Posterior reversible encephalopathy syndrome

Posterior Reversible Encephalopathy Syndrome (PRES) is a neurological disorder characterized by reversible brain dysfunction and characteristic radiological findings. It typically presents with a variety of symptoms, including headaches, seizures, altered mental status, visual disturbances, and focal neurological deficits.

Causes

• The exact cause of PRES is not fully understood, but it is believed to be associated with dysregulation of cerebral blood flow and endothelial dysfunction. Several factors and conditions have been identified as potential triggers for PRES, including:
• Hypertension: Uncontrolled high blood pressure is the most common cause of PRES. Rapid elevation in blood pressure can impair the autoregulation of cerebral blood flow, leading to brain dysfunction.
• Kidney Dysfunction: Kidney diseases, including renal failure, transplant rejection, and use of immunosuppressive medications, have been associated with PRES. The precise mechanisms linking kidney dysfunction and PRES are still under investigation.
• Immunosuppressive Medications: Certain immunosuppressive drugs used in the treatment of cancers, organ transplantation, and autoimmune diseases have been implicated in PRES. These medications can disrupt the normal vascular endothelium function and contribute to PRES development.
• Preeclampsia and Eclampsia: These pregnancy-related conditions, characterized by high blood pressure and organ damage, can lead to PRES. Eclampsia is a severe form of preeclampsia that involves seizures.
• Chemotherapy: Some chemotherapeutic agents, particularly those used in the treatment of cancers, have been associated with PRES. The exact mechanisms involved in chemotherapy-induced PRES are not fully understood.

Symptoms and Diagnosis

The symptoms of PRES can vary but often include:

• Headaches
• Seizures
• Altered mental status
• Visual disturbances (blurred vision, cortical blindness)
• Focal neurological deficits (weakness, sensory loss)
• The diagnosis of PRES is primarily based on clinical presentation and characteristic findings on neuroimaging, such as magnetic resonance imaging (MRI) of the brain. Imaging typically reveals bilateral abnormalities predominantly affecting the posterior cerebral hemispheres.

Treatment

• The primary goal of treating PRES is to identify and address the underlying cause while managing symptoms and preventing complications. Treatment strategies may include:
• Blood Pressure Management: Controlling blood pressure is crucial, especially in cases associated with hypertension. Medications may be administered to lower and stabilize blood pressure.
• Seizure Management: Antiepileptic drugs are used to manage seizures associated with PRES.
• Supportive Care: Monitoring vital signs, providing symptomatic relief, and addressing any associated complications or underlying conditions are important aspects of supportive care.
• Withdrawal or Modification of Triggering Agents: In cases where PRES is associated with specific medications, their withdrawal or modification may be necessary under the guidance of a healthcare professional.

Prognosis

With appropriate treatment and management of the underlying cause, most individuals with PRES experience a complete or near-complete resolution of symptoms. However, severe cases or delays in diagnosis and treatment can lead to complications, such as permanent neurological deficits or, rarely, death. Early recognition and intervention are crucial for optimizing outcomes.

See Also

• Hypertensive Crisis
• Preeclampsia
• Eclampsia
• Seizures
• Neuroimaging

References

• Hinchey, J., Chaves, C., Appignani, B., Breen, J., Pao, L., Wang, A., & Pessin, M. S. (1996). A reversible posterior leukoencephalopathy syndrome. New England Journal of Medicine, 334(8), 494-500. doi: 10.1056/NEJM199602223340803
• Fugate, J. E., & Rabinstein, A. A. (2015). Posterior reversible encephalopathy syndrome: Clinical and radiological manifestations, pathophysiology, and outstanding questions. The Lancet Neurology, 14(9), 914-925. doi: 10.1016/S1474-4422(15)00111-8
• Bartynski, W. S. (2008). Posterior reversible encephalopathy syndrome, part 1: Fundamental imaging and clinical features. American Journal of Neuroradiology, 29(6), 1036-1042. doi: 10.3174/ajnr.A0928

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