Neural tube defects are congenital malformations affecting the brain, meninges, and skull that occur early in development. The most common defects involve the spinal cord and range from spina bifida occulta to more severe myelomeningocele. Preventing neural tube defects involves ensuring adequate folate intake during the first trimester of pregnancy. Infections of the nervous system can involve the meninges (meningitis) or brain parenchyma. Acute bacterial meningitis presents with neutrophils in CSF and requires prompt antibiotic treatment. Brain tumors include gliomas arising from glial cells and neuronal tumors. The most common pediatric brain tumor is medulloblastoma, an aggressive, poorly differentiated neoplasm in the

1. DR ZAINAB

2. CONGENITAL MALFORMATIONS AND
PERINATAL BRAIN INJURY

3. Malformations:::
Neural Tube Defects

4. AFFECTED AREAS
 CHARACTERIZED BY ABNORMALITIES INVOLVING NEURAL
TISSUE, MENINGES, AND OVERLYING BONE OR SOFT TISSUES.

5. HOW TO PREVENT NEURAL TUBE
DEFECTS ??

6. PREVENTION
 FOLATE DEFICIENCY DURING THE FIRST TRIMESTER SHARPLY
INCREASES RISK
 ADMINISTRATION OF FOLATE TO WOMEN OF CHILD-BEARING
AGE REDUCES THE INCIDENCE OF NEURAL TUBE DEFECTS BY UP
TO 70%.
 THE COMBINATION OF IMAGING STUDIES AND MATERNAL
SCREENING FOR ELEVATED Α FETOPROTEIN HAS INCREASED THE
EARLY DETECTION OF NEURAL TUBE DEFECTS.

7. TYPES
 • THE MOST COMMON DEFECTS INVOLVE POSTERIOR END OF
NEURAL TUBE, FROM WHICH SPINAL CORD FORMS.
 THESE CAN RANGE FROM ASYMPTOMATIC BONY DEFECTS (SPINA
BIFIDA OCCULTA) TO SPINA BIFIDA, A SEVERE MALFORMATION
CONSISTING OF A FLAT, DISORGANIZED SEGMENT OF SPINAL
CORD ASSOCIATED WITH AN OVERLYING MENINGEAL
OUTPOUCHING.

8. CONTD
 MYELOMENINGOCELE IS AN EXTENSION OF CNS TISSUE THROUGH
A DEFECT IN THE VERTEBRAL COLUMN THAT OCCURS MOST
COMMONLY IN THE LUMBOSACRAL REGION.
 PATIENTS HAVE MOTOR AND SENSORY DEFICITS IN THE LOWER
EXTREMITIES AND PROBLEMS WITH BOWEL AND BLADDER
CONTROL.

9. CONTD
 ANENCEPHALY IS A MALFORMATION OF THE ANTERIOR END OF
THE NEURAL TUBE THAT LEADS TO THE ABSENCE OF THE
FOREBRAIN AND THE TOP OF THE SKULL.

10. CONTD
 AN ENCEPHALOCELE IS A DIVERTICULUM OF MALFORMED CNS
TISSUE EXTENDING THROUGH A DEFECT IN THE CRANIUM.
 IT MOST OFTEN INVOLVES THE OCCIPITAL REGION OR THE
POSTERIOR FOSSA.
 WHEN IT OCCURS ANTERIORLY, BRAIN TISSUE MAY EXTEND INTO
THE SINUSES.

11. Forebrain Malformations
 MICROENCEPHALY DESCRIBES THE GROUP OF MALFORMATIONS
IN WHICH THE VOLUME OF BRAIN IS TOO SMALL; USUALLY IT IS
ASSOCIATED WITH A SMALL HEAD AS WELL (MICROCEPHALY).
 MEGALENCEPHALY, EXCESSIVE BRAIN VOLUME THAT IS ALWAYS
ASSOCIATED WITH A LARGE HEAD, IS FAR LESS COMMON AND IS
MOSTLY ASSOCIATED WITH RARE GENETIC DISORDERS.

12. CONTD
 HOLOPROSENCEPHALY, CHARACTERIZED BY DISRUPTION OF
NORMAL MIDLINE PATTERNING.
 MILD FORMS SHOW ABSENCE OF THE OLFACTORY BULBS AND
RELATED STRUCTURES (ARRHINENCEPHALY).
 IN SEVERE FORMS, THE BRAIN IS NOT DIVIDED INTO
HEMISPHERES OR LOBES, AND THERE MAY BE FACIAL MIDLINE
DEFECTS SUCH AS CYCLOPIA.

