Diffuse softening of the brain and edema might be observed in individuals affected by advanced HSV (Herpes Simplex Virus) encephalitis. The HSV-1 strain mostly affects the adults, whereas HSV-2 strain is linked to neonatal encephalitis. In the absence of treatment, the mortality rate for HSV-1 encephalitis is about 70%. If left untreated, the mortality rate for neonatal HSV-2 encephalitis lies between 15-57%.
The human brain is a part of the central nervous system of the human body. It is one of the most complex organs of the human body. It is protected by the skull. Meninges refer to the three layers of protective membranes that envelop the brain. The cells of the brain are classified into neurons and neuroglia, whereas the brain tissue is classified into gray matter and white matter. Though the brain is protected by the skull, meninges, as well as the cerebrospinal fluid, it could get damaged in the event of traumatic brain injuries. Brain function could be adversely affected due to certain medical conditions and brain injuries. Encephalomalacia, which is commonly referred to as cerebral softening, is a medical condition that is characterized by a localized softening of the brain tissue.
Encephalomalacia could be caused due to a wide range of reasons, which might include:Trauma
More often than not, this condition occurs due to a traumatic brain injury. Blunt, as well as penetrating trauma during an accident or assault could be the reason behind the softening of the brain tissue. Head trauma could occur in the event of a hard blow to the head that causes the brain to hit against the skull. Penetrating head trauma could occur in case of a wound caused by a sharp weapon. Brain tissue could even get inflamed due to trauma during a surgical procedure.Stroke
A stroke is said to occur when the blood supply to a part of the brain is interrupted or reduced, which in turn deprives the brain tissue of nutrients and oxygen. Strokes can be ischemic or hemorrhagic. While the former occurs due to a lack of blood supply, the latter is a result of bleeding within the brain. The hemorrhagic strokes occur due to the rupturing of blood vessels in the brain, whereas ischemic strokes are likely to occur in the event of blockage due to a blood clot.Brain Hemorrhage
The term 'hemorrhage' refers to bleeding within the brain. It could occur due to traumatic brain injuries. Elevated blood pressure, aneurysms, abnormalities in blood vessels, certain types of cancers, drug abuse, etc., are some of the common contributing factors of brain hemorrhage.
Besides the aforementioned factors, certain infections can also lead to inflammation and cerebral softening.
Types of Encephalomalacia
Depending on the type of brain tissue that is affected, this condition is classified into:✦
When this condition affects the white matter of the brain, it is referred to as leukoencephalomalacia. The white matter is composed of myelinated long nerve fibers called axons. Myelin refers to a white fatty substance that covers the axons, thereby forming a protective sheath. Myelin is formed by glial cells. The axons connect different parts of gray matter to each other. These carry out the task of transmitting signal from one end of the cerebrum to another. These also transmit signals in between the cerebrum and the lower brain centers.
On the other hand, encephalomalacia of the gray matter is referred to as polioencaphalomalacia. The gray matter is a vital component of the central nervous system. It plays an important role in memory, muscle control, sensory perception, emotions, and speech.
Based on the color and extent of damage, encephalomalacia is categorized into✦
White softening, which is also referred to as atrophic softening, is believed to occur due to poor nutrition resulting from the restricted supply of blood. The white color is due to the lack of blood supply. The term 'red softening' is associated with the obstruction of blood supply due to a blood clot or any mechanical obstruction. Hemorrhage of a cerebral artery or its branches could also be a contributing factor. The red color could be attributed to the inflammation of the brain tissue due to bleeding within the brain. In case of yellow softening, the color of the brain tissue appears to be cream or yellowish-white. This type of softening of the brain is due to the buildup of atherosclerotic plaque in the arteries of the brain.
The symptoms of encephalmalacia would depend on the lobe or the part of the brain that is affected by cerebral softening. For instance, mood swings and memory loss might be experienced, if encephalomalacia has affected the frontal lobe of the brain. The symptoms might include:✦
Bouts of extreme drowsiness✦
Problems related to balance and coordination✦
Temporary or permanent blindness✦
Onset of terminal coma in later stages
Diagnosis and Treatment
There's no specific cure for the softening of the brain tissue. However, it is essential that this condition is diagnosed at an early stage. Imaging studies such as a CT scan or an MRI scan can help in identifying the changes in the consistency of the brain tissue, as well as the extent of damage. The treatment of encephalomalacia will depend upon the underlying cause. This condition can also affect neonates and infants, who might develop multicystic encephalomalacia (development of multiple cystic cavities of various sizes in the cerebral cortex) in the event of trauma caused by hypoxia-ischemic events during the perinatal period (period from five months before birth to one month after birth).
It must be noted that the prognosis of encephalomalacia is poor in case of infants. The life expectancy is greatly reduced, and the affected infant might even have neurological problems. However, the prognosis is better in case of adults, provided the diagnosis is made in the early stages and treatment is administered at the earliest. The treatment is aimed at preventing the condition from worsening. If a stroke or hemorrhage is the underlying cause, then precautions must be taken to prevent another stroke. For dealing with neurological deficits, occupational therapy, physical therapy, speech/language therapy, etc., would be suggested. In some cases, the treatment would involve the removal of the affected part of the brain.
On a concluding note, encephalomalacia is a serious medical condition that can cause irreversible brain damage, which in turn could affect one's ability to lead a normal life. Thus, the underlying cause of this condition must be treated at the earliest to lower the risk of brain damage.