CHILDHOOD AUTISM OR AUSTIC DISORDER(AD)
(A simple, clinical point of view)
PHILIP JOHN MD
Policlinic & EEG Labs, 
Valanjambalam Cochin -686016
INTRODUCTION
 Many a autistic child may be taken as merely mentally retarded or  behavourally disturbed. Many of them are brought to the physician for slow development of language and may be passed of as 'just a late talker'. 
 Childhood autism is not a functional psychosis; neither is it childhood schizophrenia
 Autism may be present at birth, and is recognisable invariably before 30months of age. Once an autistric, the child is forever an autistic-even- though treatment today greatly modifies the phenomenology. 
 This old 'Kanner's syndrome' is not caused by parents or environment  as used to be believed. It is the result of abnormal cortical development; it is a global disorder of specific neurochemical  processes in the brain - a severe neuro-psychiatric disorder.
HISTORICAL NOTE
In 1943, half a century ago, leo Kanner published his first paper of 11 cases of 'locked-in' children, a syndromse he called 'Infantile Autism'. In that very first paper he got so close to the true clinical nature of autism that its description remains remarkably accurate even today.
In 1944, Asperger reported on a similar group of children; Asperger's Syndrome only connotes the high functioning group of cases with autism.
International Classification of Deseases (ICD-IO) describes Childhood Autism under caregory F 84.00. Diagnostic and Statistrical Manual (DSM IIIR) calls the same syndrome as Autistic Disorder (AD).
Prevalence
Epidemiology in AD is a grey area of research because of the difficulties in making a firm diagnosis. There is a great overlap with other disorders like mental retardation which makes prevalence rates studies an onerous task.
Only Western investigations are available, which highlight a few salient features. These studies reveal that the prevalence rates may be 45 cases per 10,000 children under 15 years of age. It certainly means that autism is not that rare after all.
90% of all autistic children manifest the syndrom before 30 months of age. There is an inequitable ratio between boys and girls-typically ratios of 5:1 are reported. Yet, when girls are affected, they are more severely affected.
Kanner's presumption that AD is an illness of the rich is no longer borne out. There is an even distribution of these disorders across socio-economic classes as well as ethnic groups.
ETIOLOGY
1 Environmental factors
 Kanner had in his original paper emphasised on the socially distant (the so-called 'refrigerator parents') parental influences on the child as the causative factor for autism. This theory that parental behaviour causes autism produced an additional painful burden on parents already coping with an exceedingly difficult, sick child. There is enough evidence now that deviant child-rearing practices do not account for autism.
2 Congential factors: Prenatal, Perinatal and Postnatal
 Although there is no consistant proof regarding these congenital factors in the pathogenesis of AD. there is some evidence that first trimester insults like bleeding, infections (esp. viral) and drugs are common in the autistic group.
3 Genetic factors
 The role of genetic mechanisms in the etiology of autism is being increasingly recognised.
 Concordance rates for autism in monozygotic (MZ) twin pairs is a about 50 percent whereas for dyzygotic twins (DZ) it is only below 10 percent.
 Siblings of autistic children are at a greater risk for autistic features like Asoerger's syndrome. Other cognitive deficits are also more in the siblings of autistic probands.
 Single gene defects producing in born errors of metabolism like Phenyl Ketonuria (PKU), galactosemia, and tuberous sclerosis etc. are associated significantly with the autistic syndrome.
 The recently recognised Fragile X Syndrome (a construction of the X Chromosome in the male Phenotype with mental retradation, macro - Orchidism, Prognathism, Large ears, Narrow faces etc. now considered the second commonest chromosomal abnormality linked to mental retardation, next only to Down's syndrome closely co-exists with autistic disorder. The significance of this finding is under investigation.
4 Biological correlates
 There is now extensive literature implicating both indoleamines and catecholamines aa well as neuropeptides in the etiology of autism.
 About one- third of autistic children show evidence of significant increase in the peripheral blood levels of serotonin (5HT) -hyperserotonemia. Drugs which reduce these levels produce an improvement in the symptoms of autism.
  Increased dopaminergic (DA) function is an agent of behavioural impairments in autism. Drugs which decrease DA activity are beneficial in some autistic children.
5 Neurophysiological and anatomical factors
 EEG : Autistic children show significant EEG abnormalities, with epileptiform activity with or with out clinical seizures, increase in slow rhythm  etc, underlining the biological basis of autism.
 PEG : Pneumo-encephalographic studies have delineated enlargement of the left ventricular system; these findings of reduced grey matter are supported by CT scan findings, although not uniformly.
 REF : Regional Cerebral Blood Flow studies have shown significant findings of reduced grey matter blood flow in both cerebral hemispheres.
 PET : Positron emission tomography studies have suggested elevated cerebral metabolic rate in autistic men.
 All these studies reinforce the cerebral (neuroanatomical) localisation in autistic disorder:
 CLINICAL FEATURES
 1 Age of onset
  It would be more appropriate to term age of onset as 'age of recognition'.
  Autism should be present from birth, yet some period of apparently normal development precedes the discernible onset is camoflagued by the seemingly normal milestones in the first year or two. But the child would have been placid and withdrawn-'a child that hardly smiles'.
 Earlier the onset, the more classic the syndrome and the more sever the deficits. The late onset presentations turn out to be high-functioning autistic (Asperger's Syndrome).
 2. Symptomatology
 DSM III R has selected 16 core symptoms of Autistic Disorder. These have been divided and classified under 3 rubrics here:
 A. Social Disturbance
 B. Communication Disturbance and
 C. Rrestricted repertoire of activities
 A. Social Disturbance
  The first rubric, social disturbance is the central component of autism. By social disturbance is meant the lack of reciprocal, mutual social interaction. Autistic Children have a congenital inability to relate to other human beings. This is contrast to his selective preoccupation with inanimate objects like a string, or part of a toy, or his own finger.
