Closed-Head Injuries Going Beyond the Thud!

Brain Trauma Types Penetrating Intracranial Injuries Closed Head Injuries Motor Vehicle Accidents are leading cause in young people 38% of cases in young people attributed to alcohol/drug abuse Increase in the elderly due to anticoagulant & antiplatelet drugs Emedicine.medscape.com

Closed Head Injuries Common Causes Automobile accidents Assaults Falls Work-related accidents Sports-related accidents. Common Symptoms Loss of consciousness Dilated pupils Respiratory issues Convulsions Headache Dizziness Nausea and vomiting Cerebrospinal fluid leaking from nose or ears Speech and language problems Vision issues Emotional and behavioral changes

Mortality Rates Severe Head injury = % Most survivors exist in a vegetative state Moderate Head Injuries = % Permanent Disability and/or severe neurological effects CT scan of left frontal acute epidural hematoma (black arrow) with midline shift (white arrow). Note the left posterior falx subdural hematoma and left frontoparietal cortical contusion.

Financial Burden Estimated to cost between 75 and 100 billion dollars annually. Why so costly? Closed-head injuries result in physiological, psychological, and psychosocial deficits that require extensive long-term rehab and care. Emedicine.medscape.com

Concussions defined as an altered mental state that may or may not include loss of consciousness that occurs as a result of head trauma. Repetitive concussions may result in chronic subclinical motor dysfunctions linked to intracortical inhibitory system abnormalities.

Table 1. American Academy of Neurology Concussion Grading Scale Grade 1Grade 2Grade 3 Transient confusion … No loss of consciousness Brief or prolonged loss of consciousness Concussion symptoms or mental status change resolves in 15 min or less Concussion symptoms or mental status change resolves in more than 15 minutes …

Concussions Sport-related concussions are frequent, with 300,000 cases reported each year. Football players and boxers are particularly exposed to repetitive concussions, leading to the condition now known as chronic traumatic encephalopathy syndrome.Football players

Cerebral Contusions What are they? caused by direct transmission of impact energy through the skull into the underlying brain and occur directly below the site of injury. Occur with skull fractures on the frontal and temporal lobes of the brain. Can expand over time – usually 24 hours to 7-10 days after the initial injury.

Contrecoup injuries Are caused by rotational shear and other indirect forces that occur contralateral to the primary injury. Rotational force causes the basal frontal and temporal cortices to impact or sweep across rigid aspects of the skull, the sphenoid wing, and petrous ridges. Delayed enlargement of traumatic intraparenchymal contusions and hematomas is the most common cause of clinical deterioration and death.

Epidural hematoma Epidural hematomas most commonly (85%) result from bleeding in the middle meningeal artery. Occur in 1% of all cases. Epidural hematomas are often associated with a "lucid interval," a period of consciousness between states of unconsciousness.

Subdural hematoma A surface or bridging vessel (venous) can be torn because the brain parenchyma moves during violent head motion. The resulting bleeding causes a hematoma to form in the potential space between the dural and arachnoid. A lucid interval is less likely to develop in this type of injury than in epidural hematomas.

Intraventricular hemorrhage Intraventricular blood is an indicator of more severe head trauma. Intraventricular blood also predisposes the patient to posttraumatic hydrocephalus and intracranial hypertension, which may warrant placement of an intraventricular catheter (if emergent drainage needed) or ventriculoperitoneal shunt for chronic hydrocephalus.

Secondary Injuries and Systemic Insults Secondary Injuries Hemorrhage Ischemia (low O 2 ) Edema Raised intracranial pressure (ICP) Vasospasm Infection Epilepsy Hydrocephalus Secondary Systemic Insults Hypoxia Hypercapnia Hyperglycemia Hypotension Severe hypocapnia Fever Anemia Hyponatremia

How is Learning Effected? Frontal and Temporal Regions greatly effected. Reasoning, critical-thinking & problem- solving skills can be altered. Speech, language abilities, short-term memory can also be effected. High variety of mental skills can be altered depending upon the severity of the contusion.

Effects of Pressure on Blood Vessels Vessels rupture, blood pools Effects of blood chemicals on Nervous Tissue? (Platelets, dissolved ions, immune cells, etc) Nervous Tissue no longer fed, oxygenated in the affected area.

Current Research Blast Force that Causes Concussions in Soldiers Hypothesis: Pulse hits chest, travels up neck to brain (Johns Hopkins University) Hypothesis: Force to the head Causes VasoSpasms

What is cerebral vasospasm? "Cerebral vasospasm" is a term that refers to physical narrowing of the central "lumen" of a brain blood vessel due to overcontraction of the vessel wall. "spasm" refers to the vessel's "spastic" or "shut down" or "constricted" physical state.

Vasospasm

Dr. Alford’s Work… Apply a specific force to a blood vessel invetro and… (a) Vasospasm ---> Hypercontracts to 1. Acute Symptoms (I don’t feel well, etc.) OR 2. Vessels re-models, contracts again and becomes smaller (b) Can lead to vessel eruption or blockage

Dr. Alford When applied to neurons, it just massively disrupts them… they stop working. A 2 nd force does not have to be as strong to trigger a vasospasm if remodeling does not occur. Dr. Alford’s Question: What causes remodeling?