Differential Diagnosis for a 78y Old Patient with Strange Behaviour, Lacking Capacity, and Recurrent Falls
Single Most Likely Diagnosis
- Delirium: Given the patient's age, strange behavior, and lack of significant medical history, delirium is a strong consideration. It is characterized by an acute onset of fluctuating cognitive impairment, often precipitated by a minor stressor in vulnerable individuals. The absence of significant findings on MRI, CT, LP, toxicology, and immunology, along with mildly elevated WCC and CRP, could indicate a non-specific response to stress or infection.
Other Likely Diagnoses
- Dementia with Lewy Bodies: This condition can present with fluctuating cognitive function, visual hallucinations, and falls, which aligns with some of the patient's symptoms. The lack of clear findings on initial tests does not rule out this diagnosis, as it often requires specific diagnostic criteria and may not be immediately apparent.
- Alzheimer's Disease: Although less likely given the acute presentation, Alzheimer's disease can have a rapid onset in some cases, especially if there are other contributing factors. The absence of significant medical history and normal initial investigations does not exclude this possibility entirely.
- Vascular Dementia: Given the patient's age and recurrent falls, vascular dementia is a consideration, especially if there are undiagnosed vascular risk factors. However, the lack of focal neurological deficits and normal imaging makes this less likely.
Do Not Miss Diagnoses
- Subdural Hematoma: Despite the absence of reported trauma, a subdural hematoma could present with non-specific symptoms such as confusion and falls in the elderly. It is crucial to consider this diagnosis due to its potential for serious consequences if missed.
- Infections (e.g., UTI, Pneumonia): Infections can present atypically in the elderly, with confusion and falls being primary symptoms. The mildly elevated WCC and CRP suggest an infectious or inflammatory process that needs to be thoroughly investigated.
- Neurosyphilis: Although less common, neurosyphilis can cause a wide range of neurological symptoms, including cognitive decline and personality changes. Given the non-specific presentation and the importance of treating this condition, it should not be missed.
Rare Diagnoses
- Creutzfeldt-Jakob Disease: This is a rare, degenerative, fatal brain disorder that can present with rapid cognitive decline, personality changes, and ataxia. The absence of specific findings on initial tests and the rarity of the disease make it a less likely but important consideration.
- Hashimoto's Encephalopathy: An autoimmune condition that can cause cognitive decline, seizures, and myoclonus. It is rare and might not be immediately suspected but is treatable with immunosuppression, making it an important differential diagnosis.
- Whipple's Disease: A rare, systemic bacterial infection that can affect the brain, causing cognitive decline, among other symptoms. It is essential to consider due to its treatability with antibiotics.