Keywords
chemical burns - dichloromethane burns - methylene chloride burns
Introduction
Chemical burns account for 3% of all burns but constitute 30% of burn deaths[1]
[2]. Sixty percent of these burns are workplace-related. Methylene chloride is a colorless,
volatile, liquid organic solvent with a sweet, chloroform like odor and is commonly
used in paint removers/strippers, metal cleaner/degreaser, and pharmaceutical manufacturing.
Its most common routes of poisoning are via inhalation in closed spaces and through
skin absorption, although occasional poisoning via oral ingestion is also reported.[3] This poisoning, although rare, has very high fatality rates.[4]
[5] Early recognition of the condition and prompt initiation of treatment are the only
measures to reduce fatality. Only one other case of methylene chloride burns is reported
in medical literature.[2] The authors are sharing their experience of a case of methylene chloride burns and
reviewing literature of this form of poisoning in this article.
Case Presentation
A 55-year-old male went to clean the paint on the inner walls of his overhead water
storage tank. When he did not return back even after an hour, his family found him
lying unconscious inside the tank. He presented to our emergency department (ED) unconscious
and burns over the face, neck, abdomen and left lower limb. There were no associated
comorbidities or any other relevant contributory or past history. He was pulseless
and had hemodynamically unstable ventricular tachycardia on arrival and was started
on advanced cardiovascular life support (ACLS). Electrical cardioversion was done
with 200 Joules of energy, and he was given 150 mg of injection amiodarone intravenous
(IV) bolus stat to achieve normal sinus rhythm. Along with this, he was given 100
mEq of injection sodium bicarbonate, 3 mg of injection midazolam, and started on 100
mL/hour of normal saline infusion in ED. Since he was having irregular breathing,
severe respiratory acidosis, and was unconscious even after ACLS, he was intubated
and shifted to medical intensive care unit (MICU). The chemical bottle brought was
labeled as “heavy duty paint remover,” with its main composition being methylene chloride.
Serial hemogram, liver and kidney function tests were done and were normal throughout
the course of his treatment. Initial arterial blood gas analysis revealed severe acidosis,
which progressively improved over the course of treatment. However, carboxyhemoglobin
levels could not be measured as the hospital did not have a co-oximeter. In the MICU,
he received the treatment, as shown in [Table 1].
Table 1
|
Drug
|
Dose and frequency
|
Route of administration
|
|
Abbreviations: CPAP, continuous positive airway pressure; DVT, deep vein thrombosis;
IPPV, intermittent positive pressure ventilation; SIMV, synchronized intermittent
mandatory ventilation.
|
|
Injection amiodarone
|
300 mg
|
Intravenous infusion
|
|
Injection cefoperazone/sulbactum
|
3 g stat followed by 1.5 g twice a day for 5 days
|
Intravenous
|
|
Injection clindamycin
|
600 mg thrice a day for 5 days
|
Intravenous
|
|
Normal saline
|
100 mL/hour for 2 days then tapered and stopped
|
Intravenous
|
|
Levosalbutamol sulfate 1.25 mg + ipratropium bromide 150 µcg in 2.5 mL
|
2.5 ml respule four times a day for 1 week
|
Nebulization
|
|
Budesonide 0.5 mg
|
2 mL respule four times a day for 1 week
|
Nebulization
|
|
Injection midazolam
|
Started at 1 mg/hour; titrated over 48 hours as per patient’s behavioral pain scale
score and then stopped
|
Intravenous
|
|
Injection fentanyl
|
Started at 100micrograms/hour; titrated over 48 hours as per patient’s behavioral
pain scale score and then stopped
|
Intravenous
|
|
Injection noradrenalin
|
Started at 40 nanograms/kg body weight/min; titrated as per patient’s mean arterial
blood pressure and stopped after 48 hours.
|
Intravenous
|
|
Ventilation
|
Patient put on IPPV mode; then, shifted to SIMV mode, CPAP mode, and finally put on
T-piece. Initially, FiO2 was kept at 70% and then reduced to 50% after 4 hours as
he started maintaining SPO2 of 100% with lesser oxygen requirement. Thereafter, it
was further weaned off.
|
|
|
Supportive measures
|
Ryle’s tube in situ for 72 hours after which it was removed.
Foley’s catheter in situ for 5 days.
