Acute thallium poisoning: clinical features, toxicokinetics and one-year neurological outcomes

Thallium poisoning is a rare but highly toxic heavy metal intoxication associated with peripheral neuropathy. However, longitudinal data integrating toxicokinetic profiles with electrophysiological outcomes remain limited.

Five patients with confirmed acute thallium poisoning were evaluated. Clinical symptoms, laboratory results, dynamic serum and urinary thallium concentrations, and electrophysiological results were recorded. All patients underwent electrophysiological follow-up one year later. Thallium elimination kinetics were analyzed using nonlinear regression.

All patients developed peripheral neuropathy. Sensory symptoms generally preceded the onset of alopecia. During treatment, dynamic monitoring showed a progressive decrease in thallium concentrations. Toxicokinetic analysis suggested an approximate first-order elimination pattern, with an estimated serum half-life ranging from 3.8 to 5.7 days. Electrophysiological studies revealed distal axonal neuropathy characterized by reduced compound muscle action potential amplitudes. At one-year follow-up, residual axonal involvement persisted in some patients.

Peripheral neuropathic symptoms may serve as an early clinical indicator of thallium poisoning. Persistent electrophysiological abnormalities despite declining thallium levels suggest incomplete neurological recovery.

Dynamic monitoring of thallium levels can help evaluate elimination kinetics during detoxification therapy. Persistent axonal injury suggests that thallium-induced neuropathy may result in long-term neurological sequelae, highlighting the importance of early diagnosis and long-term electrophysiological monitoring.