Case 16 Flashcards
1
Q
What is urban defined as in the UK?
A
Built-up areas with a population of 10,000 or more usual residents
2
Q
Why is occupation no longer seen as a primary criterion for the definition of rural?
A
There’s been a decline in the proportion of rural dwellers involved in agriculture
3
Q
What are rural areas subdivided into?
A
Town and fringe
Village
Hamlet and isolated dwellings
4
Q
What sort of intracranial haemorrhages can occur spontaneously?
A
Subarachnoid
Intracerebral
Intraventricular
5
Q
What sort of intracranial haemorrhages result from head injury?
A
Extradural
Subdural
6
Q
What is hydrocephalus?
A
Abnormally large amount of CSF within ventricles
7
Q
What is the brain, blood, CSF composition of the head?
A
80% brain
10% blood
10% CSF
8
Q
What is the classical triad of symptoms for raised ICP?
A
Headache
Nausea
Vomiting
9
Q
What is Cushing’s triad?
A
Increased systolic blood pressure (with a widened pulse pressure), bradycardia and abnormal respiratory pattern
10
Q
What are the symptoms and signs of raised intracranial pressure?
A
Triad: Headache, nausea, vomiting
Altered consciousness
Ophthalmoparesis (extraocular muscle weakness) due to CN III, IV or VI palsies
Vital sign changes
Cushing’s triad: increased systolic blood pressure (with a widened pulse pressure), bradycardia, abnormal respiratory pattern
Papilloedema – more chronic presentation
11
Q
What does CN IV supply and what occurs in CN IV palsy?
A
Superior oblique
Diplopia when looking medially and downwards
12
Q
What does CN VI supply and what occurs in CN VI palsy?
A
Lateral rectus
Convergent strabismus/ esotropia
13
Q
What is esotropia?
A
Inward squint/ convergent strabismus
14
Q
What is a lucid interval?
A
Temporary recovery of consciousness after a blow to the head before relapse into coma
Sign of intracranial arterial bleeding - extradural haematoma
15
Q
What are the symptoms of subarachnoid haemorrhage?
A
Blinding occipital pain Neck stiffness Photophobia Nausea/ vomiting Diplopia Brief loss of consciousness Stroke-like symptoms
16
Q
What can cause subarachnoid haemorrhage?
A
Cerebral aneurysm (most-likely non-trauma cause)
Hypertension
Anticoagulants
Ateriovenous malformation
17
Q
What can cause hydrocephalus?
A
Obstructive: tumour/ abscess/ cyst/ congenital aqueduct stenosis/ chiari malformation (lower brain pushed towards spinal cord)
Non-obructive: intracranial haemorrhage/ infection/ post-traumatic - overproduction/ lack of CSF reabsorption
18
Q
How can non-obstructive causes of hydrocephalus be treated?
A
Ventriculoperitoneal shunt - CSF reabsorbed via abdominal lining
19
Q
How can obstructive causes of hydrocephalus be treated?
A
Endoscopic 3rd ventriculostomy - opening created in floor of 3rd ventricle
20
Q
How is subdural empyema treated?
A
Urgent craniotomy to remove empyema (pus)
Antibiotics for 6-12 weeks
21
Q
What passes through the transverse foramina?
A
Vertebral artery and vein
Sympathetic plexuses
22
Q
What passes through the vertebral foramina?
A
Vertebral canal - spinal cord/ meninges/ fat/ spinal nerve roots/ vessels
23
Q
What does the carotid sheath contain?
A
Common and internal carotid arteries Internal jugular vein Vagus nerve CN X Some deep cervical lymph nodes Carotid sinus nerve Sympathetic nerve fibres
24
Q
What does the carotid sheath communicate with superiorly and inferiorly and how could this be problematic?
A
Superiorly: Cranial cavity
Inferiorly: Mediastinum
Potential pathways for spread of infection and extravasated blood
25
What nervous structure lies behind the carotid sheath?
Sympathetic trunk
26
What is the role of thyroid hormone?
Control the rate of metabolism
27
What is the role of calcitonin?
Controls calcium metabolism
28
What is the role of parathyroid hormone (PTH)?
Controls metabolism of phosphorus and calcium in the blood
29
What does the thyroid gland secrete?
