Anatomo-Physiological Peculiarities of Nervous System

REQUIREMENT FOR THE EVALUATION OF INFANT WITH SUSPECTED NEUROLOGICAL DISORDERS

1. Carefully elicited history
2. Accurate assessment and interpretation of physical signs. 
3. Working knowledge of the expected rate of growth and development of the child & the accepted range of deviation from the norm. 

 

THE HISTORY 

Should include adequate information regarding

• Child’s prior health 
• Acquisition or loss of developmental milestones 
• Family history. 
• Social and physical environment

Such considerations may modify the child’s response to illness or provide clues to inciting factors.

 

INTRAUTERINE DEVELOPMENT OF NERVOUS SYSTEM

2ND WEEK

• Nervous system develops from ectoderm 

3RD WEEK

• Primary neural plate forms

LATER

• It divides into neural tube 
• Neural tube later gives rise to:
  • spinal cord 
  • brain 
  • neural crest cells (pons, PNS, meninges melanocytes, adrenal medulla) 

10 TH – 18TH WEEK 

• Most intensive dividing of nervous cells takes place 
• Critical period of formatting of CNS 
• Any injury sustained during this period is likely to impair brain growth. (infections, metabolic, toxic, vascular disorders)

 

AGE PECULIARITIES OF NS

• The brain is the most morphologically developed organ @ birth bout its functional abilities are immature. 

 

STAGE	BODY WEIGHT
Newborn	1/9th of body weight
End of 1st year	Doubles 1/11th – 1/12th body weight
5 years	1/13 – 1/14th body weight
Adult	1/40th body weight

 

• The brain tissue is characterized by rich vascularization, but the back-flow of blood is weak
• This courses easy development of brain elema a collection of toxic substances.
• Neurocytes need as much as in 22x more oxygen than any Somatic cell 
• That is why lots of diseases in infancy lead to development of hypoxic excephalophetty 

 

CEREBRO-SPINAL FLUID

 

AGE	Amount
Newborn	30 – 40 ml
12 Months	40 – 60 ml
Adolescence	Up to is 150 ml

 

NEUROCYTES 

• The adult person has got 16 million of neurocytes 

 

AGE	NEUROCYTE %
At birth	25 % of the amount of all undifférenticated cells in the brain
6th month	66% of the amount of all undifférenticated cells in the brain
1 year	90-95% of the amount of all undifférenticated cells in the brain
18 months	100% of neurocytes are similar to those of adults

 

• * Proper nutrition, development, caring for the child & absence of diseases are so important during this period.

NEUROLOGIC EVALUATION IN CHILDREN

1. History taking,
   1. Chief complaints 
   2. Present illness
   3. Family history 
   4. Past history 
   5. Physical examination 
   6. Neurological examination 
   7. Mental status 
   8. Stance and Locomotion 
   9. Motor System 
   10. Sensory System 
   11. Reflexes 
   12. Cerebellar System
2. CONGENITAL DEFECTS OF THE NS next lesson
   1. 1. Hydrocephalus 
      2. Microcephaly 
      3. Erb Palsy 
      4. Cerebral Palsy 
      5. Febrile sei aures 
      6. Seizure disorder 
      7. Tic disorders

    

DISORDERS 

Acute meningitis. 

• The most common bacterial infection of the central nervous system in childhood.

Etiology

1. The most common causes of meningitis are bacterial pathogens

1. Group B Streptococci 
2. Gram -ve enteric bacilli (klebsiella, enterobacter)
3. E. coli 
4. Listeria monocytogenes 
5. Neisseria meningitidis
6. Strep. pneumonia 

2. Viral agents 
3. fungus
4. Tuberculosis & Spirochetes pathogens. 

 

Pathogenesis 

• Colonizations or infection of the upper respiratory tract with the bacteria responsible former meningitis occurs @ some time or another in the majority of otherwise normal infants & children 
• Symptoms are either mild or inapparent. 
• In a few, infection leads to blood invasion 
• Children fail to clear the bloodstream of these organisms and disease takes root.

Signs and Symptoms 

• Beyond newborn period highest attacks occur between 3-8 months.
• Incidence remains high till 4yrs of age 
• Infants under 1 month show
  • Irritability
  • lethargy 
  • Unusual cry 
  • Seizure 
  • Poor feeding 
  • Vomiting
  • High fever
  • Signs of meningeal irritation (absent)
• Infants older than 4 months produce
  • fever 
  • Stiff neck 
  • Irritability
  • Seizures
  • Increased interstitial pressure 
• In older children
  • Headache 
  • Muscle & back pain 
  • Stiff neck 
  • Photophobia

Diagnostic Tests 

1. Fundoscopy 
2. Lumbar puncture & examination of CSF 
3. Blood Cultures 
4. Cultures of nose of throat

 

CENTRAL NERVOUS SYSTEM DISORDERS 

• These remain a significant source of childhood morbidity a mortality especially in infants & children & 3 yrs in whom immunologic defense mechanisms are less developed & clinical signs more pronounced.