Traumatic brain injury

Blunt head injury leading to a brief loss of consciousness (or 'dazed'). Sometimes followed by a transient basic amnesia syndrome that clears within min to hours

- Increased risk of permanent brain damage if further concussions occur in close temporal proximity

• - Post concussion syndrome:
• HA, dizziness, fatigue, sleep disturbance, nausea, vomiting, depression... improves over many months; all better by 1 year

• Bruise of the brain
• Neurological deterioration in first few days, then improvement. Maximal improvement in ~6 months
• - does NOT cause loss of consciousness-Mechanism: falls
• 1. Coup contusion - at the site of impact
• 2. Contrecoup contusion - remote from site of impact (Frontal lobes, Temporal lobesmost often; regardless of site of impact)
• - old contusions: yellow brown patches ("plaque jaune")

<img src="GFMedia/FE643C19-22E0-4370-8577-01F83336484D-2185-0000022E53DFA90B.png">

• "multifocal", may be microscopic, often asymmetric
• Pathophysiology: blunt head injury at high speed. Rotational velocity of gray/white matter is different --> shear forces on brain
•    -gray-white junctions preferentially in Frontal and Temporal lobes, then in corpus callosum and finally dorsolateral midbrain 
• Presentation: Loss of consciousness for min to days; Maximal recovery within 1-2years
•  +/- hemorrhage

<img src="GFMedia/48B3D882-823B-46D9-BC0E-851AD607EDB0-2185-00000230DDE9020C.png">

• "classic" presentation: loss of consciousness, lucid interval, subsequentdeterioration, (death)
• - Mechanisms: Falls and assaults. (most often associated w/ temporal or parietalbone fracture that *lacerates the middle meningeal artery*)

Radiograph: "lens-shaped" mass that compresses underlying brain --> herniation

<img src="GFMedia/58DD76AFE27B-4465-8B7F-910BA24BA2F9-2185-00000235E2079289.png">

Tx: most need evacuation (surgery) to avoid expansion

neuro exam for pt w/traumatic brain injury

• GCS 3 - worst possible
• GCS 15 - highest, best possible

-BEST GCS score in first 24 hours provides good measurement of severity and prognosis oftraumatic brain injury IN PATIENTS WITH DIFFUSE AXONAL INJURY

• Other measures:
• - length of time pt is unconscious
• - extent of permanent retrograde amnesia
• - * post traumatic amnesia
• - ***(best) neurological and neuropsychological status after maximal recovery

• Chronic >> acute (acute acts like epidural hematoma)
• Presentation: mild impact to head... days or weeks later may develop neurological sx (headache, hemiparesis)
• Pathophys: tearing of the bridging veins (that drain to superficial cortical veins --> superiorsagittal sinus or other).

-expands in the subdural space between the dura and arachnoid: "crescent-like shape"

<img src="GFMedia/C57E2485-DA26-48B5-BD81-72B660B6CBC4-2185-00000239C8C8B240.png">

Risk factors: brain atrophy (more stretch of bridging veins); bleeding disorders

Tx: Most gradually regress, even those that do not often don't require treatment

• - Blunt head injury (most common); ruptured saccular aneurysm (most feared)
• Clinical: asymptomatic, or sx of meningeal irritation (meningismus)
• -blood in subarachnoid space --> vasospasm (stroke risk in following days/week)
• -can lead to delayed complications: hydrocephalus (often normal pressure hydrocephalus)

• Presentation:
• -older individuals
• -large ventricles; NORMAL PRESSURE
• - Cognitive dysfunction
• - Gait disorder
• - urinary bladder dysfunction (later in natural history)

Tx: lumboperitoneal shunt

• problematic: older pts and Alzheimer's pts have enlarged ventricles, cognitive and gaitdisorders...
• -test by large volume LP, see if gait improves

• syndrome: paroxysm (1-2 seconds) of SEVERE stabbing or lancinating pain most often in V2, V3distribution of CNV
• trigger point

• Pathophys: compression of trigeminal nerve near entry zone into the pons by small tortuousbranches of basilar artery
• -arterial pulsation --> demyelination --> cross talk --> syndrome

Tx: antiepileptic drugs carbamazepine and phenytoin (prolong inactivation stage of voltagegated Na channels); gabapentin, baclofen; surgical decompression

~coup injury of the brainimpact may be transient or persistent, may be associated with a fracture or dislocation

Spinal shock! initially lasting (up to) weeks. can interfere with evaluation

• pathology of spinal cord...
• **most often presents as syndrome of "midline external compression"

chronic onset, side pain and decreased range of motion

increasing compression leads to worsening neurological dysfunction

• 1) Loss of proprioception/fine touch
• 2) UMN dysfxn (lower > upper)
• 3) Truncal ataxia
• 4) Neurogenic bladder (sometimes)

dorsal column and corticospinal tract affected due to midline compression from the ventral surface: slipped disc

• nerve root (spinal nerve)
• presentation: shooting pain, somatosensory loss or abnormality (dermatome), lower motorneuron dysfunction (weakness) (myotome)

-herniation of the "x-y" disc compresses the "y" root (i.e. L4-L5 herniation usually compresses the L5 root)

-lumbosacral radicular pain often referred to as "sciatica" (misnomer)

at the level of cauda equina, can lead to syndrome "neurogenic claudications"

• Presentation: pain, numbness that arises **with walking, resolved with rest
• -peripheral pulses in feet are normal
• -sx MINIMIZED or gone when exercising with forward flexion at the hips

• 1. Carpal tunnel syndrome
• 2. Tardy ulnar palsy
• 3. Saturday night palsy
• 4. Peroneal palsy at fibular head
• 5. Meralgia paresthetica

chronic compression injury of the median nerve in the carpal tunnel

Pathophys: excessive repetitive movement with prolonged extension or flexion at the wrist

-Tinel's sign: tapping over the carpal tunnel causes neuropathic shooting pain

Dx: nerve conduction studies

Tx: steroid injections, surgical decompression

• chronic compression injury of the ulnar nerve at or near the ulnar groove (posterior aspect of elbow)
• -nerve conduction studies are the gold standard for diagnosis

Tx: stop leaning on elbows, surgical efficacy is controversial

acute compression of the radial nerve in the spinal groove at the level of the mid-humerus

• Presentation: awaken from a sleep in which they were sedated (alcohol, drugs, etc.)
• -Weakness of all radial-innervated muscles DISTAL to the triceps
• -somatosensory loss in radial territory of the hand (dorsal hand, lateral to 4th digit, sparing the tips)
• "wrist drop"

• Presentation: crossing legs, prolonged squatting and walking forward (strawberry pickers)
• -Neuropathic pain, sensory loss, weakness
• -"foot drop"

peroneal nerve = fibular nerve

somatosensory loss: dorsal aspect of the foot and anterolateral lower leg

weakness of tibialis anterior, peronei, extensor hallucis longus, and extensor digitorum brevis (inversion is OK, eversion is weak)

chronic compression of the lateral femoral cutaneous nerve in the inguinal region

• **Pure somatosensory loss (anterolateral thigh from groin to knee)
• -often neuropathic pain
• **No weakness
• Risk factors: Excess fluid/tissue (obese, pregnant), tight garmets

• Up to 10% of all pts who have LP
• -headache comes on shortly after pt arises
• -resolves completely within moments of lying down.
• (headaches resolve within days to 2 weeks)

MRI shows diffuse enhancement of meninges (due to venous dilation)

Tx: conservative, blood patch: injection of blood into epidural site where the spinal tap was done

spontaneous: associated with straining or non-harmful fall