Vascular and Nonvascular Intracranial Causes of Orofacial Pain

Key Points

Intracranial causes of head, neck, and orofacial pain are numerous and may lead to disability or death if not managed expeditiously.

Rapid neurologic referral is warranted if patients have neurologic symptoms and findings.

Diagnoses of intracranial causes of head, neck, and orofacial pain rest primarily on a careful history, a healthy respect for “red flags,” and a willingness to rapidly evaluate further.

The SNOOP acronym is a useful mnemonic device for screening each patient’s situation.

If red flags disclose features consistent with a worrisome cause of pain, the patient should be referred to the appropriate medical specialist immediately for further management.

By their very nature, intracranial causes of orofacial pain are difficult to diagnose and do not usually offer pathognomonic features. These disorders may present in a nonspecific fashion with only mild to moderate pain but cause significant morbidity and, in some cases, mortality, if not detected and addressed appropriately and immediately. Thus, a careful analysis of the patient’s history with special emphasis on identification of red flags offers the best chance of appropriate testing, accurate diagnosis, and referral.

This chapter reviews intracranial sources of orofacial pain that may be life-threatening or impair a patient’s ability to accomplish independent activities of daily living (Box 4-1). The codes from The International Headache Society (IHS) and/or The International Classification of Diseases, Tenth (ICD-10) and Ninth (ICD-9) Editions are provided for each disorder.

Preliminary Investigation

Certain tissues are extremely sensitive,^1,2 while others are relatively insensitive to pain (Box 4-2). Because many intracranial structures are insensitive to pain, intracranial pathologic processes must be diagnosed according to other concomitant symptoms or historical facts (ie, red flags). Signs of extracranial pathology are more specific and correspond better with the location of the pain. The American Headache Society’s mnemonic tool, SNOOP, outlines aspects of a patient’s signs and symptoms that suggest the presence of a life-threatening disorder³ (Box 4-3).

Systemic symptoms or disease

Pain in the setting of systemic features such as fever, weight loss, arthralgias, stiff neck, or rash could represent the effects of meningoen-cephalitis, bacteremia/sepsis, collagen vascular diseases, or neoplastic processes. Preeexisting risk factors, such as human immunodeficiency virus (HIV), cancer, or chronic treatment with immunotherapy, predispose to serious disease. HIV is associated with both intracranial infections and cancer.

Neurologic signs or symptoms

Neurologic signs or symptoms, ranging from mild confusion or sedation to frank neurologic deficits such as aphasia or hemiparesis, typically herald more than a primary pain disorder. At times, migraine attacks can be accompanied by changes in cognition and word-finding abilities, hemisensory symptoms, visual field defects, or hemiparesis, but migraine is a diagnosis of exclusion (ie, you can diagnose migraine with specific criteria, but you must rule out concomitant secondary causes for the headache). Focal neurologic signs and symptoms such as hemiparesis, visual obscuration, diplopia, dizziness/vertigo, imbalance, or numbness warrant further investigation to rule out transient ischemic attack, stroke, a mass lesion, infiltrating lesions affecting multiple cranial nerves, arteriovenous malformations, thrombotic disease, or remote or immunologic effects of malignancy or focal/systemic infections.

Many primary headache syndromes may present with neurologic deficits that apparently stem from a particular focus. In basilar migraine, signs and symptoms appear to be produced by a focus of pathology in the distribution of the basilar artery and include imbalance, dizziness, vertigo, dysarthria, bilateral visual and sensory symptoms, and diplopia. In familial hemiplegic migraine, patients may present with stroke-like features of hemiparesis, dysarthria, and confusion. Obviously, these “benign” syndromes warrant urgent referral to rule out worrisome causes.

Onset sudden

A sudden-onset, severe, and generalized or localized headache must be considered serious until proven otherwise. The differential diagnosis for life-threatening acute-onset headaches must include subarachnoid or intracerebral hemorrhage, ruptured or unruptured aneurysm, cerebral venous thrombosis, carotid or vertebral artery dissection, cerebral infarction and hyper-tensive encephalopathy, ischemic stroke that can become hemorrhagic, and central nervous system infections.^4–6 Headaches precipitated by a cough, a sneeze, straining, or exertion, although possibly benign, warrant imaging of the brain to exclude an intracranial structural lesion, such as a tumor or Arnold-Chiari malformation. Headache that actually awakens a patient from sleep needs to be investigated further to rule out causes of increased intracranial pressure (eg, tumor, abscess, inflammatory processes, although migraineurs often awaken at 4 to 7 am with a headache in progress). Posttraumatic headache certainly may manifest without any identifiable pathology; however, fractures, various hematomas, or infection must be excluded. Positional headache starting or worsening upon standing, with improvement on lying down, can be a sign of a low-pressure headache due to a cerebrospinal fluid (CSF) leak. Headache upon lying down can be due to increased intracranial pressure related to an intracranial mass. Headaches presenting only in the morning may be associated with obstructive sleep apnea, medication overuse, brain tumor, or oral parafunctional habits.

