Cranial nerve palsy in diabetes: ‘Hunt’ for the diagnosis · cranial nerve palsy, followed by...

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Introduction Neuropathy is an important compli- cation of diabetes with a reported prevalence of around 50% for patients with 25 years of diabetes. 1 While the vast majority of such patients have distal symmetrical neu- ropathy, some patients develop focal and multi-focal neuropathies, includ- ing cranial nerve palsies. It is impor- tant for the clinician to think about a wide variety of differential diagnoses in patients with diabetes presenting with cranial nerve palsy, as there are significant implications in treatment and prognosis depending on the cause. We report a case of an appar- ently straightforward diabetic cranial neuropathy but a ‘hunt’ for the diag- nosis led to targeted treatment with prognostic implications. Case report A 55-year-old woman, with a two-year history of well-controlled type 2 diabetes, presented to her general practitioner with headache and clinical signs consistent with right sixth nerve palsy. A provisional diag- nosis of diabetic cranial neuropathy was considered with plans for a conservative line of management. However, her headache progressively worsened and she was referred to a neurologist. Cranial unenhanced CT scan was unremarkable. The consult- ing neurologist made a provisional diagnosis of suspected idiopathic intracranial hypertension (IIH) due to reported blurring of the right disc margin. A cerebrospinal fluid analysis with opening pressure was not documented. Acetazolamide was prescribed with no remission from headaches, at which point she was referred to our institution. Examination of her eyes revealed right sixth and pupil-involving partial third nerve palsy. Optic fundi revealed blurring of the right disc margins. Visual acuity and fields were normal. The rest of the neurological examination was normal. Cranial gadolinium-enhanced MRI revealed a normal brain parenchyma. An enhancing soft tissue mass of size 1.5x1.3cm was seen involving the right orbital apex, superior orbital fis- sure and cavernous sinus (Figure 1a). Vasculitic screen, tuberculosis, sarc - oidosis and lymphoma work-up were negative. A diagnosis of Tolosa-Hunt syndrome was made. Steroid therapy (methyl prednisolone 0.75mg/kg/ day) was instituted with dramatic res- olution of headaches. Glycaemic con- trol was optimised and steroid taper was instituted after two weeks. Her eye movements normalised by four weeks. A follow-up MRI of orbits after 12 weeks revealed complete resolu- tion of the mass (Figure 1b). Follow up one year later showed no recur- rence of the condition. Discussion Ophthalmoparesis in a diabetic patient is the result of microvascular PRACTICAL DIABETES VOL. 30 NO. 5 COPYRIGHT © 2013 JOHN WILEY & SONS 201 Case report Cranial nerve palsy in diabetes: ‘Hunt’ for the diagnosis Abstract A 55-year-old diabetic woman presenting with right sixth nerve palsy was diagnosed initially as having diabetic cranial neuropathy. Worsening headache and reported blurring of the right optic disc margin warranted further evaluation. CT scan of the brain was normal and a diagnosis of idiopathic intracranial hypertension was made. Her headache worsened and a partial pupil involving third nerve palsy evolved, at which point she was referred to our institution. Cranial MRI revealed features suggestive of Tolosa-Hunt syndrome and she responded dramatically to steroid therapy. While third nerve palsy is the most common cranial neuropathy in diabetic patients, sixth nerve palsy merits a wide array of differential diagnoses. A gadolinium- enhanced MRI of the brain is the preferred imaging modality for evaluating such patients, before branding them as having diabetic cranial neuropathy. Copyright © 2013 John Wiley & Sons. Practical Diabetes 2013; 30(5): 201–202 Key words cranial nerves; diabetes S Meenakshi-Sundaram 1 MD, DM, Department of Neurosciences SN Karthik 1 MD, DM, Department of Neurosciences S Bharathi 1 DM, Department of Neurosciences A Periyakaruppan 1 MD, DM, Department of Radiology T Badrinarayanan 1 MS, Department of Ophthalmology K Swaminathan 1 MD, FRCP(Edin), Department of Endocrinology 1 Apollo Speciality Hospitals, Madurai, India Correspondence to: Dr Krishnan Swaminathan, MD, FRCP(Edin), Consultant Endocrinologist, Apollo Specialty Hospital, Lake View Road, Madurai, India; email: [email protected] Received: 1 March 2013 Accepted in revised form: 11 March 2013

Transcript of Cranial nerve palsy in diabetes: ‘Hunt’ for the diagnosis · cranial nerve palsy, followed by...

Page 1: Cranial nerve palsy in diabetes: ‘Hunt’ for the diagnosis · cranial nerve palsy, followed by sev-enth and sixth nerve in that order.3 Thus, sixth nerve palsy in a diabetic patient

IntroductionNeuropathy is an important compli-cation of diabetes with a reportedprevalence of around 50% forpatients with 25 years of diabetes.1While the vast majority of suchpatients have distal symmetrical neu-ropathy, some patients develop focaland multi-focal neuropathies, includ-ing cranial nerve palsies. It is impor-tant for the clinician to think about awide variety of differential diagnosesin patients with diabetes presentingwith cranial nerve palsy, as there aresignificant implications in treatmentand prognosis depending on thecause. We report a case of an appar-ently straightforward diabetic cranial neuropathy but a ‘hunt’ for the diag-nosis led to targeted treatment withprognostic implications.

