Authors: Mehreen Thayani (1Department of Neurology, Emory University, Atlanta GA, USA), H. A. Jinnah (1Department of Neurology, Emory University, Atlanta GA, USA; 2Department of Human Genetics, Emory University, Atlanta GA, USA; 3Department of Pediatrics, Emory University, Atlanta GA, USA)
Categories: Article
Source: Parkinsonism & related disorders
Authors: Mehreen Thayani, H. A. Jinnah
Cervical dystonia is defined by excessive contraction of muscles that produce abnormal postures and movements of the head, neck, and sometimes the shoulders. Many affected individuals also have pain, local muscle hypertrophy, and/or abnormally increased EMG activity. However, abnormal movements are considered the defining feature.
Three cases are described suggesting that some features of cervical dystonia may occur without abnormal movements. In these cases, the only clinical features are pain, local muscle hypertrophy, or abnormal EMG activity. These features may occur years before abnormal movements emerge, or they may occur coincidentally with dystonia affecting regions other than the neck. In some cases, some features associated with cervical dystonia may occur without any obvious abnormal movements.
Some symptoms of cervical dystonia may occur without abnormal movements of the head or neck. The purpose of this report is not to question current diagnostic criteria for cervical dystonia, but to call attention to a phenomenon that deserves further attention. Such cases may be considered to have a pro-dromal form of cervical dystonia or a formes fruste of cervical dystonia. Whatever diagnostic label is applied, the phenomenon is important to recognize, because symptoms may be readily alleviated with botulinum toxin.
A 50-year-old man noticed he could not keep his eyelids open. An ophthalmologist observed excessive blinking and spasms, and he was diagnosed blepharospasm. At age 51, his exam revealed increased blinking, pretarsal blepharospasm, and occasional spasms of the orbital orbicularis oculi. He also reported sensations of “pulling” in his neck, but no abnormal movements were evident in the head, neck, or shoulders. Blepharospasm was treated with onabotulinumtoxinA with good results. Over the next year, abnormal lower facial movements emerged, along with increased complaints of “pulling” sensations in the neck and increasing neck pain. He later reported “jerking” head movements that emerged only in the evening. At this point his neurological exam revealed blepharospasm and orofacial dystonia, but abnormal movements or postures were not evident in the head, neck, or shoulders. In the ensuing year, very subtle backward jerks of the head were observed rarely on exam, although blepharospasm remained the dominant problem. His treatment regimen was changed to cover blepharospasm along with neck muscles where he felt the most discomfort, predominantly the trapezius and levator scapulae on the left. Over the next 7 years he received injections every 10–12 weeks, with 90–95%% reductions in blepharospasm and 70–90% reductions in neck pain. This case illustrates blepharospasm with typical spreading to the lower face. Eventually, abnormal movements of the head emerged, indicating further spread to include cervical dystonia (CD); however, non-motor neck discomfort preceded overtly abnormal head movements by several years.
A 48-year-old woman developed slowly progressive hoarseness of her voice. An otolaryngologist diagnosed abductor laryngeal dystonia. At age 54, she developed very dry and scratchy feelings of her eyes, excessive blinking, and spasms of eye closure. An ophthalmologist diagnosed blepharospasm, suggesting spread of her dystonia from her larynx to the face. At age 55, she developed sensations of muscle tightness in the posterolateral neck and shoulders, worse on the left, especially in the evenings. She did not notice any abnormal postures or movements of the head, neck, or shoulders. The exam at this point revealed a very breathy voice with frequent voice breaks consistent with abductor spasmodic dysphonia. She had persistent tonic narrowing of the palpebral fissures with superimposed phasic spasms of the eyelids and other facial muscles characteristic of craniofacial dystonia. There were no abnormal movements of the head, neck, or shoulders. There was no obvious neck or shoulder muscle hypertrophy. However, palpation revealed tenseness and tenderness of multiple muscles in the posterolateral neck and trapezius, especially on the left. EMG revealed abnormally high activity in multiple posterolateral neck muscles, even when fully relaxed. She was treated with incobotulinumtoxinA in the upper face and posterolateral neck regions with substantial benefits. Over a 10-year period when she received repeated treatments every 10–12 weeks, she regularly reported 90–95%% reductions in eye discomfort and 70–90% reductions in neck pain and neck muscle tension. Now more than 10 years following development of laryngeal dystonia, she has so far not yet developed any abnormal postures or movements of the head, neck, or shoulders. This case illustrates spread of laryngeal dystonia to the face. Her neck symptoms and the EMG findings suggest possible spread to the neck too, but overtly abnormal movements required for the diagnosis of CD have not yet emerged.
A 38-year-old woman developed pain and feelings of muscle tightness in the left neck and shoulder region gradually over a period of several days. She never noticed any abnormal movements of the head, neck, or shoulders. There was no history of preceding trauma, migraine headaches, or features suggestive of a neuromuscular or orthopedic cause. An extensive workup was unrevealing, including imaging of the head, neck, and shoulders. Her pain persisted despite treatment with physical therapy, acupuncture, muscle relaxants, and oral medications. At age 50, the neurological exam revealed no abnormal postures or movements of the head, neck, or shoulders. There were no restrictions to head or neck mobility. However, there was a visible and palpable area of focal hypertrophy in the region of the posterolateral left neck and left trapezius. This region also was very tense and hard to palpation. EMG revealed marked overactivity in the region of the left splenius capitus and cervicus, levator scapula, and especially the trapezius. EMG activity persisted even at rest, and normal activity was found elsewhere. She was treated with rimabotulinumtoxinB and reported substantial reductions in pain and muscle tension beginning several days after injections and lasting for nearly 3 months. Over the next 8 years, she regularly reported 70–90% reductions in pain and muscle tension but required treatment approximately every 12 weeks when symptoms returned. She never developed any abnormal postures or movements in any region of her body. This case cannot be diagnosed with CD because of the absence of abnormal movements. However, her non-motor symptoms were considered to be potentially related to dystonic muscle contractions based on focal hypertrophy, EMG findings, and response to BoNT injections.
