Acute Headache: Diagnosis by Stephanie J Nahas MD (Dr
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Acute headache: diagnosis By Stephanie J Nahas MD (Dr. Nahas of Thomas Jefferson University has no relevant financial relationships to disclose.) Originally released October 21, 2004; last updated December 4, 2017; expires December 4, 2020 Introduction This article incudes discussion of diagnosis of acute headache; migraine; thunderclap headache; tension-type headache; headache with systemic illness or systemic symptoms; migraine aura; headache triggered by cough, exertion, or orgasm; headache during pregnancy or postpartum; positional headache; headache in the elderly; sinus symptoms and headache; and ocular disorders. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations. Overview Headache is a common chief complaint in acute settings. The diagnosis of acute headache can be challenging and should proceed in an orderly fashion. An important first step is to distinguish primary from secondary headaches. The approach is to seek “red flags” that suggest the possibility of secondary headache. If 1 of these features is identified, the physician must conduct the workup indicated by the red flag and, thereby, diagnose any secondary headache disorder that is present. In the absence of secondary headache, the clinician proceeds to diagnosing a primary headache disorder. In this article, the author follows this approach to discuss the differential diagnosis of acute headaches. Key points • Migraine is the most common diagnosis in the evaluation of acute headache. • Secondary causes must be ruled out in all cases of acute headache presentation, mainly based on “red flags” uncovered in the history and physical/neurologic examination. • A systematic approach to the headache, characterizing it in terms of duration, quality, location, and accompanying symptoms, speeds the diagnosis. Headache classification Headache is a common type of recurrent pain and 1 of the most frequent symptoms in neurology. Although virtually everyone gets occasional headaches, there are well-defined headache disorders that vary in incidence, prevalence, and duration (Robbins and Lipton 2010). Before 1988, the headache classification systems that were available did not have clear operational rules, and nomenclature varied widely. In 1988, the International Headache Society instituted a classification system that has become the standard for headache diagnosis and, particularly, for clinical research (Headache Classification Committee of the International Headache Society 1988). The 2nd edition of the International Classification of Headache Disorders (ICHD-2) was released in September of 2004 (Headache Classification Committee of the International Headache Society 2004), and the 3rd edition (ICHD-3 beta) was issued in July 2013 (Headache Classification Committee of the International Headache Society 2013). According to this system, headaches are divided into 2 broad categories: primary headache disorders and secondary headache disorders. In secondary disorders, headaches are attributed to another condition, such as a brain tumor, infection, or head injury; for the primary disorders, no specific cause can be found. Headache is the fifth most common chief complaint in the emergency department in about 2% of patients, or 2 million visits annually in the United States (Goldstein et al 2006). Internists and neurologists are often called to evaluate, or are consulted by, patients during a headache attack. The diagnosis of acute headache is challenging and should proceed in an orderly fashion. Crucial elements include a thorough history, supplemented by general medical and neurologic examinations, and laboratory testing and neuroimaging of selected patients. Approaching a patient with acute headache An important first step in acute headache diagnosis is to distinguish a primary from a secondary headache. Most patients who have an acute headache have a primary headache disorder (Friedman and Lipton 2011), but the probability of secondary headaches increases in the emergency department. Certain “red flags” suggest the possibility of secondary headache. Once these features are identified, the physician must conduct the workup indicated by the red flag (Table 1) and diagnose the secondary headache disorder if one is present. Table 1. Red Flags in the Diagnosis of Headache Red flag Consider Possible investigations Sudden-onset headache • Subarachnoid hemorrhage, • Neuroimaging first and foremost • Lumbar puncture (after • See Table 2 for differential neuroimaging evaluation) diagnosis Worsening headache pattern • Mass lesion • Neuroimaging • Subdural hematoma • Medication overuse Headache with cancer, HIV, or • Meningitis • Neuroimaging other systemic illness (fever, neck • Encephalitis • Lumbar puncture stiffness, cutaneous rash) • Lyme disease • Biopsy • Systemic infection • Blood tests • Collagen vascular disease • Arteritis Focal neurologic signs or • Mass lesion • Neuroimaging symptoms other than typical • AVM • Collagen vascular evaluation visual or sensory aura • Collagen vascular disease Papilledema • Mass lesion • Neuroimaging • Idiopathic intracranial • Lumbar puncture (after hypertension neuroimaging evaluation) • Encephalitis • Meningitis Triggered by cough, exertion, or • Subarachnoid hemorrhage • Neuroimaging Valsalva • Mass lesion • Considerer lumbar puncture • Posterior fossa pathology Headache during pregnancy or • Cortical vein or cranial • Neuroimaging postpartum sinus thrombosis • Carotid dissection • Pituitary apoplexy Modified from: (Lipton et al 2008) Table 2. Differential Diagnoses of Thunderclap Headache Vascular etiologies Subarachnoid hemorrhage Cervical artery dissection Aneurysmal thrombosis or expansion Cerebral venous thrombosis Hypertensive crisis Reversible cerebral vasoconstriction syndrome (especially for recurrent thunderclap headache) Pituitary apoplexy Retroclival hematoma Nonvascular etiologies Spontaneous intracranial hypotension/hypovolemia Colloid cyst of the third ventricle Meningitis Sinusitis (especially sphenoid) Primary cough, sexual, and exertional headache Primary thunderclap headache (idiopathic) Identifying secondary headaches Herein we discuss common red flags, the differential diagnoses suggested by these red flags, and the appropriate investigation required by each one. It is important to emphasize that red flags indicate an increased probability of secondary headache. The presence of a red flag increases the need to perform further investigation, but the patient must be analyzed in the context of the overall clinical picture. Certain “comfort signs,” such as acknowledgement of a typical headache trigger, a family history of similar headaches, or the presence of typical signs and symptoms of a primary headache disorder may offset minor red flags. Some clinical scenarios may prompt the clinician to ascribe a secondary diagnosis erroneously, leading to incorrect treatment. (1) Sudden onset of severe headache (thunderclap headache). The sudden onset of a severe (explosive) headache must be investigated. Although it is not the most common cause of thunderclap headache, subarachnoid hemorrhage is the most feared. A meta-analysis showed that 10% to 43% of patients with subarachnoid hemorrhage demonstrate thunderclap headaches (incidence varies in different settings) (Polmear 2003). More studies have also identified the following features as predictive of subarachnoid hemorrhage: age greater than 40, witnessed loss of consciousness, neck stiffness, onset during exertion, vomiting, blood pressure greater than 160/100, and arrival by ambulance (Perry et al 2010; Perry et al 2013). All patients with thunderclap headache should have an expedient and exhaustive search for an underlying cause. These include serious intracranial vascular disorders, such as aneurysmal subarachnoid hemorrhage, intracerebral hemorrhage, cerebral venous (or sinus) thrombosis, arteriovenous malformation, arterial dissection (intra- and extracranial), CNS angiitis, pituitary apoplexy, and reversible cerebral vasoconstriction syndrome, which is increasingly recognized as a cause of recurrent thunderclap headaches (Calabrese et al 2007; Sheikh and Mathew 2014). Other organic causes of thunderclap headache are colloid cysts of the third ventricle, CSF hypotension, acute sinusitis (particularly with barotrauma), and meningoencephalitis (Ju and Schwedt 2010). A thunderclap headache evaluation should include head CT and a lumbar puncture if the CT is negative to evaluate for subarachnoid hemorrhage first and foremost. If these studies are unrevealing, many clinicians will then order an MRA or CTA in effort to discover an aneurysm if suspicion remains high, especially within 12 hours of ictus. Some authors have argued that all patients with explosive headache should be evaluated with conventional angiography even when all the other examinations (including MRA) are normal (Linn and Wijdicks 2002; Polmear 2003). However, as noninvasive vascular technology has improved greatly over time, this argument loses some strength (Chen et al 2008; Grayev et al 2009). More recently, a mathematical analysis suggested that a follow-up lumbar puncture is highly cost- effective, but that CTA is questionable in this regard with no clearly defined utility (Malhotra et al 2016). If no aneurysm is revealed, or if a different etiology is highly suspected based on the presentation, other studies are warranted. When considering cerebral venous thrombosis, CT is often inadequate for diagnosing it, and MRV or CTV is necessary to exclude this