according to a new retrospective chart review.
“Future prospective studies are needed to better understand this disabling disorder,” wrote Randolph W. Evans, MD, of Baylor College of Medicine of Houston, and Dana P. Turner, PhD, of Massachusetts General Hospital and Harvard Medical School in Boston. Their study was published Oct. 28 in Headache.
To categorize the infrequently reported clinical features of NDPH, the researchers launched a retrospective study of patients who were provisionally diagnosed with NDPH by Dr. Evans at an outpatient clinic in Houston from Sept. 1, 2011, to Feb. 28, 2020. Of the 328 patients whose diagnosis ultimately matched the ICHD-3 criteria, the average age at onset was 40.3 years (range 12-87 years). Approximately 70% were White, and nearly 66% were women. Two hundred and sixty were diagnosed with the migraine phenotype and 68 were diagnosed with the tension-type phenotype.
Key features
The median duration of NDPH at the time of the initial consult with Dr. Evans was 0.7 years, and it was 1.9 years at the time of the last visit. Almost 33% of patients with the migraine phenotype had a history of episodic migraine compared with 16.2% with the tension-type phenotype. Headaches were side-locked unilateral in 8.5% (n = 28) of all patients, and 3.6% (n = 12) had a thunderclap onset.
The most common clinical features across all patients included noise sensitivity (72.1%), light sensitivity (71%), moderate pain at the time of initial consult (57.9%), pressure pain (54.9%), and throbbing pain (50.9%). Nausea was reported in 157 patients and vomiting was reported in 48 patients, all of whom were in the migraine phenotype group. Thunderclap onset was far more prevalent in the migraine phenotype group (11 patients) compared with the tension-type phenotype group (1 patient), as was vertigo (19 patients compared with 1) and visual aura (21 compared with 0).
The top precipitating factors across all patients included stressful life events (20.4%), an antecedent upper respiratory infection or flu-like illness (10.1%), and antecedent extracranial surgery (1.5%). Exacerbating or aggravating factors were far more prevalent in the migraine phenotype group compared with the tension-type phenotype group, with stress (14.6% vs. 5.9%), bright or flashing light (10.4% vs. 1.5%), loud noise (8.5% vs. 0%), and lack of sleep (6.5% vs. 4.4%) leading the way.
The months with the most onsets were June (8.5%), January (7.6%), and February (7.6%); there was no clear seasonal or cyclical variation. The most common prognostic type across all patients was persisting (refractory) at 93%, followed by remitting (self-limiting) at 4.3% and relapsing-remitting at 2.7%.
Unlocking a medical mystery
“This is the largest case review study ever published on NDPH, especially because most people think it’s a fairly rare disorder when it’s actually not,” Herbert G. Markley, MD, of the New England Regional Headache Center in Worcester, Mass., said in an interview.
“The thing people need to understand is that they may have a lot of these patients in their practice and not realize it,” he added. “They keep trying one medication after another, and the patients are giving up, and the doctors are giving up. It’s terrible. We don’t know what causes it, and we don’t know how to treat it. It’s one of the biggest mysteries left in medical science.”
“My idea about this condition, and this is shared by others, is that NDPH is not a diagnosis that describes a cohesive group of patients but rather a group of people who share certain features,” Morris Levin, MD, director of the Headache Center at the University of California, San Francisco, said in an interview. “And they would be better served if this diagnosis was split into different categories.”
Dr. Morris Levin
While praising Dr. Evans and Dr. Turner for their categorization and classification work, Dr. Levin asked, “Let’s say you diagnose someone with NDPH; does that in any way help you with management of this person? The answer is no. Some might say, ‘If you put the patients in the migraine phenotype group, then you can use migraine treatments.’ My point would be: then call it migraine.
“I believe another way to approach NDPH might be to create subcategories of migraine and tension-type headaches,” he added. “A migraine that is either intermittent or nonexistent suddenly becomes daily. That could be a subcategory; rather than being called NDPH, call it ‘new persistent chronic migraine.’ Or ‘new persistent chronic tension-type headache.’ Perhaps that would serve us better in terms of grasping the underlying mechanisms and the best treatment for these patients.”
Along the same lines, Dr. Markley echoed Dr. Evans’ call for more prospective studies and more research on possible medication, hoping to fuel further understanding of this debilitating disorder.
“I think this will be a landmark study for people to look back on,” he said, “especially for anyone going into the headache specialty who has never heard of this type of headache and keeps wondering why they can’t help certain patients, no matter how many medications they try.”
The authors acknowledged their study’s limitations, including its single-center nature and the data abstraction process being performed by just one person. They added, however, that Dr. Evans is a “very experienced researcher with more than 30 years of experience in headache medicine who was abstracting his own patients, data that were very familiar to him.”
Dr. Evans and Dr. Turner declared no potential conflicts of interest.