A clinical study of the cranial nerve involvement in leprosy. .
Aejaz Ali Wani, MD, Vipin Gupta, MD* and Dr. Nighat Jan.
Egyptian Dermatology Online Journal 5 (2): 3* Associate Professor & consultant dermatologist
Department of Dermatology, Venereology & Leprology, Govt. Medical College Jammu. Jammu & Kashmir, India.
Submitted: October 26th, 2009.
Accepted: November 20th, 2009.
Background: Leprosy commonly affects the cranial nerves predominantly the 5th (trigeminal nerve) and the 7th (facial nerve). Lepra reactions are risk factors for cranial nerve involvement.
Objective: To study the frequency and pattern of cranial nerve involvement in leprosy and to find its relation with facial patch.
Patients and methods: The present clinical study was undertaken on 100 consecutive leprosy patients to find out the involvement of cranial nerves in leprosy and to study the relationship between cranial nerve involvement and leprosy patch/patches on facial skin.
Results: Cranial nerve involvement was detected in 22 patients on clinical grounds; 7 Borderline Tuberculoid (BT), 6 Lepromatous Leprosy (LL), 6 Borderline Lepromatous (BL), 1 Pure Neuritic (PN), 1 Tuberculoid Tuberculoid (TT) and 1 Borderline Borderline (BB). The most commonly involved cranial nerves were the facial and trigeminal, seen in 9% each; followed by the olfactory in 6% and the auditory in 3%. Most cases with facial and trigeminal nerve involvement were of BT leprosy types while the majority with olfactory and auditory nerve involvement was of the lepromatous leprosy type (BL, LL). The association between lagophthalmos of recent origin, type 1 lepra reaction and significant facial patch was statistically significant.
Leprosy is the most common cause of treatable peripheral neuropathy in India and probably also in the world because of the large number of affected individuals perhaps closely matched by diabetic neuropathy . A cardinal sign is sensory loss which always precedes paralysis in all types of leprosy . Leprous neuropathy is characterized by involvement of superficial nerve trunks in areas such as ulnar, radial cutaneous, median, common peroneal, supra orbital and greater auricular which are cool and liable to trauma . Any cranial nerve can be affected predominantly the 5th and the 7th . The zygomatic branch of facial nerve which supplies the orbicularis oculi muscle is the most frequently affected . Appearance of type 1 reaction puts a patient at risk of nerve damage and secondary deformities . Early recognition and medical treatment of early nerve damage with steroids may result in full restoration of nerve function. The presence of significant facial patch around eyes or over malar region together with type 1 lepra reaction is a severe risk factor for the development of lagophthalmos and paralysis of other facial muscles . Hypaesthesia and anaesthesia are most often observed in maxillary division of the 5th nerve . In most cases of facial nerve involvement in leprosy, there is sensory impairment or hypopigmented and hypoanesthetic patch as well in the territory of trigeminal nerve especially over the maxillary branch. It becomes conceivable that leprosy infection entering the malar skin through sensory fibres progresses in such a way that it involves the peripheral motor branches of facial nerve in the area . Sensorineural hearing loss is more in lepromatous leprosy with ENL (Erythema Nodosum Leprosum) reaction . Involvement of nasal mucosa is greatest in lepromatous leprosy. The present study was undertaken to assess the frequency and pattern of involvement of cranial nerves, to characterize the type of leprosy that may be associated with damage of cranial nerves and to unravel some characteristics that were not explored in the past.
Material and methods
One hundred consecutive leprosy patients diagnosed on the basis of skin lesions, nerve involvement, slit skin smear examination and histopathological examination enrolled / attending the urban leprosy centre were screened for cranial nerve involvement irrespective of the type, duration or treatment status of the disease. Detailed history and complete clinical examination of each patient was performed with respect to age, sex, duration of disease, number, morphology and distribution of skin lesions including facial patch if any, nerve involvement with particular emphasis on cranial nerve involvement, duration of cranial nerve involvement, type of leprosy and treatment status. Ophthalmological and ENT consultations were conducted wherever required. Patients with complaints like nasal stuffiness, deviated nasal septum, intranasal adhesions and scarring in nasal mucosa (i), cataract (ii), history of head injury (iii, iv, vi, vii), acute/chronic ear discharge/drug intake such as aminoglycosides, salicylates, antiepileptics, tranquillizers, diuretics or family history of hearing loss (viii), history of diabetes, hypertension, renal impairment, anaemia etc were excluded because related cranial nerve couldn't be assessed accurately in them.Individual cranial nerves were tested clinically for sensory, motor and special functions. No specialized laboratory or electrophysiological tests were conducted (except audiometery for confirmation of sensironeural hearing loss). The recorded data was tabulated and analysed using chi square test.
Results and observations
The study material included 76 males and 24 females in the age ranging from 10 to 70 years. Twenty- two patients had cranial nerve involvement; 9 (18%) of 50 PB and 13 (26%) of 50 MB cases. Most of the patients with cranial nerve involvement were in age group 21-40 (50%) with a mean age of 42 years and male female ratio of 3.4:1.The majority of cases were of BT (32%) followed by LL (25%), BL (20%), TT (9%), PN (9%) and BB (5%). Thirty percent of BL patients had cranial nerve involvement followed by 24% LL and 22% BT.
Table 1: Cranial nerve involvement across the spectrum.Facial and trigeminal nerves were the most commonly involved cranial nerves. On analysis of spectrum of leprosy, 4 out of 9 cases of facial nerve involvement were seen in BT, 2 each in BL and LL and 1 in BB. Trigeminal nerve involvement was seen in 4 BT patients, 2 each of BL and LL patients and 1 each of PN and TT patients. Involvement of the olfactory nerve was seen in 6 patients, 3 of them had LL, 2 BL and 1 BT. Auditory nerve affection was seen in 3 patients only, 1 each of BT, BL and LL (Table 1).