Final Project for "Understanding the Brain - The Neurobiology of Daily Life"
Cerebellum damage caused by Arteriovenous malformation (AVM) - an abnormal connection between arteries and veins, bypassing the capillary system A Case Study
Final Project Components Here are the three components required for the peer review: The project is mainly about a real case of AVM hemorrhage which affect the brain stem function temporarily and the cerebellum permanently. The former was life threatening, the latter permanently impair movements (of thought, speech and thought) The main functions of the cerebellum is motor coordination and motor learning (thought/cognition is also implicated) Anatomy and functions of the cerebellum are covered in lecture 0 through 8 in Week 8
Legend The narrative of the case is in white Annotation for terms used in the narrative is in yellow. Please skip the yellow pages if you are familiar with the term.
Main Idea The cerebellum contains more neurons than the rest of the brain. But what does it do?
Modulation/regulation of movement
Background Last year, during a school reunion cruise trip, I met the wife of one of my school mate, who suffered a life threatening stroke 10 years ago. I was taking the Coursera course, Medical Neuroscience offered by Duke University at the time. The wife, Mrs X, has ataxic gait, a cardinal sign of a cerebellar damage (week 8 lecture 1), apparently caused by the stroke. After the trip, the husband sent me her medical record. Since I am not a medical doctor, it took me some effort to annotate and understand what happened. With knowledge gained from the Medi-Neuro course and this course, I was able to have a overall understanding of the case and the resulting disabilities Mrs X suffers.
Cerebellum Disorders Stanford Cerebellum Examination Mrs. X exhibits symptoms of lesions to cerebellum Ataxic gait characterized by a broad stance, with wide staggering quality Decomposition of multi-joint movements Dysdiadochokinesia - Inability to perform rapid alternate movements (confirmed by her husband) All these can be seen in the following link and reviewing Week 8 lectures will help understanding these disorders
Key points for the case study Stroke AVM hemorrhage and its consequences Brainstem damages Cerebellum as the modulator of movement Motor cortex Brain stem
How It Happened One evening 10 years ago, Mrs. X suffered sudden onset of severe neck pain and headache She soon fainted and lapsed into coma Her husband called the ambulance to rush her to hospital
At the hospital 1. Intubated the insertion of a tube into an external or internal orifice of the body for the purpose of adding or removing fluids. 2. CT brain scan indicates cerebellar hemorrahage, and IVH - intraventricular hemorrhage
Diagnosis 1. GCS 4 Glasgow Coma Scale oSevere, GCS < 8-9 oModerate, GCS 912] oMinor, GCS 13 2. Pupils equal but sluggish to light
Operation Procedures 1 Urgent craniotomy and ICP done a large AVM was found occupying the left cerebellum 2. A craniectomy procedure includes the removal of a bone flap Craniectomy the flap is not returned right after the procedure Craniotomy the flap is returned after the procedure 3. Partial removal of a clot Partial because of profuse bleeding 4. posterior fossa decompression done The posterior cranial fossa is part of the intracranial cavity, located between the foramen magnum and tentorium cerebelli. It contains the brainstem and cerebellum
Posterior Cranial Fossa
Posterior Cranial Fossa arteries and veins
Atriovenous Malformation An AVM is a tangled bundle of blood vessels where arteries connect directly to veins with no capillary bed between. AVM Normal
Procedure Record (1) 1. 6 cm ventricular catheter inserted blood-stained ventricular CSF under high pressure 2. Patient was then turned to prone position face down 3. Supine first with right frontal burr hole made Supine is lying down with face up 4. Midline suboccipital incision made to expose Post Cranial Fossa and C1 (first cervical vertebrae) Sub-occipital
Procedure Record (2) 5. The underlying brain was quite tense 6. Suboccipital craniotomy and C1 laminectomy performed craniectomy procedure also includes the removal of a bone flap laminectomy is a surgical procedure that removes a portion of the vertebral bone called the lamina. 7. USG confirmed the hematoma was located at the left cerebellum, with a diffuse AVM lying medial to the clot. USG - ultrasound-based diagnostic imaging AVM Atrovenous Malformation 8. The hematoma was actually inside the AVM nidus, making removal of clot hazardous and bleeding from AVM arterioles was difficult 9. Finally hemostasis was secured The cerebellum tension was fair ICP measured was about 10-12 mmHg
Procedure Record (3) 10. No further attempt of clot removal was tried 11. Duraplasty done with fascia graft A reconstructive operation on the open dura mater that involves a primary closure or secondary closure with another soft tissue material (muscle, fascia, allograft dura). 12. Dura was covered with gelfoam 13. Wound closed in layers with vicryl and nylon 14. 1 wound drain Inserted 15. Keep Systolic Blood Pressure < 110 mm Hg and control Intracranial Pressure 16. Procedure completed 17. Haematunia (blood in urine) subsided after 18 days
Procedure Record (4) At 23rd day, pre-operative embolization of the Left PICA done Posterior inferior cerbellar artery (PICA) is the largest branch of the vertebral artery, one of three main arterial blood supplies for the cerebellum Embolization deliberately blocking a blood vessel At 30th day, pre-operative embolization of distal right superior cerebellar artery At 66th day, operation to remove AVM Condition improved to GCS 15 points (see slide 11) 2 times of pre-op embolization done Admit for removal of AVM Total removal done Confirmed by intra-op angiogram
Summary Principal Diagnosis Acute bilateral cerebellar haemorrhage underlying absormality, arteriovenous malformation cerebellar AVM bleeding Hydrocephalus "water on the brain," is a medical condition in which there is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles, or cavities, of the brain Respiratory failure and loss of consciousness Temporary damages to the brain stem
Pathology The resulting tangle of blood vessels, often called a nidus (Latin for "nest"), has no capillaries. It can be extremely fragile and prone to bleeding
The Cause AVM in the cerebellum Hemorrhage caused damage to cerebellum and brainstem Brainstem damage caused the cessation of normal breathing and induced coma loss of consciousness CO2 detection in the pons ; Breathing pattern generation in the medulla (lecture 9.6) Lasting cerebellum disorders
Cerebellar Dysfunction Mrs. X shows many effects of cerebellar damages (see Stanford Video on slide 6) 1. Ataxic gait - walking 2. Decomposition of movements For example, touching ones finger to ones nose requires the coordinated activity of shoulder, elbow, and wrist joints. Cerebellar patients must first perform the shoulder movement, then the elbow movement, and finally the wrist movement in sequence, rather than as one, uniform motion 3. Dysmetria Instability of a limb as it approaches a target, typically overshooting or undershooting
Cerebellar Dysfunction (cont.) 4. Intention tremor When making a movement to a target, cerebellar patients often produce an involuntary tremor that increases as they approach closer to the target 5. Dysdiadochokinesia Impairment of rapid, alternate, repetitive movements (see Stanford Video on slide 6) 6. Deficits in motor learning cerebellar damage causes deficits in motor learning in both human patients
Non-motor effects There are ways in which the processing that the cerebellum does for motor output could also be applied to non-motor output thought and emotion In social situation, Mrs. Xs social interaction is not as agile Slurred speech Following multi-facet arguments or narratives Similar to multi-joint movement, thought process involves chunking that requires a normally functioning cerebellum
Cerebellar Plasticity and Rehabilitation According to some recent research, after an