PRACTICAL IMPLICATIONS
Head drop in myasthenia gravis may be a triggering factor for new daily persistent headache-like presentation. Possibility of cervicogenic basis should be considered for the persistence of headache.
New daily persistent headache (NDPH) is a chronic primary headache disorder with a characteristic temporal profile of sudden onset headache that persists daily from the onset.1,2 The core diagnostic criteria for NDPH include clearly remembered onset of headache and persistence of daily headaches for >3 months3 Several predisposing factors including infectious illness, stressful life events, and surgical procedures have been described in approximately half the patients; however, the precise pathogenesis is not understood.1,2,4 This report describes NDPH-like presentation triggered by head drop in a patient with acute onset of myasthenia gravis (MG). The daily headaches persisted despite spontaneous remission of MG. Later, the patient developed recurrence of myasthenic symptoms, and the headache remitted after pyridostigmine was started.
Case
A 70-year-old man, janitor by occupation, while scrubbing the floor 4 months before his clinic visit, developed sudden severe headache from the midforehead to the back of the head along with an inability to hold his head up. There was no nausea, vomiting, dizziness, confusion, vision changes, or extremity weakness. The head drop improved after rest but recurred whenever he was up and about. In the following days, he developed difficulty in chewing and swallowing, slurred speech, drooling, double vision, and drooping of eyelids. His symptoms progressed for 2–3 weeks, plateaued for 2 months, and then improved with complete resolution within 3 months of onset. Meanwhile, he continued to have severe daily headaches and dull neck pain. The headache was not positional. He denied associated nausea, vomiting, photophobia, phonophobia, or history of headaches. Physical examination revealed normal neck muscle strength and range of movement, and no neurologic deficit. Laboratory blood work was normal for blood counts, chemistry, erythrocyte sedimentation rate, C-reactive protein, thyroid function, and antinuclear antibody. Acetylcholine receptor antibody level was 2.97 nMol/L (normal <0.03), and striational antibody titer was 1:320 (normal <1:40). MRI of the cervical spine showed moderate cervical stenosis from C4 to C7. Brain MRI without and with contrast and CT scan of the chest with contrast were normal.
He was prescribed topiramate as empiric preventive treatment for daily headaches. Treatment with sumatriptan was ineffective. On follow-up, the headaches were unchanged in pattern and severity. Four months after his initial clinic visit, mild ptosis and dysphagia recurred. Treatment with pyridostigmine achieved good control of these symptoms along with dramatic improvement in headaches. On follow-up, he reported intermittent dysphagia, was started on prednisone 15 mg daily, and later, maintained on 5 mg prednisone daily. Headache frequency at the 6-month follow-up averaged twice a month. Topiramate was discontinued, and he has had only occasional headaches during further follow-up for 1 year.
Discussion
Head drop is a well-known feature of generalized MG and may be the presenting feature.5 Our patient had unusual presentation with acute onset of isolated head drop and instantaneous severe headache that persisted despite spontaneous remission of MG-related symptoms including neck muscle weakness. The abrupt onset and unremitting daily headache from the beginning is commensurate with the diagnosis of NDPH.3 In this acute setting, secondary causes such as CSF leak and cervical arterial dissection merit consideration. CSF hypotension seems unlikely in this patient because of the absence of orthostatic headache and normal brain MRI with contrast. Although a cranial MR or CT angiogram was not performed, the clinical features in our patient do not suggest cervical artery dissection as a cause for his headache.
Cervicogenic factors such as cervical spine hypermobility and endotracheal intubation have been reported to predispose to NDPH.1 Improvement of headache after cervical-based management was observed in this category of patients.1,2 Although a clear cervicogenic trigger was noted in our patient, the mechanism for persistent headache and prompt improvement on initiation of pyridostigmine is uncertain. Some patients with NDPH may respond to corticosteroids6; however, this patient received prednisone after the headache had remitted. One may consider spontaneous remission as noted in some patients with NDPH4 or a placebo effect accompanying improved MG symptoms; however, the dramatic and sustained improvement favors response to pyridostigmine.
Cervicogenic headache is described as “headache caused by a disorder of the cervical spine and its component bony, disc and/or soft tissue elements.”3 The underlying mechanism involves the convergence and overlap of trigeminal and cervical nociceptive afferents in the trigemino-cervical complex.7 It is possible that in our patient, continued mild/subclinical neck muscle weakness and resultant stress on neck structures led to persistent excitation of the trigemino-cervical complex and improvement of neck muscle strength with pyridostigmine ameliorated the headache. In summary, this patient likely had cervicogenic basis for the NDPH-like presentation.
Study Funding
No targeted funding reported.
Disclosure
The author reports no disclosures relevant to the manuscript. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp.
Appendix Authors
Footnotes
Funding information and disclosures are provided at the end of the article. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp.
- Received March 27, 2020.
- Accepted August 7, 2020.
- © 2021 American Academy of Neurology
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