More than Just a Headache

The Headache 

Despite the high prevalence of fifty percent among the global population, the common headache is often underestimated, under-recognized, and under-treated [1]. Different sensations associated with headaches have been experienced by most individuals throughout their lifetime; many report having various degrees of pressure that may be described as throbbing, constant, sharp, or dull [2]. While headaches can be easily dismissed by healthcare providers, it is essential to differentiate how common symptoms may be a sign of underlying issues. In order to understand how the symptoms of a headache are commonly misdiagnosed and may indicate potential underlying physiological issues, it is important to analyze the types of headaches, symptoms, potential effects on the brain over time, and treatment. 

Like other conditions, headaches can be broken down  into several subtypes. As many as 150 subtypes of headaches have been reported with primary and secondary headache subtypes being the two main types. Primary headaches include tension-type headaches, migraine headaches, cluster headaches, and daily persistent headaches while secondary headaches are considered to be a symptom of underlying issues [2]. Secondary headaches present themselves similarly to primary headaches. However, it is essential to consider the surrounding circumstance of the headache, as this context may signal certain underlying conditions including strokes, head injuries, seizures, or trigeminal neuralgia. Some symptoms for secondary headaches include fevers, a sudden or abrupt onset, any changes in typical pattern, progressive headaches, or if the pain was precipitated by sneezing, coughing, or exercise [3]. 

Neuroanatomy of the Headache

Many of us understand the symptoms that define a headache, but the explanation of how headaches cause pain is another story entirely. The fifth or trigeminal cranial nerve located in the skull is the largest of the cranial nerves, and is primarily responsible for providing motor and sensory information such as touch, pain, and temperature [4]. The trigeminal nerve is composed of three branches that conduct sensations from the scalp, blood vessels, meninges, face, mouth, neck, eyes, and throat [5]. In fact, our brain tissue lacks nerves that are pain sensitive, so the sensations and discomfort we feel during a headache are a manifestation of sensations that are sent through the trigeminal nerve to the thalamus [5]. The thalamus is the relay center of the brain and processes incoming information. From that point, information about touch, pain, temperature, and vibrations is sent to the brain. Through these processes, the brain is informed of these sensations that present as symptoms of headaches including pain and other associated symptoms such as vomiting, diarrhea, trouble with concentration, and more [5]. 

A Headache’s Effect on Neurological Health 

The World Health Organization (WHO) describes health as the “absence of disease or disability,” as well as “a complete physical, mental and social well-being” [6]. Similar to how other physiological diseases and disorders interrupt our quality of life, the headache has the capability to do the same. Recent research on impacted cognitive function, increased risk for brain lesions, and structural and functional changes in the brain suggests that the headache can have devastating consequences on our neurological health [7, 8]. Cognitive functions are composed of mental processes like perception, attention, memory, decision making, language comprehension, and other behaviors. When these processes are disrupted, they can impede our daily lives. 

Migraines are a type of headache that is characterized by recurrent headaches with varying levels of throbbing and pulsating pain, and is being investigated on how it can affect cognitive functions [9]. Functional imaging studies and neuropsychological standardized tests have demonstrated  that headaches may affect cognitive domains including reaction times, attention, memory, verbal skills, and executive functions [7]. Case control studies, case series, and population based cohort studies have shown an alteration in the connectivity in migraine patients and health controls have indicated  mild effects on basic attention, delayed verbal skills, and moderate effects on sustained attention, working memory, processing speed, and visuomotor scanning speed [7]. Another study on frontal lobe dysfunction in patients with chronic migraines notes impairment in problem solving and decision making in migraine patients vs healthy controls [10]. 

Neurological imaging techniques allow both researchers and physicians to explore and measure activities and structures of the brain. Due to techniques such as MRIs, different regions of the brain have been investigated in order to develop a deeper understanding of its function. An MRI, magnetic resonance imaging, is an imaging technique that uses magnetic fields and computer-generated radio waves to create detailed images of internal structures in the body [11]. The white matter of our brains is critical in the exchanging of information and communication between different parts of our brains, and it contains our nerve fibers and the extensions of our nerve cells [12]. A study concluded that there was significant risk for migraine sufferers as compared to non-sufferers in developing deep white matter lesions, a marker of cerebrovascular small vessel damage that is associated with vascular risk burden [8]. The mechanism by which migraines may affect risk of developing white matter lesions may be due to inflammation and issues with the blood brain barrier which affects cerebrovascular integrity within the brain [8]. 

