Flashcards in B06W13 Deck (101):
What is the concept of a neuromodulator? What is this concept also known as?
Effect on a neuron of a mediator which is not a classical transmitter, which may result in a change in pre-synaptic release or receptor responsiveness (i.e., NO, arachadonic acid metabolites). May also be called neuronal plasticity
Name a direct agonist of the GABA receptor
List 4 functions of dopamine
1. Motor control (basal ganglia) 2. Behaviour and reward pathways 3. Endocrine control (hypothalamus and pituitary) 4. D2 receptors in medulla (vomiting/nausea)
What would be the clinical result of stimulating the D2 receptors in the medulla?
Describe the process that is common to neurodegenerative disorders such as Alzheimers, Huntington's chorea, mad cow disease etc.
Protein mis-folding and mutations - common pathways is accumulation of aggregates of insoluble protein intra or extracellularly with neurotoxicity and cell death (and the site of damage determines the clinical presentation)
List the 4 cardinal features of Parkinson's disease
Tremor, rigidity/stiffness, slow movements (bradykinesia - patient MUST have this for diagnosis) and loss of balance/postural stability
What are the 5 'a's to alzhemiers?
Anomia, amnesia, apraxia, agnosia and aphasia
Which 3 components of family history are important in Parkinson's disease?
Family of history of PD, Essential Tremor, Restless Leg Syndrome
List some non-degenerative Parkinson mimics
Vascular (i.e., lacunar stroke), trauma, antipsychotics
List some degenerative Parkinson mimics
Diffuse Lewy Body Disease, progressive supranuclear palsy, cortico-basal degeneration, multiple system atrophy
Describe the characteristics of tremor in early Parkinsons
Shake at rest but not as apparent when performing a movement (is often asymmetrical in early stages)
Why is motor power not affected in Parkinsons?
Pyramidal tracts not affected
Describe what happens to Parkinsons patients in REM vs nREM sleep
Nothing happens in nREM sleep, but patients tend to thrash around in REM
List at least 5 types of tremor
Physiological, essential, orthostatic, cerebellar, dystonic, drug induced, neuropathic, psychogenic and Parkinsonian
Describe the characteristics of unsteadiness in PD
Usually not first complaint, marked unsteadiness when turning and hesitation when starting. May also exhibit freezing (dose relates, multitasking and from cues)
List some of the non-motor features of PD
Apathy, anosmia, decreased REM sleep and increased REM movement, fatigue, pain, dribbling, panic attacks
List some of the special examinations in PD
Bradyphrenia, glabellar tap, blink rate, dexterity, dysautonomia, release reflexes and postural reflexes
List the red flags for PD mimics
Symmetrical onset, absence of tremor, motor weakness, dysautonomia, rapid onset, dystonia and apraxia
List the clinical features seen in cases of progressive supra nuclear palsy
Frequent falls, axial involvement and retropulsion
List the clinical features seen in cases of multiple system atrophy
Rapid progression, dysphagia, stridor, dysautonomia
List the clinical features seen in cases of cortico-basal ganglionic degeneration
Alien hand phenomenon, dystonia, myoclonus, hemispatial neglect and apracia
List the clinical features seen in cases of diffuse Lewy body disease
Cognitive decline and hallucinations
List some of the side effects of L-dopa in the treatment of Parkinsons
Confusion, hallucination, urinary retention, drowsiness, valvulopathy, serosal fibrosis, gambling, hypersexuality, hypotension
What is the most common presentation of PD?
What is psychosis?
Severe debilitating mental illness, in which symptoms such as delusions, hallucinations and disordered behaviour prevail
The targets of anti-psychotic drugs are via which 3 main receptors?
Dopamine, 5-HT/serotonin and muscarinic acetylcholine
Discuss some of the desired effects of anti-psychotic drugs
Decreased motor activity, reduced hallucinations (seen clinically as apathy, reduced initiative with decreased aggression but retention of intellect) - may also be anti-emetic
List some of the side effects of anti-psychotic drugs
Extrapyramidal: acute dystonia, tardive dyskinesia and involuntary movements; Endocrine: blocking D2 receptors increases prolactin secretion (gynecomastia); Anti-muscarinic: blurred vision, dry mouth and urinary retention; Cardiac: prolongation of QT interval and potential drug interactions
List a drug specific side effect of chlorpromazine
List a drug specific side effect of clozapine
Bone marrow suppression
List the 3 main mechanisms of anti-depressant drugs
1. Inhibit mono-amine re-uptake 2. Mono-amine receptor antagonists 3. Mono-amine oxidase inhibitors
List at least 2 classes of anti-depressant drugs that work by inhibiting mono-amine re-uptake
SSRIs, TCAs, mixed noradreneline and 5-HT reuptake inhibitors and herbal (St John's Wart, weak)
What is lithium and what is it used for?
Monovalent cation which can substitute for sodium in excitable tissues (used in treatment of mania)
Why can lithium cause polyuria?
