Lightning Injuries

An expert panel from last year’s Wilderness Medical Society Annual Meeting have produced Guidelines for the Treatment and Prevention of Lightning Injuries.  Of course, there is not a great deal of high quality evidence in this area but the guidelines are a good summary of expert opinion.

To provide guidance to clinicians about best practices, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the treatment and prevention of lightning injuries. These guidelines include a review of the epidemiology of lightning strikes and recommendations for the prevention of lightning strikes, along with treatment recommendations organized by organ system. Recommendations are graded based on the quality of supporting evidence according to criteria put forth by the American College of Chest Physicians.

Here are some of the key points:

An estimated 400 lightning strikes occur annually in the United States, with a lifetime risk of lighting strike estimated at 1 in 10, 000.  Most victims are males between the ages of 20 and 45.

There are four types of lightning injury

  1. Direct strike – rare, caused by uninterrupted connection between the lightning bolt and the individual
  2. Contact injury – when a persons is in contact with object struck by lightning
  3. Side splash – the current follows the path of least resistance and “splashes” from a nearby object to the victims body
  4. Ground current – the lightning travels through the ground from the strike point to the recipient

Prevention

When thunder roars, go indoors

In the wilderness setting, leave high risk areas such as ridgelines, summits, ski-lifts, water or isolated trees.  Relying on timing lightning flashes with thunderclaps may engender a false sense of security.
 Individuals should instead rely on observing signs of impending storms and seeking cover accordingly. Individuals should wait a minimum of 30 minutes after hearing the last thunderclap before resuming outdoor activity.
The safest shelters are buildings or hard-topped vehicles.  In the wilderness, possible shelters include deep caves, dense forests or deep ravines.

When lightning strike is imminent, sit or crouch with knees and feet close together to create only one point of contact with the ground.  Hmmm, and cross your fingers?

In a mountain climbing environment, tie off individually and discard metal items to avoid contact burns.

Injuries and Treatment

Cardiac

The mechanism of sudden death from lightning strike is simultaneous cardiac and respiratory arrest. Death is rare should a victim survive the initial lightning strike.

Asystolic arrest classically occurs due to simultaneous depolarization of all myocardial cells, although ventricular fibrillation may also occur.  The medullary respiratory centre remains paralysed after return of  cardiac automaticity, so a second cardiac arrest may result if ventilation is not supported.  For this reason, those patients without vitals signs or spontaneous respirations should take priority.

Resuscitation should follow basic and advanced life support algorithms.  In fact, mortality from cardiac arrest due to lightning strike has a lower mortality than cardiac arrest in the general population.

Direct strikes are more likely to cause cardiac arrest.  Other types of strikes may cause transient ECG abnormalities.

Patients with any of the following high risk indicators for lightning strike should have a screening ECG and echocardiography.

  • Suspected direct strike
  • Loss of consciousness
  • Focal neurologic complaint
  • Chest pain or dyspnea
  • Major trauma defined by Revised Trauma Score 4
  • Cranial burns, leg burns or burns 10% TBSA
  • Pregnancy

Neurologic

Neurologic injuries are common and may include transient loss of consciousness, headache, weakness, confusion and memory loss.
Keraunoparalysis is transient paralysis after lightning strike and is thought to be caused by overstimulation of the autonomic nervous system leading to vascular spasm.
Typically lasting several hours, the affected limbs exhibit pulselessness, pallor or cyanosis, and motor and sensory loss.  Spinal injury must be excluded, particularly if paralysis continues despite resolution of vascular symptoms.

Lightning strike may also cause hypoxic encephalopathy, intracranial heamorrhage and a multitude of delayed neurological syndromes.

Dermatologic

The pathognomonic Lichtenberg figures are a “ferning” pattern on the skin usually occurring within an hour of lightning strike and resolving within 24 hours.  No treatment is required.

Lightning strike can cause linear burns from sweat vaporization, punctate burns from current exiting deep tissues, and full-thickness burns from contact with  heated objects.

