Which of these is a structural cause of altered mental status?

A brain tumor is classified as a structural cause of altered mental status because it involves a physical change or abnormality in the brain's structure. This can lead to increased intracranial pressure, disruption of normal brain function, and potential damage to specific areas that regulate consciousness, cognition, and behavior.

When the brain is affected by a tumor, whether benign or malignant, it can impact neural pathways and neurotransmitter balance, which are crucial for maintaining clear and stable mental status. Symptoms resulting from a brain tumor may include confusion, memory issues, personality changes, and alterations in consciousness, all of which are indicators of altered mental status.

In contrast, the other options represent non-structural causes of altered mental status, often related to metabolic or systemic conditions. For example, hypoxia refers to inadequate oxygen supply to the brain but does not involve a physical change in brain structure itself. Similarly, kidney and liver failure can lead to biochemical imbalances and toxicity in the body that affect mental status, but these do not involve a direct alteration in the brain's physical structure.