Positron emission tomography scan in cortical visual loss in patients with organophosphate intoxication
Section snippets
Case 1
A 37-year-old woman who had experienced blurred vision and vertical nystagmus for approximately 1 year visited our outpatient department. She had been attacked by her boyfriend with an injection of 15 ml O-ethyl-O-p-nitrophenyl phenylphosphonate over her left buttock area on July 1995. She had been sent to a local hospital and received atropine injection as an antidote. She was transferred to our hospital. Endotracheal intubation with ventilatory support was given immediately. Atropine and
Results
In case 1, the FDG-PET images showed remarkably decreased FDG uptake in the visual cortex (Fig 3B). The metabolic values (visual cortex/cerebellum ratio of FDG uptake) for the occipital visual areas were also lower than the mean metabolic values of the visual cortex in normal volunteers (Table 1).
In case 2, the metabolic images revealed hypometabolism in the visual cortex (Fig 3C). The metabolic values for the occipital visual cortex were decreased in comparison with the normal reference values
Discussion
Organophosphate insecticides act as irreversible cholinesterase inhibitors. The inhibition of cholinesterase activity leads to the accumulation of acetylcholine at synapses, causing overstimulation and subsequent disruption of transmission in both the central and the peripheral nervous systems. The clinical manifestations of acute organophosphate poisoning include overstimulation of muscarinic, nicotinic, and central nervous system receptors.7 Muscarinic overstimulation may show miosis;
References (22)
- et al.
Organophosphate poisoning
Ann Emerg Med
(1987) - et al.
Retinal degradation in rats exposed to an organophosphate pesticide (fenthion)
Environ Res
(1983) - et al.
Intense brain cortical enhancement on CT in laminar necrosis verified by biopsy
AJNR Am J Neuroradiol
(1987) - et al.
Early CT findings of global central nervous system hypoperfusion
AJR Am J Roentgenol
(1983) - et al.
CT of generalized gray matter infarction due to hypoglycemia
AJNR Am J Neuroradiol
(1981) - et al.
MRI demonstration of cortical laminar necrosis and delayed white matter injury in anoxic encephalopathy
Neuroradiology
(1990) - et al.
Physiologic functional imaging in “functional” visual loss
Surv Ophthalmol
(1996) - et al.
Cerebral metabolism and patterned visual stimulationa positron emission tomographic study of the human visual cortex
Neurology
(1988) Assessment of neurotoxic potential of chlorpyrifos relative to other organophosphorus compoundsa critical review of the literature
J Toxicol Environ Health
(1995)Eye injury by organic phosphorus insecticides (preliminary report)
Jpn J Ophthalmol
(1971)
Chronic optico-neuropathy due to environmental exposure of organophosphate pesticides (Saku disease)clinical and experimental study
Nippon Ganka Gakkai Sasshi
Cited by (19)
Retrochiasmal Disorders
2018, Liu, Volpe, and Galetta's Neuro-Ophthalmology: Diagnosis and ManagementClinical Toxicology of Anticholinesterase Agents in Humans
2010, Hayes' Handbook of Pesticide ToxicologyClinical Toxicology of Anticholinesterase Agents in Humans
2010, Hayes' Handbook of Pesticide Toxicology, Third Edition: Volume 1Brain injury due to acute organophosphate poisoning: Magnetic resonance imaging manifestation and pathological characteristics
2007, Neural Regeneration ResearchPET and SPECT Imaging of Neurotoxicity
2020, PET and SPECT in NeurologyClinical features of organophosphate poisoning: A review of different classification systems and approaches
2014, Indian Journal of Critical Care Medicine