13. CONTD
 INCLUDE LOSS OF GYRI, WHICH MAY BE COMPLETE
(LISSENCEPHALY) OR PARTIAL
 INCREASED NUMBER OF IRREGULARLY FORMED GYRI
(POLYMICROGYRIA).

14. POSTERIOR FOSSA ANOMALIES

15. Posterior Fossa Anomalies
 THE MOST COMMON MALFORMATIONS IN THIS REGION OF THE
BRAIN RESULT IN
MISPLACEMENT OR ABSENCE OF PORTIONS OF THE
CEREBELLUM.

16. CONTD
 DANDY-WALKER MALFORMATION IS CHARACTERIZED BY AN
ENLARGED POSTERIOR FOSSA, ABSENCE OF THE CEREBELLAR
VERMIS, AND A LARGE MIDLINE CYST.

17. INFECTIONS OF THE NERVOUS
SYSTEM

18. Routes of infection….
 HEMATOGENOUS SPREAD
 DIRECT IMPLANTATION OF MICROORGANISMS
 LOCAL EXTENSION
 PERIPHERAL NERVES

19. TYPES OF INFECTIONS

20. Types
 SUBDURAL
 EPIDURAL

21. Meningitis
 MENINGITIS IS AN INFLAMMATORY PROCESS INVOLVING THE
LEPTOMENINGES WITHIN THE SUBARACHNOID SPACE; IF THE
INFECTION SPREADS INTO THE UNDERLYING BRAIN, IT IS
TERMED MENINGOENCEPHALITIS.

22. Types of meningitis
 INFECTIOUS MENINGITIS CAN BE BROADLY DIVIDED INTO:
 ACUTE PYOGENIC (USUALLY BACTERIAL),
 ASEPTIC (USUALLY VIRAL), AND
 CHRONIC (USUALLY TUBERCULOUS, SPIROCHETAL, OR FUNGAL)
SUBTYPES.

23. ACUTE PYOGENIC MENINGITIS
(BACTERIAL MENINGITIS)

24. Causative agents
 IN NEONATES………….. ESCHERICHIA COLI AND GROUP B
STREPTOCOCCI
 IN ADOLESCENTS AND YOUNG ADULTS, NEISSERIA MENINGITIDIS
IS THE MOST COMMON PATHOGEN
 IN OLDER ADULTS………. STREPTOCOCCUS PNEUMONIAE AND
LISTERIA MONOCYTOGENES

25. Clinical/lab findings
 LUMBAR PUNCTURE REVEALS AN INCREASED PRESSURE
 EXAMINATION OF CSF SHOWS ABUNDANT NEUTROPHILS,
ELEVATED PROTEIN, AND REDUCED GLUCOSE.
 UNTREATED PYOGENIC MENINGITIS IS OFTEN FATAL, BUT WITH
PROMPT DIAGNOSIS AND ADMINISTRATION OF ANTIBIOTICS,
MOST PATIENTS CAN BE SAVED.

26. MORPHOLOGY
 MACROSCOPIC
 IN ACUTE MENINGITIS, AN EXUDATE IS EVIDENT WITHIN THE
LEPTOMENINGES ON THE SURFACE OF THE BRAIN.
 THE MENINGEAL VESSELS ARE ENGORGED AND
PROMINENT, AND TRACTS OF PUS MAY EXTEND ALONG BLOOD
VESSELS
 MICROSCOPIC
 NEUTROPHILS MAY FILL THE ENTIRE SUBARACHNOID

27. CONTD
 MICROSCOPIC
 NEUTROPHILS MAY FILL THE ENTIRE SUBARACHNOID SPACE OR, IN
LESS SEVERE CASES, MAY BE CONFINED TO REGIONS ADJACENT TO
LEPTOMENINGEAL
BLOOD VESSELS.
…… IN UNTREATED MENINGITIS, GRAM STAIN REVEALS VARYING NUMBERS
OF THE CAUSATIVE ORGANISM.
……SEVERE INVOLVEMENT OF LEPTOMENINGEAL VEINS (PHLEBITIS) MAY
LEAD TO VENOUS OCCLUSION AND HEMORRHAGIC INFARCTION OF THE
UNDERLYING BRAIN….

28. Aseptic Meningitis (Viral Meningitis)
 EXAMINATION OF THE CSF
 LYMPHOCYTOSIS
 MODERATE PROTEIN ELEVATION, AND
 NORMAL GLUCOSE LEVEL…..

