An unusual case of isolated sixth cranial nerve palsy in leprosy
Published Web Locationhttps://doi.org/10.5070/D38bp5v9b3
Letter: An unusual case of isolated sixth cranial nerve palsy in leprosyBase Hospital New Delhi, Delhi, India
Sanjeev Vaishampayan MD, Priyanka Borde MD
Dermatology Online Journal 18 (8): 16
Cranial nerve involvement is not common in leprosy. The fifth and seventh cranial nerves are the most commonly affected in leprosy. Herein we present a patient with Hansen disease (BL) with type I reaction who developed isolated involvement of the sixth cranial nerve leading to lateral rectus muscle palsy. He responded to timely anti-reactional therapy and it produced a good response. Careful observation of patients with lepra reaction is needed to avoid damage to important organs.
Cranial nerve involvement is not common in leprosy. The fifth and seventh cranial nerves are the most commonly affected in leprosy. Herein we report a patient with Hansen disease (BL) with type I reaction who developed isolated involvement of the sixth cranial nerve leading to lateral rectus muscle palsy.
|Figure 1||Figure 2|
A 34-year-old male presented with reddish, raised, anesthetic lesions over the face, trunk, and upper and lower extremities of 3 months duration. They were non-itchy and non-tender. His general and systemic examination was unremarkable. Dermatological examination revealed multiple variably sized, erythematous, hypoesthetic plaques, present at the root of nose extending below left eye, right cheek, left side of neck, left shoulder, and trunk (Figures 1 and 2). In addition, multiple variably sized, hypoesthetic, hyperpigmented, ichthyotic plaques were seen over the right arm, forearm, and both lower legs. Left infra-orbital, bilateral ulnar, and right common peroneal nerves were thickened and non-tender. Slit skin smear was 1+ for AFB (L) bacilli. His skin biopsy confirmed the diagnosis of Hansen disease (borderline lepromatous).
A final diagnosis of Hansen disease (BL) with cutaneous type I reaction was confirmed. He was started on MB-MDT and anti-reactional therapy with oral prednisolone 50 mg per day because the plaque over the face showed potential for involvement of the facial nerve. A few of the erythematous lesions resolved. One month later, he developed acute gastroenteritis and dehydration, for which he was treated with oral antibiotics and IV fluids. Although his condition stabilized, the next day he developed inward rotation of the left eye (Figure 3). There was no history of previous eye complaints or injury.
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Ophthalmological examination revealed strabismus of 21 degrees that indicated mild paralysis of the left lateral rectus muscle (left 6th nerve palsy). MRI of the brain and orbits was done to rule out intracranial lesions and did not reveal any abnormality. He was given muscle relaxant eye drops and an occlusive patch to cover the left eye. The dose of oral prednisolone was increased to 60 mg per day to prevent further deterioration of lateral rectus palsy.
After two months his strabismus completely recovered. As the lepra reaction regressed, the dosage of oral prednisolone was tapered and stopped. Currently (i.e., 6 months later) he is on anti-leprosy treatment and has had no further episodes of type 1 reaction or recurrence of the sixth nerve palsy (Figure 4).
Cranial nerve involvement is not frequently seen in leprosy [1, 2]. In our hospital, out of 214 leprosy patients treated in last 3 years, only 4 patients showed involvement of cranial nerves along with other peripheral nerves. Multiple cranial nerve involvement was studied by Kumar et al . Dhar et al had reported the involvement of fifth, sixth, seventh, and eighth cranial nerves in a patient with lepromatous leprosy . U. Dhaliwal et al have reported a 39-year-old male patient with leprosy, ENL, and orbital involvement. This patient had developed second, third, fourth, and fifth cranial nerve palsies leading to blindness, complete ptosis, complete ophthalmoplegia, and absence of corneal sensations .
However, isolated involvement of the sixth cranial nerve in leprosy as seen in our patient has not been mentioned in the English literature. Common causes of sixth nerve palsy are fracture of the base of skull and intracranial lesions causing increased pressure, such as tumors, aneurysms, or infections (meningitis). Refractive errors, monocular lesions like cataract, aphakia, severe congenital ptosis, or anisometropia can be associated, but these were ruled out in our patient. Hence by exclusion, leprosy with type I reaction is the only possible cause of sixth nerve palsy in this case. Patients with leprosy lesions on the face and patients having lepra reactions complicated by infection should be observed extra carefully to detect and treat all cases of neuropathy in a timely fashion.
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