Ultrasound for Pneumothorax Detection

This 15 minute lecture takes a look at ultrasound for pneumothorax detection.

It discusses lung sliding, lung pulse, comet tail artefact, B-lines, A-lines, and the contact or lung point.

It also touches on potential pitfalls including the non-ventilating lung, COPD / emphysema and lung bullae, and surgical emphysema.

https://gmep.org/media/14315

James Rippey

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Ultrasound of Acute Angle-Closure Glaucoma

History

This woman in her seventies presented with a painful red eye.

This video shows and describes the ultrasound features of acute angle closure glaucoma.

Discussion

Definition of acute angle-closure glaucoma:

At least 2 of the following symptoms:

  • ocular pain (often with unilateral headache)
  • nausea/vomiting
  • history of intermittent blurring of vision with halos

And at least 3 of the following signs:

  • IOP greater than 21 mm Hg
  • conjunctival injection
  • corneal epithelial edema
  • mid-dilated nonreactive pupil
  • shallow chamber in the presence of occlusion

Mechanism of Acute Angle-Closure Glaucoma

Aqueous humor is produced by the ciliary body in the posterior chamber of the eye. It passes from the posterior chamber, through the pupil, and into the anterior chamber. From the anterior chamber, the fluid is drained into the vascular system via the trabecular meshwork and canal of Schlemm contained within the angle.

In acute angle closure glaucoma the iris is pushed or pulled anteriorly, closing the angle between cornea and iris. This blocks the trabecular meshwork and prevents the egress of aqueous humor from the eye. The result is a rapid increase in intraocular pressure and the constellation of resulting signs and symptoms. Without rapid reduction in the pressure vision can be permanently lost.

Background to Ocular Ultrasound Biomicroscopy

Ultrasound biomicroscopy is now frequently performed by ophthalmologists to assess the structures of the anterior chamber.

A 50MHz probe is used, which can image to a depth of around 5mm.

Scanning is done through an open eye, with an anaesthetised cornea. Structures can be accurately assessed even if the cornea is hazy and gonioscopy is not possible.

I was unable to find a description of ultrasound performed in the emergency department for acute-angle closure glaucoma and here present my findings.

I used am 18MHz hockey stick probe and scanned through the shut eyelid, with copious amounts of sterile gel placed between probe and skin. I pressed very lightly and firstly explored the anterior chamber, and then the optic nerve and disc.

The anterior chamber of the affected eye was shallow, with a closed angle, and anterior displacement of the lens. Cupping of the optic disc was also evident.

Management of the Case

Our management followed standard guidelines with urgent referral to ophthalmology, rest, acetazolamide IV and then orally, topical steroid, topical B-blocker and later pilocarpine. The patient ultimately went for laser peripheral iridotomy.

References

Freedman J, Aherne A, Sinert R, et al.  Acute angle-closure glaucoma. Medscape Reference Drugs Diseases and Procedures http://emedicine.medscape.com/article/798811-overview reviewed 24/04/2013

Dada T, Gadia R, Sharma A, et al, Ultrasound biomicroscopy in glaucoma. Surv Ophthalmol. 2001 Sep-Oct;56(5):433-50.

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