What is the most likely diagnosis for an older adult exhibiting short-term memory issues and disorientation following a spouse's death?

In examining the scenario of an older adult who presents with short-term memory issues and disorientation following the death of a spouse, the most appropriate diagnosis is related to a temporary but acute change in mental status. Delirium, especially when associated with a urinary tract infection, is characterized by such sudden changes and cognitive impairments.

Delirium typically presents as fluctuating levels of consciousness, which may include confusion and disorientation. It can be precipitated by various factors, including infections, especially in older adults. A urinary tract infection can lead to such cognitive disturbances, particularly in individuals who might already be in a vulnerable state, such as experiencing grief or loss. The timing of the symptoms following the loss of a spouse also aligns with the acute onset commonly seen in delirium.

Other options, while relevant to mental health, do not align as closely with the symptoms and context. Alzheimer's disease, for example, usually presents with a gradual decline in cognitive function rather than an acute change. Major depressive disorder could lead to cognitive issues, but it typically involves a more pervasive, persistent mood change rather than isolated short-term memory loss after a traumatic event. Severe anxiety disorders can also impact concentration and memory, but they do not typically cause disorientation to the extent that