Case Report
The patient is a 16-years-old Tunisian boy known for nephrotic syndrome related to a minimal change disease diagnosed based on a renal biopsy in October 2021. In February 2022, he was admitted to the Nephrology department for a corticosteroid-resistant NS with severe adverse events of glucocorticoids (Cushing syndrome, glaucoma, and dyslipidemia).On clinical examination, the boy’s weight was 75 kg, his height was 1.68m, and he was afebrile and had no respiratory symptoms. His blood pressure was 130/70 mmHg with a heart rate of 80 beats per minute. He also had lower limb edema related to his nephrotic syndrome. Regarding his corticosteroid nephrotic syndrome, we decided to start CSA treatment at a dose of 3mg/kg/day with progressive tapering of corticosteroids.
On the fifth day of CSA start, the patient presented two short left clonic focal seizures with a duration inferior to two minutes. After one minute, he had a third motor focal onset seizure with secondary generalization and conscious alteration. The recovery of consciousness was after 30 minutes. Apart from a high CRP, biological tests were in the normal range and could not explain these symptoms (Table 1). Intravenous sodium valproate was initiated quickly and we have not objectified a new seizure. The cranial magnetic resonance imaging (MRI) showed leptomeningeal enhancement with a predilection in the cerebellar hemispheres (Figure 1). The cerebrospinal fluid (CSF) analysis shoIntravenouswed normal cellularity with hyperproteinorachia (0.71g/l) (Table 2) and the CSF bacterial culture was negative. In the meantime, the patient experienced sinus tachycardia, with one episode of fever. Therefore, we decided to perform nasopharyngeal RT-PCR for SARS-CoV-2since the patient was in contact with a COVID-19 subject. The test returned positive.
Although the RT-PCR for SARS-CoV-2in the CSF was negative, the data from the MRI and the CSF analysis, along with the positivity of the nasopharyngeal RT-PCR for SARS-CoV-2, led to the diagnosis of secondary encephalitis to SARS-CoV-2infection. As a result, we decided to discontinue CSA, being immunosuppressive, during the infectious period.
For the next ten days, the patient showed no recurrence of the seizure, did not require oxygen therapy, and did not present any new symptoms. After a second nasopharyngeal swab for SARS-CoV-2 that was negative, the patient was declared cured. The analysis of the CSF of a second lumbar punction analysis showed normal cellularity with normal glycorrhachia and proteinorachia. The patient was discharged with a maintenance oral dose of sodium valproate. Two weeks later, the patient had not experienced any recurrence of neurological symptoms and he had a persistent severe nephrotic syndrome. Therefore, we decided to restart CSA treatment. Despite being under an anti-epileptic drug, the patient experienced generalized tonic-clonic seizure one day after the immunosuppressant resumed treatment. This allowed us to rectify the diagnosis and relate the seizures to the CSA. A second cranial MRI (Figure 2) showed a progression of the previous lesions and the appearance of new cortical and subcortical hyperintensities in axial FLAIR- weighted and diffusion in the biparietal and right frontal lobe with an exaggerated meningeal gadolinium enhancement in front of these lesions. Imaging, as well as clinical data and the causal link with the taking of the treatment, the diagnosis of CSA-induced PRES, was retained. As an alternative to CSA, we opted for Rituximab at a dose of 1g per dose (two doses spaced two weeks apart) with good clinical and biological tolerance.