Brain injuries may be caused by:
- Physical injuries such as road traffic accidents causing concussion or contusion. The skull may be intact but the brain within seriously damaged.
- Poisons or toxins including natural substances such as snake venom and man-made products such as organophosphate insecticides.
- Metabolic disorders including:
- Kidney failure
- Liver failure
- Thyroid disease
- Adrenal disease
- Nutritional deficiencies such as lack of thiamine
- Vascular disease preventing blood from reaching the brain
- Malformations, both inherited or caused by illness and disease
- Tumours and other space-occupying "lesions" such as polyps or cysts
- Inflammations such as meningitis or encephalitis placing pressure on brain tissue.
Brain injuries cause behaviour or movement changes. The most dramatic behaviour changes involve seizures, stupor or coma. Paralysis may be caused by brain or spinal cord injury.