Mild TBI (Concussion) Not Just Less Severe But Different

Transcription

1 Mild TBI (Concussion) Not Just Less Severe But Different

2 Disclosures Funded research: 1. NIH: RO1 Physiology of concussion , Co-PI, $2,000, American Medical Society of Sports Medicine: RCT of Aerobic exercise, Co- PI,$400,000.

3 Purpose Provide diagnostic criteria for mild traumatic brain injury (mtbi) and concussion. To describe the metabolic and physiological changes that occur with mtbi. Discuss the alternative explanations of symptoms such neck injury, vestibular problems, ptsd etc.

4 Definitions of MTBI DSM V: loss of consciousness < 30 minutes; PTA < 24 hours; GCS Disorientation and confusion initially Rehab Med: any loss of consciousness or PTA or alteration of mental state/neurologic signs of injury

5 Is a concussion a mtbi? Simple answer: YES Concussion as a term generally used when injury occurs in sport mtbi generally used in reference to other causes such as motor vehicle crashes mtbi always involves some level of permanent brain injury

6 mtbi Symptoms Cognitive Reading comprehension difficulties Problem solving difficulties Lost easily Confusion Planning difficulties Easily distracted Forgetting Losing train of thought Somatic Headache Dizziness Sleepiness Behavioral/Affective Job performance Interpersonal relations Impatience

7 REMINDER Mechanics of Severe TBI Diffuse Axonal Injury: shearing of long axons Rotational effects especially on the brain stem Contusions and hemorrhages Hypoxia (respiratory depletion)

8 Mechanics Usually Involves Acceleration Deceleration of Brain/Head

9 Metabolic Cascade after Concussion % of normal Glutamate K minutes hours days (Giza & Hovda, 2001) UCLA Brain Injury Research Center

10 Metabolic Cascade after Concussion % of normal K+ Glucose Glutamate minutes hours days (Giza & Hovda, 2001) UCLA Brain Injury Research Center

11 Metabolic Cascade after Concussion Calcium % of normal K+ Glucose Glutamate minutes hours days (Giza & Hovda, 2001) UCLA Brain Injury Research Center

12 Metabolic Cascade after Concussion Calcium % of normal K+ Glucose Glutamate minutes hours days Cerebral Blood Flow (Giza & Hovda, 2001) UCLA Brain Injury Research Center

13 Metabolic Cascade Massive release of Potassium Vascular constriction (reduced cerebral blood flow) Increased demand for glucose and oxygen by injured areas (despite reduced blood flow): Brain Energy Crisis Body produces various proteins that might serve as biochemical markers (e.g. S100ß) which may be neuroprotective or bi-products of neurological insult Cytochrome P450 is reduced during the first day and then increased during the next two weeks

14 Implications of Metabolic Cascade In extreme, extra cellular K plays a role in convulsions Tremendous Metabolic Stress Placed on Already Damaged Neural Tissue Disturbance of Metabolic Autoregulation: ANS: Sympathetic overdrive CBF: Increased during exercise Brain is very vulnerable to subsequent injury

15 TAU Axon stretch injury breaks microtubules Tang-Schomer et al., FASEB J 2010

16 Sex Differences: Human ipsc Neurons Obviousness Dolle et al., Exp. Neurol. 2018

17 Computational Modeling of Male vs Female Axonal trauma Dolle et al., Exp. Neurol. 2018

18 fmri Concussion vs Recovered (Leddy et al 2013) Concussed Recovered

19 Concussion produces alterations in the ANS Dysregulation of CBF Decreased at rest Increased during exercise Higher resting HR at rest Decreased HRV at rest Decreased HR during exercise Sympathetic at rest (Difficulty attaining a parasympathetic state) Parasympathetic influence during exercise

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21 Autonomic Nervous System SYMPATHETiC Flight or Fight PARASYMPATHETIC Rest and Digest

22 Sympathetic Fight or flight Quick response system (not intended for long periods) Characterized by increased HR and decreased HRV Pupil dilation Experienced by the individual Disconcerting Anxious (over time anxiety morphs into depression) Light and sound sensitivity Dizziness Exercise intolerance

23 Parasympathetic Rest and Digest Increased blood flow to internal organs Contraction of ciliary muscles facilitating accommodation Modulation of vital functions to achieve homeostasis How patient feels Difficulty achieving a restful state Difficulty going to and staying asleep Nausea Irritable bowel Loss of appetite Difficulty with close vision

24 Other Important Signs of mtbi Fatigue Cognitive or Behavioral? Associated with every source of disability Attention deficit Does not generally appear as a symptom Reaction Time Speed of information processing Most commonly associated with metabolic changes

25 Further Signs of mtbi Exercise Intolerance Decreased CO2 Sensitivity Decreased cerebral blood flow at rest Decreased ability to control cerebral blood flow during exercise Ocular-Motor difficulties

26 Exercise (In)Tolerance Buffalo Concussion Treadmill Test Also have a protocol for an exercise bike Key outcome: Heart Rate when patient is unable to continue due to symptoms

27 Treadmill Test Results Predict Recovery Rate 13 98

28 Differential Diagnosis Anxiety (20) 5% Migraine (15) 5% Diagnoses PCS (22) 20% CVO (22) 55% Resolved (19) 15%

29 Differential Diagnosis Somatization, Factitious Disorder Depression (reactive) Possible to have neurologically based symptoms of depression Pain/Neck (Whiplash) Vestibular damage Chronic Fatigue

30 Clinical Interview Symptoms at the time of the injury and after (compared to pre-trauma) Presence of amnesia Retrograde amnesia Anterograde (post traumatic) amnesia Be alert to vestibular problems Be alert to cervicogenic issues

31 Return to Play Decisions Return to previous level of cognitive function? Symptom free state No symptoms with exercise When in doubt sith them out

32 Assessment On the field: It is all in the eyes In the ED: Physical exam (amnesia, eyes, balance); CT?; Worry: Internal bleed (headache, vomiting) GP: History; Physical exam; Exercise tolerance? Cervicogenic issues; Vestibular system

33 Treatment ED: Rest (48 hours) GP: Symptom based (e.g. Sleep, Sleep hygiene) Dysautonomia: (Sub-Threshold) Exercise Neck/Vestibular/Occulomotor: PT etc.

34 CBF in Adolescents Satterthwaite et al 2014 (N=922)