Archive for December, 2006

Toxins #5 – Fugu Poisoning

December 29, 2006

Pufferfish Poisoning = Fugu:

Even though it is a bit exotic, no blog on fish poisoning would be complete without a discussion of Takifugu, a Japanese delicacy.

This is a more of an intentional than accidental poisoning, in that someone purposely ate a fish that they knew was toxic and could potentially kill them. 

But, they ate it anyway.

In the wilderness setting, someone would have to catch a pufferfish and then decide to eat it. 

In the process they could get fugu poisoning.

Fugu, or to be exact, Takifugu, is a pufferfish that is commonly found in oceans between the latitudes of 45N and 45S. 

When approached by a predator, if inflates itself to 2 -4 times its normal size. 

As a further defense, it also contains a deadly poison – Tetrodotoxin in its internal organs, sex organs, and skin. 

In order to serve this “delicacy,” you have to be a specially trained and licensed fugu chef. 

Tetrodotoxin:

Tetrodotoxin or anhydrotetrodotoxin 4-epitetrodotoxin, is a neurotoxin that is 1200 times deadlier than cyanide.
 
It causes paralysis of the muscles but leaves the victim fully conscious as they die of asphyxiation.
 
The pufferfish does not produce the toxin but instead harbors a Pseudomonas bacteria in its tissues that elaborates the tetrodotoxin.

Symptoms of Fugu poisoning:

History – they have recently been eating pufferfish
Onset is rapid – minutes
Muscular paralysis
Dyspnea and respiratory failure

Treatment of Fugu poisoning:

Support respiratory and circulatory systems until the effects of the tetrodotoxin
wears off.

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Toxins #4 – Shellfish Poisoning

December 27, 2006

Shellfish Poisoning

A local guy showed us how to harvest fresh oysters and clams.  For dinner we ate a big old bucket of fresh-from-the-sea raw oysters, and a pile of steamed clams for dinner. What a treat.  But, within a few hours, we all developed nausea and a sort of drunken feeling – a little hard to walk straight and a kind of floating sensation.  I wouldn’t want to take a sobriety test right now. 

Shellfish Poisoning:

There are three forms of shellfish poisoning, Paralytic, Neurotoxic, and Amnesic.

All caused by the consumption of filter feeders that have fed upon dinoflagellets containing different types of saxitoxins.

These poisonings usually occur with a bloom of the algae such as Red Tide – when the water temperatures and nutrients are favorable for rapid multiplication of the algae, and their numbers increase to the point where they color the water red or brown. 

When this occurs, areas of shellfish harvesting should be closed to prevent the consumption of the filter feeders. 

Like ciguatoxin, these saxitoxins are also heat-stable, so cooking will not eliminate the
biotoxins.

History is important in the diagnosis, in that they have recently eaten filter feeders; mussels, clams, oysters, scallops, cockles, crabs, or lobsters. 

As these filter feeders feed upon the dinoflagellets and diatoms, they concentrate the various types of saxitoxins in their gut tissues. 

Unfortunately, these tissues are usually consumed with the rest of the filter feeder. 

The exception is the scallop. If the adductor muscle is the only portion of the scallop that is eaten, it is safe because it does not contain the saxitoxins.

These three forms of shellfish poisoning; Paralytic, Neurotoxic, and Amnesic, are caused by three different types of saxitoxin, each from a different type of dinoflagellet or diatom that was consumed by the filter feeder.

Paralytic Shellfish Poisoning:

Symptoms: 

Onset is 2 – 24 hours.
Paresthesias of the face, arm, legs
Headache
Dizziness
Nausea
Muscular incoordination
“Floating sensation”

Severe Symptoms:

Muscle paralysis
Respiratory failure
Death is rare, but it can occur due to respiratory failure in 2 – 24 hours.
 
