Brainstem hemorrhage itself is a very dangerous disease. Patients with a large amount of bleeding generally find it difficult to recover and may even result in a vegetative state or death.

The occurrence of fever in brainstem hemorrhage mainly has two reasons. First, brainstem hemorrhage can cause central fever, which is mainly due to damage to some autonomic nerves, leading to problems with the body's temperature regulation function. If central fever occurs, it is quite dangerous and indicates a poor prognosis, necessitating active physical cooling.

Secondly, patients with brainstem hemorrhage are often in a comatose and bedridden state, making them highly susceptible to various complications, such as pulmonary infections and urinary system infections. If fever arises due to these infections, it also indicates a poor prognosis, with relatively high mortality and disability rates.

Overall, the occurrence of fever in patients with brainstem hemorrhage is quite dangerous and indicates a poor prognosis.