Norepinephrine, also known as noradrenaline, is a medication used to treat people with very low blood pressure. It is the typical medication used in sepsis if low blood pressure does not improve following intravenous fluids. It is the same molecule as the hormone and neurotransmitter norepinephrine. It is given by slow injection into a vein.Common side effects include headache, slow heart rate, and anxiety. Other side effects include an irregular heartbeat. If it leaks out of the vein at the site it is being given, norepinephrine can result in limb ischemia. If leakage occurs the use of phentolamine in the area affected may improve outcomes. Norepinephrine works by binding and activating alpha adrenergic receptors.Norepinephrine was discovered in 1946 and was approved for medical use in the United States in 1950. It is available as a generic medication. Medical uses
Norepinephrine is used mainly as a sympathomimetic drug to treat people in vasodilatory shock states such as septic shock and neurogenic shock, while showing fewer adverse side-effects compared to dopamine treatment. Mechanism of action
It stimulates α1 and α2 adrenergic receptors to cause blood vessel contraction, thus increases peripheral vascular resistance and resulted in increased blood pressure. This effect also reduces the blood supply to gastrointestinal tract and kidneys. Norepinephrine acts on beta-1 adrenergic receptors, causing increase in heart rate and cardiac output. However, the elevation in heart rate is only transient, as baroreceptor response to the rise in blood pressure as well as enhanced vagal tone ultimately result in a sustained decrease in heart rate.
It is very rare that the symptoms are actually coming from the cyst. In most cases, there is another disorder in the knee (arthritis, meniscal (cartilage) tear, etc.) that is causing the problem. Initial treatment should be directed at correcting the source of the increased fluid production. Often rest and leg elevation are all that is needed. If necessary, the cyst can be aspirated to reduce its size, then injected with a corticosteroid to reduce inflammation. Surgical excision is reserved for cysts that cause a great amount of discomfort to the patient. A ruptured cyst is treated with rest, leg elevation, and injection of a corticosteroid into the knee. Bakers cysts in children, unlike in older people, nearly always disappear with time, and rarely require excision.Ice pack therapy may sometimes be an effective way of controlling the pain related to Bakers cyst. Heat is also commonly used. A knee brace can offer support giving the feeling of stability in the joint. Exercise
Many activities can put strain on the knee, and cause pain in the case of Bakers cyst. Avoiding activities such as squatting, kneeling, heavy lifting, climbing, and even running can help prevent pain. Despite this, some exercises can help relieve pain, and a physiotherapist may instruct on hamstring stretching to reduce pressure on the Bakers Cyst, and strengthening exercises for the quadriceps and/or the patellar ligament. References
External links
 Media related to Bakers cyst at Wikimedia Commons