Onset after age 40 years

In patients older than 40 years, new-onset and/ or progressive or changing headaches warrant evaluation. Migraines may begin at any age, but the vast majority of individuals will have onset by the time they are 30 years old. Headache in older patients with no prior history is more likely due to tumor or vascular disease and, in rare cases, hormonal changes in women. Contingent upon the entire history and physical examination, the dentist should consider referral for either a computerized tomography (CT) scan or magnetic resonance imaging (MRI) of the head and blood tests such as erythrocyte sedimentation rate (ESR) to rule out giant cell arteritis, complete blood count (CBC) to rule out anemia and serious blood dyscrasias, T4 to rule out thyroid disease, and a Lyme titer. Progressively worsening headaches at any age need to be carefully assessed.

Pattern change

When patients experience their first headache or the worst headache of their life, or if there is a change in attack frequency, severity, associated symptoms, or quality, the clinician should review the case for other red flags and seriously consider further investigation. Of course, any migraine can be the worst headache of a person’s life, but patients with migraine can also develop serious secondary causes of headache that must be identified. Chronic, recurrent headaches that have similar features over time are not likely due to a serious cause, but changes should always be noted.

Headache Associated with Vascular Disorders (IHS 6)

Acute ischemic cerebrovascular disease (IHS 6.1)

Headache associated with acute ischemic cerebrovascular disease (IHS 6.1)⁷ is well recognized but poorly understood. Although the pain is usually mild to moderate, there is nothing pathognomonic about the quality, severity, or location of the head pain associated with cerebral ischemia. This etiology should be considered based on the accompanying neurologic deficits that present in an acute fashion, often in a person older than 50 years, and seem temporally related to the head pain, which will typically be a different type of headache than that previously experienced by the patient. Posterior circulation dysfunction (in the vertebral and basilar artery distribution) is more likely to cause headache than carotid artery dysfunction. Neurologic deficits include visual obscurations, diplopia, weakness, numbness, altered cognition, dysarthria, aphasia, and ataxia. Transient ischemic attacks present with every neurologic deficit that might be seen in an acute ischemic stroke, commonly amaurosis fugax and weakness or numbness on one side, but these deficits resolve by definition within 24 hours and usually within 20 minutes. Signs or symptoms consistent with cerebral ischemia warrant emergency referral to a physician.

This cause of headache typically affects older individuals with vascular risk factors (eg, diabetes, coronary disease, hypertension, hypercholesterolemia, and tobacco use); however, stroke can occur at any age. A CT image of the head may be sufficient for diagnosis, especially if there is a question of acute bleeding, but an MRI scan and a diffusion-weighted MRI scan will have a much higher sensitivity and specificity for detection of acute cerebral ischemia and tissue damage. The differential diagnosis for a patient with headache and neurologic symptoms must include migraine, and a personal as well as familial history should be sought. An older migraineur who develops a headache with new neurologic symptoms or findings on examination should be considered to have vascular compromise until proven otherwise. Treatment for the headache must be individualized, but typically this pain lasts a few days at most and vasoactive drugs are contraindicated.

Intracranial hemorrhage (IHS 5.5 and 6.2)

Headache secondary to traumatic intracranial hematoma may be due to an epidural hematoma (IHS 5.5.1; ICD-10 S06.4; ICD-9 852.40) or a subdural hematoma (IHS 5.5.2; ICD-10 S06.5; ICD-9 339.20). Headache secondary to nontraumatic intracranial hematoma may be due to an intracerebral hemorrhage (IHS 6.2.1; ICD-10 I61; ICD-9 784.0) or a subarachnoid hemorrhage (SAH) (IHS 6.2.2; ICD-10 I60; ICD-9 430).⁷ Like pain associated with ischemia, pain stemming from hemorrhage is best diagnosed according to its accompanying symptoms.