Neurotoxic Shellfish Poisoning:

Symptoms:

Onset in 1 – 3 hours.
Paresthesias of the mouth, arms, and legs
Incoordination
Gastrointestinal upset: nausea, vomiting, diarrhea
Can have temperature reversal

Amnesic Shellfish Poisoning:

Biotoxin is from a diatom – Nitzchia pungens

Symptoms: 

Onset in 2 – 24 hours
GI distress: nausea, vomiting, diarrhea
Dizziness
Headache
Disorientation
Permanent short-term memory loss – yes PERMANENT

Severe Symptoms:

Seizures
Weakness progressing to paralysis
Death

Treatment of all forms of shellfish poisoning:

Supportive care; rest, liquids, and treat the symptoms.
There are no antitoxins available.
Spontaneous recovery in 2 days to months. 
The short-term memory loss can be permanent.

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Toxins #3 – Scromboid Poisoning

December 25, 2006

Scromboid Poisoning:

We went to a local restaurant on the beach last night, known for their fresh mackerel caught that day.  It was delicious.  But, several hours later we all had nausea, vomiting, diarrhea, a red rash, sweating, and a strong metallic taste in our mouths.  We must have had too much of the cheap local beer. 

Scromboid:
 
Scromboid poisoning occurs when tuna, mackerel, or bonito are caught, but not properly refrigerated before cooking and eating. 

If the fish is not kept alive or refrigerated bacterial spoilage of the fish will occur. 

The bacteria will multiply in the fish flesh and convert the histidines, naturally occurring chemicals in the flesh of the fish, to histamines. 

When the fish is later eaten, the individual will essentially get an overdose of histamines. 

Like the biotoxins, the histamines are heat-stable, so cooking does not offer protection.

Symptoms:

Onset occurs in 2 minutes to 2 hours
Rash
Flushing
Diarrhea
Vomiting
Abdominal pain
Sweating
Headache
Burning or swelling of the mouth
Metallic taste

Treatment:

Antihistamines.
May need epinephrine, i.e. treat like anaphylaxis.

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Toxins #2 – Fish Biotoxins

December 21, 2006

Ciguatera Poisoning:

Can occur when various marine finfish (barracuda, red snapper, grouper, amberjack, sea bass, triggerfish, or other reef fish) are consumed. 

Because they are high up on the food chain, they can accumulate a great deal of the biotoxins in their digestive organs.

The risk is in eating any large fish from tropical and subtropical waters of the West Indies, Caribbean, Pacific, and Indian Oceans between the latitudes of 35N to 35S.

In these waters the filter feeders have been consuming small dinoflagellets (algae), in particular, Gambierdiscus toxicus, and these algae contain ciguatoxin (CTx-1).  As the ciguatoxin progresses up the food chain, it becomes concentrated in the intestinal tracts of the fish. 

If they have not been cleaned properly, eliminating the contents of the bowel, consuming them can be toxic due to ciguatoxin.

Signs & Symptoms of Ciguatera Poisoning:

Ciguatera can cause gastrointestinal, neurological, or cardiovascular symptoms.

History – the patient has recently eaten fish, from a species of marine finfish.

Onset of symptoms is typically in about 6 hours but can occur in 10 minutes – 24 hours after eating the fish.

Symptoms:

Gastrointestinal – usually mild:

Nausea

Vomiting

Diarrhea

Numbness & tingling about the mouth and extremities (paresthesias)

Neurological – can be severe:

Paresthesias

Muscle pain – myalgia, arthralgia

Dizziness & vertigo

Headache

Sensation of temperature reversal: hot feels cold and cold feels hot

Cardiovascular – can be severe:

Dysrythmia – Arrhythmia

Bradycardia

Tachycardia

Decreased BP (hypotension)

Treatment:

Is strictly supportive care: rest, liquids, and treat the symptoms.

There is no antitoxin.

It may take days to weeks to recover.  

Deaths are rare; they are secondary to respiratory and cardiovascular failure.

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Toxins #1 – The Manchineel Tree

December 18, 2006


This week we find ourselves in the Caribbean so it seems fitting to write a few informative blogs about medical emergencies, specifically potential poisons that are peculiar to this part of the world. 

