Mustard gas
The name mustard is because
the original product had a strong smell of mustard, due to impurity. Though
the present day product is odorless, when combining with a number of substances
in the field has a garlic odor, or rotten onion odor. Mustard gas is synonymous
of sulphur mustard, or yperite. It is a 2,2’-di(chloro-ethyl)-sulphide.
The name yperite (or yprite) comes from the Belgian village of Ypres where
it was used for the first time by the German army in 1917. In German it
was called "Lost"
The name "blistering" refer
to the production of blisters and burns in the affected skin. However mustard
agent causes lung and eye injuries, as well as intestinal mucosa injury
if ingested. It should be called blistering and tissue-injuring agent.
Mustard was synthesized
in 1822, its blistering and tissue injuring properties were observe in
the 1860s. After its use in World War 1, in the 1930s it was discovered
that activity was unchanged if the sulphur atom was substituted by a nitrogen
atom. These new agents are called nitrogen-mustards, for instance 2,2’three(chloroethyl)amine,
or HN3. In studying mustard gas toxicity it was noticed that both sulphur
mustard and nitrogen mustards were causing bone marrow depression few weeks
after exposure. There was bone marrow hypoplasia and lymph nodes hypoplasia.
This observation led to the idea of utilizing these agents in the treatment
of prolipherative disorder of bone marrow and lymph nodes such as leukemia
and limphoma. In the 1940s Gilman of Yale University pioneered the use
of nitrogen mustards in the treatment of limphoma. Since then nitrogen
mustards have become an important group of cancer chemotherapy agents.
Among the most common nitrogen mustards are Chlorambucil (Leukeran) and
Cyclophosphamide (Cytoxan). These cancer chemotherapy agents are cell-cycle
phase non specific, which means are acting on the dividing cells, though
to a more or less degree they still can have toxicity to non proliferating
cells. At the dosage of 0,1 mg/Kg body weight / daily Chlorambucil, and
of 3 mg/Kg body weight/daily Cyclophosphamide, are active in a number of
leukemia, lymphoma and solid tumors. As collateral toxicity they are carcinogenic,
mutagenic, suppressing gonadal activity with amenorrhea – azoospermia.
The immune response is depressed, and in combination with the bone marrow
depression both will cause increased incidence of microbial infection,
delayed healing, gengival bleeding and stomatitis. There will be loss of
hair in the scalp. The common mechanism is attack to DNA strand (alkylation,
by which the name alkylating agents). Now all the described action are
seen in the delayed damage caused by mustard gas exposure, and explain
the observed pathology, for instance burns which are healing very slowly
compared with burns from other causes.
Yet the blistering and direct
tissue injury effect of mustard gas (sulphur mustard) are acute and their
basic mechanism is against structural proteins and peptides in to the cells
and cell membranes. This activity has carefully been eliminated or strongly
reduced in cancer chemotherapy by molecular manipulation and dosage of
nitrogen mustards..
Physical and chemical
properties
Though is frequently called
mustard gas, in reality is a liquid with low volatility. It does behave
like a gas around the site of explosion when used in rockets or artillery
shells. It can be mixed with mainly two other substances, Lewisite and
chlorinated rubber polymer (thickened mustard). Lewisite (2 part of Lewisite
and three parts of mustard) makes the mixture more active at lower temperature.
The addition of chlorinate rubber polymer makes the mixture more persistent
and more difficult to remove by decontamination.
Mustard is somewhat soluble
in water, where it is slowly hydrolyzed (inactivated). In running water
due to surface mixing inactivation proceed more rapidly, while in stagnant
water persistency can be of several months. This is due to the tendency
of large volume of mustard agent in stagnant water to remain in undissolved
bulk. Hydrolysis is more rapid in alkaline environment. Bleaching powder
and chloramines react rapidly with mustard and non-poisonous oxidized products
are formed. This is the base for water and hypochlorite (bleach) use
in decontamination procedure.
Detection
Mustards form colored complex
molecules with para-nitrobenzpyridine thus making possible to detect minute
amount. There exist single and three color detector paper, as well as water
testing kits. They are not presently available.
Protection
Ordinary clothing gives
little or no protection against mustard agent. In addition to the respiratory
route, mustard penetrates the skin and is easily absorbed by the intestine
if ingested. Masks only do protect the eyes and lungs during gas spreading,
but are otherwise useless because the gas does penetrate through the skin.
Special full gear total body equipment is therefore needed for protection,
including a hood and overboots.
All this equipment is available
only in special ad hoc military units. Is unrealistic to expect it to be
available for the population by en large, and even for paramedical civilian
personnel. One has to use good sense and being alert. Arriving on the scene
of an attack the mustard agent can be found persisting everywhere but much
less so in the air because is not a gas and will not persist in great amount
in the air. This despite the presence of odor of garlic, or rotten onion.
However conjunctivitis has been reported after exposure of one hour duration
in barely perceptible odor environment. In case of smelling of garlic,
rotten onion, "fishy" smelling, geranium oil smelling (Lewisite) is advised
to move oneself and the exposed individual somewhere else to carry out
decontamination. Rubber surgical type gloves must be wear and changed frequently.
Water used for washing is still containing active mustard and must be disposed
of accordingly.
