# Thallium Poisoning: Case Report and Scoping Review on Diagnostic Delay and Therapeutic Outcome
## 5 Discussion
### Our Observations  
Our clinical case matches those of other cases that have been documented in the literature, where the presence of a triad has been demonstrated, raising the possibility of thallium intoxication. This triad includes alopecia, signs of motor or sensory neurological impairment, and abdominal pain [98]. However, alopecia appears, as we have seen, several days after the onset of the clinical picture, which is initially characterized by paresthesia and sharp pain. Following thallium exposure, the presentation pattern typically includes vomiting, nausea, and abdominal pain in the first few hours after exposure, peripheral sensorimotor neuropathy after four or more days, and generalized alopecia weeks later. Cases of accidental poisoning have been reported recently [99], as well as cases of attempted suicide [31] and criminal intoxication in different countries, including Italy [59; 100; 101; 102]. A case of acute, nonintentional thallium poisoning was due to thallium-contaminated alternative medicine [103]. However, reports of poisoning were more frequent in the past. Thallium poisoning during pregnancy may have fetal effects ranging from severe toxicity with residual sequelae to outwardly normal development [104]. A recent case of criminal intoxication with long-term misdiagnosis and neurologic outcomes has also been observed [65]. Another case of criminal intent was studied for three years in six different hospitals without reaching a diagnosis [66]. Chronic intoxication is sometimes suspected with the onset of alopecia [61]. However, since thallium is tasteless, odorless, and water-soluble, and can be absorbed through the skin, inhaled, or ingested, thallium intoxication is frequently misdiagnosed, or the diagnosis is delayed. A retrospective analysis of cases with delayed admission showed significant symptoms associated with central nervous system damage and changes in magnetic resonance images and electroencephalograms [63]. Cases of severe neurological impairment with coma have been shown to respond positively to treatment; but the rarity of these occurrences prevents the generalizability of these observations [63]. Recently, an interesting report of a case of accidental thallium poisoning in a chemist who survived 10 years after intoxication has been published [68]. The first symptom was numbness in the feet; this rose up the legs, causing terrific pain. The paralysis included the digestive system, thus making the body unable to absorb food and causing cachexia. Severenerve damage was followed by alopecia. Initially, a neurologist diagnosed Guillain-Barre syndrome and prescribed immunoglobulin treatment and plasmapheresis. This incorrect treatment had no effect, whereas the correct diagnosis and treatment with Prussian Blue resulted in a very slow improvement. Thallium was used in the laboratory, but there had been no occupational exposure; the metal had probably been ingested through beverages. The early recognition of the diagnosis is generally the key to successful treatment, as was seen recently in reported cases of contaminated meat poisoning [19]. Cases of delayed diagnosis have an unfavorable outcome, as in the one recently reported by [PERSON] [105]. A 41-year-old male was admitted with acute polyneuropathy and abdominal pain. The patient received treatment for suspected Guillain-Barre syndrome and subsequently for autoimmune encephalopathy. Over the following 42 days, he exhibited progressive muscle weakness, delirium, and alopecia, ultimately leading to a diagnosis of thallium toxicity. After treatment with a combination of Prussian Blue, activated charcoal, and continuous venous hemofiltration, the patient showed improvement; however, neuropsychiatric and neuromuscular sequelae persisted. This case demonstrates that delaying a diagnosis until symptoms have evolved can compromise the possibility of recovery and, probably, the life of the patient. The decision to proceed with the administration of Prussian Blue was taken before obtaining confirmation of water pollution and poisoning.