Differential Diagnosis for Posterior Reversible Encephalopathy Syndrome (PRES)

Primary Differential Considerations

The American College of Radiology suggests that cerebral amyloid angiopathy-related inflammation (CAA-ri/ABRA) is a main differential diagnosis for amyloid-related imaging abnormalities (ARIA) in patients on anti-amyloid monoclonal antibody therapy, with the discriminating feature being the history of anti-amyloid MAB therapy 1
The American College of Radiology also notes that both CAA-ri/ABRA and ARIA present with similar T2 FLAIR hyperintensities and microhemorrhages, requiring careful differentiation 1

The American College of Radiology recommends considering cerebral amyloid angiopathy-related inflammation (CAA-ri/ABRA) as a key differential diagnosis for PRES, particularly in patients with a history of anti-amyloid monoclonal antibody therapy 1
Liver International suggests that in cirrhotic patients presenting with neurological symptoms, chronic infectious and autoimmune meningoencephalitis must be systematically excluded, with CSF analysis being essential when an infectious etiology is suspected 2

Liver International recommends obtaining a complete medical history, including recent infections, trauma, withdrawal, and psychotropic drugs, in cirrhotic patients, as well as conducting blood tests for electrolytes, glucose, calcium, cell blood count, inflammatory proteins, blood urea, and creatinine 2
Liver International notes that asterixis is strongly suggestive of metabolic encephalopathy, but can also occur in uremia, hypercapnia, hypoglycemia, and urea cycle defects 2
Liver International suggests that toxic-metabolic encephalopathy accounts for a significant portion of cases and includes conditions such as uraemic encephalopathy, recurrent hypoglycaemia, hypo/hyperthyroidism, and inherited metabolic disorders, with correction of electrolyte imbalances being essential 2

The American College of Radiology notes that subacute infarcts can mimic PRES on imaging, particularly in posterior circulation, and that cerebral microangiopathy (vascular leukoencephalopathy) must be considered, especially in patients with metabolic syndrome and NAFLD 1
Liver International suggests that cerebrovascular disease, including cerebral microangiopathy, should be considered in the differential diagnosis of PRES, particularly in patients with risk factors such as metabolic syndrome and NAFLD 2

The American College of Radiology recommends considering subarachnoid hemorrhage as a differential diagnosis for PRES, particularly when sulcal FLAIR hyperintensity is present, and notes that CT is useful to exclude intracranial hemorrhage when MRI is not immediately available 1
The American College of Radiology also notes that hypertensive microhemorrhages and cerebral amyloid angiopathy are differential considerations for ARIA-H (hemorrhagic form of PRES-related changes) 1

The American College of Radiology recommends an essential initial workup that includes brain MRI (preferred over CT) with DWI, T2 FLAIR, and T2* GRE or SWI sequences, as well as blood tests for electrolytes, glucose, calcium, complete blood count, inflammatory markers, and renal function 1
Liver International suggests that blood pressure monitoring and history of hypertension are crucial in the diagnostic workup of PRES, as well as medication history, particularly immunosuppressants, chemotherapy, and recent drug changes 2
Annals of Oncology recommends considering clinical context, including eclampsia, renal failure, autoimmune disorders, and transplantation, in the diagnostic approach to PRES 3

The European Society of Radiology recommends MRI as the gold standard for diagnosing Posterior Reversible Encephalopathy Syndrome (PRES) due to its superior tissue contrast, sensitivity, and specificity in detecting the characteristic vasogenic edema pattern, allowing for differentiation from competing diagnoses that require different management strategies 4, 5

The American College of Radiology suggests that MRI's superior soft tissue characterization enables clinicians to confidently exclude conditions that mimic PRES, such as intracranial hemorrhage, which can be excluded using T2* GRE or SWI sequences 4
The American College of Radiology also recommends using MRI to differentiate PRES from acute ischemic stroke in the posterior circulation, infectious encephalitis, and CNS vasculitis, which show different enhancement patterns and vessel wall abnormalities on contrast-enhanced sequences 5, 6, 7

The European Heart Journal recommends an MRI protocol that includes T2-weighted and FLAIR sequences to identify hyperintense edema in cortical and subcortical regions, DWI with calculated ADC maps to confirm vasogenic edema, and T2* GRE or SWI sequences to detect microhemorrhages 4, 6, 5

The Journal of the American College of Radiology states that CT head without contrast has significant limitations, including low tissue contrast resolution that prevents detection of subtle white matter edema, and may appear completely normal in early PRES, making MRI a more reliable diagnostic tool 8, 7