Urgent Care Medicine Secrets E-Book

Robert P. Olympia, Rory O'Neill, Matthew Silvis

• Publisher: Elsevier
• Year: 2017
• ISBN:
  9780323477833
• Topic: Medicina
• Subtopic: Medicina de familia y práctica general

For more than 30 years, the highly regarded Secrets Series® has provided students and practitioners in all areas of health care with concise, focused, and engaging resources for quick reference and exam review. Urgent Care Secrets, a new volume in this bestselling series, features the Secrets' popular question-and-answer format that also includes lists, tables, and an easy-to-read style – making reference and review quick, easy, and enjoyable.

• The proven Secrets® format gives you the most return for your time – concise, easy to read, engaging, and highly effective.
• Provides an evidence-based approach to medical and traumatic complaints presenting to urgent care centers, focusing on presenting signs and symptoms, differential diagnosis, office management, and when to refer for higher level of care.
• Covers the full range of essential topics for understanding today's practice of urgent care – essential information for physicians, nurse practitioners, and physician assistants.
• Clear illustrations, figures, and flow diagrams expedite reference and review.
• Top 100 Secrets and Key Points boxes provide a fast overview of the secrets you must know for success in practice and on exams.

II

Pediatric Urgent Care Medicine

Outline

Chapter 12. Fever

Chapter 13. Headache

Chapter 14. Eye Complaints

Chapter 15. Ear Pain, Nasal Congestion, and Sore Throat

Chapter 16. Cough

Chapter 17. Neck Pain and Masses

Chapter 18. Chest Pain

Chapter 19. Abdominal Pain

Chapter 20. Nausea, Vomiting, Diarrhea, and Dehydration

Chapter 21. Urinary and Urologic Complaints

Chapter 22. Vaginal Complaints

Chapter 23. Skin Rashes and Infections

Chapter 24. Common Newborn Complaints

Chapter 25. Limp

Chapter 26. Head and Neck Trauma

Chapter 27. Chest and Abdominal Trauma

Chapter 28. Extremity Trauma

Chapter 12

Fever

Ariella Nadler, MD, and Jeffrey R. Avner, MD

1. What causes fever?

The body has a “central thermostat” comprised of a specialized group of neurons in the hypothalamus that act to maintain the body at a physiologic “set point.” This set point changes when pyrogens (endogenous or exogenous substances that produce fever) stimulate an inflammatory response that increases the production of prostaglandin E, which in turn acts on the hypothalamus to raise the set point. When the body’s temperature is lower than the set point, various mechanisms are employed to increase heat production and raise the body’s temperature to be in balance with the new set point, resulting in fever.

2. What are the different phases of the febrile response?

The first phase of the febrile response is the “chill” phase. Various mechanisms, including increasing cellular metabolism, increasing skeletal muscle activity through involuntary shivering, peripheral vasoconstriction, and seeking a warmer environment are employed in order to raise the body’s temperature to a new set point. The “flush” phase occurs as the set point is lowered back toward normal body temperature with illness resolution or administration of antipyretics. This phase is characterized by peripheral vasodilation, sweating, and seeking a cooler environment as the body seeks to lower its temperature to the new set point.

3. Is there a difference between fever and hyperthermia?

Yes, fever is a physiologic response, and hyperthermia is not. Fever is an elevation of body temperature that is regulated by the body’s internal thermoregulatory center in the hypothalamus, whereas hyperthermia represents elevation of body temperature due to an external environmental source, with no input from the body’s thermoregulatory center. Temperature elevation secondary to hyperthermia is dangerous as the thermoregulatory center does not stimulate vasodilation and sweating to lower the temperature, as it would in the case of fever.

4. Is normal body temperature 98.6°F (37°C)?

There is no single normal value for body temperature. Rather, there is a range of normal that can vary in each person by as much as 0.5°C from the mean, based on various factors. These include time of day (lowest in the morning and highest in the evening), age (higher in infants), sex, physical activity, and ambient temperature.

5. So where did the value 98.6°F come from?

The value 98.6°F is attributed to Carl Wunderlich, who published, in 1868, a study in which he used a foot-long axillary thermometer to take 1 million temperature readings in more than 25,000 patients and found 98.6°F to be the mean temperature; hardly accurate by today’s standards.

6. Which method of temperature measurement is most reliable (axillary, oral, rectal, tympanic) or does it not really matter?

Table 12.1 compares the different methods of temperature measurement. As each have pros and cons, it is most important to use a consistent form of measurement to monitor changes in body temperature. Keep in mind these methods measure body temperature at a peripheral site, which lags behind the core body temperature.

7. Can children have fever even if they don’t have an elevated body temperature?

When children are in the “chill” phase of fever, their body temperature may not be elevated, as the core body temperature may not have reached the thermoregulatory center’s new set point. However, children may manifest symptoms of the febrile response such as shivering, cool skin, tachycardia, tachypnea, and decreased appetite. Fever will likely occur 20–30 minutes after the development of these systemic symptoms.

8. Is it “feed a cold and starve a fever” or the other way around?

Although generally dismissed as folklore, there may be some physiologic explanation for this classic proverb, which dates back to the 1500s. Studies show that food intake upregulates cell-mediated immunity (via increased interferon-gamma production) that can help fight viral infections such as colds, while withholding food increases humoral immunity (via upregulation of IL-4), which is helpful in fighting bacterial infections, historically thought to be the predominant cause of fever.

Table 12.1

Methods of Temperature Measurement

Method	Pros	Cons	Normal range, mean °C (°F)	Fever °C (°F)
Axilla	Comfortable Safe	Lag time Inaccurate during chill phase and skin cooling from sweating	34.7–37.3, 36.4 (94.5–99.1, 97.5)	37.4 (99.3)
Oral (sublingual)	Comfortable (children >5) Safe Less lag time More accurate	May be affected by recently consumed fluids or evaporative effects of mouth breathing	35.5–37.5, 36.6 (95.9–99.5, 97.9)	37.6 (99.7)
Rectal	Safe Closest to core temperature Not affected by environmental factors	Less comfortable Concern for cross-contamination if standard precautions aren’t followed	36.6–37.9, 37.0 (97.9–100.2, 98.6)	38.0 (100.4)
Tympanic	Comfortable Safe Cost effective	Difficult to aim thermometer at TM Cerumen may block TM	35.7–37.5 (96.3–99.5, 97.9)	37.6 (99.7)
Temporal	Comfortable Safe	Low diagnostic accuracy	36.4–37.7 (97.5–99.9)	37.8 (100.0)

9. Is there a value that is considered a “high” fever (or how hig...