The Headache’s Risk of Misdiagnosis 

The emergency department is home to countless cases each day, but this consistently heavy caseload makes the emergency room a high risk site for diagnostic errors [13]. With regard to acute cerebrovascular cases, there was a significant amount of misdiagnosis when the patient described having milder, nonspecific, or transient symptoms related to their headaches [13]. These patients presented with headache symptoms to the ER. Despite non-traumatic headaches being identified as the fifth leading cause for emergency department visits, with roughly 3.8 million visits per year, only a small percentage of patients were provided with imaging and concrete diagnoses [14]. 

Headaches are experienced by billions of people every year with some leading to debilitating symptoms, like migraines. It is essential to consider specific symptoms of headaches, as this context may signal certain underlying conditions. The neuroanatomy of our brain and other structures are evidently involved in the circuitry that headaches intersect with. Given the prevalence of diagnostic errors, it is important to advocate for our neurological health and understand how the headache can be more than just a headache. 

References:

1. World Health Organization. (2023). Headache disorders.  https://www.who.int/news-room/fact-sheets/detail/headache-disorders 

2. Cleveland Clinic. (n.d.). Headache: What it is, types, causes, symptoms & treatment. https://my.clevelandclinic.org/health/diseases/9639-headaches 

3. Do, T. P., Remmers, A., Schytz, H. W., Schankin, C., Nelson, S. E., Obermann, M., Hansen, J. M., Sinclair, A. J., Gantenbein, A. R., & Schoonman, G. G. (2018). Red and orange flags for secondary headaches in clinical practice. Neurology, 92(3), 134–144. https://doi.org/10.1212/wnl.0000000000006697 

4. Huff, T., Weisbrod, L. J., & Daly, D. T. (2022). Neuroanatomy, Cranial Nerve 5 (Trigeminal). In StatPearls. StatPearls Publishing. 

5. NIH. (2023, January 20). Headache. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/headache 

6. Amzat, J., & Razum, O. (2014). Health, disease, and illness as conceptual tools. Medical Sociology in Africa, 21–37. https://doi.org/10.1007/978-3-319-03986-2_2 

7. Vuralli, D., Ayata, C., & Bolay, H. (2018). Cognitive dysfunction and migraine. The journal of headache and pain, 19(1), 1-14.

8. Kruit, M. C., van Buchem, M. A., Launer, L. J., Terwindt, G. M., & Ferrari, M. D. (2010). Migraine is associated with an increased risk of deep white matter lesions, subclinical posterior circulation infarcts and brain iron accumulation: The population-based MRI camera study. Cephalalgia, 30(2), 129–136. https://doi.org/10.1111/j.1468-2982.2009.01904.x 

9. U.S. Department of Health and Human Services. (n.d.). Migraine. National Institute of Neurological Disorders and Stroke. https://www.ninds.nih.gov/health-information/disorders/migraine 

10. Mongini, F., Keller, R., Deregibus, A., Barbalonga, E., & Mongini, T. (2005). Frontal lobe dysfunction in patients with chronic migraine: A clinical–neuropsychological study. Psychiatry Research, 133(1), 101–106. https://doi.org/10.1016/j.psychres.2003.12.028

11. Mayo Foundation for Medical Education and Research. (2021, September 4). MRI. Mayo Clinic. Retrieved April 22, 2023, from https://www.mayoclinic.org/tests-procedures/mri/about/pac-20384768 

12. Sampaio-Baptista, C., & Johansen-Berg, H. (2017). White matter plasticity in the Adult Brain. Neuron, 96(6), 1239–1251. https://doi.org/10.1016/j.neuron.2017.11.026 

13. Tarnutzer, A. A., Lee, S.-H., Robinson, K. A., Wang, Z., Edlow, J. A., & Newman-Toker, D. E. (2017). Ed misdiagnosis of cerebrovascular events in the era of modern neuroimaging. Neurology, 88(15), 1468–1477. https://doi.org/10.1212/wnl.0000000000003814 

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