Hyperglycemia-induced posterior reversible encephalopathy syndrome: A rare cause of reversible blindness.

Posterior reversible encephalopathy syndrome (PRES) is an amalgam of clinical and radiological entities, which is reversible if diagnosed and treated promptly. It is characterized by varying neurological manifestation of seizure, headache, visual loss with typical magnetic resonance imaging findings of symmetric distribution of changes involving the parietooccipital lobes, which reflects vasogenic edema. The common causes include hypertension, renal failure, eclampsia, preeclampsia, sepsis, diabetic ketoacidosis, sepsis, cytotoxic drugs, and autoimmune disorders. Although it has been reported in association with diabetic ketoacidosis in few cases, its association with hyperglycemia in the absence of any other clinical or metabolic derangements is extremely rare. We report here a case of reversible blindness caused by hyperglycemia-induced PRES in a 21-year-old female. Copyright:

Introduction

Posterior reversible encephalopathy syndrome (PRES) is a neuroradiological entity characterized by varying neurological manifestation reflected by characteristic brain imaging findings.[1] The clinical manifestation includes headache, seizure, visual disturbances, and other focal neurological deficits. The common causes include hypertension, renal failure, eclampsia, preeclampsia, sepsis, diabetic ketoacidosis, cytotoxic drugs, and autoimmune disorders to name a few.[2] Typical magnetic resonance imaging (MRI) findings include symmetric distribution of changes involving commonly the parietooccipital lobes and reflect vasogenic edema.[3] It is usually true to its name, i.e. reversible in nature provided it is recognized at an early stage and managed promptly. Its association with diabetic ketoacidosis and rapid correction of hyperglycemia has been well established. However, hyperglycemia alone without any other metabolic derangement has not been reported as a cause of PRES. We report here a 28-years-old female with PRES secondary to hyperglycemia.

Case Report

A 28-year-old non-pregnant female with type 1 diabetes mellitus on basal bolus insulin presented with complaint of headache and blurring of vision for 2 h. The blurring of vision progressed to complete loss of vision over a period of 2 h. She had no history of fever, seizure episodes, trauma, weakness of any body part, any preexisting ocular abnormalities, hypertension, or any other co-morbidity. She had missed doses of insulin for the last 2 days. On clinical examination, her blood pressure was 110/72 mmHg and she was found to have only perception of light with normal pupillary reflex and normal fundus. Signs of meningeal irritation were absent. Rest of the clinical examination was found to be normal. A retinal examination performed by the ophthalmologist was found to be normal. On investigations, her blood glucose level was found to be very high in the absence of urinary ketone and normal arterial blood gas. Her serum electrolytes, renal, and liver function parameters were found to be normal. Noncontrast computed tomography of brain revealed hypo densities in the parietooccipital lobe and corpus callosum. Contrast-enhanced magnetic resonance image of brain showed T2 FLAIR hyperintensity involving bilateral occipital region [Figure 1], bilateral occipital and parietal region [Figure 2], splenium of corpus callosum [Figure 3], and deep white matter of right centrum semiovale [Figure 4] suggestive of atypical PRES. All other causes of PRES were ruled out and a diagnosis of hyperglycemia-induced PRES was made. She was managed for hyperglycemia and she had complete recovery of vision in 5 days with no neurological deficit.

Figure 1

MRI brain showing T2 FLAIR hyperintensity involving bilateral occipital region

Figure 2

MRI brain showing involvement of splenium of corpus callosum

Figure 3

MRI brain showing bilateral T2 hyperintensity in both occipital and parietal region

Figure 4

MRI brain shows T2 FLAIR hyperintensity involving the deep white matter of right centrum semiovale

Discussion

Posterior PRES is a neurological disorder characterized by varying clinical manifestation of headache, seizure, altered sensorium, and visual loss. It is believed to be associated with vasogenic edema commonly involving the white matter of occipital and parietal lobes. Of the various implicated causes, hypertension, renal dysfunction, use of immunosuppressive drugs are the common ones. Few cases have also been reported in diabetic ketoacidosis (DKA) and rapid correction of hyperglycemia. Oun et al. have reported a case of reversible blindness associated with DKA in a 45-year-old female.[4] Sathyanarayana et al. have recently reported a case of PRES in association with DKA in a 13-year-old child.[5] Edema secondary to dysregulated sodium hydrogen exchange mechanism, accumulation of various toxic ketoacids, and osmotic diuresis has been believed to the cause in DKA.[6] However, our patient had only hyperglycemia without any other clinical or metabolic derangements. We could come across only one such case in the literature reported by Kawaguchi et al.[7] The underlying pathogenesis of PRES in hyperglycemia in the absence of ketoacidosis and other metabolic derangements is not fully elucidated, but is thought to be caused by endothelial dysfunction caused by excessive circulating inflammatory cytokines.[8] It becomes important because hyperglycemia is associated with increased serum proinflammatory cytokines including circulating levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) and have shown to regulate expression of vascular endothelial growth factor and it may increase vascular permeability leading to vasogenic edema in PRES.[9]

There are no definitive diagnostic criteria for PRES, and diagnosis is based mainly on the radiological and clinical findings and its reversibility on treatment. With the current epidemic-like situation of diabetes mellitus and its associated complications, the role of the primary care physicians becomes all the more important to identify complications such as PRES, which is reversible and associated with the very good outcome if diagnosed early and treated accordingly. Early diagnosis and addressing of the inciting cause are imperative to reduce the neurological sequalae and morbidity.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.