CR - Environmental Disorders

Question 1

What is the order of tissue resistance to the flow of electrical current?

Answer 1

Least resistance - nerves, blood vessels, muscles, mucous membranes, moist or wet skin
Intermediate resistance - dry skin
Greatest resistance - bone, tendon, fat

Question 2

Which organ system is least sensitive to an acute radiation exposure?

Answer 2

Central nervous system

Question 3

What is the clinical feature that distinguishes heat stroke from heat exhaustion?

Answer 3

Central nervous system dysfunction
(in heat exhaustion, mentation is not impaired)

Question 4

Which ENT injury is most likely to be present in a survivor of a lightning strike?

Answer 4

Rupture of the tympanic membranes

Question 5

At what temperature does the hypothermic patient lose the ability to generate heat by shivering?

Answer 5

Below 32C (90F)

Question 6

A patient complains of severe muscle cramping involving the calves, thighs, and shoulders. Questioning reveals that the cramps began after a bout of intensive physical activity and profuse sweating, during which he had been replacing fluid losses with a hypotonic solution. His body temperature is normal. What is the most likely diagnosis?

Answer 6

Heat cramps.
Inadequate replacement of salt from loss through sweating leads to hyponatremia and muscle cramps

Question 7

What is the modified “rule of nines” which may be used in children?

Answer 7

Head = 18%
Abdomen = 9%
Thorax = 9%
Back = 18%
Each arm = 9%
Each leg = 13%
Perineum = 2%

Question 8

Core temperature less than ____ is associated with increased myocardial irritability and can cause nearly any tachydysrhythmia or bradydysrhythmia, including conduction delays

Answer 8

30C (86F)

Question 9

What is the most important cause of morbidity and mortality in near drowning?

Answer 9

Hypoxia

Question 10

In patients with this injury, close observation (sometimes in the hospital) and referral to a plastic or oral surgeon is indicated because there is possibility of labial artery hemorrhage as the eschar separates

Answer 10

Electrical burns of the lip / mouth (particularly to commissures)

Question 11

Rapid rewarming is the key initial therapy for this environmental emergency?

Answer 11

Frostbite

Question 12

A patient presents with an acute abdomen after being outdoors. You notice that there is only mild tenderness but there is impressive rigidity.

What is the suspected diagnosis?

Answer 12

Black widow spider bite
(Bite is typically not noticed to the lower extremity or genitalia)

Question 13

A scuba diver develops acute confusion and ataxia immediately after an ascent to surface.

What is the diagnosis

Answer 13

Arterial gas embolism

Question 14

A patient presents with extreme fatigue and profuse sweating while training on a very hot day. He complains of lightheadedness, nausea, vomiting, and a dull headache. He is tachypneic, tachycardic, and hypotensive. Body temperature is only mildly elevated. What is the most likely diagnosis?

Answer 14

Heat exhaustion.

Electrolyte and fluid losses from sweat lead to hypovolemia and decreased cardiac output; no significant abnormalities on neurologic testing, may have some ataxia and lightheadedness

Question 15

The whole body dose of ionizing radiation determines the timing of onset of symptoms. The higher the level of exposure, the ___ symptoms develop

Answer 15

Earlier

The first signs are most commonly GI symptoms: nausea, vomiting, diarrhea and bloody stools. Symptoms start with doses >1Gy or 100 rad. LD50 when doses reach 4.5 Gy

Question 16

What is the best predictor of survival in patients with radiation exposure?

Answer 16

The absolute lymphocyte count, 48 hours after exposure.

(Andrews lymphocyte nomogram)

Question 17

What is the treatment of puncture wounds (stings) from sea urchins, stingrays, or lionfish?

Answer 17

1. Remove the victim from the water immediately.
2. Address possible allergic reaction
3. Hot water immersion at highest temperature patient can tolerate for 30 minutes or until pain resolves
4. Normal wound management
5. Prophylactic antibiotics for deeper wounds, foreign bodies, or in immunocompromised patients

Question 18

Concerning the initial management of patients with radioactive skin contamination, is it preferable only to wash or to wash and scrub the skin?