Manchineel Tree Poisoning: The Death Apple 

Recorded on the internet is an account of what happened to two curious gentlemen while staying on a Caribbean island:  Strolling along a beautiful, deserted beach in the Caribbean, they found some fruit that looked like small green apples under a large tree overhanging the beach. After one of the gentlemen took a bite of an apple and found it to be quite sweet and tasty, his friend and he both then each ate one and found them very satisfying.  After 10 minutes or so, they noticed an unusual burning sensation in their mouths that evolved into swelling and tightness of the throat and difficulty swallowing.  Alcohol seemed  to make the symptoms worse.      

poisonous tree 

Manchineel Tree: 

One particular toxic plant worth mentioning is the manchineel tree, Hippomane mancinella, also known as the beach apple or death apple.  This tree grows on the shores of islands and coastlines of the Caribbean Sea.  A large deciduous tree that has a small green apple-like fruit, it is considered to be one of the most poisonous plants on earth.  Given this distinction, it is a tree worth being able to recognize when traveling in this part of the world.  Do not sit under it, even during a rain storm, as the droplets of water falling off it contain enough toxic latex to cause a severe contact dermatitis.  For the same reason do not touch the leaves, the bark, or burn the wood.  The apple-like fruit of the tree contains a potentially deadly poison.  The two adventurers mentioned in the preceding paragraph might well have expired from their experimental taste-test.

This  tree contains tigliane phorbol esters.  Skin contact can cause blistering, burns, erythema, swelling, and inflammation.  If ingested, it will cause burning and swelling of the oral mucosa, esophageal ulcerations, edema, and cervical lymphadenopathy, making it impossible to swallow, difficult to talk, and hard to breathe.

 

Treatment consists of cleansing the skin with soap and water to remove the plant latex, being careful to avoid further exposure and using  antihistamines to minimize the immune response and the edema.

There is more information about this and other ocean-related toxins in a recent Wilderness Medicine Newsletter, entitled Poisonous Pearls.

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Cold-Related Injuries #10 Hospital Management of Hypothermia

December 16, 2006

1.  Recognize Hypothermia:
Use low-reading thermometers and use esophageal thermometer to monitor core temperature.

2.  Airway: 
Obtain a patent airway and ventilate. 
Beware – using heated, moist air will suppress the shivering mechanism.
Shivering is the most efficient way to rewarm.

3.  ECG and continuous cardiac monitoring:

4.  Monitor Labs:
CBC, electrolytes, glucose, ABG (do not adjust for temperature)

5.  Initiate rewarming:
Shell: if > 30°C, maintain blood sugar to encourage shivering, peripheral rewarming.
Core: if < 30°C and unconscious, arteriovenous fistula and body cavity lavage.
In cardiac arrest, cardiopulmonary bypass is preferred for rewarming.

6.  Warning:
Low core temperature potentiates the fibrillatory effect of elevated K and a low pH.

An excellent reference is:
Chapter 58, Hypothermia and Hyperthermia, Clinical Critical Care Medicine, Albert, et. al., published by Mosby 2006.

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Cold-Related Injuries #9 Hypothermia – The Alligators

December 14, 2006

Alligators:
Like alligators, these are some of the problems that seem to sneak up and bite you when you least expect them.

1.  Not recognizing cold, stiff, cyanotic patient as resuscitatable.
The unconscious hypothermia victim, <86°F, has stopped shivering and is in a state of suspended animation (not hibernation). 
They appear breathless – a slow, shallow breath every 10 – 15 seconds.
They appear pulseless; at <90°F the blood is 190% thicker than usual, therefore, the pulse is not palpable, and the heart valves are not slamming shut, so no heart sounds.
The skin is very cool, pale gray or cyanotic, and firm to the touch.
If alive, they are curled up in the fetal position. 
When they die, they tend to extend their limbs and may have vomitus in or around their mouth.
If alive, when you gently pull on an arm, it will extend out; when released, it will flex back against the body.  It takes life to contract a muscle.

