Here are 4 such case reports/case series and a review of the subject:
Case Series, DeLong 1981: This report describes 3 previously-normal children, ages 5(F), 7.5(M) and 11(F) that developed autism due to brain inflammation from an infectious illness. The authors state:
"
We report three cases in which striking autistic features developed in previously normal children in the course of an acute encephalopathic illness…"
AND
"
These three children each demonstrated a full-blown autistic syndrome in the course of an acute encephalopathic illness…The cases are presented as examples of an acquired and reversible autistic syndrome in childhood, affording some insight into the neurologic substrate of that syndrome."
AND
"
…the behavioral syndrome was acquired at a clearly definable time, in the context of an acute encephalopathic illness…"
Full paper: Acquired reversible autistic syndrome in acute encephalopathic illness in children
Case Report, Marques, 2013: This report describes a previously healthy 32-month old girl that suffered a viral infection of the nervous system. The child experienced "
marked developmental regression, autistic features, persistent stereotypes and aphasia" (aphasia=loss of speech).
The authors described this case as "
…encephalitis leading to developmental regression with autism spectrum disorder and correlating these 2 distinct entities." (encephalitis = brain inflammation)
The authors rule out inborn metabolic disorders as a cause (this argument also applies to the other case reports):
"
Our patient was previously healthy, with adequate psychomotor development until this infectious episode. Additionally, newborn screening and metabolic tests performed on the admission were negative (normal values for ammonia and lactate) and MRI images do not suggest metabolic disorders. Finally and most importantly, she had a favorable outcome with improvement in all skills and development quotient enhancement. These features do not support an inborn error of metabolism, which are characteristically progressive and lead to severe mental retardation."
Full Paper: Autism Spectrum Disorder Secondary to Enterovirus Encephalitis
Case Report, Ghaziuddin, 2002: This report describes a previously healthy 11 year old boy that developed illness with fever, seizure and brain inflammation. In the following months, the child developed autism, and never fully recovered. The authors state:
"
On the DSM-IV symptom checklist for autistic disorder, he met all the criteria for autism except the onset criterion because he did not have a history of any symptoms before three years of age."
AND
The authors state that this case "…
provides further evidence that autistic symptoms can sometimes emerge after the age of three years following an external event such as an infection."
Full Paper: Autistic Symptoms Following Herpes Encephalitis
Case Report: Gillberg, 1986: This report describes a previously healthy 14 year old girl that developed illness with fever, seizure and brain inflammation. In the following 70 days, she developed all the symptoms of autism, including echolalia, loss of speech, hand-flapping and other self-stimulating behavior. She never recovered. Gillberg states:
"
I will describe the case of a 14-year-old-girl who developed all the classical symptoms of autism over a 70-day period after the onset of convulsions in herpes simplex encephalitis (presumptive diagnosis on the basis of clinical, neurochemical, and neurophysiological tests). Only the age criterion is not met, since she was totally psychiatrically healthy up to her 14th year of life."
AND
"
Severe autistic features-including gaze aversion, abnormal reactions to sound, delayed and immediate echolalia after initial muteness, typical hand-flapping stereotypies, and the acquisition of a set of routines and insistence on sameness that make everyday life totally restricted-developed over a 3-month period after the onset of encephalitis and still remain."
Full Paper: Onset at age 14 of a typical autistic syndrome: A case report
