Unlocking the Mystery of PRES: What You Need to Know About This Reversible Brain Condition
"Atypical cases reveal critical insights into posterior reversible encephalopathy syndrome, emphasizing the importance of early diagnosis and management."
Posterior reversible encephalopathy syndrome (PRES) is a condition that can affect the brain, typically causing temporary problems. Usually, PRES involves the back part of the brain. It's known for being reversible, meaning patients can recover well with the right treatment. Understanding this condition is vital for early diagnosis and effective management.
PRES is often linked to conditions like severe high blood pressure, kidney failure, autoimmune disorders, certain medications, and eclampsia. Common signs include confusion, seizures, headaches, and vision problems. Doctors use MRI scans to look for swelling in the brain, particularly in the white matter, which is often seen in the posterior regions.
While PRES usually affects the back of the brain, a recent case highlights an unusual presentation involving the temporal pole. This case emphasizes that PRES can occur in different ways, and recognizing these variations is crucial for proper diagnosis and treatment. The involvement of the deep white matter, including the temporal pole, is rarely seen in ischemic stroke, making it a potential sign of PRES.
Recognized, but Underreported
PRES is a clinical and radiological syndrome associated with combinations of seizures, altered consciousness, headache, and visual disturbances, and it is also associated with hypertension. Its epidemiology and associated manifestations have been described as underreported, despite increasing recognition of the condition. The available sources do not provide a verified incidence figure or other population-level statistics.
Clinical and Imaging-Based Recognition
PRES is identified as a clinical-radiological syndrome, with symptoms that can include headache, encephalopathy, seizures, and visual disturbances. It is linked to varied underlying conditions and exposures, including severe hypertension, renal dysfunction, autoimmune disease, sepsis, and cytotoxic or immunosuppressive agents. Its name can be misleading, and the condition is described as having heterogeneous causes and neuroimaging findings. These sources characterize recognition and diagnosis but do not specify a single definitive diagnostic test or treatment protocol.
Atypical PRES Case: Deep White Matter Involvement
A 55-year-old man was admitted to the emergency department with mild confusion. Over the previous three months, he had been making mistakes at work and feeling fatigued. On the day of admission, he couldn't stand up on his own. He had a history of untreated high blood pressure (170/120 mmHg) for three years, along with alcohol abuse, gastric ulcers, and a cleft lip palate. His diet was poor, and he smoked 40 cigarettes daily for 25 years.
- Hemoglobin: 12.8 g/dL
- Leukocyte Count: 14,050/mm²
- Platelet Count: 140,000/mm²
- Serum Creatinine: 8.43 mg/dL
- Urea Nitrogen: 106 mg/dL
- Mild hypokalemia (potassium: 3.0 mEq/L)
Imaging and the Evolving Picture of PRES
A review reports that established diagnostic criteria for PRES are lacking, while contrast CT and MRI are essential to diagnosis; it highlights T2-weighted and FLAIR MRI sequences. The syndrome’s name does not fully capture its range: it is not always reversible and may extend beyond posterior brain regions or white matter. A 2025 review describes ongoing advances in neuroimaging and biomarker research, alongside increased use of cytotoxic agents and newer immunotherapies, including tyrosine kinase inhibitors and anti-CD19 chimeric therapies.
An Unsettled Mechanism
The pathophysiology of PRES is not completely understood. One proposed explanation is that rapidly developing hypertension impairs cerebral blood-flow autoregulation, disrupts the blood-brain barrier, and causes hyperperfusion. This process is thought to result in vasogenic edema, but the source presents it as a proposed mechanism rather than a settled account.
Variation Across Patients and Conditions
PRES is characteristically described as reversible, but it can result in long-term disability. One single-center study set out to identify clinical and radiological factors unique to children with PRES compared with adults, though the supplied source summary does not report its comparative findings. PRES is also discussed alongside reversible cerebral vasoconstriction syndrome (RCVS) as a question of whether the conditions are distinct entities or part of a spectrum.
Key Takeaways: Recognizing PRES and Its Variations
This case highlights the importance of considering PRES in patients with severe hypertension and neurological symptoms, even when the presentation is atypical. The involvement of the deep white matter, especially the temporal pole, is a less common finding but should raise suspicion for PRES.
A Recognized Clinicoradiological Syndrome
A review describes PRES as a clinicoradiological syndrome involving acute cerebral endotheliopathy, followed by disruption of the blood-brain barrier and vasogenic edema. It also notes that PRES has been increasingly recognized since its first description in 1996. Together, these points frame the condition as an increasingly recognized syndrome with a proposed biological sequence linking endothelial injury and brain swelling.
Symptoms and Context Matter
PRES can present with visual changes, headache, altered mental status, and seizures, alongside white matter edema in the posterior parietal region. It was first described in 1996 by Hinchey and colleagues as Reversible Posterior Leukoencephalopathy Syndrome. A 2024 case-report summary says that, in half of cases, the clinical context involves vasoactive substances such as cannabis, antidepressants, or nasal decongestants and/or the postpartum period.
Early diagnosis and treatment, including blood pressure control and hemodialysis, can lead to significant clinical and radiological improvement. Recognizing the varied presentations of PRES is crucial for timely intervention and better patient outcomes.
While the pathophysiology of PRES is not fully understood, rapidly developing hypertension is believed to disrupt cerebral blood flow autoregulation, leading to vasogenic edema. Further research is needed to better understand the mechanisms underlying PRES and identify potential risk factors.