Dropped head syndrome (DHS) is an uncommon clinical syndrome, which requires complex diagnostic evaluation. A variety of neuromuscular and neurodegenerative disease can produce weakness of head extensor muscles and consequently lead to head drop. Inflammatory myopathy has been described as a cause of DHS, however head drop has only exceptionally been reported as being the presenting symptom of this disorder. We describe an original case of DHS as an initial and predominant manifestation of inflammatory myopathy with histopathological features of polymyositis, with an excellent response to immunosuppressive treatment.
- muscle disease
- neuromuscular disease
- musculoskeletal syndromes
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Pronounced weakness of the paravertebral cervical extensor muscles leads to head drop, a clinical syndrome characterised by abnormal and excessive cervical kyphosis or reducible ‘chin to chest’ deformity.
Dropped head syndrome (DHS) or ‘camptocephalia’ can be provoked by a variety of neuromuscular, neurodegenerative and traumatic disorders, and also occurs as an isolated disorder restricted to neck extensors without known underlying disease—‘isolated neck extensor myopathy’.
Inflammatory myopathies (IM) have been infrequently reported as cause of this highly disabling condition.
The purpose of this report is to describe an original case of DHS as an initial and predominant clinical manifestation of IM, probable polymyositis (PM) with excellent response to immunosuppressive therapy.
A 71-year-old woman with a history of arterial hypertension was referred for neurological consultation after she developed head drop. Difficulty extending her neck had begun insidiously and progressed gradually over next 5 months. She also had asthenia, anorexia with weight loss, but denied ocular or bulbar symptoms except mild swallowing difficulty. Moderate cachexia and marked cervical extensor weakness with complete head drop were visible on examination (figure 1A) The patient was unable to elevate her head against gravity, although head extension could be done passively without important movement restriction or pain. There was mild weakness of proximal muscles of upper limbs: shoulder abduction (Medical Research Council (MRC) scale 4/5), with normal strength in the remaining muscle groups of upper and lower extremities. She could stand up from sitting position repeatedly without evidence of muscle fatigability and there was no weakness of extraocular, facial or bulbar muscles. Muscle stretch reflexes were diffusely brisk, plantar responses were flexor and Hoffman sign was absent. There was mild weakness of proximal muscles of upper limbs.
MRI of the cervical spine revealed mild spondylitic changes without signs of spinal compression or foraminal stenosis.
Routine blood analysis demonstrated: serum creatine kinase level 1609 U/L, mild elevation of aspartate aminotransferase 87 UI/L and alanine aminotransferase 60 UI/L.
Nerve conduction studies and low-frequency repetitive nerve stimulation were normal. Needle electromyographic (EMG) examination revealed fibrillation potentials and positive sharp waves in several of the examined muscles, more abundant in bilateral deltoid, right biceps brachii and paravertebral thoracic muscles, with normal or myopathic (reduced duration, polyphasic) motor unit action potentials (MUAP). Full interference pattern was registered at submaximal effort in deltoid and brachial biceps muscles.
Urinalysis and thyroid function tests were normal. Serologic studies for antinuclear antibodies, antineutrophil cytoplasmic antibodies, rheumatoid factor, antiacetylcholine receptor (Ach-R) antibodies and myositis-specific antibodies were normal.
Thoracic–abdominal–pelvic CT was unremarkable.
Biopsy of the left brachial biceps demonstrated marked variability of myofibre size, myofibre necrosis and regeneration, perivascular and endomysial lymphocytic cell infiltration and myofibre surface expression of major histocompatibility-class 1 antigen. These biopsy findings were compatible with a diagnosis of IM, probable PM (figure 2A,B).
Motor neuron disease: combined upper and lower motor neuron signs and symptoms are typical in this disorder. Asymmetric limb weakness is the most common presentation, with relatively predictable pattern of progression leading to quadriparesis and ultimately bulbar involvement, although initial manifestation can occur in any body segment; axial onset manifested by head drop is uncommon. EMG detects neurogenic changes. Muscle biopsy, although not a routine diagnostic procedure for motor neuron disease, demonstrates neurogenic features of chronic denervation with reinnervation.
Myasthenia gravis: isolated head drop can rarely occur as initial presentation of myasthenia gravis and is usually accompanied by ocular and bulbar signs with characteristic diurnal variation and fatigability after exercise. In suspected cases, positivity of either Ach-R or muscle-specific kinase antibodies and electrodiagnostic studies (repetitive nerve stimulation and measure of neuromuscular jitter) are diagnostic.
Inflammatory or degenerative myopathies: several other myopathies can give rise to head drop. The type of onset, tempo of progression, family history, as well as biopsy or genetic testing can help distinguish them from polymyositis.
