Session 6: Group Work Flashcards
What clinical signs are visible in the image?
Miosis
Partial ptosis
Some anhydrosis
What is this collection of signs called?
Horner’s syndrome
Explain how these signs arise.
Partial ptosis - innervates the smooth muscle component (minor) of the levator palpabrae superioris
Miosis - innervates the dilator pupillae. Unopposed parasympathetic signalling leads to constriction of the pupil
Anhydrosis - innervates the sweat glands of the face
The GP has arranged for an x-ray. Why?
Because it could be a pancoast tumor
What are the differences of Horner’s syndrome to lesion of the oculomotor nerve?
More severe ptosis in CN III
No anhydrosis
Dilation of the pupil instead of constriction
Motor weakness of the eye
How can you be sure that it is the left eye in the image that has the abnormality and not the right eye?
If you shine a light in the eye of the constricted eye and there is an consensual response in the opposite eye.
If there is, then the affected eye is the one being shone into.
A 40 year old lady presents with a history of sweating and palpitations. The
doctor notes the following clinical sign on initial inspection
and determines no evidence of exophthalmos.
What clinical sign do you think the GP has noticed?
Bilaterally constricted pupils
Explain why this sign has arisen as a result of her underlying condition.
She might have Grave’s disease or another type of hyperthyroidism.
T3 and T4 are sympathomimetics which mimics the action of the adrenaline leading to increased sweating (poor tolerance to heat), heart palpitations and constriction of the pupils.
What single blood test would be most useful to determine the diagnosis?
T3 and T4
TSH
TSI
On examining the patient the ED doctor notes that there is a small haematoma
in the area of the pterion. What is the pterion?
The most brittle part of the skull bone in the junction of the temporal, sphenoid, frontal and parietal bones.
What does the image show?
Explain what you see.
Lens shaped haematoma.
Extradural haemorrhage
Between which meningeal layers has this bleeding occured in? (Extradural)
Between the inner table of the skull bone and the periosteal layer of the dura.
With reference to your understanding of the anatomy in this area, explain
why the abnormality shown in the CT scan has arisen from the patient’s
injury. Why does it form the shape seen?
The haematoma is expanding but only to the suture line of the area it’s ruptured in.
It is confined to the space of its suture lines because at the suture lines the periosteal layer of the meningeal dura adheres very closely and cannot expand further.
When the doctor re-examines the patient he notices that one of the pupils
has become dilated.
With reference to your understanding of anatomy and the autonomic innervation of the pupil, explain why this clinical sign has now developed.
Compression of the oculomotor nerve. The parasympathetic fibres are on the periphery on the nerve so they are the first ones to become impinged.
This leads to paralysis of the sphincter pupillae.
Leads to unopposed sympathetic action and the pupil cannot constrict so it dilates.
When the doctor tests the patient’s pupillary light reflexes, he notes that the right pupil does not react to light. However, the left pupil still constricts
(consensual light reflex).
Explain, with reference to the pupillary light reflex why the direct pupillary light reflex is lost in the right eye, but the consensual in the left eye
remains.
Because the optic nerve is not damaged or impinged. This means that the afferent sensory signals are being sent.
Only on one side there is impingement of the oculomotor nerves. This means that the on the left side the oculomotor nerve is intact and not impinged.