2.  Field use of CPR on a functional heart.
If possible, attach to a cardiac monitor. If flatline, they are in arrest.
If they have a cardiac rhythm, they are not in PEA – you just can’t feel the weak pulse.

3.  Criteria for pronouncing dead:
No palpable pulse and ECG is flat line.
No respirations.
Skin color is pale gray, cyanotic, and cold.
They have rigidity.
Pupils are fixed.
Failure to revive after rewarming –  “Not dead until warm and dead.”

4.  Continuing active rewarming past 32°C with a high K and a low pH.
Remember, hypothermia is not a disease.  Take your time.
These folks have normal physiology for that temperature.  With rewarming, the cells hve to have time to adjust the chemistry and move the K back into the cells.

5.  Using too many drugs when cold; anti-arrhythmics, calcium channel blockers.
We do not know how drugs affect the body at subnormal core temperatures, this has never been studied.  Hypothermics have poor peripheral circulation.  Drugs end up pooling in the peripheral circulation. With rewarming, the peripheral circulation is re-established. The drugs will flood into the system with potentially disasterous consequences, i.e. post rewarming overdose.

6.  Confusing immersion with submersion.
Immersion
– When immersed, the airway does not go below the surface of the water.
This is shell hypothermia not drowning, and patients are easily resuscitated.
Submersion – their airway went below the surface; they have drowned, have core hypothermia, and are harder to resuscitate.

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Cold-Related Injuries #8 – Treatment of Hypothermia

December 12, 2006

STAGES OF HYPOTHERMIA:

98.6F – Normal
97F – Brain fails; judgment fails; protective and survival instincts fade.
96F – Shivering begins as a constant (uncontrollable) fine motor tremor.
94F – Shivering increases, coordination fails, tripping and falling begin.
92F – Shivering becomes intense; patient is unable to walk.
90F – Shivering becomes convulsive, fetal position is adopted; patient is unable to talk.
86F & below – “Metabolic Icebox”:  unconscious, ashen gray, may appear pulseless/breathless.

TREATMENT:   

Remove from immediate danger and further exposure.
GET DRY & KEEP DRY. Insulate with hypothermia wrap.
Give warm, sweet liquids – Jell-O if conscious.

Click on the image below to see a hypothermia wrap.

hypo-wrap-for-blog.gif

The Hypothermia Wrap – “The Human Burrito”

Remove wet or damp clothing.
Insulate with multiple layers of dry material, clothing, blankets, sleeping bags.
Cover and insulate their head with a warm hat.
Super-insulate their feet and add chemical heat packs if you have them.
Insulate from the ground with ensolate pads.
Surround with a windproof & waterproof layer.

PREVENTION: 

Know your enemy: 
Be prepared for wet, wind, and cold.
Wear fabrics that stay warm when wet (NO COTTON!).
Stay dry. Stay well HYDRATED.
Snack often on quick-burning carbohydrates – sugar.
Carry bivouac gear and know how to use it.
Be attentive to yourself, to your companions, and to the environment.
Do not tolerate the cold or cold extremities.
React early & quickly.

For more detailed information on Hypothermia see the Jan/Feb 2004 issue, When Jack Frost Bites, and the Nov/Dec 2004 issue, Frozen Mythbusters, of the Wilderness Medicine Newsletter. Click on this link to learn more about or subscribe to the Wilderness Medicine Newsletter.

This blog is powered by the Wilderness Medicine Newsletter, now celebrating 20 years of publication. The WMN is published and distributed online six times each year by TMC Books, and subscriptions cost as little as $10 per year. To find out more, or to subscribe online, click here.

Cold-Related Injuries #7 – Hypothermia

December 10, 2006

HYPOTHERMIA

Hypothermia is a lowering of body’s core temperature to level where normal brain & muscle function are impaired.
It is the one of the most common threats and causes of wilderness emergencies.
We are a hairless mammal, designed for the hot tropics, not the cold environs.
We have little or no defense against the cold, other than behavior, i.e., wear warm clothing.

THERMOREGULATION:
Balance of heat production & heat loss.
Thermoequilibrium is monitored & controlled by the brain.
Thermoregulation is performed by the skin, via the vasculature.