Signs and symptoms
There will be a delay of
some two hours between exposure and the onset of symptoms. The described
mechanism of action does take that much of time at the cellular level.
However if mustard has been mixed with Lewisite, this agent is immediately
and acutely causing pain, clearly because somehow does damage or stimulate
immediately the superficial pain fibers. If immediate pain is referred
by exposed individual this means Lewisite was present in the mixture. Fortunately
decontamination procedure and first aid are the same whether Lewisite was
present or not.
So about two to four hours
after the exposure there will a series of worsening signs of inflammation
of eyes, lung and skin. Depending on the amount of exposure there will
be aching of the eyes follows by inflammatory signs of conjunctivitis,
abundant tears and swelling of the lids. Hoarseness and cough and sneeze,
rhinorrhea, burning of the throat. Cough will be initially dry then may
progress to copious expectoration. The skin will be red in the contaminated
part, and blisters will then appears. Some areas might be more affected
then other typically arm pit and perineum, or popliteal fossa and anterior
elbow. The severity of lesions will determine their progression. It is
at this stage decontamination of at least skin and eyes will arrest damage
of agent persistency and reduce infective complication.
Nothing much can be done
about ingested mustard. There might be loss of appetite, and vomit and
bloodstained feces or bloody diarrhea in the worst cases.
Later damage and consequences
will be the one mentioned in the cancer chemotherapy collateral damage.
Prophylaxis and treatment.
Decontamination
There is no drug treatment
available to prevent the effect of mustard.
There is no specific treatment
available for the treatment of mustard lesions, the aim of therapy is to
1) Relieve symptoms 2) Prevent infections 3) Promote healing.
We are talking of decontamination
of eyes skin mucous membrane and wounds. All contaminated clothing should
be removed wearing rubber gloves and placed in plastic bag without touching
the outer surface of the bags. Bags should be closed by one other person,
placed in a second bag and given to patients or family. (This is to avoid
unnecessary accumulation in one site only of contaminated material. If
possible and alternatively a specific contaminated waste disposal method
will be followed) The family must be instructed in burying the bags or
else empty the bags content, without touching it, in heavy chlorinated
(bleach) water for decontamination, and washed without touching it with
large load of detergent.
Fresh surely uncontaminated
cloth should be given to wear, if appropriate, at the end of decontamination.
If burns are present they should receive first aid dressing and referred
– transported to the designated referral hospital accordingly
Eyes
Should be gently washed
with water, diluted baby shampoo can be used instead of soap, then rinsed
with saline solution (physiologic, 0,9%), or if available, isotonic sodium
bicarbonate (1,26%). Saline solution and or isotonic sodium bicarbonate,
both diluted to tolerance, can be used to rinse mouth and throat. Liquid
used for washing should be disposed off with intelligence. If eyelids are
swollen they should gently be separated before washing. If corneal lesion
obviously present antibiotic eye ointment and atropine eye ointment should
be applied b.i.d (twice a day) to prevent infection and adhesion of the
iris, and application should be continued till medically indicated. Systemic
antibiotics are indicated if infection is obviously spreading.
Skin
Main decontamination for
skin is done with diluted hypochlorite solution, 0,05% dilution can be
obtained mixing ten cc. of 4,5% commercially available hypochlorite (bleach,
Javel water,) in one liter of water, then with water and soap, finally
washing with water again, in the order given. Rinsing fluids should be
treated as still potentially damaging. Known more affected areas such as
armpit, perineum and genitalia, popliteal and antebrachial fossa, should
carefully be insisted upon. Fresh surely uncontaminated clothes or track
suites or pajamas should then be used for redressing.
Wounds
Wounds should be inspected,
if particle present they should be removed with sterile, if available,
forceps. It is mandatory to remove ‘thickened’ mustard (mustard combined
with rubber polymers), if necessary kerosene should be used to facilitate
removal. Further diluted hypochlorite solution, 0,005% which is one to
two cc per liter of commercially available 4,5% hypochlorite (bleach) solution,
should be used to irrigate the wound. (NATO manual suggest irrigation
of wounds with a more concentrated solution, 0,3% to 0,5% for two minutes
followed by rinsing. However NATO manual discourage "wet" shower type decontamination,
with the only exception of open contaminated wound. While increasing the
concentration of hypochlorite should increase the degree of decontamination,
yet that concentration is irritating and possibly damaging exposed tissue.
–J Burn Care Rehabil, 1991 sep-Oct; 12(5) 420-4. If at all possible a lower
concentration is probably better). Water, if possible sterile, or boiled,
or at least drinkable should then be used for final rinsing before sterile
dressing applied. Anything removed from wound being suspected of contamination
should be dealt with in a bleach solution to minimize possible vaporizing
of gas.
If appropriate ad hoc showers
are available, one should add bleach to the water tank in the proportion
given, which is 10 cc of 5% bleach per liter of water. The shower area
should be decontaminated in between patients with higher concentration
of bleach chlorinated water with common household detergent added using
common floor cleaning swap.
There are chlorinated powders and ointments which offer better deactivation (NATO manual recommend this type of "dry" decontamination) and do away with the need of water and washing and the risk of contaminated water, but they are not presently available.