In clinical practice, secondary infections of the central nervous system (CNS) represent rare yet severe complications of their respective primary infections. In this case report, we describe a 22-year-old patient with a medical history of Asthma bronchiale, who developed significant neurological deficits after a respiratory infection. The neurological symptoms progressed despite antibiotic therapy with vancomycin, ampicillin and ceftriaxone. The patient's cerebrospinal fluid and a cranial magnetic resonance imaging (MRI) furnished evidence of acute meningoencephalitis. Microbiological assessment confirmed an acute mycoplasma pneumonia infection. Changing the patient's antibiotic regimen to minocycline and prednisolone led to significant clinical improvement. Pathomechanisms and therapeutic options to treat meningoencephalitis will be discussed in the following.