Cervical palsy presenting with inability to hold the head erect or to lift the head from the pillow (“hanging, or dropped, head” syndrome, “camptocormia”) This is caused by weakness of the posterior neck muscles and of the sternocleidomastoids and other anterior neck muscles. In advanced forms of this syndrome, the head may hang with chin on chest unless the patient holds it up with the hands. There may be difficulty differentiating the condition from a dystonic anterocollis; in the latter there is palpable tonic spasm of the sternomastoid and posterior neck muscles. A pattern of neck and spine extensor weakness also occurs in advanced Parkinson disease. A common error in all these cases is to attribute the problem to structural disease of the cervical spine.
This topographic pattern occurs most often in idiopathic polymyositis and IBM, in which cases it is often combined with mild dysphagia, dysphonia, and weakness of girdle muscles. The same symptom may be a feature of motor neuron disease and is infrequently the presenting feature of that process. Myasthenic patients commonly complain of an inability to hold up their heads late in the day; both flexors and extensors of the neck are found to be weak. Occasionally, this pattern of weakness is observed in patients with nemaline rod myopathy. Cases of hanging head have appeared many years after local radiation of the neck and thorax for Hodgkin disease as described by Rowin and colleagues and with syringomyelia (Nalini and Ravishankar).
There is, in addition, a poorly characterized local myopathic process isolated to the cervical paraspinal muscles, which has no distinguishing histopathologic or histochemical features but has accounted for many of the cases of neck extensor weakness that we have encountered. The condition is observed in elderly persons, in some series mainly men, but our experience has included as many women. There is severe but relatively nonprogressive weakness of the neck extensors and only mild weakness of shoulder girdle and proximal arm muscles. Katz and colleagues have suggested the designation “isolated neck extensor myopathy” in preference to dropped head syndrome. What has been referred to as a bent spine syndrome (for which the term camptocormia is also used) is probably the same entity and may follow after years of the condition affecting the neck, or it may surface independently. These conditions of cervical weakness are reviewed by Umapathi and colleagues and by Azher and Jankovic. Several recent series have suggested that mutations in RYR1 that encode for ryanodine receptor may be a common cause of late onset axial myopathy and neck extensor weakness-bent spine syndrome (Løseth et al). Mutations in RYR1 are more commonly associated with the central core congenital myopathy or malignant hyperthermia as noted in a later section, “Central Core Myopathy (RYR1 Mutation).”
The major types of progressive muscular dystrophies, when advanced, usually affect the anterior neck muscles severely. Syringomyelia, spinal accessory neuropathy, some form of meningoradiculitis, and loss of anterior horn cells in conjunction with systemic lymphoma or carcinoma may differentially paralyze the various neck muscles.