 The child 'locks into his self', resulting in a lack of responsiveness to others. Another human being is treated as part of the furniture. An autistic child has no empathy, no capacity to understand the emotional distress of another human being unlike all normal children.
  Conversely, autistic children do not seek comfort in the evet of distress or pain.
 These children do not experience anxiety precipitated by strangers. (stranger-anxiety), as they relate even to family members as strangers.
 Normal children learn behaviour by imitation of adults, like waving bye-bye or engaging in social play. The inability imitate social interaction makes it impossible for autistic children to learn by reciprocation, or to make any peer friendships.
 B. Communication Disturbance
 The second core-symptom complex is of communication disturbance. Language is for communication. Children engage in communication through non-verbal means.
 Modes of non verbal communication are eye-to-eye contact, gestures, facial expressions, body posturing etc. The autistic children have an inability to use any of these. A painful complaint noticed by mothers is that the baby dose not stretch its hands in anticipation of being picked up.
 For verbal communication, the vocabulary has to grow at a great pace and the normal child learns to use these words to express its inner thoughts. Many autistic children may have a good range of vocabulary, but are unable to use these words for meaningful communication.
 Some autistic children use words only for self stimulation, eg. repeating a word over and over (verbal stereotrypy). This type of qualitative disorders of the use of words is a salient feature of Pervasive Developmental Disorders. Another disturbance seen is echolalia-echoing your words immediately. )Pronoun reversal, ie. refering to self in third person is another disorder. The child may say, "you want milk" to mean "I want milk", or use his own name instead of 'I'.
 Any attempt by others communications is ignored, resented or resisted as an intrusion into his barricaded world.
 C. Restriction of repertoire of activities
  Markedly restricted repertoire of activities and interests is another core rubric.
 As a result of social and communicative impairment, the autistic child has ony a small store of activities to stimulate him, so he cling on to those activities over and over.
 Gradually the child develops an 'obsessive insistance to maintain the sameness' in his environment and activities. He becomes persistantly fascinated and attached to parts of inanimate objects like the broken wheel of a toy car or a string. Or he may become continually preoccupied for hours with the examination one of his fingers.
 Motor stereoypy also is seen  in most autistic children, as stereotyped  repetitive body movements, eg. rocking or head bangin, or other sekf-injurious behaviour (SIB). Thus, each autistic child gravitates into a narrow environment, a cocoon. Any change, even trivial, in this environment produces a violent insistance on sameness is so marked that sometimes, even a vase being moved from its usual position in his room creates an abysmal distress.
 Physical characteristics
  Kanner had remarked on the intelligent physiognomies of autistic children but that turned out to be a myth. There are no pathognomonic physical abnormalities in autistic children. Markedly retarded autistics may give the impression of physical stigmata. Physical features of associated disorders have to be of course, looked for eg. the typical facies of the Fragile X syndrome or the adenoma sebaceum of tuberous sclerosis.
 Cognitive Defecits
  Kanner went wrong in the assumption that autistic children exhibited normal levels of intelligence. In fact, children with autism are not neurologically normal. (It must be a case of mixed-up wiring and faulty connections in the brain). Therefore, cognitive functions are certainly impaired to varying degrees depending on the severity of autism.
  Most significantliy current research with appropriate IQ testing shows beyond any doubt that 75% of autistic children are mentally retarded.
  Deficits of attention ( concentration), Motor control, and Perception (DAMP) are marked features in autism according to recent research.
  Many parents talk of the child's unusual ability to remember trivial details from the past, or its musical or painting ability are quite frequently encountered in AD children.
  Autistic children are terrible with verbal skills. On the other hand, many of them perform well in motor skills and designs.
  About 25% of AD children develop seizure disorder before adolescence and may require life - long anti-epileptic drugs (AEDs). Cognitive deficits associated with seizure disorder and the use of AEDs are then to be anticipated .
 Differential diagnosis
  A specific question asked of psychiatrists is to rule out autism in a child with mental retardation and disturbed behaviuor. Frankly, this can sometimes be a difficult proposition; a substantial propartion of case overlap with one or more other entities.
 In the multiaxial classificatory schemes,
 Axis I  is syndromal Diagnosis
 Axis II deals with Developmental Disorders and
 Axis III with physical Disorders
 In Axis I : The differential diagnosis here involves Schizophrenia and Attention Deficit Hyperactivity Disorders (ADHD).
 Axis II : Presents difficulties . Here the differential diagnosis is considered with Mental Retardation, as well as Specific Developmental Disorder (SDD) eg. congenital aphasias, dyslexias etc. More than 75% of autistic children are retarder producing a greate overlap between autism and mental retardation in a given case.
 Specific Developmental Disorders like dyslexia are easier to differentiate, because these children have normal development in every other sphere of activity.
 In Axis III, one has to rule out Hearing disorders, Gullie's de la Tourette syndrome (a good number of autistic children also have tics), degenerative disorders of CNS producing dropping of milestones etc.  It should also be remembered that epilepsy is associated with 25% of autistic children.
 Autistic Disorder and mental Retardation
 For practising clinicians, it may be of some use to dwell at length over the common differences between Autistic Disorder and Mental Retardation (MR), As already stated, there is considerable overlap between them and co-existance. Autistics have mental retardation and retarted children may have autistic symptoms. In such an event both diagnosis have to be specified as evidently they are not mutually exclusive.
 Although differential diagnosis between AD and MR is complex in younger patients, it would help to remember that autistic children have some period of normal development recognition of there symptoms. mental retardation however expresses it self as delayed milestones right from the start.
 It will be practical to go back to the already described 3 rubrics of clinical presentation of Autistic Disorder.