 Others

  • Cataracts comprise the majority of eye injuries, and can occur between 2 days and 4 years after lightning strike.
  • Tympanic membrane rupture is common, and can occur from a combination of blast trauma and electrical injury.
  • Abnormalities in memory and concentration
  • Depression, sleep disturbances,  emotional lability, and aggressive behavior.
Bomana

Kokoda part 2 – On the Trail

Fluids

Your body’s fluid balance will be placed under considerable stress while hiking in the humid mountain jungle of Papua New Guinea.
Risks of dehydration include strenuous exercise, hot climate and illnesses such as diarrhoea. Some blood pressure medications called diuretics can also increase your risk of dehydration. Symptoms include increased thirst, dry mouth, decreaed urine output, weakness, fatigue and confusion. Severe dehydration can lead to seizures, coma and death.

Too much fluid can be equally dangerous. The practice of “drinking as much as possible” has lead to a condition called exercise associated hyponatraemia (EAH).  Symptoms of EAH include lightheadedness, confusion, weakness, seizures and even death.
Just how much should you drink? The best guide is your body’s thirst requirement.

Only drink fluids when you are thirsty.

A rough guide is a maximum volume of 750ml/hour, with 1000ml/hour the absolute limit.

Diarrhoea

Diarrhoea during travel is thought to affect 10 million travelers each year. The most common cause is a bacteria called E. coli. Traveller’s diarrhoea is characterized by frequent loose bowel motions, abdominal cramps, nausea and vomiting. On trail, it can complicate an already grueling exercise with severe dehydration and fatigue.
The bacteria that cause traveller’s diarrhoea are sensitive to some antibiotics, including ciprofloxacin, norfloxacin and azithromycin. Prophylactic antibiotic treatment is not recommended for healthy adults.

This risk of contracting traveller’s diarrhoea can be substantially decreased by strict adherence to simple hygiene precautions. Wash hands before eating and after going to the toilet, purify all water, ensure food is freshly cooked and fruit (and nuts) are peeled.

For those who get traveller’s diarrhoea while on the Trail, a single large dose of antibiotic is usually all that is required
Ciprofloxacin – 1.5g
Norfloxacin – 800mg
Azithromycin – 1g

Chafing

Chafing is a potentially serious problem in the moist jungle environment of Papua New Guinea, leading to bleeding, skin infections and extreme discomfort. It can be prevented by the wearing of bike-pants-style elastic undergarments such as Skins. Careful, early attention should be given to any areas that appear to be chafing with liberal use of barrier ointments like Bepanthen. Infected chafing areas may require antibiotic therapy.

Injuries

The Kokoda Trail traverses slippery, steep, uneven slopes and sometimes treacherous river crossings. Almost any injury is possible. Those suffering serious injuries will require evacuation, usually by a combination of jungle stretcher and helicopter.
Injury prevention measures include:

• Boots with good ankle support and grip
• Trekking poles – one or two, depending on personal preference. Trekking poles decrease the amount of force going through your knee and ankle joints and also provide stability on slippery downhills
• Personal carrier. Decreasing the load on your back will improve your balance and decrease back strain injuries. A personal carrier will also assist you across log bridges and in slippery areas of the track.

Personal medical kit

Everyone’s personal medical kit is different, but here is a list to start you off.

Malaria prophylaxis
Ibuprofen or similar anti-inflammatories
Antibiotics – We recommend cephalexin (for wound infections, urinary tract infections) and ciprofloxacin (for diarrhoea)
Antihistamine – for allergies, insect bites/stings
Antifungal ointment or powder
Bepanthen or similar barrier ointment
Mosquito repellent
Sunscreen
Disinfectant gel for handwashing
Waterproof elastoplast – two rolls
Strapping tape – two rolls
Blister dressings – prevention and treatment
Band-Aids (waterproof)
Pocketknife – with scissors, tweezers, etc
Sports drink powder – useful for masking taste of purified water.