Thyroid hormone
| Calcitonin
30
```
What are the changes seen in cranial nerve III palsy and from lack of innervation to what?
Eye direction
Eyelid
Pupillary size
Accommodation
```
Eye points down and out - superior/ medial/ inferior rectus/ inferior oblique
Ptosis - levator palpebrae superioris
Pupil dilation - sphincter pupillae
Unresponsive to accommodation - ciliary muscle
31
When would a patient need to be intubated?
When GCS is less than 8
32
What supply the thyroid and parathyroid glands?
External carotid artery - Superior thyroid artery
| Subclavian artery - Inferior thyroid artery
33
What does the brachiocephalic trunk bifurcate into?
R subclavian
| R common carotid
34
What does the sternocleidomastoid muscle attach to?
Superior nucal line, occipital bone
Mastoid process, temporal bone
Has a clavicular and sternal head
35
What innervates the sternocleidomastoid?
CN XI
36
Which spinal segments/ roots does the brachial plexus arise from?
Anterior rami of C5, C6, C7, C8 and T1 spinal nerves
37
What is the rima glottidis?
Vocal folds
38
What are the extrinsic laryngeal muscles?
Infrahyoid
Suprahyoid
Stylopharyngeus
39
What are the intrinsic laryngeal muscles?
```
Cricothyroid
Thyroarytenoid
Posterior and lateral cricoarytenoids
Transverse and oblique arytenoids
Vocalis
```
40
What nerve supplies the intrinsic laryngeal muscles?
Recurrent laryngeal nerve (from CN X)
| Except for cricothyroid - external laryngeal nerve (from CN X)
41
Which extrinsic laryngeal muscle depresses the hyoid and larynx?
Infrahyoid
42
Which extrinsic laryngeal muscles elevate the hyoid and larynx?
Suprahyoid
| Stylopharyngeus
43
What is the action of the transverse and oblique arytenoids?
Adduct arytenoid cartilages and intercartilaginous portion of vocal folds - closing rima glottidis
44
What is the action of vocalis?
Relaxes posterior vocal ligament while maintaing/ increasing tension of anterior part
45
What is the action of posterior cricoarytenoid?
Abducts vocal folds - opening airway
46
What is the action of lateral cricoarytenoid?
Adducts vocal folds - closing airway
47
What is the action of thyroarytenoid?
Relaxes vocal ligaments - decreasing pitch
48
What is the action of cricothyroid?
Stretches and tenses vocal ligament - increasing pitch
49
Which muscles are involved in closing the airway/ rima glottidis?
Lateral cricoarytenoid
| Transverse and oblique arytenoids
50
Which 4 bones make up the palate?
Maxilla
Palatine
Vomer
Sphenoid
51
Which 3 bones make up the calvaria (skullcap/ vault of skull)?
Frontal
Parietal
Occipital
52
Which 7 bones make up the orbit?
```
Frontal
Sphenoid
Zygomatic
Maxilla
Ethmoid
Lacrimal
Palatine
```
53
Which 3 bones make up the anterior cranial fossa?
Frontal
Ethmoid
Sphenoid
54
Which 3 bones make up the middle cranial fossa?
Sphenoid
Temporal
Parietal
55
Which 3 bones make up the posterior cranial fossa?
Temporal
Occipital
Parietal
56
Which 10 bones make up the facial skeleton?
```
Frontal
Parietal
Temporal
Sphenoid
Nasal
Zygomatic
Ethmoid
Lacrimal
Maxilla
Mandible
```
57
Which 4 bones form the pterion?
Frontal
Parietal
Temporal
Sphenoid
58
Compare the dura mater to the pia
Dura - tough, thick, external, fibrous
| Pia - delicate, thin, internal, vascular
59
If the cavernous sinus became infected, which structures are liable to damage?
```
(O TOM CAT)
O TOM: lateral wall from top to bottom
CA: inside sinus
Oculomotor nerve
Trochlear nerve
Ophthalmic nerve (CN V1)
Maxillary nerve (CN V2)
Internal carotid artery
Abducens nerve
```
60
What are the symptoms of a venous thrombus in the cavernous sinus?
