WEEK FOUR; Hypothermia & Hyperthemia

Question 18 Julia's heart rate is 120 bpm, which is at the upper limit of normal for her age. Her father asks the pediatrician why the heart rate is higher today than it usually is when Julia visits the pediatrician. Why might her heart rate be higher than usual?

(A) and (B) are correct.

If Jeremy became disoriented or lost consciousness and his skin began to feel dry and warm what would you expect has happened?

Jeremy's condition has worsened and he is now experiencing heat stroke.

Because the diagnosis is viral infection, the pediatrician does not recommend an antibiotic. (Antibiotics are used to treat bacterial, not viral, infections) What treatment do you think the pediatrician would recommend given that Julia has a fever and diarrhea?

Drink plenty of fluids

What region of the brain is primarily responsible for thermoregulation (i.e., control of body temperature)?

Hypothalamus

What should make Julia's parents suspect dehydration from the fever and diarrhea?

If julia has little to urine

The paramedics assess Jeremy's cardiovascular function by checking his pulse, heart rate and blood pressure. If you were the paramedic, which of the following findings would you expect?

Jeremy's heart rate is elevated. I expect that Jeremy is dehydrated due to his high sweat rate and potentially insufficient fluid replacement, and the HR elevation is an attempt to maintain the necessary cardiac output.

Here is the Case Study you will use to answer questions 13-18. I hope you enjoy the case! Temperature Case Study #1 (Fever) Julia is a 6 year girl whose father brought her to the pediatrician's office today with a complaint of fever, nausea, and non-bloody diarrhea for 24 hours. Her parents have been giving her acetaminophen for the fever every 6 to 12 hours. The highest temperature her parents obtained at home was 38.6°C (101.5°F), taken orally. Julia has been able to eat and drink without vomiting. Today Julia complained of a stomach ache, which worried her father, causing him to bring her in to the pediatrician's office. Currently her temperature is 38.3°C (101.°F), blood pressure is 95/55, and heart rate is 120 bpm. After the pediatrician performs a physical exam he diagnoses Julia with viral gastroenteritis. Julia shivers throughout the physical exam. Should this concern the pediatrician, and why?

No, because shivering is a heat-promoting mechanism and a normal part of febrile response to infection.

What mechanisms are employed by the body to increase body temperature?

Shivering Increased metabolic rate

Rectal temperatures are a better indicator of core body temperature than are oral temperatures.

True

Fever is controlled hyperthermia.

True. - Fever is the result of the hypothalamic setpoint being elevated, resulting in the hypothalamus regulating temperature in an abnormally elevated range. Because the hypothalamus is still controlling the hyperthermia, shivering and sweating will be triggered to heat or cool the body. This is different from heat shock, in which hypothalamic controls fail and body temperature spirals upward, out of physiological control.

How does a viral infection result in fever?

When exposed to a virus, the body's white blood cells (leukocytes and macrophages) release pyrogens which then act on the hypothalamus to raise body temperature.

Hypothermia is defined as

abnormally low body temperature

____________ thermoreceptors provide information about blood temperature in the body core.

central

Heat transfer from a warmer object to a cooler object when the objects are in direct contact is called ______________.

conduction

It is very hot afternoon and you turn on a window fan to circulate air in your room. You feel cooler when the air begins to circulate because you are losing body heat due to ____________________.

convection

The term hyperthermia refers to _______________________.

elevated body temperature

Mean (average) body temperature is 37°C (98.6°F). Anyone with a temperature greater than mean body temperature is febrile (i.e., has a fever).

false

Here is the Case Study you will use to answer questions 19-21. I hope you enjoy this case, too. Temperature Case Study #2 (Exercise-induced Hyperthermia) Jeremy is a 23 year old man who is running a half marathon. Race day is unseasonably warm and humid. Paramedics stationed at the 11 mile (approximately 18 km) point along the race course notice that Jeremy has stopped running and is in distress. The paramedics intervene with Jeremy and immediately notice that he is sweating and his skin feels warm. Jeremy complains of dizziness, a headache and slight nausea. What do you suspect Jeremy is experiencing?

heat exhaustion - Because Jeremy's thermoregulation mechanisms (i.e., subcutaneous vasodilation causing the skin to feel hot and sweating) are still working, the correct answer is heat exhaustion.

Which of the following is a heat loss mechanism?

increased sweating

The loss of heat across the mucous membranes that line the mouth and airways is called ________________.

insensible heat loss

___________ is the loss of heat in the form of infrared waves

radiation