It has been found that genetic predisposition varies among the different PPA variants, with PNFA being more commonly familial in nature than LPA or SD.The most convincing genetic basis of PPA has been found to be a mutation in the GRN gene. Most patients with observed GRN mutations present clinical features of PNFA, but the phenotype can be atypical. Diagnosis
Diagnostic criteria
The following diagnosis criteria were defined by Mesulam:
As opposed to having followed trauma to the brain, a patient must show an insidious onset and a gradual progression of aphasia, defined as a disorder of sentence and/or word usage, affecting the production and comprehension of speech. The disorder in question must be the only determinant on functional impairment in the activities of the patients daily living. On the basis of diagnostic procedures, the disorder in question must be unequivocally attributed to a neurodegenerative process.Whether or not PPA and other aphasias are the only source of cognitive impairment in a patient is often difficult to assess because: 1) as with other neurologically degenerative diseases, such as Alzheimers disease, there are currently no reliable non-invasive diagnostic tests for aphasias, and thus neuropsychological assessments are the only tool physicians have for diagnosing patients; and 2) aphasias often affect other, non-language portions of these neuropsychological tests, such as those specific for memory. Classification
In 2011, the classification of primary progressive aphasia was updated to include three clinical variants.
Pneumothorax ex vacuo is a rare type of pneumothorax which forms adjacent to an atelectatic lobe. It is seen preferentially with atelectasis of the right upper lobe and is the result of rapid atelectasis producing an abrupt decrease in the intrapleural pressure with subsequent release of nitrogen from pleural capillaries. Treatment
Treatment consists of bronchoscopy rather than chest tube drainage. Radiographically, pneumothorax ex vacuo is suggested when an atelectatic lobe or lung, particularly right upper lobe atelectasis, is surrounded by a focal pneumothorax. Related illness
"Trapped lung" presents in the same way as pneumothorax ex vacuo and can occur in patients with visceral pleural thickening and following drainage of an effusion. == References ==