Case reportA 55-year-old woman, with a two-yearhistory of well-controlled type 2 diabetes, presented to her generalpractitioner with headache and clinical signs consistent with rightsixth nerve palsy. A provisional diag-nosis of diabetic cranial neuropathywas considered with plans for a conservative line of management.However, her head ache progressivelyworsened and she was referred to aneurologist. Cranial unenhanced CTscan was unremarkable. The consult-ing neurologist made a provisionaldiagnosis of suspected idiopathicintracranial hypertension (IIH) due

to reported blurring of the right disc margin. A cerebrospinal fluidanalysis with opening pressure wasnot documented. Acetazolamide wasprescribed with no remission fromheadaches, at which point she wasreferred to our institution.

Examination of her eyes revealedright sixth and pupil-involving partialthird nerve palsy. Optic fundirevealed blurring of the right discmargins. Visual acuity and fields werenormal. The rest of the neurologicalexamination was normal. Cranialgadolinium-enhanced MRI revealed a normal brain parenchyma. Anenhancing soft tissue mass of size1.5x1.3cm was seen involving theright orbital apex, superior orbital fis-sure and cavernous sinus (Figure 1a).Vasculitic screen, tuberculosis, sarc -oidosis and lymphoma work-up werenegative. A diagnosis of Tolosa-Huntsyndrome was made. Steroid therapy(methyl prednisolone 0.75mg/kg/day) was instituted with dramatic res-olution of headaches. Glycaemic con-trol was optimised and steroid taperwas instituted after two weeks. Her eyemovements normalised by fourweeks. A follow-up MRI of orbits after12 weeks revealed complete resolu-tion of the mass (Figure 1b). Followup one year later showed no recur-rence of the condition.

DiscussionOphthalmoparesis in a diabeticpatient is the result of microvascular

PRACTICAL DIABETES VOL. 30 NO. 5 COPYRIGHT © 2013 JOHN WILEY & SONS 201

Case report

Cranial nerve palsy in diabetes: ‘Hunt’ forthe diagnosis

AbstractA 55-year-old diabetic woman presenting with right sixth nerve palsy was diagnosed initially ashaving diabetic cranial neuropathy. Worsening headache and reported blurring of the right opticdisc margin warranted further evaluation. CT scan of the brain was normal and a diagnosis ofidiopathic intracranial hypertension was made. Her headache worsened and a partial pupilinvolving third nerve palsy evolved, at which point she was referred to our institution.

Cranial MRI revealed features suggestive of Tolosa-Hunt syndrome and she respondeddramatically to steroid therapy. While third nerve palsy is the most common cranial neuropathyin diabetic patients, sixth nerve palsy merits a wide array of differential diagnoses. A gadolinium-enhanced MRI of the brain is the preferred imaging modality for evaluating such patients, beforebranding them as having diabetic cranial neuropathy. Copyright © 2013 John Wiley & Sons.

Practical Diabetes 2013; 30(5): 201–202

Key wordscranial nerves; diabetes

S Meenakshi-Sundaram1

MD, DM, Department of Neurosciences

SN Karthik1

MD, DM, Department of Neurosciences

S Bharathi1DM, Department of Neurosciences

A Periyakaruppan1

MD, DM, Department of Radiology

T Badrinarayanan1

MS, Department of Ophthalmology

K Swaminathan1

MD, FRCP(Edin), Department of Endocrinology

1Apollo Speciality Hospitals, Madurai, India

Correspondence to: Dr Krishnan Swaminathan, MD, FRCP(Edin),Consultant Endocrinologist, Apollo Specialty Hospital, Lake View Road, Madurai, India; email: [email protected]

Received: 1 March 2013Accepted in revised form: 11 March 2013

Page 2: Cranial nerve palsy in diabetes: ‘Hunt’ for the diagnosis · cranial nerve palsy, followed by sev-enth and sixth nerve in that order.3 Thus, sixth nerve palsy in a diabetic patient

ischaemia and is often painful.2Diabetic cranial neuropathies usu-ally involve the third, fourth andsixth cranial nerves. The oculomo-tor nerve is more frequently affectedin diabetes than its counterparts. Ina large retrospective study of 8150hospitalised diabetic subjects, iso-lated third nerve palsies accountedfor the majority of patients with cranial nerve palsy, followed by sev-enth and sixth nerve in that order.3Thus, sixth nerve palsy in a diabeticpatient merits consideration of awide variety of differential diagnosesbefore being labelled as ‘diabeticcranial neuropathy’.

