These include CYLD, OPTN, SQSTM1 and TBK1. These genes have been implicated in the autophagy pathway. No genetic causes of FUS pathology in FTD have yet been reported. Pathology
There are three main histological subtypes found at post-mortem: FTLD-tau, FTLD-TDP, and FTLD-FUS. In rare cases, patients with clinical FTD were found to have changes consistent with Alzheimers disease on autopsy. The most severe brain atrophy appears to be associated with behavioral variant FTD, and corticobasal degeneration.With regard to the genetic defects that have been found, repeat expansion in the C9orf72 gene is considered a major contribution to frontotemporal lobar degeneration, although defects in the GRN and MAPT genes are also associated with it. Diagnosis
FTD is traditionally difficult to diagnose owing to the diverse nature of the associated symptoms. Signs and symptoms are classified into three groups based on the affected functions of the frontal and temporal lobes: These are behavioural variant frontotemporal dementia, semantic dementia, and progressive nonfluent aphasia. An overlap between symptoms can occur as the disease progresses and spreads through the brain regions. Structural MRI scans often reveal frontal lobe and/or anterior temporal lobe atrophy but in early cases the scan may seem normal. Atrophy can be either bilateral or asymmetric. Registration of images at different points of time (e.g., one year apart) can show evidence of atrophy that otherwise (at individual time points) may be reported as normal.
It also increases intracranial pressure, causing the brain to shift, lose blood supply, be crushed against the skull, or herniate. Larger hematomas cause more damage. Epidural bleeds can quickly compress the brainstem, causing unconsciousness, abnormal posturing, and abnormal pupil responses to light. Diagnosis
Diagnosis is typically by CT scan or MRI. MRIs have greater sensitivity and should be used if there is a high suspicion of epidural hematoma and a negative CT scan. Differential diagnoses include a transient ischemic attack, intracranial mass, or brain abscess.Epidural hematomas usually appear convex in shape because their expansion stops at the skulls sutures, where the dura mater is tightly attached to the skull. Thus, they expand inward toward the brain rather than along the inside of the skull, as occurs in subdural hematomas. Most people also have a skull fracture.Epidural hematomas may occur in combination with subdural hematomas, or either may occur alone. CT scans reveal subdural or epidural hematomas in 20% of unconscious people. In the hallmark of epidural hematoma, people may regain consciousness and appear completely normal during what is called a lucid interval, only to descend suddenly and rapidly into unconsciousness later. This lucid interval, which depends on the extent of the injury, is a key to diagnosing an epidural hematoma. Treatment
Epidural hematoma is a surgical emergency. Delayed surgery can result in permanent brain damage or death. Without surgery, death usually follows, due to enlargement of the hematoma, causing a brain herniation.