A Rare Case of Cyclophosphamide-Induced Posterior Reversible Encephalopathy Syndrome in a Patient with Anti-GBM Vasculitis, and Review of Current Literature

Posterior Reversible Leucoencephalopathy Syndrome: Case Series, Comments, and Diagnostic Dilemma

PURPOSE OF REVIEW

To report a series of patients with clinical and radiological features suggestive of posterior reversible encephalopathy syndrome (PRES) related to diverse etiologies emphasizing its pathophysiological basis.

RECENT FINDINGS

Posterior reversible encephalopathy syndrome (PRES) may present with a broad range of clinical symptoms from headache and visual disturbances to seizure and altered mentation. Typical imaging findings include posterior-circulation predominant vasogenic edema. Although there are many well-documented diseases associated with PRES, the exact pathophysiologic mechanism has yet to be fully elucidated. Generally accepted theories revolve around disruption of the blood-brain barrier secondary to elevated intracranial pressures or endothelial injury induced by ischemia from a vasoconstrictive response to rising blood pressure or toxins/cytokines. While clinical and radiographic reversibility is common, long-standing morbidity and mortality can occur in severe forms. In patients with malignant forms of PRES, aggressive care has markedly reduced mortality and improved functional outcomes. Various factors that have been associated with poor outcome include altered sensorium, hypertensive etiology, hyperglycemia, longer time to control the causative factor, elevated C reactive protein, coagulopathy, extensive cerebral edema, and hemorrhage on imaging. Reversible cerebral vasoconstriction syndromes (RCVS) and primary angiitis of the central nervous system (PACNS) are invariably considered in the differential diagnosis of new cerebral arteriopathies. Recurrent thunderclap headache (TCH), and single TCH combined with either normal neuroimaging, border zone infarcts, or vasogenic edema, have 100% positive predictive value for diagnosing RCVS or RCVS-spectrum disorders. Diagnosis of PRES in some circumstances can be challenging and structural imaging may not be sufficient to distinguish it from other differential diagnostic considerations like ADEM. Advanced imaging techniques, such as MR spectroscopy or positron emission tomography (PET) can provide additional information to determine the diagnosis. Such techniques are more useful to understand the underlying vasculopathic changes in PRES and may answer some of the unresolved controversies in pathophysiology of this complex disease. Eight patients with PRES resulting from different etiologies varying from pre-eclampsia/eclampsia, post-partum headache with seizures, neuropsychiatric systemic lupus erythematosus, snake bite, Dengue fever with encephalopathy, alcoholic liver cirrhosis with hepatic encephalopathy, and lastly reversible cerebral vasoconstriction syndrome (RCVS). Additionally, a diagnostic dilemma between PRES and acute disseminated encephalomyelitis (ADEM) was notable in one patient. Some of these patients did not have or only very transiently had arterial hypertension. PRES may underlie the clinical conundrum of headache, confusion, altered sensorium, seizures, and visual impairment. PRES need not necessarily be always associated with high blood pressure. Imaging findings may also be variable. Both clinicians and radiologists need to familiarize themselves with such variabilities.

A Rare Case of Cyclophosphamide-Induced Posterior Reversible Encephalopathy Syndrome in a Patient With Acute Lupus Nephritis Flare

Posterior reversible encephalopathy syndrome (PRES) is a syndrome encompassing both clinical and radiological manifestations with white matter vasogenic edema predominantly of the posterior and parietal lobes of the brain. It may accompany several medical conditions including immunosuppressive/cytotoxic drugs. We present a case of cyclophosphamide-induced PRES in a patient treated for acute lupus flare with biopsy-proven lupus nephritis. A 23-year-old African American female presented with non-specific symptoms over a six-month period on a medical background of systemic lupus erythematosus and biopsy-proven focal lupus nephritis class III on hydroxychloroquine, prednisone, and mycophenolate mofetil for which she was non-compliant. She was borderline hypertensive, tachycardic, saturating well on ambient air, and alert and oriented. Laboratory workup revealed electrolyte imbalance, elevated serum urea, creatinine, and B-type natriuretic peptide, low serum complements, and elevated double-stranded DNA (dsDNA) with negative lupus anticoagulant, anti-cardiolipin, and B2 glycoprotein antibody. Chest imaging revealed cardiomegaly with small pericardial effusion, left pleural effusion, and trace atelectasis, with no deep vein thrombosis on Doppler ultrasound. She was admitted to the intensive care unit for lupus flare with severe hyponatremia and was continued on mycophenolate mofetil, hydroxychloroquine, and prednisone 60 mg for induction therapy as well as intravenous fluids. Hyponatremia resolved, and blood pressure was controlled. She became fluid overloaded and anuric, with pulmonary edema and worsening hypoxic respiratory failure not responding to diuretic challenges. Daily hemodialysis was started, and she was intubated. Prednisone was tapered down, mycophenolate was switched to cyclophosphamide/mesna. She became agitated, restless, and confused, with waxing and waning consciousness and hallucinations. She was continued on bi-weekly cyclophosphamide for induction therapy. After the second dose of cyclophosphamide, her mentation worsened. Non-contrast MRI showed extensive bilateral cerebral and cerebella deep white matter high-intensity signals suggestive of PRES, which was new compared to one year prior. Cyclophosphamide was held and her mentation improved. She was successfully extubated and discharged to a rehabilitation center. The exact pathophysiological mechanism of PRES is not known. Endothelial damage and vasogenic edema have been hypothesized as possible mechanisms. Severe anemia, fluid overload, and renal failure are some of the causes of endothelial dysfunction and vasogenic edema with disruption of the blood-brain barrier, which were found in our patient, but repeated dosing of cyclophosphamide worsened her condition. Discontinuation of cyclophosphamide led to a significant improvement and complete reversal of her neurologic symptoms, implying that prompt recognition and management of PRES is vital to prevent permanent damage and even death in these patients.