The clinical features, together with results of the muscle biopsy, showing the presence of perivascular and endomysial inflammation, muscle fibre necrosis and absence of rimmed vacuoles, inclusions and mitochondrial abnormalities, strongly suggest PM and not an inclusion body myositis (IBM). Moreover, the favourable response after corticosteroid treatment never occurs in IBM.
The presence of considerable inflammation in the muscle biopsy makes necrotising autoimmune myopathy (NAM) unlikely. No statin use, absence of SRP antibodies or malignancy would provide some additional evidence against NAM.
Isolated neck extensor myopathy: this disorder develops over weeks to months, without further progression, and in some cases improves spontaneously. Weakness is restricted to neck extensors. Laboratory study results, including muscle biopsy are nonspecific, without findings of inflammation.
Oral corticoisteroids at doses of 1 mg/kg/day associated with mycophenolate sodium 360 mg two times per day were started with slowly tapering of corticoids over 1 year.
Outcome and follow-up
After initiating treatment, she experienced progressive recovery of the neck strength, accompanied by improvement of general appearance and weight gain. After 6 months, she could hold her head upright without limitation (figure 1B). Three years after initiation of treatment, she is stable without any signs of progression.
Pronounced weakness of neck extensor muscles can be part of a variety of neuromuscular diseases, although it infrequently occurs as the sole or predominant clinical manifestation of any individual disorder.1
The differential diagnosis of DHS is vast and complex. According to a recent review, more than two-thirds of all cases with DHS were caused by four etiologies: isolated neck extensor myopathy was the most common, followed by Parkinson disease, myasthenia gravis and amyotrophic lateral sclerosis. In the remaining cases, DHS was attributed to 17 different pathologies.1
IMs are heterogeneous group of systemic diseases which principally affect skeletal muscles, even though non-specific systemic signs or extraskeletal involvement can be present. Based on clinical features, autoantibody profile and histopathological findings, the four major categories of IM are dermatomyositis, PM, NAM and sporadic IBM.
PM typically presents with proximal limb or truncal muscle weakness without skin rash that develops insidiously over weeks to months.2 Involvement of neck flexor muscles is commonly described during the evolution, but neck extensors are usually spared. This feature probably explains why PM has only exceptionally been described as a cause of DHS.3–10
There are several case reports of DHS due to focal myositis of cervical extensor muscles.8 Some patients had muscle biopsies that demonstrated severe inflammatory infiltration and responded favourably with immunosuppressive treatment.8 9 It is unclear if these cases are a separate nosological entity or represent a manifestation of polymyositis restricted to neck extensors muscles. In our patient, the pathological process was more extensive as there was electrophysiological evidence of an active inflammatory process, also observed in muscle biopsy, in clinically unaffected muscle groups.
In patient with PM presenting as DHS, the diagnostic process requires exclusion of other conditions, including: motor neuron disease, myasthenia gravis, mitochondrial and other rare hereditary myopathies. In patients with DHS, significant increase of serum CK, characteristic EMG features (fibrillation potentials, sharp waves and polyphasic short duration low amplitude or myopathic MUAP), normal repetitive nerve stimulation and absence of anti Ach-R antibodies can help exclude the most frequent mimics.
Muscle biopsy is needed for definitive diagnosis, as it helps to differentiate IM subtypes and distinguish them from non-IM.
Though histopathological changes are not pathognomonic and similar features can be seen insporadic IBM or muscular dystrophies, the overall clinical context and excellent response to immunosuppressive treatment strongly supports PM in our patient.
MRI of skeletal muscle can be helpful and has become recently a routine diagnostic tool which increases diagnostic accuracy, identifies suitable sites for biopsy or sometimes even monitors treatment response.11
Early diagnosis, prompt initiation of immunosuppressive treatment and the lack of significant muscle atrophy, fibrosis or long-standing disease were probable significant factors to the favourable outcome in this case. This highlights the importance of avoiding delay in the evaluation and treatment.
To the best of our knowledge, this is the third case of DHS as a presenting or predominant manifestation of clinically and histopathogically defined PM.6 7 In the two cases described previously, there was concurrent significant proximal upper limb weakness, while our patient had prominent head drop with only mild shoulder weakness.
PM should be considered in the differential diagnosis of DHS as these patients can have favourable response and improve significantly with immunosuppressive therapy.
Dropped head syndrome is an uncommon and highly disabling condition with a broad differential diagnosis.
Inflammatory myopathies usually present with symmetric proximal limb or truncal weakness but exceptionally can affect neck extensor muscles leading to head drop.
Inflammatory myopathies should be considered in cases with dropped head because immunosuppressive treatment can result in a favourable outcome.
Contributors TI is the principal author of the manuscript, responsible for the patient during hospitalisation and most part of editing. PDG was responsible for follow up and editing of 'case presentation'. MOP analysed the muscle biopsy, participated in editing of the hystopahological findings and discussion. FMM did the electrophysiological studies, performed muscle biopsy and was responsable for reviewing the work in progress and correction of the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.