Diagnosis of poisoning

Baselt, R. C., Inappropriate Use of Immunoassays as a Quantitative Tool, /. Anal. Toxicol, 13,1,1989. Staub, C., Hair Analysis Its Importance for the Diagnosis of Poisoning Associated with Opiate Addiction, Forensic Sci. Int., 63, 69, 1993. 

When tablets or capsules are found in the immediate vicinity of, or in the possession of, an unconscious patient, it is reasonable to assume that a drug overdose has been taken. If the patient responds to supportive treatment and no active measures are contemplated, toxicological analyses are of historical interest only. Conversely, when circumstantial evidence is lacking, a diagnosis of poisoning may be difficult to sustain simply on die basis of clinical examination, since coma induced by drugs is not readily differentiated from that caused by disease processes. The role of the laboratory is important in several types of poisoning cases. 

The presence of miosis is a most important sign and is more helpful in determining the diagnosis of poisoning than measurement of erythrocyte AChE activity soon after presentation. The absence of miosis either raises serious doubt about the diagnosis, if exposure was secondary to the release of vapour, or suggests that exposure has produced only sub-clinical poisoning. 

Toxicology is the science which involves the investigation of the poisoned patient. In the symptomatic patient, the diagnosis of poisoning is made more often on clinical rather than laboratory findings. In all cases of suspected poisoning, the following biochemical determinations should be requested ... 

Diagnosis of poisoning is often made clinically. Symptoms may be specific or non-specific. 

Measurement oi blood and urine levels are used in diagnosis of poisoning. 

Essential clinical laboratory tests. Simple, readily available clinical laboratory tests may provide important clues to the diagnosis of poisoning and may guide the investigation toward specific toxicology testing. 

---