Thymus (Human Anatomy): Image, Function, Diseases, and Treatments

The thymus is a main lymphoid organ that is situated adjacent to the pericardium in the mediastinum and anterior section of the inferior mediastinum. It is part of the lymphatic system, along with the tonsils, adenoids and spleen, and it's also part of the endocrine system.

It is relatively large in infants and grows till puberty reaches and than its size shrink/decreases with age and the immune system too becomes week with its decreasing size. It consists of two lobes that are joined together by an isthmus, a kind of connective tissue. The thymus is split into lobules, and each lobe comprises the cortex on the outside and the medulla in the centre.

A soft, bilobed organ with an encapsulation, the thymus gland is. The thymus is deep to the sternum and anterior to the major arteries of the heart. It reaches the four costal cartilages from the level of the inferior poles thyroid gland above.

The phrenic nerves run parallel to the gland on both its left and right sides, supplying the diaphragm. An isthmus connects the thymus' two separate lobes in the middle.

• A crucial part of our immune systems is the thymus. Through processes of positive and negative selection, it serves as the first location where T cells mature their immune systems. B cells and T cells develop in the bone marrow and thymus, respectively.
• The thymus is where hematopoietic precursor cells develop into T cells. It also suppresses the signs of ageing because of the chemicals it secretes, which slow down the ageing process. They also aid in maintaining memory and learning skills.
• Melatonin is a hormone that is primarily responsible for regulating sleep and is released by the thymus.
• The pancreas produces the insulin hormone of the thymus, a hormone that controls blood sugar. Growth hormone is a hormone that the pituitary gland releases to control growth, while prolactin is a hormone that the pituitary gland releases to promote breast development but is really made in the thymus gland.

• Systemic Lupus Erythematosus: Systemic lupus erythematosus is an autoimmune condition that affects the kidneys, brain, skin, joints, and other bodily organs. It is an inflammatory condition brought on by the immune system attacking its own cells and tissues.
• Hyperthyroidism: The increased synthesis of the thyroid hormone thyroxine, which causes a rise in body metabolism, is known as hyperthyroidism. Symptoms like hyperactivity, irritability, or restlessness, abnormal heart rhythm, fast heart rate, palpitations, restlessness and nervousness can be seen.
• Type 1 Diabetes: This kind of diabetes is brought on by a drop in insulin levels, which is necessary for the thymus gland's growth and proper operation. As a result, the thymus gland does not work as effectively.
• Congenital Athymia: Patients with this uncommon condition have no detectable thymus. It is a relatively uncommon condition marked by the lack of a healthy thymus. It has a number of hereditary and syndromic illnesses in common.
• Thymoma and Thymic Carcinoma: Thymoma and thymic carcinoma are conditions in which the thymus develops malignant cancer cells. Myasthenia gravis and other autoimmune paraneoplastic disorders have a connection to thymoma. Cough and chest discomfort are thymoma and thymic cancer symptoms.
• Myasthenia Gravis: Myasthenia gravis is an autoimmune condition that causes fatigue to become worse as the day wears on and muscles are utilised. Autoantibodies cause the acetylcholine receptors present in postsynaptic neuromuscular junctions to be destroyed, which causes the symptoms.
• Di George Syndrome: This syndrome is characterised by aplasia of the thymus, which has a severe adverse impact on T-cell development and leads to immunodeficiency, increasing infection vulnerability. White blood cells in other organs are unaffected. Cleft palate, hypoparathyroidism, and heart abnormalities are some of this syndrome's further symptoms.
• Systemic Lupus Erythematosus: This is an autoimmune condition that produces persistent systemic inflammation is called systemic lupus erythematosus. There may be signs like fatigue, joint pain, rash, and fever.
• Rheumatoid Arthritis: Rheumatoid arthritis is an autoimmune condition that results in persistent joint tissue inflammation. Severe joint pain is the disease's primary symptom. The immune system of the body targets its own tissue, which includes joints. Internal organs are attacked in extreme instances.
• Pure Red Cell Aplasia (PRCA): This is an uncommon condition that results in anaemia as a result of erythropoiesis failure. There are signs like normocytic, normochromic anaemia, which is connected to peripheral blood reticulocytopenia and few or missing erythroblasts in the bone marrow.
• Hypogammaglobulinemia: Low blood levels of immunoglobulin or antibodies are the root cause of the condition known as hypogammaglobulinemia. The primary elements of the humoral immune response, immunoglobulins are capable of recognising antigens to initiate a biological response and eliminate the infectious cause.
• Hypothyroidism: This is a condition in which there is decrease in thyroid hormones because the thyroid gland doesn't produce enough of hormones as per the need of the body. Hypothyroidism's deficiency of thyroid hormones can disrupt such things as heart rate, body temperature and all aspects of metabolism. Hypothyroidism is most prevalent in older women.

