3Department of Pediatrics and Child Health, Shree Hindu Mandal Hospital, P.O BOX 581 Dar es Salaam, Tanzania
KEY CLINICAL MESSAGE:
Acute Necrotizing Encephalopathy leads to devastating neurological sequelae and even death. Clinician should try to miss this diagnosis whenever there is a viral infection with neurological deficit especially in pediatric age group.
ABSTRACT
Acute Necrotizing Encephalopathy (ANE) is a rare disease affecting the central nervous system. It leads to devastating neurological sequelae with a mortality rate of approximately 30%. Clinicians should have high suspicion whenever there is neurologic deficit and history of viral infections especially involving upper respiratory tract in the paediatric age group.
INTRODUCTION
Acute necrotizing encephalopathy (ANE) is a rare cause of acute encephalopathy which was first described in 1995 by Mizuguchi whereby it was thought to affect population of Eastern Asia particularly children.[1] The condition affects the central nervous system and is characterized by altered level of consciousness usually accompanied with seizures. It has been described as having a radiological hallmark of multiple symmetrical lesions involving the thalami, brainstem, and tegmentum.[2, 3] This is preceded by viral infections which mainly affect the central nervous system leading to life threatening neurological sequelae and even death.[3] After the advancement of imaging modalities such as magnetic resonance imaging (MRI), sporadic cases have been reported to occur elsewhere especially in the western countries.[2] As per the previous reports, this condition predominantly affects not only children but also adolescents and, in a few cases, the adult population.[3] We report the first case of acute necrotizing encephalopathy of childhood from Tanzania treated with a good outcome.
CASE PRESENTATION
A 9-year-old male patient of African descent was seen at our emergency department (ED) with a three-day history of inability to speak. The informant was his father who reported that his son’s symptoms started suddenly which were accompanied by decreased level of consciousness and excessive sleepiness over the period. Prior to the alarming symptoms mentioned above, the patient had severe headache which he reports to be excruciating to the point that the child was crying all the time. At the beginning of his illness, he was taken to the near-by clinic whereby he was prescribed analgesics and antibiotics for presumptive upper respiratory tract infections, since the child had features suggestive of tonsillitis.
On examination at our ED, the child was well nourished boy but ill looking, semi-conscious with Glasgow coma score (GCS) E4V1M5 = 10. He had nasogastric tube (NGT) in-situ, and his airway was patent and protected. His pupils were equally reactive to light, motor function on both the upper and lower limbs power were 3/5 and 2/5 respectively. The patient had opisthotonos posture with positive Kernig’s sign which initially made us think of meningitis. Due to the patient’s decreased level of consciousness assessing all cranial nerves was not easy. However, at least he had a normal gag reflex that he could protect his airway. His haematological and biochemistry laboratory investigations were unremarkable including procalcitonin level, except for the raised serum transaminases ALT 56.3 (1 – 50 U/L) and AST 139.2 (1 – 50 U/L). He was also screened for dengue, malaria, SARS-CoV-2, and HIV which were all negative. Other viral serology tests were unavailable at our centre. Lumbar puncture was not done due to evidence of cerebral oedema in brain computed tomography (CT) scan (Figure 1). The patient was then given hypertonic saline 150 ml of 3% sodium chloride, antibiotics, and antiviral as empirical treatment for meningitis.
Despite the initial therapy until the third day, the patient’s condition was not improving hence a brain MRI was done showed bilateral thalami involvement with hyper intensity on flair images with central haemorrhagic transformation. The putamen and central white matter showed restricted diffusion (figure 2). Based on these findings a new diagnosis of ANE was made. Thus, the decision of administering intravenous immunoglobulin (IVIG) was sought and he was given 25g as a single dose. After 7 days of treatment, the patient’s GCS improved, and later he was discharged through physiotherapy clinic. The patient was seen after 2 weeks at our hospital clinic as a follow-up. There was a remarkable improvement in his motor function as he was able to walk on his own without any support. He was well coherent with the conversation except for his slurred speech, otherwise all other cranial nerves were intact.