Neurology Quiz 2

(Ref. Harrison 19th p 1785)
• At the moment of aneurysmal rupture with major SAH, the ICP suddenly rises. This may account for the sudden transient loss of consciousness that occurs in nearly half of patients. Sudden loss of consciousness may be preceded by a brief moment of excruciating headache, but most patients first complain of headache upon regaining consciousness. The patient often calls the headache "the worst headache of my life": however, the most important characteristic is sudden onset. The headache is usually generalized, often with neck stiffness, and vomiting is common.
Anterior communicating artery or MCA bifurcation aneurysms may produce deficits that can include hemiparesis, aphasia, and abulia.
A third cranial nerve palsy, particularly when associated with pupillary dilation, loss of ipsilateral (but retained contralateral) light reflex, and focal pain above or behind the eye, may occur with an expanding aneurysm at the junction of the posterior communicating artery and the internal carotid artery.
A sixth nerve palsy may indicate an aneurysm in the cavernous sinus, and visual field defects can occur with an expanding supraclinoid carotid or anterior cerebral artery aneurysm.
Occipital and posterior cervical pain may signal a posterior inferior cerebellar artery or anterior inferior cerebellar artery aneurysm.
Pain in or behind the eye and in the low temple can occur with an expanding MCA aneurysm. Thunderclap headache if written in question again favours diagnosis of SAH.

(Ref: Harrison 20th p 3070; Harrison 19th p 2573)
• In right handed people the dominant parietal lobe is the left parietal lobe and it is supplied by left middle cerebral artery.
It is the involvement of left parietal lobe that causes aphasia.
The question is however on right middle cerebral artery which if occluded will cause damage to right parietal lobe leading to apraxia and neglect as primary symptoms.
Occlusion of right middle cerebral artery will cause left sided face weakness and hemiplegia. Dysarthria can be explained by facial weakness.

(Ref: Harrison 20th p 152; Harrison 19th p 171)
Causes of Reversible dementia
1. Hypothyroidism
2. Thiamine deficiency
3. Vitamin B12 deficiency

4. Normal pressure hydrocephalus
5. Subdural hematoma
6. Chronic infection
7. Brain abscess

(Ref: Harrison 20th p 3116; Harrison 19th p 2612)
• Square-Wave Jerks (SWT) are inappropriate saccades that take the eye off the target, followed by a nearly normal inter saccadic interval (approximately 200 msec), and then a corrective saccade that brings the eye back to the target.
• It is a normal finding but occurs at an exaggerated frequency in patients of Progressive supra-nuclear gaze palsy.
• PSP is a Parkinsonism variant with concomitant damage at superior colliculus.
• Superior colliculus is one of the generators of Square wave jerks and this explains why textbook mentions the Square wave jerks on Electro-oculography as suggestive of diagnosis of PSP
• It also explains the recurrent falls in these patients and continuous snarling expression on the face.
• The development of early gait disturbance, falls, hyperextension of neck and characteristic abnormalities of vertical gaze suggest progressive supranuclear palsy (PSP) Early urinary incontinence, orthostatic hypotension, and dysarthria suggest multiple system atrophy (MSA).
• The early appearance of drug-induced hallucinations will suggest diagnosis of DLB.