Turtle headache is a subtype of the broader category of hypnic headache. This condition is a rare, episodic headache syndrome first described in late 1980. Hypnic headaches can occur as either a primary headache disorder or potentially secondary to a malignant process. It also has the names "clock-wise" headache or an "alarm clock" headache due to its clinical features. It characteristically presents as a strictly sleep-associated headache with a repetitive pattern in the sense that it occurs at the same time every night. According to the ICHD-3 criteria, attacks have to occur on at least 10 days a month for greater than 3 months and last for 15 minutes up to 4 hours after waking. Many patients report some motor activity during headache attacks such as reading or eating. Restlessness or autonomic symptoms, which are characteristic of cluster headaches, are not observed with hypnic headaches. Most patients report moderate pain that can be either bilateral or unilateral. There may be some underlying association between migraines and hypnic headaches, but most individuals had their last migraine attack years before the presentation of the hypnic headache. As mentioned previously, the turtle headache is a small subtype of hypnic headaches. Not much is known regarding this type of headache, but it typically occurs in the morning after awakening and after going back to sleep. It is usually bilateral and occurs when an individual retracts his/her head under the blankets, like a turtle retreating into its shell.
The etiology of turtle headache is unknown but is suspected to be due to gray matter volume changes in the posterior hypothalamus, which is the biological clock of the human body. There have been some studies about the volume of the hypothalamus as a diagnostic biomarker of chronic migraine. While not specific to turtle or hypnic headache, this can play an important role in solidifying the etiology of these headaches. A recent study examined this relationship and found evidence of functional connectivity and structural plasticity within the hypothalamus in concordance with the pathogenesis of migraines. Another study compared hypnic headaches and cluster headaches, which showed decreased and increased gray matter volume, respectively, in the posterior hypothalamus. In terms of turtle headache, There is not much known about the pathophysiology. While changes in the hypothalamus are one of the suspected theories, so is the role of hypoxia. Studies have demonstrated a possible link between hypoxia, migraine, and cluster headache, but the exact mechanism of this is not yet known.
In terms of hypnic headaches in general, they typically appear after the age of 50 years old, but there have been rare reports in patients as young as 8 years old. There is a slight female predominance in terms of these headaches with a ratio of about 3 to 2. The actual incidence and prevalence of hypnic headaches are not known because it is likely underdiagnosed. The same goes for turtle headaches because there is so little information about them that patients are likely not getting diagnosed with them in the first place. There have been no reported familial cases nor is the frequency of the condition known. The majority of why all of this information is so obscure and unknown is because of the lack of knowledge in terms of diagnosis. Many patients who may suffer from turtle headaches or other forms of hypnic headaches never get the exact diagnosis, and thus, the statistics behind the condition remain a mystery.
As mentioned already, there is not much data regarding hypnic headaches in general, and there is even less available about the pathophysiology of turtle headaches. There are theories that hypoxia is a cause of the headache based on the premise that the headache occurs when individuals pull the blanket over their heads into an environment with less oxygen. There are several reasons why this may play an essential role in determining the exact pathophysiology behind turtle headaches. High-altitude headache has been well studied and reportedly occurs in almost 80% of individuals who ascend to heights above 3000 meters. Hypoxia has been found to cause cerebral vasodilation, which results in increased capillary pressure and edema, leading towards the symptoms of a headache. Cortical spreading depression is known to play a role in the pathogenesis of migraines. There have been studies demonstrating that this phenomenon is inducible by hypoxia. Finally, there are suspicions that metabolic failure in the setting of deficient mitochondrial energy metabolism might have a role in the pathogenesis of headaches. This failure is present in the setting of hypoxia in between migraine attacks and may sensitize migraine patients to hypoxia.
When obtaining a history from these patients, they will typically endorse recurrent episodes of throbbing or sometimes dull head pain that occurs only during sleep and awakens them from sleep. They will state that they frequently occur, sometimes more than ten times per month and will last upwards of fifteen minutes when they awaken the patient. Some patients will endorse migraine-like symptoms, including nausea and vomiting, as well as photophobia and phonophobia. Others will suffer from autonomic features such as rhinorrhea or lacrimation. The physical exam is generally benign in these patients. It merits noting that any abnormal examination should have a workup and further investigation to rule out brain tumors, which can cause individuals to awaken early due to headaches.
Diagnosis of this headache is almost entirely dependent on history, taking revealing a headache that occurs during sleep and causes awakening, typically in a middle-aged adult. It is important to rule out other primary or secondary headaches causing nocturnal attacks. Regarding turtle headaches specifically, individuals will have a pattern where the headache occurs after awakening and then attempting to go back to sleep by pulling the blanket over his/her head. Furthermore, neuroimaging (either in the form of a CT scan of the brain or MRI of the brain) should be obtained in individuals with a new or nocturnal headache to rule out an intracranial mass as the cause. No lab work can assist in the evaluation of these headaches.
The basis of treatment for hypnic headaches is typically on anecdotal evidence. There are no clear-cut studies or answers, and a multitude of medications and interventions have been tried, including oxygen inhalation. Usually, the initial management of this condition begins with caffeine and indomethacin. Melatonin and flunarizine have been effective in a few patients. If those are unsuccessful, lithium has been shown to provide benefit, but it comes with lots of side effects both in the short and long term including nausea, tremor, and kidney/liver dysfunction.
