Showing posts with label Ophthalmology. Show all posts
Showing posts with label Ophthalmology. Show all posts

Thursday, November 4, 2010

fever, chills, rigors

DEFINITION FEVER
elevation of body temperature that exceeds the normal daily variation and occurs in conjunction with an increase in the hypothalamic set point—for example, from 37C to 39C (shift of the set point from “normothermic” to febrile levels)

CHILLS
a sensation of coldness

RIGORS
exaggerated shivering

how all of these related?
fever comes with abnormally high body temperature, but why the patient can has chills and rigors (or shivering)?

read more below

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Wednesday, November 3, 2010

vital signs

heart rate
respiratory rate
blood pressure
temperature
pain score

i'm not very sure whether pain score is still the vital sign, but in 2008, KKM add in the 5th vital sign which is PAIN SCORE.



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Thursday, July 15, 2010

Infranuclear opthalmoplegia

CASE :

Young male teenager presented with 1 week history of progressively worsening vision of his left eye. He claims that he cannot see well with that eye. He has fever and headache as well. He has severe facial acne.
Cranial nerve examination noted left sided external and internal opthalmoplegia,and loss of sensation over the left forehead. Other neurological examination is normal. What can be your diagnosis?

DISCUSSION :


All the 3rd, 4th and 6th cranial nerves, together with opthalmic branch (V1) and maxillary branch (V2) run forward in the lateral wall of cavernous sinus.

V2 (maxillary branch of trigeminal nerve) leaves the mid-portion of cavernous sinus to exit the skull through foramen rotundum.

V3 (mandibular branch) langsung not in the lateral wall of cavernous sinus at all. Exits the skull through foramen ovale as soon as it leaves the trigeminal ganglion.

So,
Retrocavernous sinus -> 3 branches of CNV, CNIII, CNIV & CNVI
Posterior portion of cavernous sinus -> CNV1, CNV2, CNIII, CNIV & CNVI
Anterior portion of cavernous sinus -> CNV1, CNIII, CNIV & CNVI

Questions :
1. What is the most likely diagnosis ?

Lesions at the left anterior portion of cavernous sinus, which is most probably due to left cavernous sinus thrombosis secondary to facial acne.

2. What is internal and external opthalmoplegia ?

Internal -> paralysis affecting only the sphincter muscle of the pupil and the ciliary muscle

External -> paralysis affecting one or more of the extrinsic eye muscles

Total opthalmoplegia -> Internal + External

3. Differential diagnosis ?

- Pituitary Tumour (Pituitary gland is situated between the left and right cavernous sinus)
- Intracavernous carotid artery aneurysm
- Cavernous-carotid arteriovenous fistula
- Metastases (eg, nasopharyngeal carcinoma extension)
- Meningioma
- Sphenoidal sinusitis

4. What other condition can present with similar conditions ?

Lesions at superior orbital fissure -> Trauma, Tolosa-Hunt Syndrome (idiopathic granulomatous disease)

Reason : After cavernous sinus, CN3,4,6 and V1 bersama-sama enter superior orbital fissure. That's all.

5. Why facial acne cause Cavernous sinus thrombosis ?

Facial acne -> Acne pecah -> Kebetulan acne burst at the place of danger area of the face -> bacteria enters Facial Vein -> ophthalmic vein connects facial vein and cavernous sinus, and because these connections are valveless, retrograde infections can spread from facial vein to cavernous sinus -> Thrombophlebitis of the cavernous sinus -> haha !

6. Other signs/symptoms of cavernous sinus thrombosis ?
- Swollen eyelids, chemosis and proptosis
- Papilloedema
- Usually involves both eye

7. Name 1 condition very similar to cavernous sinus thrombosis ? State the difference.

Orbital cellulitis. Jawapan dekat Dhingra pg 191.

Summary : Cavernous sinus thrombosis is more acute, involve both eyes.

8. How to confirm cavernous sinus thrombosis ?
CT scan

9. Other source of cavernous sinus thrombosis ?
Dhingra pg 191.

Please correct me if I am wrong, some of these questions is I sendiri fikir punya. Thanks.

Source : Red book of neuro examination, Dhingra, Oxford

Thanks to Dr. Yeoh for asking us this interesting case through facebook. It's very rare but it happens in Teluk Intan.
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Thursday, June 24, 2010

Hering's Law


Abnormalities of the abducting eye in internuclear ophthalmoplegia reflect an adaptive process that helps overcome the adduction weakness of the opposite eye.

This response operates under the constraints of Hering's law of equal innervation: any attempt to increase the innervation to a weak muscle in one eye must be accompanied by a commensurate increase in innervation to the yoke muscle in the other eye.


Source : http://www3.interscience.wiley.com/journal/109677683/abstract


Thanks to Dr Ngiu for asking this question after showing us patient with Right Internuclear Ophthalmoplegia today.


A115262

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Internuclear Ophthalmoplegia

When a person looks to the side opposite the affected (right) eye, the following happens:

  • The affected (right) eye, which should turn inward, cannot move past the midline. That is, the affected eye looks straight ahead.
  • As the other eye (left) turns outward, it often makes involuntary, repetitive fluttering movements called nystagmus That is, the eye rapidly moves in one direction, then slowly drifts in the other direction.
  • May have double vision.


Internuclear ophthalmoplegia (INO) is a manifestation of intrinsic brainstem disease.

It is caused by a lesion involving the medial longitudinal fasciculus between the abducens and oculomotor nuclei.

Typically INO results from conditions which produce ischemia or demyelination in the brainstem.

The chief clinical features are an adduction deficit in the eye on the side of the lesion and nystagmus in the contralateral eye on attempted lateral gaze.

*******************************

Internuclear ophthalmoplegia is impairment of horizontal eye movements caused by damage to certain connections between nerve centers in the brain stem.

In internuclear ophthalmoplegia, the nerve fibers that coordinate both eyes in horizontal movements—looking from side to side—are damaged. These fibers connect collections of nerve cells (centers or nuclei) that the 3rd cranial nerve (oculomotor nerve) and the 6th cranial nerve (abducens nerve) originate from.

In older people, the disorder usually results from a stroke, and only one eye is affected.

In younger people, it usually results from multiple sclerosis, and both eyes are often affected.

Less common causes include Lyme disease, tumors, and toxicity due to a drug (such as tricyclic antidepressants).

Horizontal eye movements are impaired, but vertical ones are not.

The affected eye cannot turn inward, but it can turn outward.


http://www.merck.com/mmhe/sec06/ch096/ch096b.html


Thanks to Dr Ngiu for showing us the patient with RIGHT INTERNUCLEAR OPHTHALMOPLEGIA today. We really appreciate the findings as mentioned above.

A115262
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