Isurava Memorial

Kokoda part 1 – Preparation

Three important medical considerations before embarking on the iconic Kokoda Trail are immunisation, assessment of medical fitness and, last but not least, malaria.

Immunisations

Current recommendations are for immunisation against

  • Typhoid
  • Hepatitis A

A combination Typhoid/Hepatitis A vaccine (Vivaxim) is available. This should be given at least 14 days (preferably one month) prior to risk of exposure.  A booster is required for Hepatitis A after 6 – 12 months which will provide immunity for up to 10 years.  A Typhoid booster is required every 3 years.

The current Australian Immunisation Handbook recommends that short term travellers should consider JE vaccination if there is “considerable outdoor activity”.  To date, no Australian trekkers in PNG have been diagnosed with Japanese Encephalitis.  A new vaccine (Jespect) was released in Australia in 2009 which has less side effects than the older vaccine.  So, on balance, trekkers to Kokoda probably should be immunised for Japanese Encephalitis.  It is a two-dose vaccine, given four weeks apart.

We also recommend ensuring Hepatitis B and Tetanus immunisations are current.

Medical Assessment

There is no medical test that can guarantee your safety while on the Kokoda Trail.  However, we believe there are steps you can take to minimise the risk.

All trekkers should be examined by their local doctor and have an electocardograph (ECG) performed.

We recommend that all trekkers over the age of 40 have an exercise stress echocardiogram prior to commencement of training.

Those with risk factors such as obesity, smoking, diabetes, high blood pressure, high cholesterol or strong family history of cardiac disease should have an exercise stress echocardiogram if over the age of 30. Trekkers with known cardiac disease should  see their cardiologist and have a stress echocardiogram or myocardial perfusion study prior to commencement of training.  Trekkers with a Body Mass Index (BMI) of greater than 35 probably shouldn’t be trekking in a remote mountainous jungle.

Malaria in PNG

Malaria is a significant problem throughout PNG and is a major risk in the major cities and also in the more remote jungle regions. Whilst it was once thought that it was too cold in the PNG highlands for the malaria transmitting mosquitos to breed, this is definitely not true. The plasmodium falciparum species is responsible for more than 85% of malaria cases in PNG however both plasmodium vivax and plasmodium malariae species are also occasionally reported. The mosquito that transmits malaria is small and frequently not noticed when biting.

Malaria Prevention

Prevention of mosquito bites is by far the most effective method for preventing malaria infection and this involves:

  • wearing long sleeve shirts and long pants – particularly in the afternoon and evening when the mosquito is most active
  • Applying DEET based mosquito repellent (Bushman’s is a good brand) – this should be applied first thing in the morning and then reapplied at lunch time and then again in the evening
  • Clothes and sleeping bag liners can be soaked in pyrethrin prior to departing for your trek (see your local trekking supplies store)
  • Sleep in a tent with mosquito netting

Doxycycline. One tablet each day for one week prior to departure until four weeks after returning home. The most common side effects are heartburn/reflux and exaggerated sunburn response. Be sure to apply adequate sunscreen if using doxycycline. This medication is also an antibiotic and theoretically provides protection against wound infections and possibly even against diarrhoeal illness (although the diarrhoea bacteria are mostly resistant).


Mefloquine
 (Lariam). One tablet each week starting 1 – 2 weeks prior to departure until four weeks after returning home. Mefloquine’s main advantage is its once-weekly dosing. Side effects include nightmares, insomnia and nausea. It can rarely lead to psychiatric disturbances and seizures. Trekkers taking beta-blocking cardiac medication, those allergic to quinine or with a history of seizures should not use mefloquine.

Atovaquone/proguanil (Malarone). Malarone is a newer combination tablet taken once daily for two days prior to departure until one week after returning home. Malarone can occasionally cause nausea, vomiting, diarrhoea, abdominal pain and headaches, although side effects are usually mild.

The most effective method of malaria prevention is to avoid mosquito bites. Liberal use of insect repellant and tents with mosquito netting are essential.