The differential diagnosis for turtle headaches is broad due to the "alarm clock" nature and presentation associated with sleep. Some of the other conditions that can potentially mimic turtle or hypnic headaches include migraine or cluster headaches, episodic paroxysmal hemicrania, medication overuse headache, nocturnal seizure with postictal headache, obstructive sleep apnea presenting with headache, nocturnal hypertension, pheochromocytoma, temporal arteritis or intracranial mass. Exploding head syndrome is a unique but uncommon condition that can be mistaken for hypnic or turtle headaches. These patients have a sensation of an explosive noise in their head that causes them to wake up, but there is no actual pain associated with it. Attacks of this nature tend to occur during transitions from wakefulness to sleep.
Turtle and hypnic headaches can last for years. Fortunately, a large portion of patients who suffer from this condition does well with treatment. A systematic review identified 70 plus patients with hypnic headaches who had follow-up ranging from six months to five years. This study found that 47% of patients had no remission of headaches. 43% had remission after undergoing treatment. 7% had a relapse after remission, and 3% had spontaneous remission. No studies have specifically looked at turtle headaches.
There are no significant complications with turtle headaches. A majority of patients, in general, obtain relief after the treatment. The debilitating effects of the headache are limited and are addressable by treating the headache.
Headaches are a common presentation in clinical practice and for the most part, are encountered by the nurse practitioner, pharmacist, and the primary care provider. However, not only are there many different types of headaches, but in some cases, the cause may be something serious like a bleed in the brain or a tumor. Thus, headache management is best with an interprofessional team.
While the general practitioners may not be aware of all types of headaches, the key is to obtain a specialist referral when the diagnosis is unknown or is atypical. The nurse practitioner or primary care physician should not initiate complex treatments for a headache until there is confirmation that there is no serious underlying pathology.
Turtle headaches can be complicated to diagnose. They are highly underdiagnosed. Individuals who suffer from hypnic headaches, the broader, "alarm clock" style headaches that encompass turtle headaches are also challenging to diagnose. It is crucial for clinicians evaluating headache patients to take a detailed and complete history as that will be where the answer lies. It is also essential to rule out any significant secondary causes of the headaches, especially in the setting of an abnormal neurological exam. The pharmacist should provide patient education regarding the different types of headaches. Simply offering an NSAID is not always the right approach; many of these patients can benefit from a headache specialist consultation. Nursing staff can assist in evaluating treatment compliance and success, as well as reporting adverse medication events to the pharmacist or physician.
Long-term relief is attainable but requires an accurate diagnosis to attempt appropriate treatments.
Patients with headaches need long term monitoring to ensure that the treatment is working. Headaches may be benign but can seriously affect the quality of life. Hence, a mental health nurse should consult the patient is there is evidence of anxiety or depression. Only with an interprofessional team approach can there be a reduction in the morbidity of headaches. [Level V]
If properly diagnosed, most headaches have a good outcome, but relapses are not uncommon.
|||Holle D,Naegel S,Obermann M, Pathophysiology of hypnic headache. Cephalalgia : an international journal of headache. 2014 Sep; [PubMed PMID: 24875926]|
|||Suzuki N, [New international classification of headache disorders (ICHD-II)]. Rinsho shinkeigaku = Clinical neurology. 2004 Nov; [PubMed PMID: 15651338]|
|||Bourgeais-Rambur L,Beynac L,Villanueva L, [Brain network dysfunctions as substrates of primary headaches]. Biologie aujourd'hui. 2019; [PubMed PMID: 31274102]|
|||Chen Z,Chen X,Liu M,Ma L,Yu S, Volume of Hypothalamus as a Diagnostic Biomarker of Chronic Migraine. Frontiers in neurology. 2019; [PubMed PMID: 31244765]|
|||May A,Ashburner J,Büchel C,McGonigle DJ,Friston KJ,Frackowiak RS,Goadsby PJ, Correlation between structural and functional changes in brain in an idiopathic headache syndrome. Nature medicine. 1999 Jul; [PubMed PMID: 10395332]|
|||Britze J,Arngrim N,Schytz HW,Ashina M, Hypoxic mechanisms in primary headaches. Cephalalgia : an international journal of headache. 2017 Apr; [PubMed PMID: 27146279]|
|||Holle D,Naegel S,Obermann M, Hypnic headache. Cephalalgia : an international journal of headache. 2013 Dec; [PubMed PMID: 23832130]|
|||Carod-Artal FJ, High-altitude headache and acute mountain sickness. Neurologia (Barcelona, Spain). 2014 Nov-Dec; [PubMed PMID: 22703629]|
|||Somjen GG,Aitken PG,Czéh GL,Herreras O,Jing J,Young JN, Mechanism of spreading depression: a review of recent findings and a hypothesis. Canadian journal of physiology and pharmacology. 1992; [PubMed PMID: 1295674]|
|||Paemeleire K,Schoenen J, (31) P-MRS in migraine: fallen through the cracks. Headache. 2013 Apr; [PubMed PMID: 23557159]|
|||Lanteri-Minet M, Hypnic headache. Headache. 2014 Oct; [PubMed PMID: 25231430]|
|||Maheshwari PK,Pandey A, Unusual headaches. Annals of neurosciences. 2012 Oct; [PubMed PMID: 25205995]|
|||Schuster NM,Rapoport AM, New strategies for the treatment and prevention of primary headache disorders. Nature reviews. Neurology. 2016 Oct 27; [PubMed PMID: 27786243]|
|||Sharpless BA, Exploding head syndrome. Sleep medicine reviews. 2014 Dec; [PubMed PMID: 24703829]|
|||Liang JF,Wang SJ, Hypnic headache: a review of clinical features, therapeutic options and outcomes. Cephalalgia : an international journal of headache. 2014 Sep; [PubMed PMID: 24942086]|