Cervical dystonia is defined by excessive contraction of muscles resulting in abnormal postures and movements of the head, neck, and sometimes the shoulders.^1–3^ Often this excessive muscle activity can be detected via EMG.^4, 5^ Many individuals also develop associated features of muscle hypertrophy or pain in the affected regions.^6–8^ However, abnormal postures or movements are required for diagnosis of CD. The other symptoms and signs (pain, muscle hypertrophy, EMG abnormality) are only supportive features. The cases presented here suggest that supportive features of CD may occur without overtly abnormal movements of the head or neck. In these cases, the only features were local pain, muscle hypertrophy, or abnormal EMG activity. These cases might be considered to have a pro-dromal form of CD (when they later develop overt abnormal movements) or a forme fruste of CD (when they do not have the typical features required for diagnosis).
Case 1 illustrates a well-recognized scenario, which involves spread of focal blepharospasm to segmental craniocervical dystonia.^9–12^ However, symptoms of pain and sensations of pulling in the neck emerged long before overt abnormal movements could be appreciated by the patient or detected by an examiner. In this case, it is reasonable to suspect that the non-motor neck symptoms preceding his abnormal head movements reflected the same underlying process. Case 2 illustrates a similar problem, except that overt abnormal movements of the head or neck have not yet emerged. Instead, underlying abnormal cervical muscle activity could be detected by EMG. These EMG findings are not diagnostic of CD, since they can be found in other situations. However, the EMG findings are consistent with numerous prior studies of dystonia that have revealed EMG evidence of excessive muscle activity in areas that do not show overt abnormal movements.^13, 14^
Case 3 did not have overt dystonic movements in any region of her body, so it is difficult to posit spread of dystonia from one region to another. However, the possibility of dystonic muscle contractions causing the non-motor symptoms is very likely in Case 1 and suspected in Case 2. Case 3 raises the question regarding whether CD or troublesome symptoms of CD may occur with non-motor symptoms but without the abnormal movements required for formal diagnosis of CD. The possibility of CD is raised by several features including focal muscle hypertrophy, pain, and EMG evidence of muscle overactivity. While none of these features are diagnostic for CD, their existence should at least raise suspicion, especially since a workup for other causes was unrevealing. Her symptoms also are not consistent with related conditions, such as fibromyalgia, which is more diffuse and does not reliably respond to BoNT. The location of her problem also is not typical of stiff-person syndrome or related neuromuscular conditions, although it is quite commonly affected in CD. Indeed, Case 3 is consistent with early observational studies of CD that described neck pain or other discomforting sensations preceded abnormal movements in up to 30% of cases, sometimes by many years, for both idiopathic CD^15, 16^ and tardive CD.^17^
The cases presented here are probably not uncommon. They not presented to question existing diagnostic criteria for CD. Instead, they are presented to raise questions regarding whether typical non-motor CD symptoms may reflect a pro-dromal form of CD or a forme fruste of CD. These cases cannot be considered “subclinical” forms of CD, in view of the reports of pain, examination features of focal hypertrophy, and EMG findings. Terms such as pro-dromal and formes fruste are not part of the typical lexicon for CD. However, they should be considered, to avoid unnecessary diagnostic testing and medical or surgical treatments during the years before the diagnosis becomes more evident. An obvious explanation for the discomfort in cases like this becomes obvious only when overtly abnormal movements emerge.
In addition to the circumstances noted above, CD without overtly abnormal movements may also occur in other situations. Examples may include individuals with prominent worsening in the evening (so that abnormal movements are not seen during daytime clinic visits), individuals with balanced over-contraction of antagonistic muscles (such as both levator scapulae), individuals with very deep muscles not readily examined (such as prevertebral longus colli), or individuals where symptoms of CD are missed because dystonia is more severe in some other region of the body. When overtly abnormal movements of typical CD are lacking, some helpful clues include unexplained neck pain with local muscle hypertrophy or abnormal EMG activity.
Neck pain and cervicogenic headaches are very common, and many affected individuals describe focal areas of tenderness, tightness, or “knots”. These conditions are not considered to be subtypes of dystonia because of the lack of abnormal movement, and various terms are sometimes used to describe them such as fibromyalgia or muscle tension or trigger point. Interestingly, a recent study of 58 individuals diagnosed with both migraine and CD revealed that headaches preceded overt movements of CD in 78%, by a mean of 16 years,^18^ raising questions regarding whether some types of headache may be pro-dromal sign of CD. Discriminating pro-dromal CD dystonia or its formes frustes from other conditions is important, because the associated discomfort can be readily treated with botulinum toxin, avoiding unnecessary diagnostic testing or surgical procedures.^18^