Thunderclap Headache

Thunderclap HeadacheInternational Classification of Headache Disorders II diagnostic criteria (ICHD II), TCHs severe intensity headaches that reach maximum intensity in less than 1 minuteTCHs are differentiated from other headaches of severe intensity (eg, migraine, cluster) by the rapidity with which they reach maximum severityPatients with a TCH requires emergent evaluation. Due to the seriousness of the condition, subarachnoid hemorrhage (SAH) is the first consideration

Causes of TC HeadacheMore CommonSubarachnoid hemorrhageUnruptured intracranial aneurysm(sentinel headache)Reversible cerebral vasoconstriction syndromesCervical artery dissectionCerebral venous sinus thrombosisSpontaneous intracranial hypotension (CSF leak)Hypertensive emergencyIntracerebral hemorrhageLess CommonSubdural hematomaRetroclival hematomaIschemic strokeMeningitisBrain tumorPituitary apoplexyColloid cyst third ventricleMyocardial infarctionAqueductal stenosisComplicated sinusitisPheochromocytomaPrimary cough, exertional, and sexual headache

Clinical PresentationHow long did it take for your headache to reach maximum intensity? TCH is diagnosed when the patient reports that the headache is severe and it reached maximum severity very rapidlyMaybe localized to 1 region, or may be holocephalicIsolated symptom or accompanied by a multitude of different symptoms, their presence dependent upon the underlying condition leading to the TCHMore common symptoms include nausea, vomiting, photosensitivity, phonosensitivity, neck pain, neck stiffness, focal neurologic symptoms, visual change, altered cognition, and altered level of consciousness.

Subarachnoid HemorrhageMost common cause of TCH, 10-25% of patients presenting with TCH will have SAH.SAH must be the first consideration in a patient with TCHMajority of SAHs (85%) are secondary to rupture of saccular aneurysmsLess common causes of SAH including non-aneurysmal perimesencephalic haemorrhage, arterial dissections, arteriovenous malformations, dural arteriovenous fistula, mycotic aneurysm, bleeding disorders, vasculitides, spinal cord vascular lesions, and substance abuse

Subarachnoid HemorrhageHeadache, typically a TCH, is the most common symptomHeadache may have spontaneous onset, or may follow physical exertion. In about 1/3 of cases, headache occurs in isolation Other symptoms, when present, may include: altered consciousness, cognitive dysfunction, seizures, visual disturbances, nausea, vomiting, meningismus, photophobia, and dizziness.2550% of patients with subarachnoid haemorrhage are initially misdiagnosed. Mortality approximately 50%, including 10-15% of SAH patients who die prior to obtaining medical services .

Unruptured Intracranial Aneurysm (Sentinel headache)sentinel headache or warning headache is a TCH that occurs days to weeks prior to rupture of an intracranial aneurysm10 to 43% of patients with SAH. Patients with sentinel headaches generally do not have meningismus, altered consciousness, or focal neurological symptoms and signs. Most commonly occur within 2 weeks of SAH, highest incidence being within 24 hours of SAHTheoretically, finding an unruptured aneurysm in a patient with TCH could lead to treatment of the unruptured aneurysm and avoidance of the impending SAH.

Reversible Cerebral Vasoconstriction SyndromesMost common presenting symptom is TCH (most often repetitive), approximately 85% of patientsHeadaches may occur spontaneously or be provoked by Valsalva maneuversTCH in isolation or accompanied by other neurologic symptoms due to cerebral edema, ischemic stroke, or transient ischemic attackMultifocal areas of intracranial vasoconstriction, no evidence of aneurysmal SAH, normal or nearly normal cerebrospinal fluid (CSF) studiesSpontaneous reversal of vasoconstriction within several months of symptom onset without any specific treatment

Cervical Artery DissectionHeadache is the most common symptom in patients with cervical internal carotid and vertebral dissections, 2/3 of patients20% report TCH. Can be diffuse in location, the typical headache is ipsilateral to the dissected artery. Most often felt in the periorbital, frontal, and temporal regionsHeadache associated with vertebral artery dissection is more commonly felt in posterior head regionsNeck pain is present with 1/3 of carotid artery and 2/3 of vertebral artery dissections

Cervical Artery DissectionHeadache most common symptom ; 6095% with carotid artery dissections, 70% with vertebral artery dissections. Most commonly gradual onset. 20% of patients present with TCH.Typically cervical artery dissections manifest with symptoms in addition to headache and neck pain. Isolated headache seen only in 2% to 8% of patients.Headache can precede other symptoms by several hours to several daysOther symptoms of cervical artery dissection include: Horners syndrome, pulsatile tinnitus, amaurosis fugax, diplopia, and other symptoms that occur due to transient ischemic attacks or strokes related to the dissected artery

