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organophosphate toxicity
Etiology: absorption through skin
Pathology:
- cholinesterase inhibition
Clinical manifestations:
1) bradycardia
2) bronchorrhea & wheezing
3) pulmonary edema
4) miosis
5) fasciculations, rarely seizures
6) abdominal pain, nausea, vomiting, diarrhea
7) urination, lacrimation, salivation, diaphoresis
8) hypoxemia, confusion
Acronyms for manifestations
1) SLUDGE
a) Salivation
b) Lacrimation
c) Urination
d) Defecation
e) GI upset
f) Emesis
2) DUMBELS
a) Diarrhea
b) Urination
c) Miosis
d) Bronchospams
e) Emesis
f) Lacrimation
g) Salivation
Laboratory:
1) plasma cholinestesase & erythrocyte cholinesterase levels are < 50% of normal
2) serial plasma cholinesterase activity to confirm trend towards normal
Special laboratory:
- pulse oximetery
- electrocardiogram, telemetry
Complications:
- patients may drown in their own secretions
- cognitive impairment with long-term exposure? [4]
Management:
1) general
- health care workers should be gowned & gloved
- remove patient's clothing
- shampoo hair
- clean all skin surfaces
- resolve respiratory symptoms
- do not wait for test results to start treatment in seriously ill patients
2) ventilatory support as needed
3) pharmaceutical agents
a) atropine 0.02-0.05 mg/kg IV every 15 minutes
- treats muscarinic effects
- titrate dose to minimize dyspnea, airway resistance, & bronchial secretions
b) pralidoxime 20-50 mg/kg IV every 2-12 hours
- treatment of CNS toxicity
- continuous infusion 1g/hour may be better
- addresses both nicotinic & muscarinic effects
c) Duodote autoinjector (atropine, pralidoxime)
d) benzodiazepine (diazepam, lorazepam) for seizures
General
toxicity; poisoning; overdose
References
- Saunders Manual of Medical Practice, Rakel (ed), WB Saunders,
Philadelphia, 1996, pg 1153-55
- Pawar KC et al,
Continuous pralidoxime infusion versus repeated bolus injection
to treat organophosphate pesticide poisoning: A randomized
controlled trial.
Lancet 2006, 368:2136
PMID: 17174705
- Medical Knowledge Self Assessment Program (MKSAP) 14,
American College of Physicians, Philadelphia 2006
- Baldi I et al.
Neurobehavioral effects of long-term exposure to pesticides:
Results from the 4-year follow-up of the PHYTONER Study.
Occup Environ Med 2010 Nov 22
PMID: 21097948
http://oem.bmj.com/content/early/2010/10/18/oem.2009.047811