What is encephalomalacia, its causes, typical imaging findings, clinical manifestations, and recommended management?

Encephalomalacia: Definition, Causes, Imaging, and Management

Definition

Encephalomalacia is the softening or loss of brain tissue following cerebral infarction, ischemia, infection, craniocerebral trauma, or other injury, characterized by blurred cortical margins and decreased consistency of brain parenchyma. 1

• The term describes macroscopic pathologic changes where brain tissue undergoes liquefaction necrosis, often surrounded by glial cell proliferation (gliosis) in response to the injury 1, 2
• In neonates and infants, multicystic encephalomalacia refers to multiple cystic cavities of various sizes in the cerebral cortex, most notably after perinatal hypoxic-ischemic events 1

Etiologies

Primary Causes in Adults

• Cerebrovascular events are the most common cause in adults, including cerebral infarction and ischemia 1, 3
• Physical trauma represents an important but underrecognized etiology, with symptoms potentially manifesting years after the initial injury 3
• Infection can lead to focal encephalomalacia through direct tissue destruction 1, 2
• Iatrogenic injury during procedures such as endoscopic sinus surgery, though rare, can cause penetrating brain injury resulting in encephalomalacia 1

Specific Clinical Contexts

• Chronic head trauma with contusions commonly results in focal encephalomalacia at the inferior frontal or anterior temporal lobes 4
• Post-acoustic neuroma resection, where cerebellar encephalomalacia occurs in approximately 57% of cases (17 of 30 patients), particularly after suboccipital approach and with larger tumors 5
• Hemorrhagic transformation and chronic subdural hematomas can lead to adjacent encephalomalacia 4

Imaging Findings

MRI (Preferred Modality)

MRI is the most sensitive imaging modality for detecting encephalomalacia and should be the primary imaging choice for subacute or chronic evaluation. 4

• T2-weighted and FLAIR sequences demonstrate areas of focal encephalomalacia as hyperintense signal with loss of normal brain architecture 4
• MRI is superior to CT for detecting subtle findings adjacent to the calvarium or skull base, including focal encephalomalacia at inferior frontal or anterior temporal lobes as chronic sequelae of previous contusions 4
• Susceptibility-weighted imaging (SWI) can identify associated microhemorrhages and hemosiderin deposition from prior traumatic axonal injury 4
• Cerebellar encephalomalacia appears as gliotic changes on T2-weighted turbo spin-echo images 5

CT Imaging

• CT has limited sensitivity for detecting encephalomalacia compared to MRI, though it can demonstrate blurred cortical margins and decreased tissue density 4
• CT is appropriate when rapid assessment is needed or MRI is contraindicated, and can identify extensive white matter disease, parenchymal atrophy, and ventricular enlargement 4
• In chronic settings, CT may show cystic changes or areas of decreased attenuation corresponding to tissue loss 4

Clinical Manifestations

Neurological Sequelae

• Intractable epilepsy is a major complication, with focal encephalomalacia representing an important cause of medically refractory partial seizures 6
• Cognitive and neurologic deficits that persist or develop in delayed fashion, including unexplained cognitive decline, focal neurological deficits, or behavioral changes 4, 3
• Non-specific symptoms such as chest tightness, dyspnea, aphasia, generalized weakness, vertigo, and giddiness may occur, particularly with temporal or parieto-occipital involvement 3, 2

Temporal Patterns

• Symptoms may manifest acutely after injury or develop in a delayed fashion, sometimes years after the initial insult 3
• In trauma cases, the interval between injury and onset of seizures is variable and does not predict surgical outcome 6

Management Approach

Diagnostic Evaluation

When encephalomalacia is suspected based on clinical presentation, obtain MRI brain without contrast as the initial imaging study. 4

• In acute presentations where rapid exclusion of hemorrhage or mass effect is needed, begin with non-contrast CT head, followed by MRI for definitive characterization 4
• For patients with chronic symptoms and known encephalomalacia, MRI is superior for detecting progression or new pathology 4

Seizure Management

For patients with intractable epilepsy secondary to frontal lobe encephalomalacia, surgical resection is highly effective, with 70% achieving seizure freedom or rare seizures only. 6

• The presence of focal fast frequency discharge (focal ictal beta pattern) at seizure onset on scalp EEG predicts seizure-free outcome (p = 0.017) 6
• Complete resection of the encephalomalacia should be attempted whenever possible, as this approaches statistical significance as a favorable predictive factor (p = 0.051) 6
• The operative strategy should include resection of the encephalomalacia and adjacent electrophysiologically abnormal tissues 6

Rehabilitation

• Tailored, well-coordinated rehabilitation is essential for optimizing functional recovery 2
• Proprioceptive neuromuscular facilitation (PNF) methods are effective for regaining motor function 2
• Tele-rehabilitation can play a crucial role in maintaining continuity of care and monitoring progress 2

Monitoring and Follow-up

• Serial neuroimaging may be warranted in patients with progressive symptoms or new neurological deficits 4
• In post-surgical cases (e.g., acoustic neuroma resection), encephalomalacia is an expected finding and does not necessarily require intervention unless symptomatic 5

Critical Pitfalls to Avoid

• Do not dismiss chronic or delayed neurological symptoms in patients with remote history of head trauma, as encephalomalacia can manifest years after injury 3
• Do not rely on CT alone for evaluating chronic neurological deficits, as MRI is significantly more sensitive for detecting encephalomalacia and associated findings 4
• Do not assume all seizures in patients with encephalomalacia are medically refractory—surgical evaluation should be considered early, particularly when focal ictal beta patterns are present on EEG 6
• In pediatric chronic head trauma, imaging often has low yield (1.5% positivity rate) and rarely changes management, so clinical judgment should guide imaging decisions 4