An epidural hematoma (IHS 5.5.1; ICD-10 S06.4; ICD-9 852.40)⁷ is most often caused by severe blunt trauma to the skull and rupture of the middle meningeal artery. Many texts refer to a “lucid interval” wherein the patient apparently recovers for the most part after head trauma only to become somnolent and then comatose in short order.⁸ This lucid interval is more the exception than the rule; more frequently, patients will continue to have severe pain followed by a change in cognition. Rapid surgical drainage of epidural hematomas is necessary to prevent mortality; therefore, a high index of suspicion after head trauma, especially in children, or temporal bone fracture is warranted.

A subdural hematoma (IHS 5.5.2; ICD-10 S06.5; ICD-9 339.20)⁷ may present acutely, subacutely, or even with chronic symptoms. The subdural space fills with blood after the bridging veins coursing through it rupture, usually after a fall or other type of head trauma. Older patients are at greater risk because they are more likely to have gait instability and their bridging veins are not as resistant to trauma. Often there is a history of minimal trauma, like a minor motor vehicle accident without direct head trauma with neurologic symptoms beginning several hours or even days later. Patients on anticoagulation therapy and those taking frequent aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) are particularly at risk, even with seemingly minimal head trauma. Pain is not always the chief complaint. Symptoms may include any neurologic deficit, such as gait disturbance, personality change, somnolence, visual disturbances, or focal changes such as hemiparesis, hemisensory changes, and visual field defects. Surgical evacuation of the hematoma is sometimes needed, but careful observation of a small subdural hematoma without brain shift or pressure can be an effective treatment.

Head pain associated with a nontraumatic intracerebral hemorrhage (IHS 6.2.1; ICD-10 I61; ICD-9 432.1)⁷ most typically presents with acute neurologic deficits. Intracerebral hematoma may be due to many etiologies (eg, hypertension, neoplasm, arteriovenous malformations) and refers to a hematoma within the brain parenchyma. If large enough, this can extend into a ventricle. This, of course, may quickly lead to coma or even death contingent upon the cause and the volume of blood, which produces concomitant destruction of cerebral tissue, mass effect, and possibly herniation of the medial temporal lobe, compressing the third cranial nerve.

Headache due to an SAH (IHS 6.2.2; ICD-10 I60; ICD-9 430)⁷ is fairly characteristic. Patients with an SAH typically present with a very sudden-onset, “thunderclap” headache. This pattern of headache reaches its maximal intensity in less than 1 minute, often within seconds. In the past, medical personnel were taught to ask whether a patient was experiencing “the worst headache of their life,” but this is not as useful as asking questions that get at the sudden nature of the onset with dramatic rise to crescendo within seconds. Being stopped in the middle of a sentence by pain or feeling as if hit with a baseball bat can be better indicators of an SAH. SAHs commonly present with nausea and vomiting, a stiff neck, or, frequently, rapid loss of consciousness. A ruptured saccular aneurysm is the most common cause of a spontaneous SAH. Whenever an SAH is suspected, the patient should be sent to an emergency room, preferably by ambulance, where a detailed neurologic exam can be performed followed by a head CT scan. If the suspicion of an SAH is high and the head CT scan is normal, the patient should then undergo a lumbar puncture to search for microscopic evidence of bleeding or xanthochromia (which may take several hours to develop) as well as to rule out other worrisome etiologies of sudden headache, like meningitis. An MRI scan should also be considered, as it may show an aneurysm or arteriovenous malformation. Key aspects of treatment include maintaining hemodynamic stability, neurosurgical consultation for either aneurysmal clipping or endovascular coiling, and treatment for avoidance of vasospasm.^8,9

The differential diagnosis of a thunderclap headache includes primary headache disorders, such as a rare, rapidly escalating migraine attack, cluster headache, exertional headache, recurrent cerebral vasoconstrictive syndrome (RCVS), which can be related to a variety of medications, and headache associated with sexual activity, as well as the secondary causes outlined in Box 4-4. The critical point is that the sudden onset of an excruciating headache, or one that becomes severe within a minute, should be considered a serious problem, such as a hemorrhage, until proven otherwise. RCVS has lately been recognized more often as a sudden severe recurrent headache with all normal examinations except for a magnetic resonance angiogram (MRA), computed tomography angiogram (CTA), or conventional angiogram, all of which may show beading of the arteries.

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