Pres Syndrome

What is Pres Syndrome?

Pres syndrome occurs due to neurotoxic condition negatively influences auto-regulatory action and that unable to control posterior circulation. In response of this causes sudden alteration of the blood pressure. In the parietooccipital regions, vasogenic edema develops, as blood brain barrier disrupted due to hyperperfusion¹. Hinchey et al. first described Pres syndrome in 1996 and after that, it attained significant clinical acknowledgement².

Pres syndrome and associated conditions

• Full form of Pres Syndrome is Posterior reversible encephalopathy syndrome and this syndrome alternatively known as reversible posterior leukoencephalopathy syndrome. The usual consequences of Pres syndrome are acute hypertension, but this association is not found in all the cases.
• Renal troubles like acute kidney injury or chronic kidney conditions are common associated conditions with Pres syndrome. The strong associations of Pres syndrome along with renal symptoms are hypertension, vascular disease, autoimmune conditions including thrombotic thrombocytopenic purpura and systemic lupus erythematosus, administration of immunosuppressive drugs like chemotherapy agents, cyclosporine, tacrolimus, and organ transplantation like the context of transplantation.
• Peritoneal Dialysis has greater risk of Press syndrome due to chronic hypertension
• Pres syndrome is associated with progressive neurologic symptoms^3,4.

Symptoms

Clinicoradiologic entity of Pres syndrome is characterized by

• Headache
• Altered mental state
• Seizures
• Disturbed vision
• Hypertensive almost 70% affected patient, though remaining cases are reported as normal or only mildly raised blood pressure

Elaborate expression of ocular symptoms includes blurred vision, in both eyes half of the same sided visual field loss ( homonymous hemianopsia), or partial or complete loss of vision due to occipital cortex of the brain become damaged (cortical blindness).

The nature of seizure attack is also specific for Pres syndrome. Commonly, seizures along with non-convulsive status epilepticus produce in Pres syndrome, but the negligible chance of development of generalized status epilepticus. In nonconvulsive status, consciousness is altered for a prolonged period and that may cause misinterpretation for postictal confusion. The postictal confusion related problems usually continue for some hours. The included signs of nonconvulsive seizures are stereotypic behaviors like gawking, frequent eye blinking, or spinning of the head and non-convulsive status along with Press syndrome can preserve for several days. This often creates confusion for drug intoxication, psychosis, or psychogenic states.

Neurological disturbance often causes mild confusion or agitation, but later affected patient become sluggish.

Brainstem deficits, nausea and vomiting rarely associated with Pres syndrome^4,5,6.

Pathophysiology

The involved pathophysiology of Press syndrome includes cerebral autoregulation disorder. Two proposed pathophysiologic mechanisms involve cerebral vasospasm and vasodilatation. The resultant of cerebral vasospasm is cytotoxic edema, whereas vasodilatation causes vasogenic edema. Another suspected culprit for Press syndrome is endothelial dysfunction.

Vascular dilation and constriction regulate cerebral blood flow and also tissue perfusion. All these relative factors equivocate extreme intracerebral hypertension. The impaired autoregulation causes chronic hypertension, as mean arterial pressure increased. Enhancement of blood pressure causes hyperperfusion and cerebral vessel damage, which ultimately leads to vasogenic edema due to interstitial extravasation of proteins and fluids. Cerebral hypoperfusion gradually occurs.

The consideration of endothelial dysfunction as a pathophysiology of the Press syndrome is due to the association of systemic inflammatory process observed in sepsis, transplantation, eclampsia and autoimmune disease. Reversible focal and diffuse abnormalities are found in an angiographic demonstration of Press syndrome and it is assumed that it can be correlated with endothelial dysfunction. Hampering autoregulation due to vasoconstriction, worsen pre-existing inflammatory endothelial dysfunction and leads to hypoxia and subsequent vasogenic edema^4,7.

Causes

The pathophysiology section of Press syndrome explains different possible conditions that may influence the onset of the disorder. Research data support that endothelial dysfunction along with autoimmune condition is responsible for Press syndrome development. Inflammatory cytokine response influences monocytes and lymphocytes to damage activated endothelial cells and that leads to an outflow of fluid and protein into the interstitium. Recent research also has been found a positive correlation between neuromyelitis optica spectrum disorders related autoimmunity for the development of the Press syndrome. This provides a possibility of intervening of autoimmune disorder leads to endothelial aquaporin 4 water channels damage and may influence to PRES⁸.

