Head Tilt and Rolling
These symptoms are usually caused by an inner ear infection, which is fairly common. The infection may be caused by mycoplasma or a secondary bacteria such as Streptococcus moniliformis or Pseudomonas. The infection causes inflammation in the inner ear, affecting the rat’s balance. This will cause the rat to hold his head tilted to one side. Without treatment, the loss of balance can get so bad the rat will roll over and over and is unable to eat. An inner ear infection can result in a permanent head tilt, especially if the symptoms are untreated. An inner ear infection can also cause facial paralysis.
An inner ear infection requires immediate treatment. I recommend using either enrofloxacin and amoxicillin together, or chloremphenicol. An anti-inflammatory, either a steroid or an NSAID, must also be given to reduce the swelling in the ear. Prednisolone, which is the most effective, can be given, but since it must be prescribed by a veterinarian it is best for the rat to be seen and have the medication appropriate titrated.
Other possible causes of a head tilt are a pituitary tumor or stroke, but the treatment for either is the same as for an inner ear infection.