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Handbook of Clinical Neurology, Vol. 82 (3rd series) Motor Neuron Disorders and Related Diseases A.A. Eisen, P.J. Shaw, Editors © 2007 Elsevier B.V. All rights reserved Chapter 11 Monomelic amyotrophy of upper or lower limbs M. GOURIE-DEVI* Institute of Human Behaviour and Allied Sciences, and Department of Clinical Neurophysiology, Sir Ganga Ram Hospital, New Delhi, India 11.1. Introduction Monomelic amyotrophy in which neurogenic atrophy is restricted to one limb is a heterogenous disorder, involving one upper or lower limb. Insidious onset of atrophy and weakness, presumed to be due to anterior horn cell involvement, starting in the second or third decade with male preponderance and sporadic occur-rence are the characteristic features. Progression is slow and followed by stabilization within a few years, result-ing in a benign outcome. Cranial nerves, pyramidal, sensory, cerebellar and extrapyramidal systems are not involved. Hirayama et al. (1959) from Japan reported atro-phy of a single upper limb and labeled it as “juvenile muscular atrophy of unilateral upper extremity.” Prabhakar et al. (1981) from India reported atrophy of muscles of one lower limb and described it as “wasted leg syndrome.” Since either one upper or lower limb is affected, Gourie-Devi et al. (1984a, 1986) suggested the eponym “monomelic amyotrophy” (MMA) as a more appropriate term. The authors further suggested that upper limb MMA may be called “brachial mono-melic amyotrophy” to differentiate it from MMA of a lower limb, which may now be called “crural monomelic amyotrophy” (Gourie-Devi and Nalini, 2003). Focal amyotrophy has been described under a variety of descriptive names, which refer to the limb involved, the site of muscles affected and the benign and non-progressive course of the disease (Table 11.1). 11.1.1. Monomelic amyotrophy of upper limb More than 300 cases have been reported from Japan (Hirayama et al., 1963; Hashimoto et al., 1976; Sobue et al., 1978; Hirayama, 2000a). The atrophy was distal and segmental, confined to one upper limb, but electromyographic abnormalities were noted in some patients in the non-atrophic upper limb. From India also more than 200 cases (including a personal series of 89 cases) have been reported of single upper limb atrophy, a large proportion of them with distal muscle involve-ment and a few with proximal muscle involvement (Singh et al., 1980; Gourie-Devi et al., 1984a,b, 1987a; Virmani and Mohan, 1985; Misra and Kalita, 1995; Pradhan and Gupta, 1997; Saha et al., 1997; Khandelwal et al., 2004; Misra et al., 2005). Reports from many other countries including Sri Lanka (Peiris et al., 1989), Korea (Kim et al., 1994), Hong Kong (Chan et al., 1991), Taiwan (Kao et al., 1993a) and Malaysia (Tan, 1985) reaffirm the frequency of MMA in Asia. Initially there were few reports from Western countries, mostly isolated cases or a small number of patients, but with increasing awareness more publications have appeared in the literature (Pilgaard, 1968; Compernolle, 1973; Engel, 1977; Adornato et al., 1978; De Visser et al., 1988). Large series of cases, notably from France and Brazil, have been published (Serratrice et al., 1987; De Freitas and Nascimento, 2000). Hirayama et al. (1963) referred to 10 cases reported by Marie and Foix in 1912, of isolated non-progressive atrophy of small muscles of hand, older age at onset of the disease in the fifth to eighth decades in eight cases and second decade in two cases. The autopsy findings in four of these patients are discussed later (§ 11.12). 