Environmental Illnesses

Human Thermal Regulation & Environmental Stress

• The human body can normally adjust to wide variations in heat, cold and altitude, but can be overwhelmed when stressors exceed physiologic limits.
• Main stressors cited in the lecture
  • Air temperature (dry bulb)
  • Humidity / vapor pressure
  • Solar load (radiant heat)
  • Wind speed (convective cooling or wind-chill)
  • Surface type (artificial turf, asphalt courts far hotter than grass)
  • Atmospheric pressure / altitude (hypobaric hypoxia)
  • Individual variables: fitness, illness, hydration, nutrition, acclimatization status, clothing/equipment, psychological factors, previous history of illness.

Altitude Illnesses (Continuum Model)

• Umbrella term = Altitude Sickness; progresses along a continuum
  1. AMS – Acute Mountain Sickness
  2. HAPE – High-Altitude Pulmonary Edema
  3. HACE – High-Altitude Cerebral Edema

Acute Mountain Sickness (AMS)

• Earliest stage; usually begins above $8{,}000\,\text{ft}$ (≈ $2{,}400\,\text{m}$).
• Etiology: Lower barometric pressure → $\downarrow$ FiO₂ → tissue hypoxia, especially during exertion.
• Classic early symptoms
  • Mild headache, dizziness, fatigue, insomnia
  • GI upset: nausea, loss of appetite, sensation of “not digesting food”
  • Sense of uneasiness; often mistaken for dietary indiscretion.
• Key admonition: “If you feel uneasy in the mountains, assume altitude first; treat other causes later.”
• Psychological traps
  • Group pace pressure in organized treks (IndiaHikes, college teams, etc.)
  • Experienced trekkers hide symptoms to avoid “looking weak.”
• Environmental trap in Himalayas: steep mountain design → rapid elevation gain (e.g., Camp 1 $8{,}000\,\text{ft}$ → Camp 2 $12{,}000\,\text{ft}$ within hours) leaves no natural acclimatization windows.
• Management & prevention
  • Golden Rule: Alert teammates/leaders at first symptom (“First alert”).
  • Stop ascent, rest, hydrate, consider prophylactic Diamox ($125–250\,\text{mg BID}$).
  • Planned acclimatization: +$<1{,}000\,\text{ft}$ sleeping elevation per 24 h, rest day every $3$ days.
  • Avoid alcohol (vasodilation + respiratory depression).

High-Altitude Pulmonary Edema (HAPE)

• Pathophysiology: Hypoxic pulmonary vasoconstriction → pulmonary hypertension → capillary leak → fluid in alveoli.
• Can occur as low as $9{,}000\,\text{ft}$; incidence peaks $11{,}000–18{,}000\,\text{ft}$.
• Early symptoms (catch before pink-frothy sputum)
  • Unusual fatigue, inability to keep pace
  • Breathlessness at rest or after trivial effort
  • New cough at altitude (>$10{,}000\,\text{ft}$)
• Advanced/red-flag signs (develop within $\approx5\,\text{h}$)
  • Pink, bloody, or frothy sputum
  • Cyanotic lips/nails, tachycardia, rails/wheezes on auscultation.
• Treatment protocol
  • Immediate descent to tree line (~$7{,}000–8{,}000\,\text{ft}$).
  • Pharmacology
  • Diamox (acetazolamide) continues $\to$ improves acclimatization.
  • Nifedipine $10\,\text{mg}$ PO → lowers pulm. artery pressure.
  • Supplemental O₂ $0.5–1\,\text{L · min}^{-1}$ via nasal cannula.
  • Keep patient warm; monitor continuously.

High-Altitude Cerebral Edema (HACE)

• Pathophysiology: hypoxia → cerebral vasodilation & capillary leak → brain swelling.
• May coexist with HAPE but can appear independently.
• Symptoms (often noticed by companions)
  • Severe throbbing headache, nausea/vomiting
  • CNS dysfunction: ataxia (can’t walk straight line), confusion, inappropriate answers, irrational behavior, coma.
• Field test: “Walk the straight line” – failure = red flag.
• Treatment
  • Rapid descent identical to HAPE.
  • Dexamethasone $8\,\text{mg}$ IM/IV load, then $4\,\text{mg}$ q4–6 h ($\uparrow$ time window for evacuation).
  • O₂ supplementation.

Epidemiologic & Timing Observations

• HAPE ≈ $70–80\%$ of serious altitude cases; HACE less frequent.
• Often manifest on descent after summit: climber ignored mild AMS on ascent, returns fatigued, deteriorates overnight.

Heat-Related Illnesses

Physiologic Spectrum

1. Heat Cramps – painful muscle spasm, usually after heavy sweating/electrolyte loss.
2. Exertional Sickling – in athletes with sickle-cell trait; mimics cramps but driven by hypoxia.
3. Heat Exhaustion – $\downarrow$ plasma volume (dehydration) or hyponatremia → core temp $<104^\circ\text{F}$.
4. Exertional Heat Stroke (EHS) – medical emergency
   • Core temperature $\ge104^\circ\text{F}$ ( $\ge40^\circ\text{C}$ )
   • CNS dysfunction (collapse, aggression, seizures, coma)

10–14 Day Heat Acclimatization Schedule (football example)

• Days 1–2: single practice; helmets only; no contact.
• Days 3–5: single practice; helmets + shoulder pads; contact limited to sleds/dummies.
• Days 6–14:
  • Two-a-days permitted (≤$5\,\text{h}$ total practice, ≥$3\,\text{h}$ apart).
  • Full pads & contact allowed.
  • Only 2 double-session days may be consecutive.
• Daily walk-through allowed (≤$1\,\text{h}$; ≥$3\,\text{h}$ separated from practice).
• Youth leagues practicing <$5$ times/week count only “on-field” days toward acclimatization.

