Neurology Flashcards
What is the most common cause of radial nerve palsy?
Entrapment at spinal grove
“Saturday night palsy”
What are the presenting symptoms of a radial nerve palsy?
Wrist and finger drop
Usually painless
What motor weakness is associated with extensor carpi radialis longus?
Wrist extension
What motor weakness is associated with extensor digitorum communis?
Finger extension
What motor weakness is associated with brachiradialis?
Elbow flexion in mid-pronation
What is the most common cause of ulnar nerve palsy?
Entrapment at ulnar grove (medial epicondyle of humerus)
What are the presenting symptoms of an ulnar nerve palsy?
History of trauma at elbow
Dorsal sensory loss
(in cyclists. problem at wrist –> no dorsal sensory loss)
Sensory disturbances and weakness –> weak grip
Usually painless
What motor weakness is associated with 1st dorsal interosseous?
Index finger abduction
What motor weakness is associated with abductor digiti minimi?
Pinkie abduction
What motor weakness is associated with flexor carpi ulnaris?
Wrist flexion
What motor weakness is associated with adductor pollicis?
Thumb adduction
What is the most common cause of median nerve palsy?
Entrapment within carpal tunnel at wrist
What are the presenting symptoms of an median nerve palsy?
History of intermittent nocturnal pain, numbness and tingling - often relieved by shaking hand
Weak grip
Positive Tinel’s sing (gently percuss over the nerve to elicit sensation of parathesia in the distribution of the nerve)
What motor weakness is associated with lumbricals I&II?
Flexion at MCP joints
What motor weakness is associated with opponent pollicis?
Thumb opposition
What motor weakness is associated with abductor pollicis brevis?
Thumb abduction
What motor weakness is associated with flexor pollicis brevis?
Thumb flexion
What is the most common cause of anterior interosseous branch (median nerve II) palsy?
Trauma to forearm
What are the presenting symptoms of an anterior interosseous branch (median nerve II) palsy?
History of forearm pain
Weak grip
Positive Tinel’s sign/Phalen’s test
No sensory change
What motor weakness is associated with pronator quadratus?
Flexion at MCP joints
What motor weakness is associated with flexor pollicus longus?
Thumb flexion
What motor weakness is associated with flexor digitorum profundus (lateral?)
Thumb flexion
What nerve runs at the front of the thigh, and what muscle group does it supply?
Femoral
Quads
What nerve runs at the medial aspect of the thigh, and what muscle groups does it supply?
Obturator
Adduction
What nerve runs posterior to the thigh, and what muscle groups does it supply?
Sciatic
Hamstrings
What is the most common cause of femoral nerve palsy?
Haemorrhage/trauma
What are the presenting symptoms of a femoral nerve palsy?
Weakness of quadriceps
Weakness of hip flexion
Numbness in medial shin
What motor weakness is associated with quadriceps?
Knee extension
What motor weakness is associated with illiopsoas?
Hip flexion
What motor weakness is associated with adductor Magnus?
Hip adduction
What nerve is located at the posterior of the calf, and what muscles does it supply?
Tibial
Gastrocnemius, soleus
What nerve is located at the anterior of the calf, and what muscle does it supply?
Peroneal
Tibialis anterior, peroneii
What is the most common cause of common peroneal nerve palsy?
Entrapment of fibular head
What are the presenting symptoms of a common peroneal nerve palsy?
Trauma, surgery, external compression
Acute onset foot drop (can invert food, ankle jerk still present)
Sensory disturbances
Usually painless
What motor weakness is associated with tibilalis anterior?
Ankle dorsiflexion
What motor weakness is associated with extensor hallucis longus?
Big toe extension
Define mononeuritis multiplex
Simultaneous or sequential development of neuropathy of two or more nerves
What are common causes of mononeuritis multiplex?
Diabetes
Vasculitis - Churg Strauss, polyarteritis nodusa
Rheumatological - RA, SLE, Sjogren’s syndrome
Infective
Sarcoidosis
Lymphoma
Describe how an aneurysm forms
Haemodynamic stress causes localised dilation of an artery
Extensive immunological and inflammatory processes
Aneurysm will either stabilise or rupture
What percentage of SAH are non-aneurysmal, and what are the potential causes of these?
15-20%
Trauma
Tumours
Arteriovenous malformation
Anti-coagulants
What are predisposing factors to aneurysm SAH?
Smoking
Female sex (1.5x risk)
HTN
What are the symptoms of a SAH?
Sudden onset headache “thunderclap”
LOC, seizures, speech/limb disturbances
Sentinel headaches (30%)
What are the signs of a SAH?
Photophobia Meningism Subhyaloid haemorrhage Vitreous haemorrhage Pulmonary oedema
Why can patients with SAH develop pulmonary oedema?
Increased catecholamines
Congestive HF and pulmonary oedema
Describe the grading system used for assessing SAH
WFNS using GCS
Grade 5 = GCS 3-6 Grade 4 = GCS 7-12 Grade 3 = GCS 13-14 (with deficits) Grade 2 = GCS 13-14 (no deficits) Grade 1 = GCS 15
What investigations are needed for a patient with a suspected SAH?
CT LP U&Es Troponin ECG ECHO
What is the role of a CT in the investigation of a patient with a suspected SAH?