Heat Production: 
Internal sources:
Basal metabolism – burning of glucose to produce heat
Nutrition/digestion – “logs on the fire”
Exercise/shivering – muscle contraction to produce heat (as byproduct)
External sources:
Fire, stoves, sun, other people

Heat Loss:         
Conduction – heat transfer from one solid object to another
Convection – heat transfer from solid object to air
Radiation – infrared energy given off by warm objects      
Evaporation – heat transfer to water during liquid to gas change

Body’s defensive reaction to cooling off: 

NO WARNING OF IMPENDING DOOM
Peripheral vasoconstriction
– skin’s attempt to decrease heat loss.
Involuntary shivering – muscles’ attempt to produce heat.
Increased basal metabolism – may increase to 5 times its normal rate.

For more detailed information on Hypothermia see the Jan/Feb 2004 issue, When Jack Frost Bites, and the Nov/Dec 2004 issue, Frozen Mythbusters, of the Wilderness Medicine Newsletter. Click on this link to learn more about or subscribe to the Wilderness Medicine Newsletter.

This blog is powered by the Wilderness Medicine Newsletter, now celebrating 20 years of publication. The WMN is published and distributed online six times each year by TMC Books, and subscriptions cost as little as $10 per year. To find out more, or to subscribe online, click here.

Cold-Related Injuries #6 – Raynaud’s Disease

December 8, 2006

Raynaud’s Disease:

This is also a non-freezing cold injury. 
It is a hypersensitivity reaction to cold exposure.
It is more of a nuisance than a limb-threatening injury.
This condition has been caused by chronic cold exposure and, for some unknown reason, the peripheral circulation has now developed an exaggerated response to the cold which now occurs at warmer temperatures, i.e., not as cold as it used to have to be.  The peripheral circulation in the hands and/or feet will now overreact and vasoconstrict or close down too much.
So, the response is too early and too much.
Upon rewarming, there is also an exaggerated response: the skin will turn red, and painful.  The extremity may also throb with pain during the rewarming process.
Once rewarmed the tissues should return to normal.

Treatment of Raynaud’s:

Avoid and limit cold exposure.
Keep the affected areas well-insulated, warm, and dry.
Avoid nicotine, caffeine, alcohol, and over-the-counter decongestants.
Drugs:  may try calcium channel blockers for their vasodilatory effects.
 Eg:  Nifedine XL 30 – 90mg po qd, or diltiazem 30 – 120mg po qid.
“Pavlovian” response trials, also known as Murray’s Method (for Dr. Murray Hamlet),  a technique to re-educate the nerves affecting the vasculature.

Rehabbing Raynaud’s or Murray’s Method:

Equipment: 2 – 4 Styrofoam coolers, 2 for hands + 2 for feet.
Warm water.
Warm inside & cool, <32°F (0°C) outside.
Fill the Styrofoam coolers with warm water, 105°F – 110°F, one set inside and one set outside.
Start inside, dressed lightly so that you are comfortable, and sit with your hands or feet in the warm water for about 5 mintues; then, get up and go outside.  Stay lightly dressed, and put your hands or feet in the warm water outside, for 5 – 10 minutes. 
For this to work your body has to be able to cool off while your hands and feet stay warm.  This is the re-education process.
You have to repeat this process about 50 times.  It seems to be most effective when you do this about 5 times a day, every other day.

Click on the images below to see full size.

raynauds-2-for-blog.gif   raynauds-1-for-blog.gif

For more detailed information on Raynaud’s Disease see the Jan/Feb 2005 issue of the Wilderness Medicine Newsletter, Non-Freezing Cold Injuries.  Click on this link to learn more about or subscribe to the Wilderness Medicine Newsletter.

This blog is powered by the Wilderness Medicine Newsletter, now celebrating 20 years of publication. The WMN is published and distributed online six times each year by TMC Books, and subscriptions cost as little as $10 per year. To find out more, or to subscribe online, click here.