Lesson
We report a rare case of Myasthenia gravis and overactive bladder successfully treated with pretibial nerve stimulation.
Case report
A 24-year-old nulliparous Lithuanian lady with Myasthenia gravis was referred by her General Practitioner to the urogynaecology clinic with a complaint of urinary incontinence for the last three years. This had become worse in the last few months.
She was treated with a course of 30 min sessions of pretibial nerve stimulation (PTNS) given weekly over a three-month period (Uroplasty). This is delivered percutaneously through the tibial nerve via temporary insertion of a 34 gauge needle electrode, inserted approximately 5 cm cephalad to the medial malleolus and slightly posterior to the tibia and connected to a hand held electrical stimulator. The patient completed the OAB-q following completion of treatment, as well as having repeat bladder diary and urodynamic studies.
At follow-up post-PTNS treatment, the patient reported being very happy, as all of her symptoms were relieved. There was a reduction in the frequency of micturition as well as absence of the previously reported leakage as measured by the frequency-volume charts. The repeat urodynamic study was normal, with a normal maximum flow rate of 46 ml/s on a total voided volume of 540 ml with a residual volume of 22 ml. Pdet maximum during filling was 20 cmH2O and voiding cystometry parameters were normal. There was absence of unprovoked detrusor contractions.
Discussion
We may speculate that the effective use of PTNS in a patient with an autoimmune condition may involve a possible immunological mechanism of action, particularly since only one course of PTNS was given, and the patient was followed up for two years with no recurrence of the condition. It is more usual for patients to require repeat courses of PTNS. Additionally, there is evidence of neural-immune interactions with a bidirectional relationship, therefore, the possibility of an immune mechanism exists, although there is currently no evidence to support this. This possibility will be explored further in a randomised controlled trial
KeywordsMyasthenia gravis, overactive bladder, detrusor over-activity, PTNS, neuromodulation