DVT prevention stockings.
|
|
The scalp, face, neck, right shoulder, left side of abdomen and left lower limb were
involved in 15% burns [Fig 1]. Fluid requirement was revised accordingly. Wounds were thoroughly washed with saline.
Facial burns had a glossy dark brown appearance, while debridement of abdominal blisters
revealed yellowish green staining of the underlying dermis. Burnt surface areas were
neutral to red and blue litmus papers. Facial and neck burns were treated with 2%
mupirocin ointment application thrice a day, while nanocrystalline silver dressings
were used for abdomen and left lower limb. The patient was on ventilatory support
for initial 48 hours after which he was extubated. After a week, the patient was discharged
on oral antibiotics and painkillers and followed-up on outpatient basis for burns
dressings. Facial burns healed in 10 days, while left lower limb and abdominal wounds
healed in 3 weeks under dressings [Fig 2].
Fig. 1 Burns right side of face. Patient on ventilatory support after cardiopulmonary resuscitation
(day 1 of admission).
Fig. 2 Burns front of Face. (2 months later).
Discussion
Methylene chloride poisoning typically occurs due to its volatile nature in a typical
setting of closed space. In the case report by Wells GG, the victim was cleaning a
3 feet × 3 feet × 6 inch vessel when toxic fumes built inside the vessel rendered
the patient unconscious, resulting in his fall and subsequently developing burns to
areas with direct contact with methylene chloride.[2] Its toxicity is due to solvent induced narcosis and carbon monoxide generation,
which leads to carboxyhemoglobinemia.[6] It metabolizes via two pathways:
-
1) At low exposure via oxidative CYP2E1 pathway, formyl chloride forms, most of which
gets metabolized to carbon mono-oxide (CO).
-
2) At higher exposures via glutathione S-transferase pathway, methylene chloride conjugates
to glutathione.
The important points learnt from our case and reviewing literature are as follows:
-
1) Methylene chloride poisoning, although rare, carries a high fatality rate.[4]
[7]
[8]
[9]
-
2) The main organ affected is the central nervous system (CNS), with presenting symptoms
varying from stupor, irritability, unconsciousness, decreased motor activity, changes
in response to sensory stimuli, acute neurobehavioral deficits, memory loss, and fatty
liver. Besides acute toxic effects, it is known to cause brain, liver, hepatobiliary,
and hematopoietic malignancies.[5] Early diagnosis and prompt initiation of treatment is the only way to prevent fatality.
Burn surgeons should be aware of this presentation to initiate appropriate prompt
treatment.
-
3) Burns are usually second or third degree.[7] Both in the case reported by Wells[2] and that being reported by the author, they healed under appropriate dressings without
any surgical intervention. Burn treatment is usually of secondary importance here,
as systemic symptoms are severe and need attention on a priority basis to save life.
This is different from acid or alkali burns where with a similar percentage of burns,
the main presenting complaints are local burn-related symptoms.
-
4) These burns may mimic livor mortis, which sets in 1 to 2 hours after cardiac arrest.
Mimicry of methylene chloride burns appearance with liver mortis may lead to a false
impression to the treating physician that patient may have suffered cardiac arrest
hours back rather than few minutes back, leading to an error of judgement, translating
to pursuance of the cardiopulmonary resuscitation with less enthusiasm and causing
death, which can be avoided if the burn surgeon is well versed with above facts.[7]
-
5) Rescuers and caregivers must wear proper gloves, gowns, and goggles before handling
these patients, else they may become victims, as the mode of this poisoning is via
inhalation and skin absorption. They must also have self-contained positive-pressure
breathing apparatus with a full-face mask for self-protection, as they are prone to
suffering inhalation injuries during rescue/treatment.[7]
-
6) Prompt recognition and early resuscitation is the only approach of preventing fatality
in methylene chloride poisoning and burns.[4]
[7]
[8]
[9]
Conclusion
Methylene chloride burns are a rare entity with dramatic systemic presentation. Burns
are usually second or third degree and can be managed conservatively as per author’s
experience and the only case report by GG Wells in 1984, however lack of knowledge
of the presentation of these burns may lead to misdiagnosis, delay in treatment, and
death. The only hope for survival in these burns is prompt recognition of the condition
and initiating treatment at the earliest.