11.1.2. Monomelic amyotrophy of lower limb Monomelic amyotrophy of a lower limb is less frequent than MMA of an upper limb. More than 130 cases (including a personal series of 36 cases) have been *Correspondence to: M. Gourie-Devi, Flat 9, Doctors Apartments, Vasundhara Enclave, New Delhi – 110096, India. E-mail: gouriedevi@yahoo.co.in, mgouriedevi@gmail.com, Tel: +91-11-22618573, Fax: +91-11-22599227. 208 M. GOURIE-DEVI Table 11.1 Eponyms used for single limb atrophy A. Upper and lower limb Monomelic amyotrophy (Gourie-Devi et al., 1984a). Benign focal amyotrophy (Adornato et al., 1978; Riggs et al., 1984). Monomelic spinal muscular atrophy (De Visser et al., 1988). Spinal monomelic amyotrophy (Serratrice, 1991). Benign monomelic amyotrophy (De Freitas and Nascimento, 2000). B. Upper limb Juvenile muscular atrophy of unilateral upper extremity (Hirayama et al., 1959). Juvenile non progressive muscular atrophy localized to hand and forearm (Hashimoto et al., 1976). Juvenile type of distal and segmental muscular atrophy of upper extremities (Sobue et al., 1978). Juvenile muscular atrophy localized to arms (Singh et al., 1980). Juvenile lower cervical spinal muscular atrophy (Kao et al., 1993a). Juvenile amyotrophy of distal upper extremity (Biondi et al., 1989). Non-familial spinal segmental muscular atrophy in juvenile and young subjects (Virmani and Mohan, 1985). Non-progressive juvenile spinal muscular atrophy of the distal upper limb (Hirayama’s disease) (Hirayama, 1991). Juvenile asymmetric segmental spinal muscular atrophy (Pradhan and Gupta, 1997). Brachial monomelic amyotrophy (Gourie-Devi and Nalini, 2003). C. Lower limb Wasted leg syndrome (Prabhakar et al., 1981). Benign monomelic amyotrophy of lower limb (Uncini et al., 1992). Benign calf amyotrophy (Felice et al., 2003). Crual monomelic amyotrophy (Gourie-Devi, 2004). reported from India (Prabhakar et al., 1981; Gourie-Devi et al., 1984a,b, 1987a; Virmani and Mohan, 1985; Chopra et al., 1987; Saha et al., 1997) and more than 40 cases from Western countries (Riggs et al., 1984; Serratrice et al., 1987; Uncini et al., 1992; De Freitas and Nascimento, 2000; Felice et al., 2003). It is note-worthy that, although numerous cases of MMA of an upper limb are described from Japan, there is only one isolated report of two cases of MMA of a lower limb (Hamano et al., 1999). 11.2. Prevalence and geographic distribution Monomelic amyotrophy constituted 8–29% of all motor neuron diseases in different series reported from India (Gourie-Devi et al., 1984a, 1987a; Saha et al., 1997). The estimated prevalence rate of MMA was 0.9, of upper limb 0.5 and lower limb 0.4 per 100,000 popula-tion (Gourie-Devi et al., 1984a; Gourie-Devi, 2004), based on the ratio of cases of monomelic amyotrophy to amyotrophic lateral sclerosis, as suggested by Kurtzke (1962), the prevalence rate of ALS having been determined to be 4 per 100,000 population (Gourie-Devi et al., 1984a, 1995). The geographic distribution of MMA of upper and lower limb in Asia and other countries is shown in Tables 11.2 and 11.3. 11.3. Classification Monomelic amyotrophy can be classified based on the limb involved and the site of muscles affected: Type 1. Monomelic amyotrophy of upper limb. Distal: Hand and forearm muscles. Proximal: Shoulder girdle and arm muscles. Global: Entire limb. Type 2. Monomelic amyotrophy of lower limb. Distal: Leg and foot muscles. Proximal: Pelvic girdle and thigh muscles. Global: Entire limb. In the majority of cases in both type 1 and type 2, the atrophy is confined to a single limb with electromyo-graphic abnormalities in the contralateral limb in some patients. In type 1, spread to the contralateral limb with atrophy and weakness may occur in 10 to 30%, but significant asymmetry is