Internal jugular vein drains the cavernous sinus
Thrombus - restricts blood flow from brain
Severe headache/ sweeling of eyes and surrounding tissue/ eye pain/ double vision
61
What is the name of CN VIII?
Vestibulocochlear
62
What is the name of CN IX?
Glossopharyngeal
63
What is the name of CN XII?
Hypoglossal
64
What foramen does CN I exit through?
Foramina in cribriform plate
65
What foramen does CN II exit through?
Optic nerve through Optic canal
66
What foramen does CN XII exit through?
Hypoglossal nerve through hypoglossal canal
67
Which cranial nerves exit through the superior orbital fissure?
Oculomotor III
Trochlear IV
Ophthalmic branch of Trigeminal V1
Abducens VI
68
Which cranial nerves exit through the internal acoustic meatus?
Facial VII
| Vestibulocochlear VIII
69
Which cranial nerves exit through the jugular foramen?
Glossopharyngeal IX
Vagus X
Accessory XI
70
What foramen does CN V2 exit through?
Foramen rotundum
71
What foramen does CN V3 exit through?
Foramen ovale
72
What arises from the internal carotid arteries?
Middle and anterior cerebral arteries
73
What arises from the basilar artery?
Posterior cerebral arteries
Pontine arteries
Superior and anterior inferior cerebellar arteries
74
What connects the basilar artery to the internal carotids?
Posterior communicating arteries
75
What does the vertebral arteries give rise to?
Basilar artery
| Posterior inferior cerebellar arteries (PICA)
76
Where do the vertebral arteries join to form the basilar artery?
Caudal border of pons
77
What sort of rash appears in meningitis?
Non-blanching
78
What arises directly from the arch of the aorta?
Brachiocephalic trunk (1st)
L common carotid artery (2nd)
L subclavian artery (3rd)
79
What lies between the clavicle and sternal heads of the sternocleidomastoid?
Internal JVP
80
Which muscles lie in the posterior triangle of the neck?
Splenius captitis
Levator scapulae
Anterior, middle. posterior scalene
Inferior belly of omohyoid
81
What are the 3 pontine branches of the basilar?
Paramedian
Short circumferential
Long circumferential
82
What does the paramedian pontine branch supply?
Anterior middle part of pons
83
What does the long circumferential pontine branch supply?
Most of the pons
84
What sort of impulses do the dorsal columns carry?
Impulses concerned with proprioception and fine/ discriminative touch
85
Where do third-order neurons of dorsal column project to?
Somatosensory cortex, postcentral gyrus, parietal lobe
86
Where do second-order neurons of dorsal column decussate?
Medulla
87
What do second-order neurons of dorsal column ascend the brainstem as?
Internal arcuate fibres in medial lemniscus
88
Is the dorsal column an ascending or descending spinal tract?
Ascending
89
What sort of impulses does the spinothalamic tract carry?
Pain, thermal sensations, course/ non-discriminative touch and pressure
90
What sort of impulses do the lateral spinothalamic tracts generally carry?
Pain and temperature
91
What sort of impulses do the ventral spinothalamic tracts generally carry?
Touch and pressure
92
Is the spinothalamic tract an ascending or descending spinal tract?
Ascending
93
Spinothalamic tract fibres decussate via what?
Ventral white commissure
94
Where do third-order neurons of the spinothalamic tract project to?
Somatosensory cortex, postcentral gyrus, parietal lobe
95
What are the spinothalamic tract fibres referred to in the brainstem?
Spinal lemniscus
96
Is the corticospinal tract an ascending or descending spinal tract?
Descending
97
What does the corticospinal tract control?
Voluntary, discrete, skilled movements
98
Corticospinal tract neurons arise from cells bodies located in...?
Cerebral cortex in motor and sensory cortices
99
What do corticospinal tract neurons pass through before entering the brainstem?
Subcortical fibre systems: corona radiata and internal capsule
100
What region of the midbrain do corticospinal tract neurons pass through?
Crus cerebri
101
What is the name of the 2 columns formed by the corticospinal tract neurons in the medulla?
Pyramids
102
What occurs when corticospinal tracts subtotally decussate at caudal medulla?
