MRCP Neuro Flashcards
What MRI brain changes are usually seen in herpes simplex encephalitis T1?
MRI brain normally shows changes in the temporal lobes. Swelling, mass effect and high signal in mesial temporal structures.
What test can you do for herpes simplex virus encephalitis? What are the CSF findings?
PCR for herpes simplex virus on cerebral spinal fluid (CSF) is a highly specific test. Other CSF findings are lymphocytosis and mildly raised red cells.
What virus commonly causes encephalitis?
Herpes simplex (HS) type 1 (70% in immunocompetent patients).
What does damage to the ulnar nerve result in?
Damage at the wrist results in wasting of the intrinsic hand muscles (other than the lateral two lumbricals) and the hypothenar eminence. This produces the classic claw hand
What is the sensory supply of the ulnar nerve?
Supplies sensation to the medial one and a half fingers
What muscles does the median nerve innervate?
The lateral two lumbricals and the thenar eminence (oppenens pollicis, abductor pollicis and flexor policis brevis). It supplies sensation to the lateral three and a half fingers
What does motor damage to the median nerve result in?
Damage to the motor branch, the anterior interosseous nerve results in inability to form and pinch grip, tip to tip, instead holding the paper between the pulp of the thumb and index finger
What is Lambert-Eaton myasthenic syndrome?
It is a pre-synaptic disorder of auto-antibody IgG directed against the pre-synaptic calcium channel leading to impaired acetylcholine release. Clinically, patients present with muscle weakness that improves with exercise.
Which kind of lung cancer is more commonly associated with paraneoplastic syndromes? Why?
Small cell lung cancers.
Due to its neuroendocrine cell origin.
Why do Paraneoplastic syndromes occur?
Result from antibody generation from or against malignant cells attacking normal tissue. Examples include antineuronal antibodies directed against the Purkinje cells of the cerebellum leading to cerebellar syndrom
Check Anti-Purkinje cell antibody levels
What is the mechanism of action of tetrabenazine?
VMAT-inhibitor (vesicular monoamine transporter 2), involved in transportation of monoamines
Indication for Tetrabenazine
Huntington’s chorea to reduce hyperkinetic movements
Which structure is implicated in chorea?
Caudate nucleus pathology is associated with chorea (for example, in Huntington’s disease).
Which structure is implicated in AD?
Hippocampus pathology is associated with short term memory impairment (for example, Alzheimer’s disease).
How does Guillain-Barre present?
Gradual development of ascending weakness with autonomic involvement
e.g.
Two week history of difficulty walking and weakness in her arms.
On examination, there was proximal and distal limb weakness which was more marked in the legs than the arms. All tendon reflexes were absent and the plantar responses were flexor. There was no sensory loss.
Blood pressure in the supine position was 140/78 mmHg (lying) and was 110/70 mmHg on standing.
How does Brown-Séquard’s syndrome present?
clinical presentation is that of ipsilateral weakness and a loss of position and vibration below the lesion with contralateral loss of pain and temperature
27M with three months of difficulty walking.
Examination reveals motor weakness of left leg in a pyramidal distribution with increase in tone. There is impaired pinprick sensation of right leg extending into the groin.
Clinical features of lateral medullary syndrome
Ipsilateral signs of Horner’s syndrome
Pharyngeal weakness and ataxia and
Contralateral signs of spinothalamic sensory loss of the limbs.
CSF features of bacterial meningitis?
high protein
low glucose, and
neutrophil pleocytosis.
How would you differentiate between mechanical and neurogenic dysphagia?
Mechanical dysphagia (for example, oesophageal and gastric carcinoma, oesophageal stricture, etc) causes dysphagia that is worse with solids than liquids
Nasal regurgitation, coughing and choking episodes during meals, dysphagia that is worse with liquids than solids and dysarthria indicate neurogenic dysphagia.
What could cause neurogenic dysphagia?
In 60+ think of myasthenia gravis and motor neuron disease.
Levetiracetam MoA?
Binds to the synaptic vesicle protein SV2A in the brain
Modulates neurotransmitter release
What is the inheritance pattern of Maple syrup urine disease?
autosomal recessive inheritance pattern
Name X-linked dominant conditions
Alport’s syndrome (in around 85% of cases - 10-15% of cases are inherited in an autosomal recessive fashion with rare autosomal dominant variants existing)
Rett syndrome
Vitamin D resistant rickets
What are the features of polyarteritis nodosa?
Mononeuritis multiplex
Fever
HTN
Nephritic renal involvement
