What is Encephalomalacia?
Encephalomalacia is the softening or loss of brain tissue that occurs after cerebral infarction, ischemia, infection, trauma, or other brain injury. 1
Pathological Definition
Encephalomalacia represents irreversible brain tissue damage characterized by:
- Softening and loss of brain parenchyma following various insults including cerebral infarction, cerebral ischemia, infection, craniocerebral trauma, or other injuries 1
- Blurred cortical margins and decreased consistency of brain tissue observed during gross pathologic inspection after infarction 1
- Formation of cystic cavities in severe cases, particularly when occurring in neonates and infants (termed "multicystic encephalomalacia") 1, 2
Etiologies by Age Group
In Neonates and Infants
- Perinatal hypoxic-ischemic events are the most common cause, leading to multicystic encephalomalacia with multiple cystic cavities of various sizes in the cerebral cortex 1, 2
- Severe asphyxia and/or hypotension during the perinatal period 2
- Subcortical leukomalacia (SCL) describes areas of necrosis developing into cystic lesions, distinguishing subcortical from periventricular lesions 2
In Adults
- Cerebrovascular events (stroke, infarction) are the most common cause in adults 3
- Physical trauma from head injuries, though less commonly reported, can cause encephalomalacia years after the initial insult 3
- Iatrogenic injury during surgical procedures, such as penetrating brain injury during endoscopic sinus surgery 1
- Anoxic-ischemic episodes from conditions like shock or mismatch blood transfusion 4
Clinical Manifestations
The neurological deficits depend on the location and extent of tissue damage:
- Cognitive impairments including attention deficits, impaired executive function, and memory problems when involving temporal or frontal regions 3
- Seizures are common, particularly with frontal lobe encephalomalacia, and may be medically intractable 5
- Motor deficits including weakness, clumsiness, or paralysis depending on lesion location 4
- Behavioral and psychiatric symptoms when frontal or temporal lobes are affected 3
- Variable severity ranging from minimal deficits to severe psychomotor retardation, depending on timing of injury and brain plasticity 4
Diagnostic Imaging
MRI is the gold standard for detecting encephalomalacia, showing:
- Increased signal intensity on T2-weighted or FLAIR sequences in affected brain regions 6
- Cystic changes with loss of normal brain architecture 6, 2
- More sensitive than CT for detecting subtle findings adjacent to the calvarium and small white matter lesions 6
- Susceptibility-weighted imaging should be included to detect paramagnetic blood products from previous hemorrhage 6
CT scanning has limited utility but may show:
Key Clinical Considerations
Irreversibility of Damage
The presence of encephalomalacia indicates previous tissue damage that cannot be reversed, so treatment focuses entirely on managing symptoms and preventing complications rather than tissue restoration 6
Timing and Plasticity
- Injuries occurring in early infancy may result in less severe neurological deficits than expected due to brain plasticity, even with extensive morphological changes 4
- Adult-onset encephalomalacia typically results in more predictable deficits corresponding to the anatomical location of injury 3
Seizure Management
For patients with encephalomalacia-related epilepsy:
- Surgical resection of frontal encephalomalacias achieves seizure freedom or rare seizures in approximately 70% of patients with intractable epilepsy 5
- Focal ictal beta discharge on scalp EEG predicts favorable seizure-free outcomes after surgery 5
- Complete resection of the encephalomalacia should be attempted when feasible, as this may improve outcomes 5
Common Pitfall
Do not assume CT is adequate for evaluation—MRI is far more sensitive for detecting encephalomalacia and associated white matter disease, and normal CT does not exclude significant brain injury 6, 7