a distinctive fea-ture, the initially involved limb being more severely affected (Gourie-Devi et al., 1984a; Sobue et al., 1978). In contrast, in type 2, atrophy is usually restricted to a single lower limb (Prabhakar et al., 1981; Gourie-Devi et al., 1984a; Virmani and Mohan, 1985; Serratrice et al., 1987) with rare instances of spread to the opposite limb (Kim et al., 1994; Felice et al., 2003). MONOMELIC AMYOTROPHY OF UPPER OR LOWER LIMBS 209 Table 11.2 Geographic distribution of monomelic amyotrophy of upper limb A. Countries in Asia India: Hong Kong: Israel: Japan: Korea: Malaysia: Sri Lanka: Taiwan: Turkey: Singh et al., 1978; Gourie-Devi et al., 1984a; Virmani and Mohan, 1985; Misra and Kalita, 1995; Pradhan and Gupta, 1997; Saha et al., 1997; Nalini et al., 2004; Khandelwal et al., 2004. Chan et al., 1991. Neufeld et al., 1991. Hirayama et al., 1963; Hashimoto et al., 1976; Sobue et al., 1978; Mukai et al., 1985; Iwasaki et al., 1987; Kikuchi et al., 1987; Konno et al., 1997; Kohno et al., 1998. Kim et al., 1994. Tan, 1985. Peiris et al., 1989. Kao et al., 1993a. Gucuyener et al., 1991. B. Countries outside Asia Australia: Belgium: Brazil: Canada: Denmark: France: Germany: Italy: Netherlands: Poland: Switzerland: USA: Kiernan et al., 1999. Robberecht el al., 1997. De Freitas and Nascimento, 2000. Oryema et al., 1990. Pilgaard, 1968. Serratrice et al., 1987; Chaine et al., 1988; Biondi et al., 1989. Schlegal et al., 1987; Schroder et al., 1999. Barontini et al., 1991; Di Guglielmo et al., 1996; Polo et al., 2003. Compernolle, 1973; Thijsse and Spaans, 1983; De Visser et al., 1988. Drozdowski et al., 1998. Kaeser et al., 1983. Engel, 1977; Adornato et al., 1978; Metcalf et al., 1987; Tandan et al., 1990; Liu and Specht, 1993; Donofrio, 1994; Rowin et al., 2001. 11.4. Clinical features The age of onset in the majority (90%) varies from 15 to 35 years with a median age of 20 years in MMA of upper limb and slightly older in MMA of lower limb Table 11.3 Geographic distribution of monomelic amyotrophy of lower limb A. Countries in Asia India: Prabhakar et al., 1981; Gourie-Devi et al., 1984a; Virmani and Mohan, 1985; Saha et al., 1997. Japan: Hamano et al., 1999. Korea: Kim et al., 1994. B. Countries outside Asia Austria: Willeit et al., 2001. Brazil: De Freitas and Nascimento, 2000. with a median age of 25 years (Hirayama et al., 1963; Sobue et al., 1978; Gourie-Devi et al., 1984a). In excep-tional cases the age at onset can be as early as 2 years and as late as 84 years, the older age at onset being more often noted in MMA of lower limb (Sobue et al., 1978; Serratrice et al., 1987; Felice et al., 2003). However, because the condition is so insidious in onset it can be difficult to determine the age at onset. There is remark-able gender preference, with men outnumbering women with a ratio varying from 3:1 to 20:1, with more men affected in MMA of lower limb compared to MMA of upper limb (Hirayama et al., 1963; Sobue et al., 1978; Prabhakar et al., 1981; Gourie-Devi et al., 1984a; Virmani and Mohan, 1985). The duration of illness at first consultation may vary from a few months to as long as 15 years, with a mean duration of 2.5 to 4.5 years (Hirayama et al., 1963; Prabhakar et al., 1981; Gourie-Devi et al., 1984a; De Freitas and Nascimento, 2000). France: Germany: Italy: Netherlands: Spain: USA: Nedelec et al., 1987; Serratrice et al., 1987. Munchau and Rosenkranz, 2000. Uncini et al., 1992; Di Muzio et al., 1994; Di Guglielmo et al., 1996. De Visser et al., 1988. Martinez et al., 1990. Riggs et al., 1984; Felice et al., 2003. 