A 66 year old female with long standing uncontrolled type 2 diabetes and hypertension presented to us with complaints of diplopia since last 2 months. There was no history of trauma and no other clinical complaints
On examination patient had esotropia in primary gaze in the left eye and reduced abduction of the left eye suggestive of lateral rectus palsy. Rest of neurological examination was normal. Patient had an isolated left 6th nerve palsy.
Q. What are the etiologies for 6th nerve palsy ?
2. Vascular- diabetic cranial mononeuropathy is one of them
4. Raised ICT including Idiopathic intracranial hypertension
5. Cavernous sinus involvement
7. Vasculitis (including giant cell arteritis)
Abducens nerve is the most common nerve involved in Diabetic patients.
Q Would a neuroimaging be required ?
This is controversial. Patel et al published a paper in 2004 in which they suggested that isolated non-traumatic sixth nerve palsy with no other neurological signs do not require a neuroimaging and require a close follow up. (1)
Q How common are diabetic and hypertension a cause of 6th nerve palsy
A population based study by Patel et al showed that diabetes was present in 23% of patients with isolate 6th nerve palsy which was more compared to controls. Isolated hypertension was similar to controls. Hypertension plus diabetes was present in 18% of patients with isolated 6th nerve palsy. (2)
Q What is the management of this condition ?
Diabetic Cranial neuropathy resolves on its own and requires no management apart from good glycemic and blood pressure control. It generally resolves over 6-12 months. Prisms may be used for symptomatic correction of the diplopia.
A paper by Broniarczyk-Loba et al suggest that injection of botulism toxin in the medial rectus can help in early resolution of the diabetic 6th nerve palsy. They suggest that this approach can be used for patients in whom the diplopia interferes with their work and function. (3)
1. Patel SV, Mutyala S, Leske DA, Hodge DO, Holmes JM. Incidence, associations, and evaluation of sixth nerve palsy using a population-based method. Ophthalmology2004;111(2):369-75.
2. Patel SV, Holmes JM, Hodge DO, Burke JP. Diabetes and hypertension in isolated sixth nerve palsy: a population-based study. Ophthalmology2005;112(5):760-3.
3. Broniarczyk-Loba A, Czupryniak L, Nowakowska O, Loba J. Botulinum Toxin A in the Early Treatment of Sixth Nerve Palsy-Induced Diplopia in Type 2 Diabetes. Diabetes Care2004 March 1, 2004;27(3):846-7.