29. MORPHOLOGY
 MACROSCOPIC
 BRAIN SWELLING
 MICROSCOPIC
 LYMPHOCYTIC INFILTRATE.

30. CONTD
 TUBERCULOUS MENINGITIS:
 PROTEIN LEVEL IS ELEVATED
 THE GLUCOSE CONTENT TYPICALLY IS MODERATELY REDUCED OR
NORMAL
 INFECTION WITH MYCOBACTERIUM TUBERCULOSIS ALSO MAY
RESULT IN A WELL CIRCUMSCRIBED INTRAPARENCHYMAL MASS
(TUBERCULOMA), WHICH MAY BE ASSOCIATED WITH MENINGITIS

31. CONTD
 SPIROCHETAL INFECTIONS:
 NEUROSYPHILIS, A TERTIARY STAGE OF SYPHILIS, OCCURS IN ABOUT
10% OF INDIVIDUALS WITH UNTREATED TREPONEMA PALLIDUM
INFECTION.
 INFECTION WITH HIV INCREASES THE RISK FOR DEVELOPING
NEUROSYPHILIS, AND THE DISEASE IS OFTEN MORE AGGRESSIVE IN THIS
SETTING.
 MENINGOVASCULAR NEUROSYPHILIS IS A CHRONIC MENINGITIS,
USUALLY INVOLVING THE BASE OF THE BRAIN, OFTEN WITH AN
OBLITERATIVE ENDARTERITIS RICH IN PLASMA CELLS AND
LYMPHOCYTES.

32. CONTD
TABES DORSALIS
 RESULTS FROM DAMAGE TO THE SENSORY NERVES
IN THE DORSAL ROOTS. CONSEQUENCES INCLUDE
IMPAIRED JOINT POSITION SENSE AND ATAXIA; LOSS
OF PAIN SENSATION, LEADING TO SKIN AND JOINT
DAMAGE (CHARCOT JOINTS); OTHER SENSORY
DISTURBANCES, PARTICULARLY CHARACTERISTIC
“LIGHTNING PAINS”; AND THE ABSENCE OF DEEP
TENDON REFLEXES.

33. CNS TUMORS

38. GLIOMAS
 GLIOMAS ARE TUMORS OF THE BRAIN PARENCHYMA
 CLASSIFIED AS ASTROCYTOMAS, OLIGODENDROGLIOMAS, AND
EPENDYMOMAS

40. Infiltrating ASTROCYTOMA
 ACCOUNT FOR 80% OF ADULT GLIOMAS
 MOST FREQUENT IN THE FOURTH THROUGH THE
SIXTH DECADES OF LIFE.
 FOUND IN THE CEREBRAL HEMISPHERES
 MOST COMMON PRESENTING SIGNS AND SYMPTOMS
ARE SEIZURES, HEADACHES, AND FOCAL NEUROLOGIC
DEFICITS RELATED TO THE SITE OF INVOLVEMENT.

41. Grades
 Grade II/IV) diffuse astrocytoma
 Gradwe III/IV anaplastic astrocytoma
 Grade IV/IV glioblastoma astrocytoma

42. Morphology
 Gross
 poorly defined, gray, infiltrative tumors that expand and distort the
invaded brain
 Range in size from a few cms to enormous lesions that replace an entire
hemisphere
 The cut surface of the tumor may be either firm or soft and gelatinous;
cystic

45. Contd
 Microscopic examination
 Cellular density that is greater than normal white matter.
 There are variable degrees of nuclear pleomorphism.

46. TYPES OF ASTROCYTOMA
 DIFFUSE ASTROCYTOMA (GRADE II),
 ANAPLASTIC ASTROCYTOMA (GRADE III)
 GLIOBLASTOMA (GRADE IV)

47. CONTD
 PROGNOSIS IS VERY POOR
 TREATMENT (RESECTION, RADIOTHERAPY, AND CHEMOTHERAPY)
 THE MEDIAN SURVIVAL IS ONLY 15 MONTHS.

48. Pilocytic astrocytoma
 Pilocytic astrocytomas (grade I/IV) are relatively benign behavior.
occur in children and young adults

49. MORPHOLOGY
 Cystic ; if solid, it may be well circumscribed or, less frequently,
infiltrative.
 Composed of bipolar cells with long, thin “hairlike” processes that are
GFAP-positive and form dense fibrillary meshworks; rosenthal fibers and
eosinophilic granular bodies
 Show limited infiltration of the surrounding brain.

