Other more common pathogens are also known to cross the blood brain barrier and cause cerebral infection. Trauma is obvious in most cases based on history and examination. One type of head trauma frequent in older people, however, is not always obvious. It is called a subdural hematoma, which is the condition of blood leaking into brain cell tissues. This type of injury can occur after very minimal trauma, and its onset can be very gradual if the leak is small.
Symptoms are headache, confusion, and lethargy and are often nonspecific.
Toxic factors - Exposure to substances such as carbon monoxide, aluminum, mercury, lead, cadmium, arsenic, nickel, airborne molds and methyl alcohol cause mental impairment. The hormonal changes that accompany aging are only recently being clearly identified. A sudden drop in the hormones estradiol and progesterone , for example, lead to menopause at about age 50. Metastatic tumors are more common. Depression Depression , stress , and grief are common causes of mental impairment that are transient and treatable.