Because it inhibits ADH
Explain why lithium can cause goitre in a large % of patients
Hypothyroidism caused by increased iodine uptake but decreased iodothyronine formation and decreased release of T3 and T4
List 3 types of drugs used in the treatment of anxiety
1. SSRI antidepressants 2. Benzodiazepines (for acute anxiety) 3. Antipsychotic drugs
How go GABA(a) receptors mediate inhibitory synaptic transmission?
By opening chloride channels
Benzodiazapines act on _____ receptors
List at least 4 effects of benzodiazepines
1. Decreased anxiety and aggression 2. Induces sleep and sedation 3. Decreases muscle tone and coordination 4. Anticonvulsant 5. Anterograde amnesia
What is Flumazenil?
Competitive benzodiazepine antagonist (competes for binding site on GABA-A receptor)
What are psychoses?
A group of heterogenous disorders characterised by misinterpretation and misapprehension of reality (characterised by hallucinations, delusions, thought disorders and catatonia)
List 4 characteristics that may present in psychoses
Hallucinations, delusions, thought disorders and catatonia
The vertebral artery ascends the cervical vertebrae within what fascia?
The vertebral artery enters the vertebral canal by penetrating which membrane?
Branches of the vertebral artery supply what areas?
Medulla and most of inferior surface of cerebellum
What areas are supplied by the PICA?
Major territories in the medulla as well as the cerebellum - including the lateral medulla, choroid plexus of the 4th ventricle, postero-inferior surface of the cerebellum
What are the branches of the basilar artery?
AICA, SCA and many pontine branches
What area is supplied by AICA?
Anterior part of inferior cerebellum and the caudal pons
What area is supplied by the superior cerebellar artery?
Superior surface of cerebellum, caudal midbrain and rostral pons
What area is supplied by the pontine branches of the basilar artery?
Pons (plus includes labyrinthine artery which supplies the inner ear)
Which arteries supply the following structures in the lower medulla: lower spinal V nucleus and tract, arcuate fibres and medial lemniscus, spinothalamic tracts and pyramids
Branches of the anterior spinal artery and vertebral artery
Which artery supplies both the gracile and cuneate nuclei of the dorsal column system?
Posterior spinal artery
Which artery supplies the following structures in the upper medulla: pyramids (corticospinal tracts), medial lemniscus (dorsal system), tectospinal tract and hypoglossal nucleus?
Anterior spinal artery
What syndrome is likely to result from a bleed or occlusion in the anterior spinal artery?
Medial medullary syndrome: CL hemiparesis (pyramidal effects), CL impairment of sensations of tactile discrimination, limb position and movement (medial lemniscus involvement), IL paralysis of tongue muscles (involvement of hypolossal nerve and nucleus)
The PICA territory includes which structures?
Vestibular nuclei, olivocerebellar fibres, spinal V nucleus and tract, solitary nucleus and tract, N. ambiguous, ST tract and descending sympathetic fibres
What syndrome is likely to result from a bleed or occlusion in the PICA?
Lateral medullary syndrome: Dysphagia (n. ambiguous), IL loss of pain and temperature to the face (spinal nucleus of V), vertigo, nausea, vomiting and nystagmus (vestibular n.), Horner's syndrome (descending sympathetics), IL limb and gait ataxia (dorsal spinocerebellar tracts and olivocerebellar tracts), CL loss of pain and temperature (STT)
Explain why there is apparent loss of sensory and motor responses in locked-in syndrome
Ischemia affects descending and ascending pathways: quadriplegia, paralysis of most/all pontine and medullary cranial nerves)
Why might a patient with locked-in syndrome present with Horner's syndrome?
Due to descending sympathetics affected by ischaemia throughout medulla and pons
What functions are retained in locked-in syndrome and why?
Occulomotor and trochlear nuclei function (due to location in midbrain with ascending fibres); hearing due to olivary nucleus laterally placed in the pons
The posterior cerebral artery and superior cerebellar artery both curve laterally and posteriorly around the midbrain. Which structure separates the 2?
What areas are supplied by the PCA?
Tectum, most of the cerebral peduncles (except most medial part), occulomotor nucleus and edinger westphal nucleus
Weber's syndrome results from occlusion of which artery?
Midbrain branches of posterior cerebral
Describe the characteristics of Weber's syndrome and link these to the structures affected
IL ophthalmoplegia and ptosis, dilation of pupil, no light response and no accommodation (CNIII), CL paralysis of arm and leg (corticospinal fibres) and CL paralysis of lower face and tongue (corticobulbar fibres)
Which are the 2 main syndromes that can result from occlusion to midbrain branches of the posterior cerebral artery? List which structures are affected by necrosis in each syndrome.
Weber's syndrome (necrosis of peducncle and CN III) and Benedikt's syndrome (necrosis of lemnisci and red nucleus)
Describe the characteristics of Benedikt's syndrome and link these to the structures affected
CL involuntary limb movements (red nucleus and ascending SCP fibres), CL loss of sensation (ascending sensory symptoms: spinal and medial lemnisci)
Describe the anatomical course of the posterior cerebral artery
Runs posteriorly along the medial/inferior margin of the temporal lobe, then dorsally along the parieto occipital sulcus
Central branches of the posterior cerebral artery pierce the surface and supply which structures?
