Pediatric Examination and Board Review (136 page)

(E) massage and gentle calf stretching

4.
After 2 hours, the girl feels much better and is ready to go home. You advise her that in the future she should try to prevent heat cramps during competition in strenuous and endurance sports lasting longer than 1 hour. Which of the following recommendations is most effective in the prevention of heat cramps?

(A) salt tablets

(B) water only before and during intense endurance exercise

(C) water and an electrolyte drink before and during intense exercise

(D) increased warm-up time and stretching of calf muscles before exercise

(E) weight loss

5.
A second marathon runner is brought in by ambulance. He is a 17-year-old male cross-country runner who collapsed at mile 23 complaining of dizziness, lightheadedness, headache, nausea. He had vomited twice in the field. His weight is 80 kg. His vital signs are BP 100/60 mm Hg, pulse 110 bpm, respiratory rate 36, tympanic temperature 101°F (38.5°C). On examination he appears confused and disoriented, and his skin is sweaty and hot to the touch. Further examination is unremarkable.

Based on the initial presentation, what is the most likely diagnosis accounting for the second athlete’s symptoms?

(A) dehydration

(B) heat stroke

(C) heat exhaustion

(D) heat syncope

(E) rhabdomyolysis

6.
You are called to the bedside of the 17-year-old male runner and you observe generalized tonicclonic seizure activity and posturing. The patient feels hot and dry to the touch. You are concerned now that the second athlete is suffering from heat stroke. Which of the following would be least likely to be found in a patient with heat stroke?

(A) a temperature of 101°F (38.5°C)

(B) an increased creatine phosphokinase level

(C) urine specific gravity higher than 1.030

(D) lactic acidosis

(E) BP of 100/60 mm Hg

7.
The nurse reports to you that the current vital signs for the boy are as follows: BP 90/50 mm Hg, pulse 120, oxygen saturation 95% on room air, temperature 106.7°F (41.5°C). What is the most important initial emergency department treatment for the athlete in Question 6?

(A) prepare the patient for emergent placement of a Swan-Ganz catheter for central venous pressure monitoring

(B) begin rapid cooling procedures

(C) administer supplemental oxygen

(D) administer room temperature IV fluids using a 1L bolus of 0.9% normal saline over 30-60 minutes

(E) administer an antipyretic medication emergently

8.
The most practical initial method to achieve rapid cooling is which of the following?

(A) whole body immersion in ice water

(B) wrapping the body in cold towels

(C) packing the body in ice

(D) spraying with water and place in front of fans

(E) ice packs in the groin and axilla

9.
You have now initiated rapid cooling and the patient is more lucid, the skin is feeling cooler and clammy to the touch. At what temperature do you want to stop rapid cooling?

(A) 37°C (98.6°F)

(B) 37.3°C (99°F)

(C) 37.7°C (100°F)

(D) 38.3°C (101°F)

(E) 39.6°C (103°F)

10.
Which of the following is the most serious form of heat illness?

(A) fever

(B) heat syncope

(C) heat stroke

(D) heat exhaustion

(E) rhabdomyolysis

11.
What environmental conditions predispose an athlete to heat illness?

(A) high ambient temperature

(B) high winds

(C) high humidity

(D) A and C

(E) A, B, and C

12.
What is the most important mechanism the body uses for heat dissipation?

(A) conduction

(B) convection

(C) radiation

(D) evaporation

(E) respiration

13.
Which of the following statements regarding heat dissipation is false?

(A) conduction occurs via indirect contact of the body with the environment

(B) convection is heat transferred from a solid surface to surrounding gas molecules

(C) radiation is the transfer of heat between the body and its environment via electromagnetic waves

(D) evaporation is the conversion of liquid to gas

(E) all of the above are true

14.
Heat cramps are most likely related to the loss of which electrolyte?

(A) Mg++

(B) Na+

(C) K+

(D) Cl−

(E) Ca++

15.
When caring for a preadolescent athlete, all of the following statements accurately describe heat illness except

(A) children are at increased risk for heat illness because of a higher surface area to mass ratio

(B) younger athletes have slower rates of acclimatization

(C) children are at decreased risk for heat illness because the circulating blood volume is less

(D) children are less efficient at sweating

(E) children’s motor movements are less efficient than those of adults during exercise