Hydration Strategy

• Primary fluid: water; sports drink (carb + electrolytes) when exercise >$60\,\text{min}$ or very intense.
• Body-mass method: weigh in/out; replace $\approx150\%$ of weight lost within $2$ h post-practice.
  • $1\,\text{lb} \text{ lost} \approx 16\,\text{oz} (0.47\,\text{L})\text{ fluid}$.
• Urine-color chart as alternative quick check (aim ≤ Color 3).
• Schedule hydration breaks every $15–20\,\text{min}$; NEVER restrict water.

Environmental Monitoring

• Wet Bulb Globe Temperature (WBGT) is gold standard; incorporates
  • Air temperature
  • Humidity
  • Solar radiation
  • Wind speed
• Measure on-site, athlete level, same surface (turf hotter than grass).
• Activity modification grid (ACSM/NATA)
  • WBGT $<82^\circ\text{F}$: normal; watch high-risk athletes.
  • $82–86^\circ\text{F}$: add rest/water every $15$ min.
  • $86–89.9^\circ\text{F}$: shorten practice; remove pads for conditioning.
  • $90–92^\circ\text{F}$: helmets only; ≤$1\,\text{h}$ total practice.
  • $\ge92^\circ\text{F}$: cancel outdoor activity or move indoors.
• Heat Index ≠ WBGT; do NOT substitute.

Exertional Heat Stroke Management (“Cool First, Transport Second”)

1. Recognize: rectal temp measurement ONLY reliable (insert $\approx13\,\text{cm}$).
2. Activate EMS but begin cooling immediately.
3. Rapid whole-body cooling until core $\le102^\circ\text{F}$:
   • Cold-water immersion tub (chest-deep; continuously stir water).
   • TACO method (Tarp Assisted Cooling with Oscillation): patient in water-ice tarp burrito; 5–6 rescuers.
   • Cooling rate goal $\ge0.15^\circ\text{C · min}^{-1}$.
4. Remove excessive clothing/equipment; support airway/head.
5. Monitor for rebound hyperthermia; reassess vitals, glucose, sodium.
6. Only transfer to ambulance after target temp reached (≈30 min window to prevent organ damage).

Cramps & Electrolyte Loss

• Often recur once they start; preventive focus: adequate sodium, "pickle-juice regimen" for serial crampers.

Cold-Related Illnesses

• Frostnip → reversible superficial cooling.
• Frostbite → tissue freezing; never rub/friction re-warm.
• Hypothermia
  • Mild: shivering, pale skin, impaired fine motor control; often occurs at $50^\circ\text{F}$ with wet clothes + wind.
  • Moderate/Severe: core $<90^\circ\text{F}$, confusion → treat as medical emergency.
• Field care
  • Move indoors/out of wind; remove wet garments; layer warm, dry clothing & blankets.
  • Warm sweet fluids if conscious; measure rectal temp for moderate cases.
  • Hot packs OK but avoid direct heat on frostbite.
• Prevention: layered clothing, monitor weather, erect shelters (ice-fishing hut, sideline tent), hot packs/hand-warmers.

Pharmacologic & Equipment Toolkit

• Altitude: Diamox, Nifedipine, Dexamethasone, portable O₂ cylinder.
• Heat: Rectal thermistor/DATATHERM, immersion tub or tarp kit, ≥$100\,\text{lb}$ ice supply, potable water, shade structure, weigh-scale.
• Cold: Hot packs, dry blankets, rectal thermometer, warmed IV fluids in severe hypothermia.

Emergency Action & Ethical Considerations

• Develop written policies (heat, cold, altitude) endorsed by administrators & coaches.
• Education for athletes, parents & staff on symptom reporting; remove stigma of “weakness.”
• Maintain equipment on-site (tub on field, not 600 yd away; gators may fail).
• Always err on life-threat first: Treat as altitude/heat until ruled out.
• Legal precedent: multiple deaths from ignoring water breaks; negligence lawsuits.

Real-World Scenarios & Examples

• University of Alabama football traveling to Boulder, CO: plan $\ge48\,\text{h}$ early arrival + monitor AMS.
• IndiaHikes trekking groups: experienced trekkers more likely to hide symptoms due to peer pressure.
• Rapid City, SD soccer match in $3^\circ\text{F}$ wind chill: ice-fishing tent used as on-site warming shelter.
• Corey Stringer (NFL) fatal heat stroke → launch of Corey Stringer Institute; gold-standard research & guidelines.

Key Numerical Benchmarks (Quick Reference)

• AMS threshold: $\ge8{,}000\,\text{ft}$.
• HAPE/HACE can appear $$9