Several factors prolonging myasthenia gravis diagnosis


By Siobhan Calafiore

14 Feb 2024

Female patients and those not currently working are likely to face longer delays in receiving a myasthenia gravis diagnosis than those who are male and employed, an Australian study suggests.

The retrospective study involved 110 patients (56% female) from three Melbourne institutions. Most initially presented with purely ocular symptoms, particularly those older than 50.

Almost two-thirds of ocular patients generalised within two years.

Generalised patients, who eventually made up 70% of the cohort, were identified as having bulbar, respiratory, or generalised weakness, with or without ocular complaints. More female than male patients presented as early-onset myasthenia gravis (MG), which was defined as younger than 50.

Researchers, led by Dr Minh Nguyen from the Department of Neuroscience at Monash Health, said potential precipitants of MG were only apparent in one-third of patients, the most common being major surgery and prior infections.

Findings published in Neurology Clinical Practice [link here] revealed that the median time from symptom onset to MG diagnosis was 102 days, with most patients (90%) receiving a definitive diagnosis within one year.

Two-thirds of diagnoses were made in outpatient settings, with most in neurology/neuro-ophthalmology, 5% in ophthalmology and 2% in general medicine settings.

Overall, female patients took longer to be diagnosed than male patients (median 145 days vs 54 days), while the biggest contributor to prolonged diagnosis was the time between symptom onset and initial presentation (median 17 days).

Patients not working at the time of symptom onset, such as retirees, stay-at-home carers and the unemployed, presented later than those working (median 59 days vs 10 days), as did female patients compared to male patients (31 days vs 14 days).

The median time taken from initial presentation to health service to neurologist referral was two days. However, the duration was extended if patients had diplopia, respiratory symptoms, or had presented to an ophthalmologist first.

Outpatient management was associated with a longer time to be seen by a neurologist from referral compared with inpatient management, and also longer times for the first diagnostic result to return and for the result to be reviewed.

Other findings indicated that ocular MG had a median greater time to neurologist review than generalised MG (median 5 days vs 1 days), electrophysiology tests took longer for outpatients than inpatients (median 21 days vs 2 days) and outpatients were also started on treatment later than inpatients.

There was no association of MG severity, ethnicity, age, medical and ocular comorbidities, and public or private health service on time to diagnosis.

The authors also noted no association between time to diagnosis and a number of clinical outcomes, including number of follow-up appointments or hospitalisations for MG flares, or the prevalence of treatments administered.

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