Lesion:
  • from latin "laesio" (to hurt) - result in holes or cavities
  • can be the result of numerous insults or diseases
  • Anoxia, hypoxia
    • reduced oxygen=bad
    • no reserve of glucose or Oxygen
    • brain needs constant flow
    • neurons without Oxygen die - necrosis, or cell death
    • complete lack of Oxygen is anoxia (heart attack, drowning)
    • reduced Oxygen is hypoxia - about 4-6 minutes before necrosis (altitude, cardiac crisis, hypercapnia)

CVA
  • Stroke
    • damage to blood vessels
    • suffocates brain tissue
    • due to a wide variety of vascular diseases
    • progression
      1. decreased O2 secondary to decreased blood supply
      2. bleeding or hemmorhage, space-occupying mass, which may press on nearby brain structures, increased ICP
      3. toxins in blood interfere with normal brain metabolism, BBB can no longer protect surrounding tissue
    • When a clot blocks your artery at the start of a stroke, the damage is swift. Consider what happens next: Every second, 32,000 neurons -- brain cells -- die; that's 1.9 million in a minute. In that same minute, your brain loses 14 billion synapses, the vital intersections between neurons. Also lost in that minute are 7.5 miles of myelinated fibers through which thoughts pass. (from here)
    • TIA - temporary
    • Infarct - blockage (thrombosis = latin for "clot")
    • Embolism - clot that has moved from one part of body to another
    • bleeding/hemmorhage
    • aneurysms - weakening in arterial wall, may or may not rupture
    • AVMs - direct and useless communication btween atreries and veins, may lead to stroke, rupture
Tumors:
  • from the Latin tumor "swelling"
  • It originally meant an abnormal swelling of the flesh.
  • synonymous with solid neoplasm (new tissue),
    • an abnormal proliferation of tissues,
    • usually caused by genetic mutations
    • resembles cells already present in human body
    • arranged in disorganized ways, do not serve functional purpose
    • often grow at expense of surrounding tissue
    • most neoplasms cause a tumor (with a few exceptions like leukemia)
  • may be benign, pre-malignant or malignant, determined by a pathologist from a biopsy or a surgical excision
Brain Tumor
  • created by abnormal and uncontrolled cell division, normally either in the brain itself
  • in the cranial nerves (myelin-producing Schwann cells: e.g., Schwannoma)
  • in the brain envelopes (meningiomas, imaging),
  • skull, pituitary and pineal gland, (pituitary tumor)
  • spread from cancers primarily located in other organs (metastatic tumors: e.g, from AIDS)
  • approx 43,800 new cases of brain tumors in US in 2005
    • 1.4 percent of all cancers
    • 2.4 percent of all cancer deaths
  • Classifications:
    • Infiltrative - take over neighboring areas of the brain and destroy its tissue
    • Non-infiltrative - encapsulated, and differentiated (easily distinguished) but cause dysfunction through compression
    • Benign - usually surrounded by fibrous caplule, non-infiltrative, will not spread
    • Malignant - invade other tissue and likely to re-grow or spread
      • likely to reappear after surgical intervention
      • difficult to completely remove (infiltrative)
      • may travel to other ortans through bloodstream (metastasis)
      • often originate from primary sites other than brain (e.g., lung or breast)
    • Grades = a complex process
      1. well-differentiated, slow growing, accompanied by few neuropsychological deficits
      2. moderately well-differentiated, intermediate rate of growth
      3. poorly differentiated, fast rate of growth
      4. undifferentiated, fast growing, poor prognosis
Symptoms
  • depend on two factors: tumor size, tumor location, time of symptom onset
  • benign tumors can remain symptom-free for years and they may accidentally be discovered by imaging exams for unrelated reasons (such as a minor trauma).
  • Large tumors - lead to elevated intracranial pressure
    • headaches, vomiting (sometimes without nausea),
    • altered state of consciousness (somnolence, coma),
    • dilatation of the pupil on the side of the lesion (anisocoria),
    • papilledema (prominent optic disc at the funduscopic examination).
  • Major factor is location of the lesion and the functional systems it affects (e.g. motor, sensory, visual, etc.) .

Types - Infiltrating

  • Gliomas - make up 40-50% of all brain tumors.
    • fast growing
    • arise from supporting glial cells
    • particularly destructive and fatal form is Glioblastoma
  • Astrocytomas - infiltrate astrocytes, a type of glial cell
  • Oligodendrogliomas - rare, slow-growing, mostly in young adults

Types - Non-Infiltrating

  • Meningiomas - represent approximately 15% of all brain tumors
    • encapsulated benign tumors
    • more frequent in women than men (2:1 ratio)
    • grow slowly, can become large before symptomatic
    • space-occupying = pressure
    • technically on brain's outer covering
    • Wiki
  • Metastatic tumors
    • nerve cells not likely to cause brain tumors
    • neurons do not grow or heal spontaneously
    • must originate elsewhere
    • always the product of a malignant (cancerous) tumor
    • early diagnosis of primary site helps prevent metastasis
    • grow fast, typically at junction of grey and white matter
    • prognosis is typically poor, as cancer invades multiple organs and produces multiple growths in brain
  • Acoustic neuromas - progressive, elnarging, benign tumors within auditory canal, arising from schwann cells

Diagnosis:

  • Early behavioral symptoms - sudden onset of headaches, nausea, loss of cognitive function, seizures
  • Triage:
    1. Headache
    2. Nausea
    3. Positive papilledema (swelling of the optic nerve, at the point where this nerve joins the eye, that is caused by an increase in fluid pressure within the skull) img
  • Neuroimaging

Survival