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Heat Cramps
From WikiSM
Contents
Other Names
- Heat Cramps
- Sweat Cramps
Background
- This page refers to heat cramps, a heat related illness
History
- Described as early as 1878 in men working in Nevada gold mines
- First described in the literature by Talbott in 1932[1]
Epidemiology
- Not well described
Pathophysiology
- General
- Occurs from diffuse sweating, loss of sodium chloride, replacing fluid loss with water
- Most commonly occurs in the hours following exercise
- Most athletes will have resolution with oral isotonic fluids
- Climate
- Typically occurs in warm, humid environments
- Can be seen in winter months in some sports (hockey goalies, cross country skiing, etc)
Etiology
- General[2]
- Not entirely understood
- Believed to be due to relative dehydration and loss of sodium from sweating
- Hyponatremia is likely exacerbated by hypotonic fluid replacement
- Magnesium, calcium, potassium also lost but are primarily intra-cellular and do not contribute to cramping
- Hyponatremia
- Sodium plays a critical electrolyte in the balance of net charges across a neuron's membrane
- Plays a vital role in maintaining baseline neuro-excitability across neurons
- Hyponatremia alters the net charge across the cell membrane, increases neuron excitability
- Increased excitability thought to trigger the sustained, inappropriate skeletal muscle contractions seen in cramping.
- Dehydration[3]
- May also be enough to trigger cramping
- Occurs through alteration in the relative concentration of interstitial sodium and neurotransmitters,
- Subsequently, athletes develop hyperexcitability and cramping
Associated Conditions
- Exercise Associated Muscle Cramps (EAMC)
- Seperate clinical entity
- Heat cramps ikely represents the extremy end of muscle cramping seen in athletes
- Heat Exhaustion
- Some authors consider heat stroke to be a symptom of heat exhaustion rater than a seperate clinical entity[4]
Risk Factors
- Sports
- American Football, especially in summer months
- Tennis
- Cycling
- Running
- Soccer
- Volleyball
- Basketball
- Baseball
- Cross Country Skiing
- Hockey
- Occupational
- Workers who toil in extreme heat
- Miners
- Stokers
- Steelworkers
- Cane cutters
- Firemen
- Roofers
- Medications
- Other
- High sweat salt content
- Age > 40
- Obesity
- Sickle cell trait
- Ethanol use
- Low baseline fitness
- Copious hypotonic fluid replacement
- Sunburns
- History of previous cramping episodes
- Sleep deprivation
- Increased duration of training or competition
Differential Diagnosis
Differential Diagnosis of Muscle Cramps
- Exercise Associated Muscle Cramps
- Hyponatremia
- Heat Cramps
- Heat Tetany
- Muscular strain or tear
- Tendinous strain or tear
- Fracture
- Nerve root irritation
- Myositis
- Peripheral neuropathy
- Claudication
Differential Diagnosis Heat Illness
- Minor
- Major
Clinical Features
- History
- Patient will report painful, involuntary, spasmodic muscle contractions
- Cramps may be brief or sustained (seconds to hours)
- Typically involves calves, then thighs and shoulders
- Physical Exam
- Cramping is often obvious on exam with increased involuntary muscle tone
- Intense pain is exhibited by the athlete while the contraction is sustained
- The patient should be neurologically intact
Evaluation
- Clinical diagnosis
- Expanded workup may be indicated if clinical picture is not clear
Classification
- Not applicable
Management
- General
- Self limited condition
- Remove athlete from game or practice
- Rest in a cool environment
- Stretching and massage
- Muscle stretching and massage can help
- Affected muscle should be held at length until the contraction resolves with a slow full stretch
- Hydration
- Mild: isotonic sports drinks or electrolyte enhanced drinks
- Severe: IV isotonic fluids
- Avoid hypotonic fluids such as water, which can worsen hyponatremia
- Home remedy: 1 quarter tablespoon of salt, 2 tablespoon of sugar, 500 cc of water[5]
- Pain/ Muscle relaxant
- May require enteral or parenteral analgesia
- In prolonged or refractory cases, benzodiazepines may be indicated
- The following lack evidence for use
- Calcium tablets
- Pickle juice
- Bananas
- Dextrose
- Sodium bicarbonate
- Quinine
Prevention
- General
- Drink isotonic electrolyte solutions during work, sport or practice[4]
- Increase dietary salt
- Add salt to sports drink
- Become acclimated with training environment
- Sweat rate
- All athletes should know their sweat rate (weight lost per hour of exercise + fluid consumed per hour during exercise)
- Provides rough estimate of how much fluid should be ingested between events, sessions, games, etc
Rehab and Return to Play
Rehabilitation
- No specific rehabilitation protocol
- Passive stretching
- Massage therapy
Return to Play/ Work
- General
- Once cramping has resolved, assess for any injuries or systemic symptoms of hyponatremia
- Athlete may return to play if exam is reassuring
- The athlete should be counseled that same day recurrence is very high and may precipitate other injuries
- If benzodiazepines are administered, the athlete should not return to play the same day
Complications and Prognosis
Prognosis
- Generally considered a self limited condition with no long term sequalae
- Lost playing time
- Common cause
Complications
- Rhabdomyolysis
- Uncommon, typically does not involve enough muscle[6]
See Also
References
- ↑ Talbott J.H., Michelsen J. Heat cramps. A clinical and chemical study. J Clin Invest. 1933; 12: 533-549
- ↑ Poynter, D. (2010). Heat Cramps: Treatment and Prevention. Athletic Training and Sports Health Care, 205-207.
- ↑ Schwellnus MP, D. N. (2008). Muscle cramping in athletes–risk factors, clinical assessment, and management. Clinical Sports Medicine, 27(1):183.
- ↑ 4.0 4.1 Donoghue, A., M.J. Sinclair, and G.P. Bates. Heat exhaustion in a deep underground metalliferous mine. Occup. Environ. Med. 57:165-174, 2000.
- ↑ Armstrong LE, Casa DJ, Millard-Stafford M, Moran DS, Pyne SW, Roberts WO. American College of Sports Medicine position stand: Exertional heat illness during training and competition. Med Sci Sports Exerc. 2007; 39:556–572.10.1249/MSS.0b013e31802fa199
- ↑ Waters T. Heat Emergencies In: Tintinalli's Emergency Medicine: A Comprehensive Study Guide. 7th ed. McGraw Hill Medical. 2011: 1339-1344
Created by:
John Kiel on 30 June 2019 22:49:39
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Last edited:
18 September 2022 00:26:04
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