Acute cerebellar dysfunction with neuromuscular manifestations after scorpionism presumably caused by Tityus obscurus in Santarém, Pará / Brazil

• We describe 58 envenoming caused presumably by Tityus obscurus in Brazilian Amazonia.
• Clinical effects of envenoming are compatible with acute cerebellar dysfunction.
• Myoclonus and fasciculation can be attributed to cerebellar or muscle dysfunction.
• Six patients developed rhabdomyolysis and two acute kidney injury.
• Envenoming by these scorpions appears to be unique to Brazil.

Scorpionism is a public health problem in many tropical countries, especially in North Africa, South India, Latin America and the Middle East. In Brazil, patients with severe scorpion envenoming have mainly cardiovascular events, including acute heart failure, acute respiratory distress syndrome and shock, death is rare. We described 58 accidents presumably caused by Tityus obscurus in Brazilian Amazonia. Patients reported a sensation of “electric shocks” which could last hours. The vast majority of patients presented a clinical picture compatible with acute cerebellar dysfunction, beginning minutes and lasting up to 2 days after the accident. They presented cerebellar ataxia, dysdiadochokinesia, dysmetry, dysarthria, dyslalia, nausea and vomiting. Besides, some patients presented myoclonus and fasciculation which can also be attributed to cerebellar dysfunction or maybe the result of direct action on skeletal muscle. Two patients had evidence of intense rhabdomyolysis and acute kidney injury. The clinical picture in this scorpion envenoming is mainly characterized by an acute dysfunction of cerebellar activities and abnormal neuromuscular manifestations and in some cases muscle injury which are not described in any other region of the world. This work presents clinical, epidemiologic, laboratory and treatment aspects of this unmatched scorpion envenoming in the state of Pará, northern Brazil.