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.