(USMLE topics) How the hypothalamus controls body temperature. How fever resets the hypothalamus. Fever versus hyperthermia. This video is available for instant download licensing here https://www.alilamedicalmedia.com/-/galleries/all-animations/immune-and-lymphatic-system-videos/-/medias/1b1d41f8-139e-44a6-8ed2-66127f951376-fever-narrated-animation
Voice by: Ashley Fleming
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Fever, clinically known as pyrexia, is an abnormal increase in body temperature, usually due to an illness. Commonly thought as an undesirable side effect of diseases, fever is actually an effective way the body uses to fight infections. Patients usually recover faster when they allow fever to run its course rather than suppressing it with fever-reducing medications. This is because a higher temperature slows down the growth of most pathogens, as well as boosts the effectiveness of the body’s immune response. It also increases metabolic rates and thereby accelerating tissue repair.
Normally, the hypothalamus keeps the body’s temperature within a narrow range around 37 degrees Celsius, or 98.6 degrees Fahrenheit. The hypothalamus acts like a thermostat. It receives inputs from heat and cold receptors throughout the body, and activates heating or cooling, accordingly. When the body is too hot, the hypothalamus sends instructions for it to cool down, for example, by producing sweat. On the other hand, when temperature drops, the hypothalamus directs the body to preserve and produce heat, mainly via the release of norepinephrine. Norepinephrine increases heat production in brown adipose tissue and induces vasoconstriction to reduce heat loss. In addition, acetylcholine stimulates the muscles to shiver, converting stored chemical energy into heat.
Fever is part of the inflammatory response. When immune cells detect the presence of a pathogen, for example, upon binding to a component of bacterial cell walls, they produce inflammatory cytokines. Some of these cytokines are fever-inducers, or pyrogenic. Pyrogenic cytokines act within the hypothalamus to induce the synthesis of prostaglandin E2, PGE2, the major fever inducer. PGE2 acts on thermoregulatory neurons of the hypothalamus to raise the body’s temperature set point. In other words, PGE2 tricks the hypothalamus into thinking that the body is cold, while in fact the temperature did not change. In response, the hypothalamus instructs the body to actively produce heat to raise body temperature above normal. Fever-reducing medications, such as aspirin and ibuprofen, work by suppressing PGE2 synthesis.
Once infection is cleared, pyrogens are no longer produced and the hypothalamic thermostat is set back to normal temperature. Cooling mechanisms, such as sweating and vasodilation, are activated to cool the body down.
While fever is usually beneficial and need not be treated, precaution should be taken to prevent body temperature from running too high, which may cause confusion, seizures and irreversible damage to the brain.
Finally, it is important to differentiate between fever and hyperthermia, the latter is often caused by extended exposures to extreme heat, or heat stroke. Unlike fever, the body’s temperature set point in hyperthermia is unchanged and the body does not produce the extra heat; its cooling system is simply exhausted and fails to compensate for the excessive external heating. Hyperthermia is always harmful and must be treated with various cooling methods. Fever-reducing medications have no effect on hyperthermia as pyrogens are not involved.
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Most of us have taken a fever reducer to dull unpleasant symptoms. Why should you never break a fever and sweat it out the natural way?

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Fever Treatment
http://www.mayoclinic.org/diseases-conditions/fever/in-depth/fever/art-20050997

“A fever is a common sign of illness, but that’s not necessarily a bad thing. In fact, fevers seem to play a key role in fighting infections.”

The Benefits of Fever

“Fever can indeed be scary, and any fever in an infant younger than 3 months is cause for major concern because of the risk of serious bacterial infections.”

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This animation and many other pain management related videos/images (in HD) are available for instant download licensing here: https://www.alilamedicalmedia.com/-/galleries/images-videos-by-medical-specialties/pain-management-images-and-videos
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Perfect for patient education.
All images/videos by Alila Medical Media are for information purposes ONLY and are NOT intended to replace professional medical advice, diagnosis or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.
Myofascial pain syndrome is a common chronic pain disorder that can affect various parts of the body. Myofascial pain syndrome is characterized by presence of hyperirritable spots located in skeletal muscle called trigger points. A trigger point can be felt as a band or a nodule of muscle with harder than normal consistency. Palpation of trigger points may elicit pain in a different area of the body. This is called referred pain. Referred pain makes diagnosis difficult as the pain mimics symptoms of more well-known common conditions. For example, trigger point related pain in the head and neck region may manifest as tension headache, temporomandibular joint pain, eye pain, or tinnitus.
Symptoms of myofascial pain syndrome include regional, persistent pain, commonly associated with limited range of motion of the affected muscle. The pain is most frequently found in the head, neck, shoulders, extremities, and lower back.
Trigger points are developed as a result of muscle injury. This can be acute trauma caused by sport injury, accident, or chronic muscle overuse brought by repetitive occupational activities, emotional stress or poor posture. A trigger point is composed of many contraction knots where individual muscle fibers contract and cannot relax. These fibers make the muscle shorter and constitute a taut band — a group of tense muscle fibers extending from the trigger point to muscle attachment. The sustained contraction of muscle sarcomeres compresses local blood supply, resulting in energy shortage of the area. This metabolic crisis activates pain receptors, generating a regional pain pattern that follows a specific nerve passage. The pain patterns are therefore consistent and are well documented for various muscles.
Treatment of myofascial pain syndrome aims to release trigger points and return the affected muscle to original length and strength. Common treatment options include:
– Manual therapy, such as massage, involves application of certain amount of pressure to release trigger points. The outcome of manual therapy strongly depends on the skill level of the therapist.
– The Spray and Stretch technique makes use of a vapor coolant to quickly decrease skin temperature while passively stretching the target muscle. A sudden drop in skin temperature provides a pain relief effect, allowing the muscle to fully stretch, and thus releasing the trigger points.
– Trigger point injections with saline, local anesthetics or steroids are well accepted as effective treatments for myofascial trigger points.
– Dry needling — insertion of a needle without injecting any solution – is reported to be as effective as injections.
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