Meninges, Ventricles, Meningitis

Question 1

What are the most common organisms causing acute bacterial meningitis?

Answer 1

1. Streptococcus pneumoniae
2. Neisseria meningitidis
3. Group B beta-hemolytic Streptococcus

Question 2

Chiari Malformations

Answer 2

• congenital hindbrain anatomic anomolies which are associated with the cerebellum, brainstem, or craniocervical junction
• result in downward displacement of the cerebellum
• tonsils herniate through foramen magnum
• usually adults
• produce hydrocephalus

Question 3

What signs/sx are associated with Chiari I?

Answer 3

1. Cerebellar tonsils below the foramen magnum
2. Syringomyelia
3. Compression of brain stem: headache (increased ICP), ataxia (cerebellar dysfunction), impaired movement (brainstem compression)

Question 4

Chiari II

Answer 4

• Less common: significant herniation through foramen magnum (cerebellar tonsils and vermis lower brainstem)
• causes aqueductal stenosis and hydrocephalus
• usually with meningomyocele

Question 5

Sx of normal pressure hydrocephalus

Answer 5

• gait distrubances
• dementia
• urinatry incontinence
• NO HEADACHE

Question 6

Distinguish between communicating and noncommunicating hydrocephalus

Answer 6

• Communicating: lateral ventricles communicate with subarachnoid space (ie: probs with chorid plexus)
• Noncommunicating: flow obstructed within the ventricular system