16.
Which of the following statements is true regarding heat exhaustion and heat stroke?

(A) heat exhaustion and heat stroke are separate clinical conditions that do not occur in the same patient suffering from heat illness

(B) hemoconcentration, urinary concentration, and hypertension are common occurrences in both conditions

(C) both conditions can result in hyperpyrexia at 105°F (40.5°C) or higher

(D) both conditions may cause an athlete to experience weakness, fatigue, dizziness, disorientation, myalgias, tachycardia, nausea, vomiting, or hypotension

(E) both conditions result in reversible tissue damage if an accurate diagnosis and prompt initiation of treatment occurs

17.
Which of the following are complications of heat stroke?

(A) permanent neurologic deficits

(B) hepatic failure

(C) uremia

(D) disseminated intravascular coagulation

(E) all of the above

18.
Which of the following statements is true regarding measurement of core body temperature in a patient with heat illness?

(A) rectal thermometers are used only in patients who feel “hot” to the touch.

(B) rectal thermometers are preferred but need only to be able to measure up to 106°F (41.1°C)

(C) oral temperatures are notoriously unreliable in exertional heat illness because of tachypnea and compliance

(D) tympanic membrane temperature measurement has been proven to reflect true core temperature because the tympanic membrane is adjacent to the hypothalamic temperature regulation center

(E) all of the above

19.
After successfully taking care of the marathon runners, you are asked by the medical student what type of preparatory advice you can give future runners. You would include all of the statements below except

(A) the sweat rate for the average endurance athlete in a temperate climate averages 1.0-1.2 L per hour and can exceed 2 L per hour in conditions of high heat and humidity

(B) sweat is hypotonic and is more hypotonic in those athletes who sweat greater volumes

(C) athletes should voluntarily drink fluids before, during, and after activities

(D) if an athlete is participating in endurance events, she or he should start taking salt tablets 2-3 days before competition

(E) proper nutrition, adequate sleep, gradual acclimatization, and avoidance of drugs/substances like alcohol, ephedra, and caffeine are important preventive measures

ANSWERS

1.
(D)
Heat cramps are a common mild form of heat illness that tend to occur after exercise and are associated with a large production of sweat during exercise. Heat cramps also occur in unconditioned athletes.

2.
(B)
All of the listed factors contribute to an increased risk of heat illness. However, dehydration and volume depletion as a result from sweating without adequate fluid replacement is the most important risk factor for heat-related illness.

3.
(C)
The best initial treatment for heat cramps is drinking an electrolyte solution (or administering 1 tsp of table salt dissolved in 500 mL of water). The underlying cause of heat cramps is total-body salt depletion. Cramping is often made worse by excessive intake of hypotonic fluids such as water. Gentle massage and stretching may be a helpful adjunct to treatment of the underlying problem. IV fluid use is generally reserved for the more severe cases.

4.
(C)
The best prevention of heat cramps is adequate hydration before and during athletic activities. Appropriate clothing, conditioning, and, in rare cases, modest increases in dietary salt are helpful interventions. Excessive water intake often worsens heat cramps because it causes further total body sodium loss.

5.
(
C
)

6.
(A)
Heat stroke is associated with temperatures of 105°F (40.5°C) or higher.

7.
(B)
In the setting of suspected heat stroke, it is vital that you initiate treatment before firmly establishing the diagnosis. In fever, the set point for temperature regulation is increased and often responds to the use of antipyretics. In the setting of heat illness, the set point for temperature regulation is maintained yet hyperthermia results because more heat is gained than lost. In hyperthermia, antipyretics are likely to be ineffective and alternative methods of body cooling are necessary.

8.
(D)
Whether in the medical tent or in the emergency department it is critical to initiate treatment immediately. The most important initial treatment is the institution of rapid cooling. The treating physician must also follow the general principles of ABC, monitor the vital signs, obtain appropriate laboratory tests, and start IV rehydration. The most effective way to achieve rapid cooling is whole body immersion in ice water. Unfortunately this method is usually not practical. The most common way to initiate rapid cooling is through the use of water sprays and fans (maximizes convection). One may also pack the athlete in ice or cold wet towels. It is important to expose as much skin as possible. One should avoid placing ice packs over the major vessels in the groin and axilla because this may result in peripheral vasoconstriction and less efficient cooling. See
Table 80-1
for summary of heat exhaustion versus heat stroke.