With brainstem localization, brainstem syndromes are typical: Wallenbergs syndrome, Webers syndrome, Millard–Gubler syndrome, Benedikt syndrome or others. Infarctions will result in weakness and loss of sensation on the opposite side of the body. Physical examination of the head area will reveal abnormal pupil dilation, light reaction and lack of eye movement on opposite side. If the infarction occurs on the left side brain, speech will be slurred. Reflexes may be aggravated as well. Risk factors
Major risk factors for cerebral infarction are generally the same as for atherosclerosis. These include high blood pressure, diabetes mellitus, tobacco smoking, obesity, and dyslipidemia. The American Heart Association/American Stroke Association (AHA/ASA) recommends controlling these risk factors in order to prevent stroke. The AHA/ASA guidelines also provide information on how to prevent stroke if someone has more specific concerns, such as sickle-cell disease or pregnancy. It is also possible to calculate the risk of stroke in the next decade based on information gathered through the Framingham Heart Study. Pathophysiology
Cerebral infarction is caused by a disruption to blood supply that is severe enough and long enough in duration to result in tissue death. The disruption to blood supply can come from many causes, including:

Thrombosis (obstruction of a blood vessel by a blood clot forming locally)
Embolism (obstruction due to an embolus from elsewhere in the body),
Systemic hypoperfusion (general decrease in blood supply, e.g., in shock)
Cerebral venous sinus thrombosis.
The traditional definitions of transudate as a pleural effusion due to systemic factors and an exudate as a pleural effusion due to local factors have been used since 1940 or earlier (Light et al., 1972). Previous to Lights landmark study, which was based on work by Chandrasekhar, investigators unsuccessfully attempted to use other criteria, such as specific gravity, pH, and protein content of the fluid, to differentiate between transudates and exudates. Lights criteria are highly statistically sensitive for exudates (although not very statistically specific). More recent studies have examined other characteristics of pleural fluid that may help to determine whether the process producing the effusion is local (exudate) or systemic (transudate). The table above illustrates some of the results of these more recent studies. However, it should be borne in mind that Lights criteria are still the most widely used criteria.The Rational Clinical Examination Series review found that bilateral effusions, symmetric and asymmetric, are the most common distribution in heart failure (60% of effusions in heart failure will be bilateral). When there is asymmetry in heart failure-associated pleural effusions (either unilateral or one side larger than the other), the right side is usually more involved than the left. The instruments pictured are accurately shaped, however, most hospitals now use safer disposable trocars. Because these are single use, they are always sharp and have a much smaller risk of cross patient contamination. Treatment
Treatment depends on the underlying cause of the pleural effusion.