Elsevier

Ophthalmology

Volume 116, Issue 11, November 2009, Pages 2236-2243
Ophthalmology

Original article
The Ice Pack Test in the Differential Diagnosis of Myasthenic Diplopia

https://doi.org/10.1016/j.ophtha.2009.04.039Get rights and content

Purpose

To investigate the diagnostic value and to establish threshold criteria for the ice pack test as an office preliminary test in the differential diagnosis of myasthenic diplopia in comparison with blepharoptosis.

Design

Prospective, comparative cohort study.

Participants

Eighty-nine patients with a recent onset of diplopia, blepharoptosis, or both were evaluated with orbital cooling in a prospective manner. Forty-eight patients presented with diplopia, 25 patients with both blepharoptosis and ophthalmoplegia and 16 patients with blepharoptosis.

Testing

All patients had the ice pack applied for 5 minutes on both eyelids at the initial orthoptic evaluation. Increasing the duration of cooling to 10 minutes was investigated in 36 diplopic patients. A complete diagnostic work-up was ordered and patients were followed up for a minimum of 6 months before diagnosis of myasthenia gravis was ascertained.

Main Outcome Measures

Difference in cover test measurements in primary position or marginal reflex distance before and after the application of the ice pack, specific cause for diplopia and blepharoptosis.

Results

Fifteen patients were diagnosed as myasthenic. The optimal cutoff point for a positive response to the ice pack test proved to be a reduction in ocular deviation in primary position by 50% or by 10 prism diopters (PD) or more for presenting deviations larger than 20 PD. By this criterion, sensitivity for the detection of myasthenic diplopia was 76.9% (95% confidence interval [CI], 49.06%–92.50%) for the 5-minute application, compared with 92.3% (95% CI, 63.5%–98.9%) sensitivity demonstrated for blepharoptosis. Increasing the time of application to 10 minutes did not improve the diagnostic value of the test. Specificity was high (98.3%; 95% CI, 90.3%–99.9%) and was demonstrated even in patients with coexisting myasthenic and dysthyroid ophthalmopathy. Patients with oculomotor nerve paresis and Horner syndrome invariably were nonresponsive to the test.

Conclusions

The ice pack test demonstrated high specificity and an acceptable sensitivity in the differential diagnosis of myasthenic diplopia. Data from this series suggest that a partial rather than a complete response to the ice pack test may be expected for myasthenic diplopia. Standardization of the method of application of the ice pack is critical for the interpretation of its effect.

Financial Disclosure(s)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Patients and Methods

One hundred two patients seeking treatment at the Orthoptic Clinic conducted by one of the authors (KIC) from June 2005 through September 2006 were evaluated with orbital cooling in a prospective manner. Subjects were enrolled among consecutive patients with diplopia, ptosis, or both at presentation. Inclusion criteria were a recent (less than 1 month) onset or unclear cause of symptoms. Patients were excluded when there was a reliable history suggesting the presence of restrictive strabismus

Results

Eighty-nine patients, 56 males and 33 females aged 27 to 83 years (mean, 54 years), were included in the study and form the basis of this report. Thirteen patients were excluded because of loss to follow-up before establishment of diagnosis, history of posttraumatic restrictive strabismus, or inflammatory cause for blepharoptosis. Mean follow-up time was 9.3 months (range, 6–30 months). No adverse effects to the application of the ice pack, except for mild to moderate discomfort within the

Discussion

After physiologic studies demonstrating a temperature-sensitive effect on repetitive nerve stimulation from myasthenic patients with local cooling,11, 12 Saavedra et al6 suggested a cold test that favorably influences neuromuscular transmission for the diagnosis of ocular myasthenia.

Subsequent studies4, 8, 13, 14, 15 confirmed the diagnostic validity of the test in the evaluation of myasthenic ptosis and suggested 2 minutes as the optimum time of application of the ice pack, from the 5 to 10

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  • Cited by (0)

    Manuscript no. 2008-1185.

    Financial Disclosures(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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