dichlorvos ( dimethyl-2 , 2-dichloro vinyl phosphate ) is an organophosphorous ( op ) insecticide with moderate human toxicity , used for insect control in food storage areas , greenhouses , barns and control of insects on livestock .
parenteral dichlorvos administration with suicidal intention is rarely reported in the literature . in one case report
, extensive muscle necrosis was reported following intramuscular injection of dichlorvos . in another case , following injection of dichlorvos subcutaneously in both wrists , a young patient developed compartment syndrome requiring fasciotomy . in both cases
, i describe the case of a young female patient , who developed atypical signs of op poisoning following subcutaneous injection of dichlorvos .
the present case report is about a 37-year - old , previously healthy female , who was admitted to our intensive care unit 18-h after alleged self - injection of 76% dichlorvos ( nuvos ) 3 ml in the upper left arm ( 3 times with a 1 ml insulin syringe ) . within an hour of the injections
, she had normal body temperature with heart rate of 90/min , blood pressure 110/70 mmhg , respiratory rate 14/min and pulse oximeter showing 100% saturation on room air .
no crackles were heard on chest auscultation . on the nervous system examination , she was jittery with slurred speech and normal cranial nerves .
she had hypertonia , brisk tendon reflexes , bilateral sustained ankle clonus and bilateral extensor plantar reflex .
local examination revealed a blister and a black necrotizing lesion over the anterior aspect of the left arm [ figure 1 ] .
she was rapidly atropinized with incremental boluses of atropine ( total dose 12 mg ) in next 30 min ( targeting a dry mouth ) followed by infusion of 1.8 mg / h .
pralidoxime infusion was started at 500 mg / h following a loading dose of 1000 mg over 20 min .
intravenous clindamycin ( 600 mg q 8 h ) was administered empirically for presumed local wound infection .
debridement of the wound showed predominant involvement of the subcutaneous tissue plane with minimal necrosis of the superficial fibers of biceps brachii .
initial routine laboratory investigations were unremarkable except elevated total count ( 16200/mm ) and mild respiratory alkalosis .
local skin necrosis with surrounding blisters her clinical course was complicated by respiratory arrest 9-h after hospital admission ( 27-h after the injection of dichlorovos ) leading to hypoxia and bradycardia .
arterial blood gas analysis post resuscitation showed - ph 7.28 , po2 - 36 mmhg , pco2 - 54 mmhg , hco3 - 22 mmhg .
serum choline esterase ( pseudo cholinesterase ) level of the same day showed a very low value of < 1 ku /
she could be successfully weaned off from the ventilator on day 4 . on day 5 , while on atropine infusion she was found to be delirious .
she was also noticed to have extrapyramidal manifestations including rigidity and left sided gaze preference .
in this case , other than the unusual route of administration , a number of atypical manifestations were found .
this includes relatively delayed respiratory failure and central nervous system ( cns ) manifestations with few muscarinic signs .
two independent mechanisms are thought to be responsible for respiratory failure following op insecticide poisoning  cholinergic cns depression in the early stage ( associated with other cholinergic features ) and late progressive neuromuscular transmission defect .
second mechanism is part of the syndrome described as  type ii paralysis  by wadia et al . or intermediate syndrome by senanayake and karalliedde . our patient developed respiratory arrest 27-h after exposure to dichlorovos .
in her clinical course she never had neck or proximal muscle weakness , though the clinical findings were not correlated electrophysiologically .
usually cns signs are manifested early in the course in the presence of peripheral muscarinic signs . in a large series published on neurological manifestations of op compounds , 8 of 200 patients had pyramidal tract signs in the form of only hyper - reflexia manifesting within 24 h of exposure .
all these patients were unconscious with florid cholinergic manifestations , including constricted pupils . in their original series of intermediate syndrome senanayake and karalliedde , observed hyperreflexia in one of their patients ( with flexor plantar reflex ) and even she had typical muscarinic signs .
extrapyramidal signs of op poisoning are often transient and may be missed in a sick patient . in a taiwanese series
cns manifestations ( both pyramidal tract and extrapyramidal ) were delayed and were associated with relatively scanty peripheral muscarinic signs .
possible explanation for these atypical manifestations in our patient could be route specific ( in this case subcutaneous ) effect of op compound ( dichlorovos ) causing isolated delayed cns depression , with few peripheral cholinergic signs .
animal experiments have shown route specific ( subcutaneous or intravenous ) cardiovascular and neuromuscular effect of op compounds in rats .
 current case report describes a 37-year - old female patient who was admitted to the hospital following subcutaneous injection of dichlorvos with an insulin syringe . 
 the only peripheral cholinergic sign observed on admission was excessive salivation with bilateral pyramidal tract signs . 
 locally she had necrosis of skin and subcutaneous tissue with surrounding blisters . 
 in the subsequent course of her illness , she developed respiratory arrest requiring ventilator support . 
 she also had delayed extrapyramidal manifestations . 
 relevant literature is reviewed . 
 possibility of route - specific , delayed predominant central nervous system effect of dichlorvos postulated . 
Introduction
Case Report
Discussion