# Thallium Poisoning: Case Report and Scoping Review on Diagnostic Delay and Therapeutic Outcome
## 5 Discussion
### Our Observations
This ex juvantibus criterion should be followed in all cases in which the clinical picture is compatible with thallium poisoning because Prussian Blue is not very toxic and induces an improvement that can be the best guide for the clinician. Even in a medically advanced country like Italy, and in a hospital that, for decades, has had a Poison Control Center, of which the first author of this article is the Director, it is not easy to obtain a water dosage and a toxicological analysis within a period of time compatible with the survival of a thallium-poisoned patient. This is the main reason that leads us to stress the need to start immediate treatment for cases that could be caused by thallium intoxication, before the diagnosis of thallotoxicosis is confirmed. The rapid relief of painful symptoms and a pause in the progression of neurological damage are important indicators that enable us to calmly await the results of toxicological tests confirming the diagnosis. Conversely, in cases where the symptoms are due to a different cause, a few days of administration of a drug of low toxicity prevents the patient from running excessive risks. Lowering blood levels as soon as possible is the main objective when treating acute thallium poisoning [55]. Prussian Blue functions as a univalent cation exchanger that improves fecal clearance, blocks the enterohepatic circulation of thallium, and preferentially binds unabsorbed thallium in the gut. Activated charcoal, which is often administered alongside Prussian Blue, improves fecal removal while simultaneously adsorbing thallium. Activated charcoal and Prussian Blue are both recognized therapies; however, Prussian Blue is the standard of care because of its greater safety and effectiveness [106]. Nevertheless, these therapies cannot eliminate absorbed thallium that has reached the bloodstream. Prussian Blue cannot sequester thallium outside of the digestive tract, and thallium has a lengthy physiological half-life. Consequently, additional research has suggested combining Prussian Blue with blood purification procedures, including continuous veno venous hemofiltration, hemoperfusion, and hemodialysis, that use extracorporeal filtration devices to eliminate thallium from the bloodstream [107,108]. Animal studies suggest that the effect of PB may be increased by the concomitant administration of an ion exchange resin (calcium polystyrene sulfonate) [109]. The recommendation to use Prussian Blue for the emergency treatment of patients with symptoms such as those described above can encounter two main obstacles: firstly, the emergency physician must be aware of thallium poisoning and its treatment and suspect the disease, and, secondly, it is essential that the drug be available. Drug availability can be a problem since the limited number of cases is an obvious impediment to the hospital supply of the drug. The lack of the drug can be a serious problem, especially in countries where the probability of thallotoxicosis is higher [50; 60]. We therefore recommend that doctors working in peripheral hospitals contact larger hospitals with clinical toxicology services. The lack of knowledge about the effects of thallium and the clinical picture of intoxication can be effectively countered by referring to facilities, such as the Poison Control Center of the Gemelli General Hospital, that are able to provide advice in doubtful cases. The case presented also raises the problem of hygiene in homes. Italian law prohibits the introduction of non-potable water into the domestic water supply, and a dwelling with the characteristics described in the case reported is deemed unfit for habitation. It is surprising that the person who was poisoned had a degree in a subject that requires knowledge of the toxic effects of thallium, and it is difficult to understand how one could live for years in such a high-risk situation.