# Thallium Poisoning: Case Report and Scoping Review on Diagnostic Delay and Therapeutic Outcome
## 3 Detailed Case Description  
A 40-year-old female patient, working as a pharmacist in central Italy, came to our emergency room after a week's progressive onset of paresthesia of the lower arms, with severe muscle pain, reduced strength, generalized asthenia, visual disturbances with conjunctival hyperemia, chest pain, abdominal pain, nausea, and diarrhea. During the week, the extent and intensity of her symptoms had gradually worsened. The patient had taken ibuprofen, without gaining relief. Finally, being unable to walk unaided because of severe pain in the trunk and limbs, and subsequently in the arms, she was confined to a wheelchair. Previously, she had been to two different peripheral hospital emergency rooms but had not been hospitalized. Eye drops had been prescribed for eye symptoms. At the clinical examination in the emergency department, the patient was alert and lucid and eupneic, with rhythmic cardiac action and normal pulmonary findings. The abdomen was treatable; [PERSON]'s and [PERSON]'s signs were negative. Severe arthralgias prevented walking and movement. There was no fever, but pharyngeal hyperemia, lymphadenopathy, and skin rashes were observed. The patient complained of paresthesia of the tingling type at the tips of the fingers and the tips of the feet, with a slight superficial hypoesthesia of the anterior surface of the legs. Discriminative tactile, thermal, and painful sensitivity was normal. The patient did not present any deficits of the cranial nerves or global strength (although this was difficult to evaluate due to the pain limitation); the index-nose test was well performed symmetrically, and she had normally evoked osteotendinous reflexes. The patient was admitted to the Department of Emergency, Anesthesiology, and Resuscitation Sciences of the Gemelli General Hospital. At anamnesis, she failed to report any chronic pathology, drug usage, or food allergies. She denied taking any food supplements, alternative medicines, cosmetics, or exotic food products. She lived in a country house and had not travelled outside Italy. She owned a cat and had a flower garden and a vegetable garden and no history of tick bites. The patient's background was further explored to assess potential chronic exposure sources, including any prior use of contaminated water, dietary habits that could increase thallium ingestion (such as home-grown produce), and possible occupational or environmental contacts. This investigation aimed to determine whether the acute presentation was compounded by underlying, low-level exposure over time that might have contributed to the severity of symptoms and a delayed diagnosis. Her vital parameters were within limits: blood pressure 121/67 mmHg, heart rate 79 bpm, SpO2 98%, and temperature 36.5 \({}^{\circ}\)C. The venous blood gas analysis showed pH 7.39, Lactates 0.7 mmol/L, potassium 3.7, and no electrolyte alterations. The chest X-ray, electrocardiogram, urine tests, and basic blood tests were negative. The blood tests for Leptospira, Borrelia, Rickettsia, Bartonella, human immunodeficiency virus (HIV), cytomegalovirusovirus(CMV), Epstein-Barr virus (EBV), toxoplasma, syphilis, hepatitis C virus (HCV), hepatitis B virus (HBV), enterovirus, adenovirus, and Chikungunya virus were all negative. Considering that the patient lived in the countryside, the doctors investigated the source of the water supply. The patient confirmed that the house was supplied with drinkable water from the public water supply, but also had well water that was not drinkable and used only for cleaning. Having learned of the existence of a well with non-potable water, the doctors investigated further by asking if the water line of the well was separate from that of the municipal water supply with potable water. To their surprise, they learned that the line was the same and that the type of water introduced into the domestic pipes could be potable or not, depending on the positioning of a valve.