Anoxia and brain tumors Flashcards
5 causes of anoxia
myocardial infarction; suffocation (e.g. drowning, strangulation); carbon monoxide poisoning; respiratory distress (e.g. severe COVID); respiratory suppression (e.g. fentanyl overdose)
Pathophysiology of anoxia
lack of oxygen supply due to insufficient cerebral blood flow or oxygen saturation in blood; multiple complex metabolic pathways to cell death; takes days-weeks to show in brain scan
4 brain regions most sensitive to anoxia
basal ganglia (globus pallidus and putamen); hippocampi (CA1 region); cerebellum (purkinje cells); watershed areas of cortex
What does severe/prolonged anoxia lead to?
coma or brain death
What happens when oxygen supply in the brain is resumed within 5-15 mins?
amnesia; executive dysfunction; ataxia (motor incoordination); proximal limb (shoulder and hips) weakness or person-in-the-barrel; visual agnosia and cortical blindness
2 causes of mild hypoxia that can result in reversible damage
being in high altitudes (deprives brains of oxygen); obstructive sleep apnea (secs-mins anoxic episodes wherein a person stop breathing and snores loudly at night)
Factors affecting prognosis of anoxia
duration and completeness of oxygen deprivation; predicted by depth of coma at admission
Survival/recovery rates for anoxia
10% survive and 5% make full neurological recovery for out-of-hospital cardiac arrests; 50% survival for ICU outcomes
4 treatments for anoxia
prevention of further hypoxia (e.g. resuscitation, oxygen); hypothermia (mixed evidence); hyperbaric oxygen therapy for CO poisoning; ECMO
Incidence of brain tumors
10-15 cases per 100000 people/year
Epidemiology of brain tumors
more common in men (except for meningiomas); mean onset age 75-85 for all types and 50-60 for primary tumors
2 origins of brain tumors
primary (brain tissue or brain’s immediate surroundings); metastatic (cancer, usually lung, that spreads to the brain)
3 most common types of primary brain tumors
meningiomas (benign/encapsulated), gliomas (malignant/cancerous); pituitary tumors (benign)
Origins of 3 most common primary brain tumors
meninges, glial cells, pituitary gland
5 pathophysiologies of brain tumors
focal invasion/destruction, local edema, compression, elevated intracranial pressure, hydrocephalus
Local edema
irritation and swelling around the site of the tumor
Hydrocephalus
tumor pushes brain tissue, obstructing flow of cerebrospinal fluid, leading to build-up in ventricles and making them enlarged
Characteristics of onset and symptoms of brain tumors
gradual onset; nature of deficits depend on location; can be focal or generalized if elevated intracranial pressure
2 most common initial symptoms of brain tumors
non-pulsing headache and seizures (both in 50% of adults)
Tumors with worse prognosis
most malignant; fast growing; highly invasive; higher rate of recurrence; low curative potential and treatment is generally palliative
Examples of tumors with worse prognosis
glioblastoma, anaplastic astrocytoma
Tumors with best prognosis
least malignant; slow growing; non-invasive; lower rate of recurrence; may be eliminated by surgery alone
Examples of tumors with best prognosis
oligoastrocytoma, meningioma
3 kinds of diagnostic workup for brain tumors
CT and MRI with enhancement; biopsy for histology; molecular genetic testing
4 kinds of treatments for brain tumors
surgery (gold standard), radiation (blasting tumor from different angles); chemotherapy; possibly immunotherapies
Surgery for benign vs malignant tumors
benign is removed; malignant is debulked or mass is reduced