53. Pleomorphic Xanthoastrocytoma
 Occurs most often in the temporal lobe in children and young adults,
usually with a history of seizures.
 Consists of neoplastic, occasionally bizarre, astrocytes, which are
sometimes filled with lipids
 Express neuronal and glial markers.
 Low-grade tumor (who grade ii/iv) with a 5-year survival rate
 necrosis and mitotic activity are indicative of higher grade tumors and
predict a more aggressive course.

55. OLIGODENDROGLIOMA
 ACCOUNT FOR 5% TO 15% OF GLIOMAS
 MOST COMMONLY ARE DETECTED IN THE FOURTH
AND FIFTH DECADES OF LIFE.
 FOUND MOSTLY IN THE CEREBRAL HEMISPHERES,
MAINLY IN THE FRONTAL OR TEMPORAL LOBES.
 TREATMENT:SURGERY, CHEMOTHERAPY, AND
RADIOTHERAPY

56. MORPHOLOGY
 WELL-DIFFERENTIATED OLIGODENDROGLIOMAS
(WHO GRADE II) ARE INFILTRATIVE TUMORS THAT
FORM GELATINOUS, GRAY MASSES AND MAY SHOW
CYSTS, FOCAL HEMORRHAGE, AND CALCIFICATION.

57. MICROSCOPIC EXAMINATION
 COMPOSED OF SHEETS OF REGULAR CELLS WITH SPHERICAL
NUCLEI CONTAINING FINELY GRANULAR CHROMATIN
SURROUNDED BY A CLEAR HALO OF CYTOPLASM And DELICATE
NETWORK OF ANASTOMOSING CAPILLARIES.
…. CALCIFICATION in 90% OF THESE TUMORS.

59. Ependymoma
 arise next to the ependyma-lined ventricular system
 In first two decades of life they typically occur near the fourth ventricle
 constitute 5% to 10% of primary brain tumors
 In adults the spinal cord is the most common location

61. MORPHOLOGY
 Solid or papillary masses arising from the floor of the ventricle
 Although they are moderately well demarcated from adjacent brain, the
proximity of vital pontine and medullary nuclei usually makes complete
extirpation impossible
 In the intraspinal tumors, the sharp demarcation sometimes makes total
removal feasible
 Composed of cells with regular, round to oval nuclei and abundant
granular chromatin.

62. Myxopapillary ependymomas

 Occur in the filum terminale of the spinal cord and contain papillary
elements in a myxoid background, admixed with ependymoma-like cells.
 Cuboidal cells, sometimes with clear cytoplasm, are arranged around
papillary cores containing connective tissue and blood vessels.

64. Neuronal Tumors
 Gangliogliomas tumors comprised of a mixture of mature neuronal and
glial cells
 They are superficial lesions that present with seizures.
 Most of these are slow growing, but the glial component occasionally
becomes anaplastic, and the disease then progresses rapidly
 Most commonly found in the temporal lobe and often have a cystic
component

65. Contd
 Dysembryoplastic neuroepithelial tumor is a rare, lowgrade (WHO Grade
I) tumor of childhood that often presents as a seizure disorder.
 It has a good prognosis following surgical resection
 Typically located in the superficial temporal lobe, although other cortical
sites are seen.

66. Contd
 Central neurocytoma typically is a low-grade (WHO Grade II) neuronal
neoplasm found within the ventricular system (most commonly the lateral
or third ventricles),

67. Poorly Differentiated Neoplasms
 Most common is the medulloblastoma, which accounts for 20% of brain
tumors in children.

68. Medulloblastoma
 occurs predominantly in children and exclusively in the cerebellum
 Neuronal and glial markers may be expressed, but the tumor is often
largely undifferentiated and corresponds to WHO grade IV.

69. MORPHOLOGY
 In children, they are located in the midline of the cerebellum, but lateral
locations are more often found in adults.
 Rapid growth may occlude the flow of CSF, leading to hydrocephalus.
 The tumor is often well circumscribed, gray, and friable, and may be seen
extending to the surface of the cerebellar folia and involving the
leptomeninges

70. Microscopic examination
 Densely cellular, with sheets of anaplastic cells
 Individual tumor cells are small, with scant cytoplasm and
hyperchromatic
Nuclei that are frequently elongated or crescent shaped
 Mitoses are abundant, and markers of cellular proliferation,