By Michael A. Spinner

As a third-year medical student on the wards, one of the most important skills to develop is learning how to generate a thorough differential diagnosis for a wide variety of clinical problems.

The correct diagnosis is not always clear-cut, and it is thus essential to consider alternative diagnoses that could account for a patient’s clinical presentation. Your differential will then directly guide your diagnostic work-up, ultimately helping you to hone in on the correct diagnosis and determine the appropriate treatment plan.

As with reading a chest X-ray or EKG, the key to generating a strong differential diagnosis is to follow a systematic approach. The mnemonic “VINDICATE” offers one such system to generate a broad and thorough differential:

V – Vascular
I – Infectious
N – Neoplastic
D – Degenerative
I – Iatrogenic/intoxication
C – Congenital
A – Autoimmune
T – Traumatic
E – Endocrine/metabolic

Suppose you’re on your neurology clerkship seeing a patient with altered mental status (AMS) and your attending asks you “what are the various causes of AMS?” Below is an example of how you could use the VINDICATE mnemonic to generate a thorough, systematic, and organized differential:

Vascular – stroke, TIA, subarachnoid hemorrhage
Infectious – meningitis, encephalitis, sepsis
Neoplastic – primary brain tumor or metastasis
Degenerative – Alzheimer’s disease, Huntington’s disease, other dementias
Iatrogenic/intoxication – narcotics, alcohol intoxication or withdrawal
Congenital – epilepsy (post-ictal state)
Autoimmune – CNS lupus, neurosarcoidosis if you want to get fancy!
Traumatic – traumatic brain injury, traumatic epidural or subdural hematoma
Endocrine/metabolic – hypoglycemia, hypo- or hyperthyroidism, hypo- or hypernatremia, hypercalcemia, hepatic or uremic encephalopathy

The patient history will certainly help you to narrow the differential and determine the most likely diagnoses. Of course not every patient presenting with AMS needs an extensive work-up for CNS lupus or neurosarcoidosis! Nonetheless, the VINDICATE mnemonic offers an effective, easy-to-remember way to systematically approach differential diagnosis for a wide range of clinical problems.

I hope that it will help you organize your thoughts and serve you well on the wards!