Thalamus, pineal, midbrain and posterior parts of the putamen and globus palidus
Cortical branches of the posterior cerebral artery supply which structures?
The entire inferior surface of the temporal lobe, lateral and medial surfaces of the occipital lobe (including V1, V2 and V3)
List the branches of the internal carotid artery
Ophthalmic (becomes central retinal a), posterior communicating, anterior choroidal artery and then ends by dividing into anterior and middle cerebral arteries
Name at least 3 of the 5 structures supplied by the anterior choroidal artery
Optic tract, hippocampus, choroid plexus of lateral ventricle, globus pallidus of lateral thalamus and internal capsule
The anterior cerebral artery passes into the ____ fissure to reach the ____ aspect of the brain
Which artery would be found running posteriorly in the cingulate sulcus, just above the corpus callosum as far as the parieto-occipial sulcus?
Anterior cerebral artery
What areas are supplied by the anterior cerebral artery?
Medial aspect of frontal and parietal lobes and a narrow strip adjacent to the interhemispheric sulcus on the dorsal surface of the frontal and parietal lobe (plus the paracentral lobule that makes up the motor and sensory representation of the leg and foot in M1 and S1 and the olfactory bulbs and tracts in the anterior hypothalamus
Which artery supplies the area of the brain that houses the motor and sensory representations of the leg and foot in M1 and S1 (i.e., the paracentral lobule)?
Anterior cerebral artery
Which artery enters the lateral fissure of the brain?
What areas are supplied by the middle cerebral artery?
Most of the lateral surface of the cerebral cortex, including frontal, parietal, temporal and anterio-lateral occipital lobes and the insula (within the lateral fissure)
Perforating branches of which vessels in the circle of Willis supply the caudate nucleus and anterior limb of the internal capsule?
Perforating branches of which vessels in the circle of Willis supply the corpus striatum and genu and upper anterior limb of the internal capsule?
middle cerebral > lenticulo-striate arteries
Perforating branches of which vessels in the circle of Willis supply the thalamus, pineal gland, midbrain, cerebral peduncles, parts of the putamen and globus pallidus?
posterior cerebral arteries
Perforating branches of which vessels in the circle of Willis supply the posterior limb of the internal capsule?
MCA > lenticulo-striate branches plus the anterior choroidal artery
Medial and lateral groups of lenticulo-striate arteries supply which structures?
Corpus striatum and extensive regions of the internal capsule
If a patient presents with contralateral hemianopsia (damage to V1-V3), which brain vessel is likely to have been occluded?
Posterior cerebral artery supplying the occipital cortex
What are the venous dural sinuses, where are they located and what is their function?
Contained between 2 layers of dura mater and drain venous blood fro the brain.
Virtually all the outflow from the cranium is via the ____ sinus > ____ ____ vein (at the _____ foramen)
Sigmoid sinus > internal jugular vein at the jugular foramen
The cavernous sinus drains blood from which structures?
Central face and orbit
What are the main indications for skull xray?
Congenital and developmental, infections, trauma (fracture or foreign body), tumours of the bone and calcifications
What sort of congenital and developmental abnormalities of the brain could be viewed on a skull xray?
Thalasemia, sickle cell anaemia
What sort of bone tumours of the skull could be viewed on an xray?
Meningioma, histiocytosis, haemangioma
What sort of metabolic abnormalities of the brain could be viewed on a skull xray?
List some of the main indications for angiography of the brain
Aneurysms, AV malformation, vascular dissection, vascular tumour
In which situation would an IV contrast CT be useful in brain imaging?
BBB prevents IV contrast from passing through to cerebrum and cerebellum. If BBB destroyed by a lesion like a neoplasm or infection, contrast passes through and reaches the lesion and surrounding brain regions
What are some of the main indications for CT of the brain?
Infections, tumours, trauma, vascular lesions and congenital and developmental abnormalities
What are the main indications for US of the brain?
Premature neonates for GM haemorrhage, congenital abnormalities, trauma, vascular and carotid artery studies by colour doppler
What is the difference between T1 and T2 weighted MRI images?
TI - all clear fluids are dark; T2 - all clear fluids are bright
What are the main indications for MRI of the brain?
Congential abnormalities, infections, tumours, trauma, vascular lesions, demyelination lesions (MS)
What is functional MRI (fMRI)?
Use of MRI equipment to detect regional changes of cerebral metabolism in blood flow, volume or oxygenation in response to task activation
What is the principle of NM imaging?
Use radioactive tracer with emits gamma rays - single photos detected by gamma camera which builds an image from many angles
What is a hallucination?
A hallucination is a perception in the absence of external stimulus that has qualities of real perception. Hallucinations are vivid, substantial, and are perceived to be located in external objective space
What is a delusion?
A fixed-false belief or impression maintained despite being contradicted by reality or rational argument, typically as a symptom of mental disorder (and not amenable to reason)
What is a thought disorder?
A disorder of cognitive organization, characteristic of psychotic mental illness, in which thoughts and conversation appear illogical and lacking in sequence and may be delusional or bizarre in content