15. Clinical syndromes of impaired circulation of the vertebrobasilar system

Question 1

Vertebral artery

Answer 1

Supplies the medulla and inferior surface of cerebellum before forming basilar artery. Basilar artery supplies brainstem from medulla upwards.

Summery vertebrobasilar system: cerebellum, pons, medulla, midbrain, thalamus, occipital cortex

Question 2

Define vertebrobasilar insufficiency

Answer 2

Caused by ischemia in the posterior circulation of the brain

Question 3

Characteristics of symptoms of vertebrobasilar insufficiency

Answer 3

Symptoms are usually transient and resolves within 24 hours

Question 4

General symptoms of vertebrobasilar insufficiency

Answer 4

The 5 D’s
- Drop attacks (weakness of quadriceps - fall to the ground)
- Diplopia
- Dyarthria
- Dizziness
- Dysphagia

Question 5

Causative agents of VBI

Answer 5

• Atherosclerosis
• Hypertension
• Diabetes
• Smoking
• Dyslipidemias

Question 6

Treatment of VBI

Answer 6

Lifestyle changes, treatment of underlying conditions. Antiplatelet and anticoagulants.

Question 7

Places of stroke of VB area

Answer 7

• Basilar artery
• Posterior cerebral artery
• Pontine branches (midbrain, pons, medulla, lacunar)
• Superior cerebellar artery
• AICA
• PICA
• Anterior spinal artery

Question 8

Posterior cerebral artery stroke

Answer 8

Most common findings
- Contralateral homonymous hemianopia
- Contralateral visual field loss

Hemisphere-dependent findings
PCA territory of the dominant hemisphere (usually left):
- aphasia
- Right hemiparesis
- Hemisensory loss

Midbrain syndromes
- Medial midbrain syndrome (Weber syndrome: ipsilat. CN III palsy, contralat. hemiplegia)
- Lateral midbrain syndrome (Claude syndrome: ipsilat. CN III palsy, contralat. ataxia)
- Paramedian midbrain syndrome (Benedikt syndrome: combination of weber and claude)
- Dorsal midbrain syndrome (Parinaud syndrome)

Features of thalamic injury
- Decreased arousal
- Aphasia
- Visual field losses
- Apathy, agitation, personality changes

Question 9

Basilary artery stroke

Answer 9

Locked in syndrome, CN VI palsy (ispilateral loss of eye abduction, medial gaze deviation), contralateral loss of fine touch, proprioception and vibration

Question 10

Locked in syndrome:

Answer 10

• Bilateral ventral pontine damage
• Due to occlusion of basilar artery
• Tetraplegia
• Bulbar palsy (bilateral impairment of function of the lower cranial nerves IX, X, XI and XII)
• Pseudobulbar palsy (dysarthria, dysphagia, facial and tongue weakness, and emotional lability)
• Preserved vertical eye movement, blinking, awareness/consciousness
• Diagnosis: CT/MRI
• Therapy: tracheostomy + mechanical ventilation + feeding tube

Question 11

AICA stroke

Answer 11

Cerebellum: ipsilateral limb ataxia
Brain stem:
- ispilateral horners syndrome, sensory loss (temperatur, pain), facial weakness, lateral gaze paralysis
- contralateral body sensory loss

Question 12

PICA occlusion (wallenberg/lateral medullary syndrome)

Answer 12

• Descending sympathetic tracts: ipsilateral Horner syndrome
• Nucleus ambigius (IX, X, XI): dysphagia, hoarsness, dysphonia
• Vestibular nuclei: nausea, vertigo, nystagmus
• CN V: Ipsilateral sensory loss face
• Cerebellum: ipsilateral ataxia

Question 13

Clinical features of MCA occlusion:

Answer 13

• Contralateral weakness and sensory loss marked in the upper limbs and lower half of the face
• Gaze deviates toward the side of infarction
• Contralateral **homonymous hemianopia **
• Aphasia if in dominant hemisphere (usually left MCA territory): Broca, wernicke or conduction aphasia
• Hemineglect if in nondominant hemisphere (usually right MCA territory): unawareness of and unresponsiveness to unilateral stimuli. Lesion usually contralateral to the stimuli