My husband had septis after surgery. he is 84 and cognitively impaired. his mri showed small vessel white matter changes, slightly greater than expected for age, as well as volume loss. he was very sharp before. could sepsis,have caused this?

Difficult to answer. Generally such changes are gradual and ongoing. Functionality is not always co=related to mri findings. Mental change may or may not occur after sepsis depending on the nature, duration and treatment used. I wish I could give you an ironclad answer. There is none. wish your husband a speedy recovery from this.

Your husband likely, prior to sepsis, had either Alzheimer's, vascular dementia or a combination of both. The infection resulted in worsening the pre-existing cognitive issues. Medication anti-cholinergic side effects likely contributed. The sepsis did not cause it but did make it worse.