Diagnosis

The following diagnostic tests are conducted for Press syndrome.

Computed tomography (CT) imaging

CT imaging tool can provide a quick evaluation. It can also eliminate the possible other causes which may contribute similar symptoms like cerebral hemorrhage or brain lesions. Ct Scan images also indicate venous sinus thrombosis, thrombosis or arterial ischemia, but 100% sensitivity of this test is achieved. Sometimes CT image is normal even in presence of Press syndrome. Therefore, CT scan is not considered as an ultimate diagnostic test for Press syndrome.

MRI

• The typical findings of Press syndrome like bilateral white matter defects in the vascular division in the posterior sections of both cerebral hemispheres, involving frequently the occipital and parietal lobes is detected in MRI. MRI can also capture hemorrhage, uneven alterations, the secluded connection of the frontal lobes, and cortical lesions.
• Standard MRI unable to provide the definite result of Press syndrome with other acute vascular diseases. Therefore the application of more specialized sequences MRI may assist to identify subtle hemorrhage, ischemia, inflammation or edema. Specialized MRI imaging tool with some contrast media can provide nephrotoxic effects.
• Magnetic resonance venography or CT scan can diagnose venous sinus thrombosis without providing nephrotoxic effects.
• Angiography can recognize thrombosis, dissection, or vasculitis.

Treatment

• There is no specific treatment for Pres syndrome. But Pres syndrome can be managed by controlling triggering factors, which provides rapid recovery.
• Press syndrome related complications such as sudden onset of hypertension, atypical drug withdrawal symptoms, eclampsia deliverance can be controlled by the withdrawal of the triggering factors.
• Antiepileptic drugs prescribed to treat seizures
• Anesthesia and ventilation may need to install in generalized status epilepticus and to defend the airway for vulnerable patients.
• In medical literature, it is mentioned that corticosteroids can improve vasogenic edema, but there is no evidence of practical usage of this drug^4,5.

Prognosis

The early diagnosis and initiation of treatment can provide a good prognosis. The identification of the patient need and fulfilling of proper medical care for the patient can lead to improvement of the patient’s condition within some weeks⁵.

References

1. Dr Bruno Di Muzio and A.Prof Frank Gaillard. et.al., Posterior reversible encephalopathy syndrome; Radiopaedia.org; Online available at https://radiopaedia.org/articles/posterior-reversible-encephalopathy-syndrome-1
2. Hinchey J, Chaves C, Appignani B, et al. A reversible posterior leukoencephalopathy syndrome. N Engl J Med. 1996;334(8):494-500
3. Fugate JE, Claassen DO, Cloft HJ, Kallmes DF, Kozak OS, Rabinstein AA. Posterior reversible encephalopathy syndrome: associated clinical and radiologic findings. Mayo Clin Proc 2010; 85:427–32
4. Esther V. Hobson, Ian Craven, S. Catrin Blank; Posterior Reversible Encephalopathy Syndrome: A Truly Treatable Neurologic Illness; Perit Dial Int. 2012 Nov-Dec; 32(6): 590–594. doi: 10.3747/pdi.2012.00152; Online available at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3524908/
5. Roth C, Ferbert A. The posterior reversible encephalopathy syndrome: what’s certain, what’s new? Pract Neurol 2011; 11:136–44
6. Kozak OS, Wijdicks EF, Manno EM, Miley JT, Rabinstein AA. Status epilepticus as initial manifestation of posterior reversible encephalopathy syndrome. Neurology 2007; 69:894–7
7. Hyo-Jeong Lee, Posterior Reversible Encephalopathy Syndrome; Medscape; Online available http://www.medscape.com/viewarticle/559553
8. Jennifer E. Fugate, Daniel O. Claassen, Harry J. Cloft, David F. Kallmes, Osman S. Kozak, Alejandro A. Rabinstein; Posterior Reversible Encephalopathy Syndrome: Associated Clinical and Radiologic Findings; Mayo Clin Proc. 2010 May; 85(5): 427–432. doi: 10.4065/mcp.2009.0590; Online available https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2861971/#R1