• Tensilon test: A syringe containing 2 mg of atropine and 10 mg of edrophonium chloride ( for immediate use in case cholinergic crisis occurs). After doing a neurological examination and taking vital signs, 2 mg of edrophonium is intravenously administered. The remaining 8mg of edrophonium is likewise administered after waiting 30 seconds and checking to make sure no negative reactions have happened. Next, the patient is instructed to carry out a series of activities. Patients with myasthenia gravis are better able to do these activities under the effect of edrophonium than they were before the injection. Edrophonium's effects endure for around ten minutes.
• CT scan: The size of the tumour may be determined via a CT scan. The most frequent diagnostic used to detect and assess a thymic tumour is a chest CT scan. To offer more information on the picture, a contrast medium, a specific dye, is sometimes administered prior to the scan. A person's vein may receive an injection of this dye.
• MRI: MRI stands for magnetic resonance imaging, which creates precise pictures of the body without the use of x-rays. The size of the tumour may be determined via MRI. Before the scan, a specific dye called a contrast medium is administered to provide a crisper image. A person's vein may receive an injection of this dye.
• Positron Emission Tomography/PET-CT Scan: A PET scan and a CT scan are often combined to form a PET-CT scan. Images of the organs and tissues within the body are produced by a PET scan. A little quantity of radioactive sugar is put into the subject's body. Cells that use the most energy absorb this sugar molecule. Cancer absorbs more of the radioactive material since it prefers to consume energy aggressively. Radiation levels in the material, however, are too low to be dangerous. The material is then detected by a scanner, which creates pictures of the inside of the body.
• Biopsy: A biopsy is the removal of a tiny sample of tissue for microscopic analysis. It may provide a conclusive diagnosis. After analysing the samples, a pathologist assesses the cells, tissues, and organs to determine the illness. Usually, the initial test for a thymic tumour is not a biopsy. Typically, imaging tests like CT, MRI, or PET scan come first in a patient's treatment.
• Blood Tests: These are used to identify thymus tumours. It may assist in excluding other issues and provide a broad assessment of overall health. People with myasthenia gravis or other autoimmune illnesses connected to thymic tumours may sometimes have specific antibodies present.
• Repetitive Nerve Stimulation: In this nerve conduction examination, electrodes are applied to the patient's skin over the target muscles. For the purpose of assessing the nerve's capacity to communicate with your muscle, doctors administer brief electrical pulses via the electrodes. The electrical correlation of clinical muscular weakness and tiredness in myasthenic patients is a decremental response on RNS. Single Fibre Electromyography: A test that monitors the electrical activity that travels from the brain to the muscle and is also referred to as an EMG. To test a single muscle fibre, a thin wire electrode must be inserted through the skin and into the muscle.

• Platelet Transfusion Therapy For Immunodeficiency: Because of the extremely low platelet counts, patients receiving treatment for or prevention of bleeding get platelet transfusions (thrombocytopenia). A platelet count of at least 5,000 per microliter of blood should be maintained at all times.
• Intravenous Gamma Globulin: Gamma globulins are protein fragments found in plasma that play an important function in infection prevention. Severely low gamma globulin levels can raise the risk of some bacterial illnesses. Chronic lymphocytic leukaemia is characterised by extremely low gamma globulin levels.
• Fresh frozen plasma transfusion for immunodeificient patients: Patients with aberrant or low levels of blood-clotting proteins may be transfused with fresh frozen plasma (FFP), the fluid that transports blood cells, and cryoprecipitate, the component of plasma that includes clotting factors (commonly referred to as cryo for short).
• Blood Transfusion for Severe Anemia and Thrombocytopenia: Untreated low red cell counts (anaemia) can induce weakness, exhaustion, and, in severe cases, shortness of breath or fast pulse. Most doctors will prescribe red cell transfusions before a patient develops significant symptoms, especially if the patient is elderly or has a history of heart or blood vessel illness.
• Antihistamines for Autoimmune Disorders: When tiny symptoms like allergies, critical haemorrhages, and rashes arise in the different sections of the body for which these drugs are utilised, this drug decreases the inflammatory reaction of the body and is effective in treating the dominating symptoms of autoimmune illnesses. Diphenhydramine, fexofenadine, acrivastine, azatadine, and clemastin are first-generation antihistamines.
• Chemotherapeutic Drugs for Thymoma and Thymic Carcinoma: Multiple chemotherapy medicines, such as Fluorouracil, Carboplatin, Cisplatin, Cyclophosphamide, and Doxorubicin, are sometimes administered in combination to try to boost their efficacy.

• Nutritional Supplement for promoting Red Cell Production: The prescription of iron, folic acid, ferrous sulphate, Paris ascorbate, and zinc is helpful in promoting red cell development when there are problems with microcytic or macrocytic anaemia. The treatment of sideroblastic anaemia also gains from it.
• Intravenous Vitamin K injections for treating Thrombocytopenia: The intravenous administration of vitamin K is used to treat thrombocytopenia when there is any form of hemolysis brought on by aplastic anaemia or sideroblastic anaemia.
• Pancreatic Enzyme Supplementation: For the treatment of a range of bone marrow marrow deficiency illnesses, as well as sideroblastic and aplastic anaemia, lipase, amylase, and protease supplements are taken orally in the form of tablets and are also given orally in the form of syrups.
• For treatment of Iron Overload: An high iron content in the blood is a side consequence of severe hemolysis and thrombocytopenia. Treatment for this ailment involves the administration of deferoxamine.
• Prophylactic Antibiotics: To prevent the transmission of germs to healthy cells, antibiotics used to treat bacterial infections, such as metronidazole, azithromycin, clindamycin, and amoxicillin, must be maintained in a sterile setting.