Unilateral or bilateral sixth nervepalsy in IIH is a non-localising effectof intracranial pressure. The involve-ment of oculomotor or trochlearnerves is seen only rarely in this con-dition. The hallmark of the disease ispapilloedema, which is often strik-ing. Diagnostic confusion arose inthis patient because of the blurrednasal margins of the right disc.While papilloedema in IIH is almostalways symmetrical, 10% of patientscan present with unilateral findingsand this can lead to an erroneousdiagnosis. An unenhanced CT scanmay miss important abnormalities ofsignificance, as was seen in thispatient. Gadolinium-enhanced MRIof the brain is the preferred test.Classical MRI features of IIH havebeen described in the literature.4However, MRI done in our patientdid not reveal any of these findings.

Tolosa-Hunt syndrome has beencharacterised by the HeadacheClassification Subcommittee of theInternational Headache Society as asyndrome of episodic orbital pain

associated with paralysis of one ormore ocular motor nerves (third,sixth or fourth) that usually resolves spontaneously but tends to relapse and remit.5 The aetiologyis unknown and granulomatousinflammation of the cavernous sinusis the characteristic feature of thedisease. This syndrome of painfulophthalmoplegia may be caused byany process exerting a mass effect onthe cavernous sinus including tuber-culosis (especially in developingcountries), sarcoidosis or lym-phoma. In addition, cases of Tolosa-Hunt syndrome have been reportedin patients with systemic lupus ery-thematosus.6 Hence, it is imperativeto screen for the above conditionsbefore a diagnosis of Tolosa-Huntsyndrome is considered. The diag-nosis in our patient became moreapparent when third nerve palsy was additionally noted. Whether partial third nerve palsy was missedduring the initial evaluation or thisevolved later was not known to us.Enhancing soft tissue lesion withinthe cavernous sinus, increase in size and lateral bulging of the ante-rior cavernous sinus contour, inter-nal carotid artery narrowing, extension towards the superiororbital fissure and orbital apexinvolvement are the imaging fea-tures of the syndrome.7

The differential diagnosis ofheadache syndromes and cranialnerve palsies in patients with dia-betes can often be challenging. Ithas to be emphasised that a detailedhistory, thorough clinical examina-tion and focused investigations areessential in the management of such patients.8 The importance of

establishing the correct diagnosis ina given patient cannot be overem-phasised. Although spontaneousremissions are known in Tolosa-Hunt syndrome, the clinical courseand pain relief can be optimisedwith steroid therapy. A dramaticresponse to steroid therapy is theusual outcome, often within 24hours, as was seen in our patient.9

Declaration of interestsThere are no conflicts of interestdeclared.

Patient consentInformed patient consent has beenobtained.

References1. Dyck PJ, et al. The prevalence by staged severity of

various types of diabetic neuropathy, retinopathy,and nephropathy in a population-based cohort: theRochester Diabetic Neuropathy Study. Neurology1993;43:817–24.

2. Wilker SC, et al. Pain in ischaemic ocular motor cranial nerve palsies. Br J Ophthalmol 2009;93:1657–9.

3. Greco D, et al. Clinical characteristics and associ-ated comorbidities in diabetic patients with cranialnerve palsies. J Endocrinol Invest 2012;35:146–9.

4. Butros SR, et al. Imaging features of idiopathicintracranial hypertension, including a new finding:widening of the foramen ovale. Acta Radiol 2012;53:682–8.

5. Headache Classification Subcommittee of theInternational Headache Society. The internationalclassification of headache disorders: 2nd edition.Cephalalgia 2004;24(Suppl 1):9–160.

6. Calistri V, et al. Tolosa-Hunt syndrome in a patientwith systemic lupus erythematosus. Eur Radiol2002;12:341–4.

7. Schuknecht B, et al. Tolosa-Hunt syndrome: MRimaging features in 15 patients with 20 episodes ofpainful ophthalmoplegia. Eur J Radiol 2009;69:445–53.

8. Schoenan J, Sandor PS. Headache with focal neuro-logical signs or symptoms; a complicated differen-tial diagnosis. Lancet Neurol 2004;3:237–45.

9. Kline LB, Hoyt WF. The Tolosa-Hunt syndrome. J NeurolNeurosurg Psychiatry 2001;71:577–82.

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Cranial nerve palsies in diabetes

Case report

Figure 1. Axial post contrast T1-weighted image (A) showing heterogeneously enhancing soft tissueenlargement involving the right anterior cavernous sinus, extending towards the superior orbitalfissure and orbital apex. The lesion shows complete resolution (B) post-treatment

A B

l Third nerve palsy is the most commoncranial neuropathy in diabetes

l The presence of a sixth nerve palsy in apatient with diabetes should warn theclinician to pursue an alternativediagnosis

l A gadolinium-enhanced MRI is theimaging modality of choice for suchpatients

l Tolosa-Hunt syndrome respondsdramatically to steroids and merits athought in the differential diagnosis ofcranial nerve palsy in patients withdiabetes

Key points