Question

Give three examples of organ-specfic and non-organ specific autoimmune disease (5 marks)

In what medical instance would you measure myoglobin and what would it indicate? (5 marks)

Answer 1

Organ specific autoimmune disease is the immune response directed to a target antigen unique to a single grand or organ.As a result the manifestations are largely limited to that organ, the manifestation may be the tissue damage or blockage of the normal function of the organ. Direct cellular damages occurs when lymphocytes or antibodies bind to cell membrane antigens causing cellular lysis or inflammatory response in the affected organ.Gradually the damaged cellular structure is replaced by connective tissue leading to decrease in the function of that organ.Examples include celiac disease(gluten sensitive enteropathy) — is an immune reaction to eating gluten which is a protein present in wheat,barley . When gluten is in the small intestine, the immune system attacks the part of the gastrointestinal tract and causes inflammation.

Graves’ disease — Over production of thyroid hormone by thyroid gland.It causes the thyroid gland to create too much of thyroid hormone in the body causing hyperthyroidism.

Hashimoto thyroiditis — chronic lymphocytic thyroiditis leads to an underactive thyroid gland(hypo thyroidism) it primarily affects middle aged women but can also occur in men.Here the immune system attacks the thyroid, a small gland at the base of the neck bow the adam’s apple.

type -1 diabetes mellitus — This happens when your immune system destroys insulin making cells in the pancreas. These are called beta cells.This is also called as juvenile diabetes as this mainly occur in children and young people.This is a chronic illness due to autoimmune destruction.

Addison’s disease — also termed as adrenal insufficiency is an uncommon disorder produced by the insufficient production of certain hormones. In Addison’s disease your adrenal gland located just above your kidneys produce too little cortisol, and often too little aldosterone.

Non-organ specific autoimmune disease— The immune response is directed towards a broad range of target antigens and as a result involves a number of organs and tissues. These diseases reflect a general defect in immune regulation that results in hyper active T- cells an d B- cells.

Rheumatoid arthritis — It is a chronic inflammatory disease, the immune system attacks the joints. The damage that is caused by RA occurs at the both sides of the body. So of a joint of an arm at one particular side of a body is affected the other side will also cause the damage of the joint.

Systematic lupus erythematosus (SLE) — It is an immune disorder that causes inflammation in connective tissue such as cartilage or lining of the blood vessel. Here the immune system accidentally attacks the healthy tissues which cause structure and flexibility to the body.

Sjogren’s syndrome — This condition attacks the glands that provides lubrication to the eyes and mouth. The hallmark symptoms are dry eyes and dry mouth but it may also affects the joints or skin.

Myoglobin is a protein that is typically found in heart and skeletal muscle tissues. The only time the myoglobin appear in bloodstream is when an injury to a muscle has happened.A myoglobin test is done to measure the level of myoglobin in the body. Your doctor may order this test if they think you’re having a heart attack. The serum myoglobin test has, for the most part, been replaced by the serum Troponin level test. This is because troponin levels are more specific to heart damage than the myoglobin levels.

The myoglobin test is commonly ordered along side other tests for cardiac bio markers. Cardiac biomarkers are substances released in to the bloodstream when damage to the heart takes place. A myoglobin test may also be taken with tests measuring troponin, creatine kinase, and creatine kinase — MB.

The range of normal results for the myoglobin test will vary slightly based on the laboratory completing the analysis. In most of the cases, the normal range for the serum myoglobin test is 0 to 85 nanogram per milliliter. Normal results will allow your doctor to rule out a heart attack.

Abnormal results can be seen in (above 85 ng/ml)

— muscular inflammation   
— muscular dystrophy
— rabdomyolysis