Confirms diagnosis
Clues to aetiology
Identifies complications (infarction, haematoma, hydrocephalus)
Prognostic (Fisher grade - the greater the amount of blood, the worse the prognosis)
When does a LP need to be carried out following a suspected SAH, and what is the characteristic finding?
~ 6 hours
Xanthochromia - yellow discolouration of CSF caused by the presence of bilirubin
Why might there be ECG changes in a patient with SAH?
Increased catecholamine release
Describe the resuscitation needed for a patient with SAH
Bed rest Fluids: 2.5-3L of normal saline Anti-embolic stockings Nimodipine Analgesia
What is the role of Nimodipine in a patient who has had a SAH?
Ca channel antagonist –> prevents dumping of calcium within cells
Describe the management of SAH
10% surgical clipping
Endovascular - coils, stents, glue
Conservative - patient unsuitable for more invasive intervention
What state is induced following a SAH, and what needs to be prescribed as a consequence of this?
Prothrombic state
DVT prophylaxis
What are some of the complications associated with SAH?
Re-haemorrhage - most common within 72h, increased risk with poorer grades or larger aneurysm
Delayed ischaemia - blood is an irritant –> occurs at d3-10 (keep well hydrated, increase BP with inotropes, prescribe nimodipine)
Hydrocephalus - obstruction of CSF (LP, drains, shunts)
Cardiopulmonary complications - myocardial function usually returns to normal in 1-3d, but can develop arrhythmias, wall motion abnormality and sudden death
Define stroke
Central nervous system infarction (which includes brain, spinal cord and retinal cells attributable to ischaemia) based on objective evidence of focal ischaemic injury in a defined vascular distribution or clinical evidence of the former with other aetiologies excluded
Describe what happens when a stroke occurs
Blood clot disrupts blood flow
Area of brain is starved of oxygen so becomes ischaemic –> loss of function (initially reversible)
Neurons depolarise - instant onset of early symptoms
Cells die –> tissue dies (irreversible)
A stroke in which part of the brain will result in weakness affecting the entire one side of the body?
Internal capsule
What artery is affected if a patient presents with expressive dysphagia following a stroke?
Middle cerebral artery (generally the left)
If a patient presents with homonymous hemianopia following a stroke, what artery has been affected?
Posterior cerebral artery
Middle cerebral artery can also cause hemianopia
If the cerebellum has been affected, what clinical signs may be present? What arteries supply the cerebellum?
Past-pointing, nystagmus
Basilar artery
Posterior cerebral artery
What percentage of strokes are due to ischaemia?
88%
Define ischaemic stroke
An episode of neurological dysfunction caused by focal cerebral, spinal or retinal infarct
What classification system enables the presenting symptoms and clinical signs to assess the type of ischaemic stroke a patient has had without the need for imaging?
Bamford Classification of Ischaemic Stroke
Define a Total Anterior Circulation Stroke (TACS), and what criteria does it need to meet?
Large cortical stroke affecting the areas of the brain supplied by both the middle and anterior cerebral arteries
3/3 of:
- Unilateral weakness (and/or sensory deficits) of the face, arm, leg
- Homonymous hemianopia
- Higher cerebral dysfunction (visuospatial disorder, dysphagia)
Define a Partial Anterior Circulation Stroke (PACS), and what criteria needs to be met?
Less severe form of TACS, in which only part of the anterior circulation has been compromised.
2/3 of:
- Unilateral weakness (and/or sensory deficit) of the face, arm, leg
- Homonymous hemianopia
- Higher cerebral dysfunction (visuospatial disorder, dysphagia)
Define a Posterior Circulation Syndrome (POCS), and what criteria needs to be met?
Involves damage to the area of the brain supplied by the posterior circulation eg cerebellum and brainstem
1/5 of:
- Cranial nerve palsy and a contralateral motor/sensory deficit
- Bilateral motor/sensory deficit
- Conjugate eye movement disorder (eg horizontal gaze palsy)
- Cerebellum dysfunction (eg vertigo, nystagmus, ataxia)
- Isolated homonymous hemianopia
Define Lacunar Syndrome (LACS), and what criteria needs to be met?
Subcortical stroke that occurs secondary to small vessel disease. There is no loss of higher cerebral functions.
1/4 of:
- Pure sensory stroke
- Pure motor stroke
- Sensori-motor stroke
- Ataxic hemiparesis
Define an intracerebral haemorrhage
A focal collection of blood within the brain parenchyma or ventricular system the that is not caused by trauma
Define a stroke caused by an intracerebral haemorrhage
Rapidly developing clinical signs of neurological dysfunction attributable to a focal collection of blood within the brain parenchyma or ventricular system that is not caused by trauma
Give three causes of intracranial bleedinig
Small vessel disease Amyloid angiopathy Abnormalities in blood vessels Blood clotting deficiencies Haemorrhagic transformation of an infarct Tumours Drug use: cocaine, amphetamines
Describe the management of an ischaemic stroke
IV thrombolysis (within 4.5h)
Thrombectomy ± IV thrombolysis (not in Scotland)
Aspirin
Stroke unit
Hemicranectomy
Describe the management of a haemorrhagic stroke
Blood pressure control
Stroke unit
Neurosurgical evacuation
What are the CV risk factors that are responsible for 85% of strokes?
HTN Obesity Lack of exercise High fat diets Cigarette smoking