Differential Diagnosis for a 71-year-old man with parkinsonism, BUN of 25, and glucose of 68
- Single most likely diagnosis:
- Parkinson's disease: This is the most likely diagnosis given the presentation of parkinsonism. The slightly elevated BUN could be indicative of mild dehydration or early renal impairment, which is common in the elderly. The glucose level is within normal limits.
- Other Likely diagnoses:
- Drug-induced parkinsonism: Certain medications, such as antipsychotics, can cause parkinsonian symptoms. The elevated BUN might suggest dehydration, which could be a side effect of medication or a separate issue.
- Essential tremor: Although less likely than Parkinson's disease, essential tremor could be considered, especially if the tremor is the predominant symptom. However, other parkinsonian features (rigidity, bradykinesia, postural instability) would need to be assessed.
- Dehydration: The elevated BUN suggests dehydration, which is common in elderly patients and can exacerbate or mimic neurological symptoms.
- Do Not Miss diagnoses:
- Stroke or transient ischemic attack (TIA): Although less likely given the chronic nature of parkinsonism, it's crucial to rule out acute vascular events, especially if there are any sudden changes in symptoms.
- Infections (e.g., urinary tract infection): Infections can cause confusion, altered mental status, and exacerbate parkinsonian symptoms in elderly patients. The elevated BUN might indicate a urinary tract infection.
- Hyperosmolar hyperglycemic state (HHS): Despite the normal glucose level, any sign of dehydration or altered mental status in an elderly patient warrants consideration of HHS, especially if there's a history of diabetes.
- Rare diagnoses:
- Wilson's disease: A rare genetic disorder that can cause parkinsonian symptoms, among other systemic manifestations. It's less likely in a 71-year-old but should be considered in younger patients or those with a suggestive family history.
- Normal pressure hydrocephalus (NPH): Presents with the triad of gait disturbance, dementia, and urinary incontinence. While the gait disturbance could mimic parkinsonism, the absence of other symptoms makes this less likely.
- Vitamin B12 deficiency: Can cause neurological symptoms, including ataxia and weakness, but parkinsonism is not a typical presentation. However, given the broad differential for neurological symptoms, it's worth considering, especially if there are other suggestive findings like macrocytic anemia.