From the Research
Mechanism of False Localizing Signs
The mechanism of false localizing signs in a right-sided focal mass effect can be attributed to several factors, including:
- Raised intracranial pressure 1
- Displacement and distortion of the brain stem by a large mass lesion 2
- Remote hyperaemia caused by brain bulk shifting due to the mass lesion 3
- Cranial nerve palsies, especially sixth nerve palsy, which can occur as false localizing signs 1
False Localizing Signs in Cranial Neuropathies
False localizing signs can occur in various cranial neuropathies, including:
- Cranial nerves III, IV, V, VI, VII, VIII 4
- Multiple cranial nerve involvement of IX, X, and XII 4
- Trigeminal nerve dysfunction, which can occur contralateral to the side of the mass lesion 2
Relation to Remote Hyperaemia
Remote hyperaemia has been found to be related to the location of the mass lesion and can lead to false localizing signs 3
- In 8 of 11 patients with remote hyperaemia, false localizing signs were found, related to the hyperaemic areas 3
- Remote hyperaemic areas may be the result of brain bulk shifting due to the mass lesion and represent the initial stage of brain herniation 3
Clinical Implications
Awareness of false localizing signs is crucial for diagnostic investigation and management of patients with intracranial mass lesions 1, 4