Rapid Responses to:
|
|
Rapid Responses: Rapid Responses published:
-
![[Read Rapid Response]](/icons/misc/sectionDOWN.gif)
Oximes
- Smarajit Chowdhry, HARDWAR INDIA 249408 (24 March 2007)
-
Calcium-activated butyrylcholinesterase in human skin acts as a natural antidote for organophosphorus pesticide poisoning
- Karin U Schallreuter (5 April 2007)
-
Prognostic value of QTc
- Roshana Shrestha (11 May 2007)
-
Meiosis or Mydriasis ??
- Abhay Nigam, P.O.Box 11049, Ras Al Khaimah, UAE (17 June 2007)
-
Chronic exposure may also be a problem
- Daniel R Hicks (22 June 2007)
|
|
|||
|
Smarajit Chowdhry, Physician R K M S Hospital, HARDWAR INDIA 249408
Send response to journal:
|
Frirst I would like to say that this is an excellent review on Organo phosphorous poisoning (OP), comprehensive and complete. But my experience at the hospital where I work where we treat at least 20 cases each year of severe OP poisoning is that we are often able to do without using Oximes at all. What is crucial is timely ventilatory support and keeping the airway clear and adequate atropinisation. To the best of my knowledge at Christian Medical College Vellore they never use oximes for OP Poisoning with no difference in outcome.
Smarajit Chowdhry
Competing interests: None declared |
|||
|
|
|||
|
Karin U Schallreuter, Professor for Clinical and Experimental Dermatology University of Bradford, Bradford, West Yorkshire, BD7 1DP, UK
Send response to journal:
|
We read with great interest the article by Roberts and Aaron(1) in the March issue of the BMJ on the management of acute organophosphorus poisoning. A special role for butyrylcholinesterase (BuChE) induction to protect suicide inhibition of acetylcholinesterase (AChE) by organophosphorus pesticides was presented as a management strategy for acute poisoning.(2) In this context we would like to make a comment. The human epidermis holds the full capacity for autocrine acetylcholine synthesis, degradation and signal transduction within keratinocytes and melanocytes.(3) Moreover, this tissue holds also a steep calcium gradient from inside to outside.(4) Recently our research group demonstrated that BuChE is highly expressed in the epidermal compartment and enzyme activity is increased 9-fold by calcium. In fact calcium binds to a specific EF-hand domain promoting rapid hydrolysis of organophosphates.(5,6) Based on these results we concluded that human skin uses BuChE to protect the activity of epidermal AChE in this tissue against toxic organophosphates.(5,6) In the light of Roberts and Aarons review it seems tempting to suggest that the induction of BuChE together with the addition of calcium could provide an effective treatment strategy for acute cases of organophosphorus pesticide poisoning. Professor K.U. Schallreuter
Competing interests:-none declared. 1 Roberts D M, Aaron C K. Management of acute organophosphorus pesticide poisoning.BMJ,March 2007; 334: 629-34 2 Eyer P. The role of oximes in the management of organophosphorus poisoning. Toxicol. Rev. 2003; 22: 165-90 3 Grando S A, Pittelkow M R, Schallreuter K U. Adrenergic and cholinergic control in the biology of epidermis: physiological and clinical significance J Invest Dermatol 2006; 126: 1948-65 4 Menon G K, Grayson S, Elias PM. Ionic calcium reservoirs in mammalian epidermis: ultra-structural localisation by ion-capture cytochemistry J Invest Dermatol 1985; 84: 508-12 5 Schallreuter K U, Gibbons N C J, Zothner C, Elwary S M, Rokos H, Wood J M> Butyrylcholinesterase is present in the human epidermis and is regulated by H2O2 :More evidence for oxidative stress in vitiligo.Biochem Biophys Res Communs 2006;349: 931-38. 6 Schallreuter K U, Gibbons N C J, Elwary S M, Parkin S M, Wood J M. Calcium-activated butyrylcholinesterase in human skin protects acetylcholinesterase against suicide inhibition by neurotoxic organophosphates.Biochem Biophys Res Communs 2007; 355: 1069-74 Competing interests: None declared |
|||
|
|
|||
|
Roshana Shrestha, MDGP kathmandu 977-01
Send response to journal:
|
I would like to thank Darren M Roberts and Cynthia K Aaron for the excellent review on managing acute organophosphorus poisoning. Acute organophosphorus poisoning is still a major cause of morbidity and mortality in Nepal since agriculture is the main occupation here and OP compounds are widely and easily available in ordinary shops and are often stored improperly due to lack of awareness of their hazards. As mentioned in this article a reduction of cholinesterase activity guides to the severity of intoxication, but cholinesterase assays are not routinely or rapidly available.The authors haven't mentioned about doing an ECG for prognostication. Early ECG evaluation with special attention to QT interval may be a useful predictor of serious cardiac morbidity and mortality, respiratory failure (1,2,3). The simplicity and promptness of evaluating an ECG allow emergency physicians to perform early and effective triage. In the initial emergency care of patients with OP poisoning, it is essential to monitor QTc interval along with other important parameters mentioned in this article. 1.Saadeh AM:Cardiac manifestation of acute carbamate and organophosphate poisoning. Heart 1997;77:461-464 2.Chuand FR:QTc prolongation indicates a poor prognosis in patients with organophosphate poisoning. American Journal of Emergency Medicine 1996;14:451-3. 3. Grmec S. GCS score and QTc interval in the prognosis of organophosphate poisoning. Academic emergency medicine 2004;11:925-30. Competing interests: None declared |
|||
|
|
|||
|
Abhay Nigam, Specialist Physician Hudaibah Medical Center, P.O.Box 11049, Ras Al Khaimah, UAE
Send response to journal:
|
Dear Sir, In reference to the article about “organoposphorous poisoning” in the June, 2007 issue, I would like to point out following: Meiosis is an important clinical sign of Organophosphorous poisoning which has not been mentioned anywhere in the article, on the contrary, mydriais is mentioned on page 129 - Box 2. Which is indeed surprising. Regards Dr. Abhay Nigam MBBS, MD (Medicine) Specialist Physician Hudaibah Medical Centre Ras Al Khaimah, U.A.E. Competing interests: None declared |
|||
|
|
|||
|
Daniel R Hicks, Programmer Byron MN 55920 USA
Send response to journal:
|
While there is significant (though certainly not abundant) information about acute organophosphate exposure available, far less is known about chronic exposure, and it's probably far less likely to be accurately diagnosed. I have become aware of this due to a family member who only retrospectively can be seen to have suffered likely chronic organophosphate exposure in repeated sub-acute exposures over a period of 2-3 years. His initial presenting complaint was leg weakness which was diagnosed as probable viral neuropathy, but a connection to occupational (farming) exposure to organophosphates was not made, and no effort was made to modify his occupational practices. Subsequently, over decades, he developed further leg weakness, along with the knee and hip joint problems that typically accompany such muscle weakness. Even more disabling were the mental/psychological problems that developed (typical for organophosphate poisoning), causing a range of paranoid and psychotic behaviors, ultimately resulting in a felony conviction. It's important to note that a patient is likely to deny the improper use of agricultural chemicals, either out of fear of legal repercussions or out of a sense of "macho". So it's vitally important for the diagnostician to have a "level of suspicion" that is informed by the local culture and the patient's occupation, in addition to explicit information from the patient. Competing interests: None declared |
|||