• This is a lateral view of the brain with the frontal lobes to the left and the occipital lobes and cerebellum to the right.

• The arrows point to numerous petechial hemorrhages which could be due to blood dyscrasias such as seen in terminal leukemias, ITP, etc. or due to toxins such as arsenic.

•The most common cause of intraparenchymal hemorrhage is hypertension

•Other causes include blood dyscrasias or rupture of vascular malformations.

•Hypertensive hemorrhages are often due to hypertensive lipohyalinosis of of small arteries with formation of small Charcot-Bouchard aneurysms.

•Blood dyscrasias cause bleeding due to inability of the blood to clot.

•Hemorrhages from vascular malformations are caused by trauma or hypertension further damaging an abnormal blood vessel wall.

•Eighty percent of intraparenchymal hemorrhages in the hypertensive are found in the basal ganglia, thalamus or white matter.

• Ten percent are seen in the pons, and 10% in the cerebellar hemispheres.
They are usually large and in 50% of cases cause death.

•They may also rupture into the ventricle which may cause death or may be helpful in decompression.

•Blood dyscrasias such as leukemias often produce many small petechial or larger hemorrhages.

•Vascular malformations may rupture due to hypertension, trauma or abnormalities of the blood vessel wall.

•Symptoms associated with hemorrhages depend on the extent of the bleed.

•Symptoms can range from a silent lesion to a devastating disability to coma and a lethal outcome.

•Intraparenchymal and intraventricular hemorrhages appear as a mass of blood in the brain tissue or ventricle.

•The walls of a large hemorrhage thought to be due to hypertension should be examined for abnormal vessels.
In blood dyscrasias, multiple smaller hemorrhages are scattered throughout the brain tissue.
Usually a large hemorrhage is associated with asymmetrical edema and herniation of structures.

•Microscopically hemorrhages are surrounded by pallor of tissue, spongiosus, and pericellular vacuolization.
If the patient survives the area of hemorrhage is walled off by reactive astrocytes and macrophages.

• There is a collagenous capsule around an old hemorrhage with hemosiderin laden macrophages still present.

• Poirer J et.al. Manual of basic neuropathology. Philadelphia: Saunders, 1990, pp.65-78,

• Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp.1311-1312.

• Current literature from PubMed at National Library of Medicine