Prosopagnosia Due to Metastatic Brain Tumor: A Case-Based Review.

Prosopagnosia, also referred to as "face blindness," is a type of visual agnosia characterized by a decreased capacity to recognize familiar faces with a preserved ability to identify individuals based on non-facial visual traits or voice. Prosopagnosia can be categorized as developmental (DP) or acquired (AP) owing to a variety of underlying conditions, including trauma, neurodegenerative diseases, stroke, neuroinfections, and, less frequently, malignancies. Facial recognition is a complex process in which different neuronal networks are involved. The infrequent but notable higher visual-processing abnormalities can be caused by lesions of the inferior longitudinal fasciculus (ILF) in the non-dominant temporal lobe. We report a rare case of AP in a 69-year-old patient who is right-hand dominant with rectal carcinoma cerebral metastases. The patient complained of dizziness, vertigo, falls, and trouble recognizing her family members' faces. The CT scan of the head with contrast revealed two metastatic brain lesions with vasogenic edema, as one of them was in the right cerebellar hemisphere, causing dislocation and compression of the ILF. Corticosteroids and osmotherapy were utilized as a conservative treatment approach, which resulted in the prosopagnosia being completely withdrawn. In conclusion, patients with primary brain tumors or metastatic disease rarely present with an isolated cognitive deficit such as prosopagnosia. Based on the anatomical features and the personalized approach, a conservative or surgical approach may be useful to improve higher cortical functioning.

Central Pontine Myelinolysis as a Late Complication After Hyponatremia and COVID-19 Infection.

Osmotic demyelination syndrome (ODS) is a rare but serious condition that is hypothesized to be a result of rapid correction of hyponatremia, with a catastrophic prognosis. The foci of demyelination may occur in either the pontine area or within the white matter of the cerebral hemispheres, which denotes a specific clinical presentation. We present the case of a post-COVID-19 patient who was diagnosed with ODS with typical clinical and radiological characteristics of both forms: central pontine myelinolysis and extrapontine myelinolysis. The clinical assessment of ODS encompasses a variety of differential diagnoses, including stroke, neuroinfection, neoplasia, and other demyelinating diseases. A specific characteristic of ODS is the delayed clinical manifestation after the hyponatremic state. Furthermore, it is noteworthy that there might be discrepancies between the clinical manifestations and the neuroimaging findings. The association between COVID-19 and ODS is unclear at the moment, although it can possibly be explained by the viral infection through multiple mechanisms such as renal dysfunction, diarrhea, or vomiting. ODS should be considered in cases of hyponatremia and neurological deterioration during the course of COVID-19 infection. Despite the fact that early detection and treatment of this syndrome can reduce the risk of short-term mortality and long-term disability, they do not guarantee complete recovery.