Differential Diagnosis
- Single most likely diagnosis
- Dementia, Alzheimer type: The patient's symptoms, such as leaving the stove on and unattended for hours, difficulty with serial sevens, and impaired memory (remembering only one of three objects after 5 minutes), suggest a decline in cognitive function, which is consistent with dementia. The patient's age (68 years) and the gradual onset of symptoms also support this diagnosis.
- Other Likely diagnoses
- Delusional disorder: The patient's belief that neighbors are forcing noxious fumes through her heating system could be a delusion, which is a characteristic of delusional disorder. However, the presence of cognitive decline and memory impairment makes dementia a more likely diagnosis.
- Major depressive disorder: The patient's anxiety and worried mood could be symptoms of depression, but there is no clear evidence of depressive symptoms such as anhedonia, changes in appetite or sleep, or feelings of guilt or worthlessness.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Hallucinogen intoxication delirium: Although the patient does not exhibit typical symptoms of hallucinogen intoxication, such as hallucinations or altered level of consciousness, it is essential to consider this diagnosis due to the potential for severe consequences, including increased risk of accidents or injuries.
- Brief psychotic disorder: The patient's delusional thinking could be a symptom of a brief psychotic disorder, but the absence of other psychotic symptoms, such as hallucinations or disorganized behavior, makes this diagnosis less likely.
- Rare diagnoses
- Schizophrenia, paranoid type: The patient's age and the absence of other psychotic symptoms, such as hallucinations or disorganized behavior, make this diagnosis unlikely. Schizophrenia typically has an earlier onset, and the patient's symptoms do not meet the full criteria for this diagnosis.
- Paranoid personality disorder: While the patient's delusional thinking could be a symptom of paranoid personality disorder, this diagnosis would not explain the cognitive decline and memory impairment, making it an unlikely diagnosis.