11.4.1. Clinical features of MMA of upper limb In monomelic amyotrophy of upper limb, the common initial symptoms are weakness and atrophy in the major-ity, followed by tremulousnesss of fingers. Coarse, intermittent nonrhythmic tremors of fingers present at rest, accentuated by outstretching of hands and on 210 M. GOURIE-DEVI voluntary action is present in 60 to 80% of patients (Hirayama et al., 1963; Gourie-Devi et al., 1984a). This feature has been observed in spinal muscular atrophy and the descriptive term minipolymyoclonus has been coined (Spiro, 1970). Minipolymyoclonus needs to be distinguished from tremors, which are generally rhyth-mic, and from fasciculations. Discharges by motor neu-rons innervating large territory of muscle are implicated in the causal mechanisms of these tremor-like move-ments, but probably not specific, and may be seen in hand weakness from most neuromuscular disorders. Fasciculations are commonly observed in atrophic muscles and also in the unaffected muscles in a few patients. Hirayama (1972) described “cold paresis,” an interesting phenomenon of aggravation of weakness on exposure to cold. Some of them also complain of stiff-ness of hands on dipping the hands in cold water, how-ever there was no clinical or electromyographic evidence of myotonia (Gourie-Devi et al., 1984a). In MMA of upper limb the distal muscles of hand and forearm are affected in more than 50% of patients, prox-imal muscles of shoulder and upper arm in 5–10% and diffuse involvement in 40% with the distal muscles more severely affected than proximal muscles. Small muscles of the hand, flexors and extensors of the wrist, chiefly C7-T1 spinal segments, are the most severely affected muscles (Figs. 11.1–11.3). Relative sparing of brachiora-dialis muscle among surrounding atrophic muscles (Fig. 11.2) is a characteristic feature of this disease (Hirayama et al., 1963). In the diffuse form with involve-ment of an entire upper limb, the additional muscles atro-phied are biceps, triceps, deltoid and scapular muscles (Compernolle, 1973; Thijsse, 1983; Gourie-Devi et al., 1984a). Unilateral atrophy of scapulohumeral muscles in C5–C6 myotomes (Fig. 11.4) was described by Kaeser (1983) from Switzerland and similar cases were observed by others (Gourie-Devi et al., 1984a; Virmani and Mohan, 1985; Amir et al. 1987; De Visser et al., 1988; Kao et al., 1993a). The pattern of muscles affected in our series of 89 patients (Gourie-Devi and Nalini, unpublished observations) is shown in Figure 11.5. 11.4.2. Clinical features of MMA of lower limb In MMA of lower limb, atrophy of the limb was noted by the patient because of pain on walking, and in nearly a third of the patients it was incidentally observed by a family member, friend or physician during consultation for unrelated illness (Prabhakar et al., 1981; Gourie-Devi et al., 1984a). Under these circumstances the precise age at onset and duration of illness may not be accurate. Muscle cramps and fasciculations have been observed in 20 to 30% of patients. Unilateral pes cavus may be a presenting feature (De Freitas and Nascimento, 2000). Unlike as in postpoliomyelitis progressive muscular atrophy there is no shortening of limb. Fig. 11.1. Mild atrophy of flexors of forearm of right upper limb best seen in semiprone position. MONOMELIC AMYOTROPHY OF UPPER OR LOWER LIMBS 211 Fig. 11.2. Atrophy of flexor and extensor muscles of right forearm with sparing of brachioradialis muscle and mild wasting of hand muscles. Fig. 11.3. Severe atrophy of thenar, hypothenar and interossei, particularly first dorsal interosseous muscle of right hand. Fig. 11.4. Severe wasting of left shoulder and upper arm muscles with normal forearm muscles. ... - tailieumienphi.vn
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