, bloating, cramps, diarrhea or constipation to hiatal hernia, irritable bowel syndrome or Crohn's Disease

Swollen Glands, Chemical Sensitivity, Headaches: Allergies often develop, usually after 3 to 5 years. Eyes can be light sensitive for 6 months or longer. Dry eyes can develop. About 20% experience vertigo, almost an out of body feeling that can be most disconcerting.

Pain and Fibromyalgia: Often diagnosed as a separate illness, fibromyalgia is basically a symptom that can occur with any autoimmune disease. If you have it, you've got pain. Often in the neck and in shoulder muscles extending down the back. Can be in the joints and muscles also. Pain and tenderness throughout the body, Muscle weakness, Joint Stiffness, Bone, joint and muscle aches, inflammation, and pains, backaches, unexplained rib and spinal column fractures, Deformed joints can be the symptoms to look for autoimmune disease.

Candida Yeast Infections: These are very common. Check your tongue. If it has a white coating, you have it. Women may get vaginal yeast infections caused by candida overgrowth. A candida infection on its own can cause a number of autoimmune type symptoms. Sinus infections often are caused by candida.

Tingling hands. Ringing ears. Cold toes. Cold fingers. Metallic taste in mouth. Caused by poor circulation and who knows what.

Chest Pain: Panic attacks, rapid heartbeat, etc. Usually blood pressure is low, though it can get high later on which may actually lead to heart attacks.

Unusual Body Temperature/ Pulse or Blood Pressure - watching the peculiar behaviour on the body temperature like low body temperature, feeling cold when others feel hot and vice versa. Even changes in blood pressure like the high or low blood pressure or fast/slow pulse is also a factor to ponder on.

Hair Loss -If anyone is experiencing Hair loss, round bald patches on the scalp, loss of facial and scalp hair, male patterned baldness, excess hair growth on the face, neck, chest, abdomen, and thigh in women, loss of hair in outer eyebrow, it can be a sign of Autoimmune Disease.