25. An interesting cause of foot drop

Footdropisanuncommonpresentationontheacutemedical takeandtospecialistclinics.Thiscasedescribesanunusualcauseof foot drop and highlights the need to consider a wide differential and start prompttreatmenttoprevent longtermcomplications. Case description: A 47 year old gentleman of Indian origin with a background of asthma diagnosed in childhood initially presented to the accident and emergency department with increasing shortness and a productivecough.Therewasnohistoryof foreigntravelorknownTBcontacts.Hewastreatedforaninfectiveexacerbationofasthmawithnebulisers, steroids, antibiotics and discharged. He was re-admitted to hospital afewweekslaterwithgeneralmalaise,apruriticrash,shortnessofbreath, leg pain and evidence of left sided foot drop. CT Chest showed pleural effusions in conjunction with a pericardial effusion. Blood tests showed raised inflammatorymarkers,aneosinophiliawithanegativeANA,ANCA and serum ACE. An echocardiogram demonstrated an element of diastolic dysfunction, however, the heart on the whole functioned normally. Hewasseenbytherheumatologyteamanddiagnosedwithavasculitisof unknown cause. He was treated with high dose IV methylprenisolone for three days followed by prednisolone 60 mg daily. The inflammatory markersreturnedtonormalwithan improvement intherashandconstitutional symptoms. Nerve conduction studies showed evidence of distal axonalsensorimotorneuropathy.Theskinbiopsydemonstratedfeatures ofadensemixedperivascular infiltratewithmoderatelydensesuperficial and deep perivascular infiltrate comprising numerous eosinophils accompanied by neutrophils, lymphocytes and histiocytes. Lung function studies showed FEV1 is 2.49 (96%) with an FVC of 3.26 (108%), ratio of FEV1/FVC 76%. A diagnosis of eosinophilic vasculitis was made and the patient received pulsed intravenous cyclophosphamide for six months followed by a tapering dose of prednisolone and azathioprine was commenced. The foot drop and pleural effusions fully resolved with residual sensory changes in both feet. He remained well for over 18 months but then recently represented with pain, swelling and erythema over the right thigh. Blood tests again showed raised inflammatory markersandaneosinophilia.Hewaspromptly treatedwithhighdosesteroids and switched to mycophenolate mofetil and maybe acandidate for novelbiologictherapyinthenearfuture. Discussion:This isan interestingandunusualcaseofamultisystemvasculitis that was challenging to diagnose and treat both in the short and long-term.Thiscomplexcasedemonstrates theneedtoconsideraunifyingdiagnosis after appropriate investigations and the benefit of specialty involvement at an early stage. The recent relapse also raises questions about longtermmanagementstrategiesandtheroleofnovelbiologics. KeyLearningPoints:Thiscase illustrates theneedforconsiderationofa wide differential diagnosis in cases of multisystem involvement with unusual neurology. Thorough investigations and involvement of specialistsatanearlystagecanresult inprompttreatmentandanimprovedprognosis. This case also high-lights the importance of regular follow-up to detectearlyrelapsesandcomplications. Disclosure:G.K.Takhar:None.A.Porter:None.S.Allard:None.