75-90% of fibres decussate to contralateral lateral corticospinal tract
10-25% remain ipsilateral and enter ventral corticospinal tract
103
Where do corticospinal tracts decussate?
Subtotal decussation at caudal medulla
Fibres that have not decussated do so further down near site of termination
So fibres of pyramidal/ corticospinal tract effectively innerve the contralateral side of the spinal cord
104
Where are dorsal columns located within the spinal cord?
Between the dorsal median sulcus and dorsal horn
105
Where are spinothalamic tracts located within the spinal cord?
Lie lateral and ventral to ventral horn
106
Where are the motor and somatosensory cortices?
Motor: Precentral gyrus
Somatosensory: Postcentral gyrus
107
What ion movements are carried out by energy-dependent active transport mechanisms present in the choroid plexus?
Transporting Mg2+ into CSF
| Removing K+ and Ca2+
108
What are the concentration of Na+ and K+ like in the CSF?
High Na+
| Low K+
109
What comes off the vertebral arteries?
Meningeal artery
Anterior and posterior spinal arteries
Posterior inferior cerebellar artery (PICA)
110
What's the brainstem structure that controls consciousness?
Ascending reticular activating system
111
Which vessel is occluded in lateral medullary syndrome?
Posterior inferior cerebellar artery (PICA)
112
What functions are lost in lateral medullary syndrome?
Contralateral pain and temp of body - spinothalamic
Ipsilateral pain and temp of face - trigeminal
Gag reflex (Dysphagia, hoarseness) - nucleus ambiguous, CN IX and X roots
Ipsilateral horner's syndrome - hypothalamic
Vertigo, diplopia, fall to ipsilateral side - vestibular nuclei
Ipsilateral ataxia - spinocerebellar
113
What happens in Horner's syndrome?
Constricted pupil
Ptosis
Inability to sweat on 1 side of face
114
Do neurons and glial cells retain the ability to divide throughout life?
Neurons - no
| Glial cells - yes
115
What are oligodendrocytes?
Schwann cells of CNS
116
What do microglia act as?
White blood cells of brain - attack/ phagocytose organisms/ damaged cells
117
How fast do axons of the PNS regrow?
About a mm a day
118
In axonal damage of PNS what stimulates break down of the cytoskeleton?
```
Calcium entering the cytosol
Activating caplain (protease) that breaks down the cytoskeleton
```
119
What prevents axonal regrowth in the CNS?
Physically blocked by glial scars
| Chemically blocked by release of inhibitory molecules released by glial cells and macrophages
120
What produces the axonal regrowth inhibitory molecule NogoA?
Oligodendrocytes
121
What produces the axonal regrowth inhibitory molecule chondroitin sulphate proteoglycans (CSPG)?
Astrocytes
122
What is petechial haemorrhage within the brain? What does it suggest?
Blood leakage at interface of grey and white matter
| Indicative of severe brain injury (even with our midline shift)
123
What is the extracellular glutamate concentration normally?
0.6 micromol/L
124
At what concentrations does glutamate become excitotoxic?
2-5 mircomol/L
125
How can ischaemia damage astrocytes?
Astrocytes can metabolise glucose anaerobically
| but not if lactic acid build up has created a pH of less than 6.6 - as glycolysis ceases and irreversible damage occurs
126
What can raise extracellular levels of glutamate to excitotoxic levels?
Compromised astrocyte metabolism of glutamate
| Neuronal rupture from traumatic brain injury
127
What blocks the glutamate NMDA receptor during resting potential?
Mg2+
128
How does increased intracellular calcium via glutamate receptors lead to excitotoxicity?
Reduced mitochondrial ATP synthesis - causing outward glutamate leakage
Osmotic swelling - cell rupture
Activate calcium-dependent enzymes that cause cell necrosis
Upregulate pro-apoptotic genes
129
```
Describe the role of the following calcium-dependent enzymes in causing cell necrosis:
Calpains
Proteases
Phospholipases
Endonucleases
```
Calpains - degrade neuronal cytoskeleton
Proteases - digest structural proteins
Phospholipases - break down cell membranes
Endonucleases - cause DNA fragmentation
130
What scavenges reactive oxygen species?
Antioxidants: vitamin C and E
| Superoxide dismutase, catalase and glutathione peroxidase enzymes