Answer 18

Washing with soap and water. May scrub skin gently until any signs of skin breakdown appear to avoid introduction of radioactive material into the underlying tissues

Question 19

Does successful recovery from tetanus confer immunity to the disease?

Answer 19

No

The patient needs full primary immunization plus boosters through the years as otherwise indicated

Question 20

Which tick-borne illness is characterized by severe retro-orbital headaches and photophobia and requires only supportive therapy?

Answer 20

Colorado tick fever

Question 21

Clinical presentation: a patient presents ill with fever and a rash. The rash begins as discrete red maculopapular lesions on the writs and ankles. It then spreads to the trunk. Early on, the lesions were blanched but later become petechial.

What disease characteristically does this?

Answer 21

Rocky mountain spotted fever

Question 22

Circular skin lesions with bright red to blue red border and a pal center are characteristic of ____ ____, which is the hallmark of early ____ ____

Answer 22

Erythema migrans
Lyme disease

Question 23

Antibiotic therapy for adults (nonpregnant and nonlactating) and children for lyme disease stage 1 is ____

Answer 23

Doxycycline for 10-14 days.
Dosing 100 mg PO BID in adults and 2-4 mg/kg divided BID with max dose of 200 mg/day in pediatrics (treatment in pediatrics not to exceed 21 days)

Question 24

Which animals are most likely to harbor the rabies virus?
Which animals are least likely vectors for rabies?

Answer 24

Most common: #1 globally is the domestic dog (only travel to foreign countries has caused fatal dog bite related rabies in the US since 2003), skunks, bats, raccoons, foxes

Least common: rodent, squirrels, chipmunks, rats and mice and rabbits have not been known to transmit rabies to humans.

Note: rabies can affect all mammals

Question 25

What is the management of a primate (ape) bite?

Answer 25

Careful hand washing for 20 minutes (exposed eyes or mucosal sites should be irrigated with rapidly flowing water for at least 20 minutes) after a bite is the best treatment for prevention of infection with herpes virus simiae (70% fatality rate).

Antiviral medication should be started based on the risk of exposure.

Prophylactic antibiotics (augmentin) to decrease infection risk; rabies post-exposure treatment and rabies vaccine.

Question 26

What are the two types of heat stroke?

Answer 26

Classic heatstroke is environmentally-induced (hot, humid weather) and occurs most commonly in those who live in homes without air-conditioning (especially the elderly) and those with inadequate fluid intake (e.g. the debilitated). Lab abnormalities are mild.

Exertional heat stroke is exercise induced (athletes, military recruits) and is associated with significant lab abnormalities: hypoglycemia, hypocalcemia, hyperuricemia, lactic acidosis and rhabdomyolysis. Acute renal failure and coagulopathy (often to a marked degree) may also occur

Question 27

How do you differentiate muscle spasms due to tetanus from those seen in patients with strychnine posioning?

Answer 27

Tetanic muscle contractions are continuous, whereas muscle spasms associated with strychnine poisoning usually have periods of relaxation between contractions (triggered by trivial stimuli such as turning on a light) lasting 30-120 second.

Also lockjaw is characteristic of tetanus, not strychnine

Question 28

An elderly patient who lives a sedentary lifestyle and is taking medications for chronic illnesses presents with sweating, not acting right, and hot dry skin. The patient lives in an unairconditioned apartment and temperatures have been in the 90s. Lab findings include respiratory alkalosis and mild metabolic acidosis, coagulopathy and CPK elevation; glucose and calcium levels are normal. What is the most likely diagnosis?

Answer 28

Heat stroke. This is a true medical emergency, characterized by an altered LOC, any neurologic findings and an elevated temperature

Question 29

You are examining a patient who has a rash that looks like chicken pox. How do you know that it isn’t smallpox?

Answer 29

In patients with smallpox (variola major) all lesions are in the same stage of eruption, unlike chicken pox (varicella)

Question 30

A young, healthy patient is engaged in strenuous exercise on a warm day in august. The patient is diaphoretic on presentation. The following findings are obtained: respiratory alkalosis and marked lactic acidosis, DIC and rhabdomyolysis (“machine oil” urine), increased BUN/creatinine, hypoglycemia and hypocalcemia. What is the diagnosis?

Answer 30

Exertional heat stroke