Spontaneous Intracranial HypotensionSyndrome of low CSF volume and/or pressure secondary to a CSF leak. Typically preceded by minor trauma such as trivial falls, lifting, coughing, and sports activities. TCH is the presenting symptom of SIH approximately 15% of casesOrthostatic headache is pathognomonic for SIH (worsen substantially when upright)Headache may worsen with Valsalva, coughing, sneezing, and bending. Other accompanying symptoms may include auditory muffling, nausea, vomiting, neck stiffness, tinnitus, dizziness, visual changes , interscapular and upper extremity radicular pain

Cerebral Venous Sinus ThrombosisTypical headache associated with CVST is subacute in onset, however 2-10% of patients with CVST present with TCH and 25% have isolated headacheContinuous with worsening pain associated with increases in intracranial pressure (Valsalva)Symptoms that commonly occur include focal neurological symptoms (eg, hemiplegia, visual changes including diplopia), altered level of consciousness, altered mental status, seizures, and tinnitus. Risk factors include hypercoagulable conditions such as thrombophilia, pregnancy, dehydration, use of oral contraceptives, cancer, and head trauma

Cerebral Venous Sinus ThrombosisInitial investigations for SAH are commonly inadequate for the diagnosis of CVSTIn patients with normal neurological examination, brain CT is normal in about 25%. In those with focal neurological deficits, there are CT abnormalities in about 90%. Subtle findings on CT can be easily misinterpreted.So if the clinical suspicion for CVST is high MRV or CTV must be considered

Primary Thunderclap HeadacheWhen no cause for TCH is identified despite a comprehensive diagnostic evaluation, primary TCH is the appropriate diagnosisDebatable whether primary TCH actually exists or is just inappropriately diagnosed. ICHD-II classification goes on to say that evidence that thunderclap HA exists as a primary condition is poor.Increased use of MRI and non-invasive vascular imaging leading to higher diagnostic rates of disorders likely to be missed by CT and CSF evaluation (eg, RCVS)

Physical ExaminationBody temperature, blood pressure, heart rate, and other vital signs Temperature Suspicion for an underlying infectious etiology

BP Suggestive of hypertensive emergency/urgency as the etiology of TCH, may initially be difficult to distinguish from elevated BP as part of a generalized pain and anxiety responseElevated blood pressure and bradycardia in a patient with reduced level of consciousness could suggest elevated intracranial pressure such as can be seen with a large SAH, intracerebral hemorrhage, and with severe cerebral edema

Neurologic examinations of TCH patients vary widely depending upon the underlying etiologyMore common findings include the presence of meningismus, papilledema, visual deficits, altered consciousness, and focal neurologic deficits..

Brain CT Without ContrastFollowing collection of the patients history and completion of the physical and neurologic examinations, brain CT without contrast is indicatedIrrespective of the interval between symptom onset and CT scanning, the sensitivity of brain CT for SAH was 92.9%. However, sensitivity was 100% for those patients who underwent brain CT within 6 hours of symptom onset The sensitivity of brain CT for detecting SAH decreases as the interval between symptom onset and image acquisition lengthens. Sensitivity approached 100% when CT

Brain CT Without ContrastBecause the sensitivity of CT is not 100% in the vast majority of cases, lumbar puncture is required if a diagnosis is not reached and not contraindicated following brain CTBrain CT without contrast may show evidence for other etiologies of TCH including:Intracranial hemorrhage, ischemic stroke, cerebral edema, CVST (eg, hyperdensity within the occluded sinus, venous infarcts/hemorrhages, edema), intracranial mass lesions, and SIH (eg, subdural fluid collections)

Lumbar PunctureLumbar puncture is performed in the evaluation of patients with TCH and nondiagnostic brain CTsYield of CSF analysis is higher when CSF is collected at least 12 hours after the onset of symptoms, however a delay in the diagnostic evaluation of the TCH patient is not recommendedRecommended for all patients: opening pressure, cell count with differential in tube #1 and tube #4, protein, glucose, Gram stain and culture, and visual inspection for xanthochromia. If available, CSF spectrophotometry high sensitivity for the diagnosis of SAH.In CT-negative SAH to differentiate SAH from a traumatic (bloody) tap, cell counts in tube #1 and tube #4 are measured and visual inspection for xanthochromia

Lumbar PunctureSAH is the likely when:RBC count in tube #1 and tube #4 remains constant or is higher in tube #4 Visual inspection for xanthochromia has sensitivity of 93%, specificity of 95%, positive predictive value of 72%, and negative predictive value of 99% for the presence of cerebral aneurysmSpectrophotometry had very high sensitivity and negative predictive value (both 100%), but low specificity (75%) and very low positive predictive value (3.3%) for detecting cerebral aneurysms in patients with suspected SAH and normal brain CTsOpening pressure maybe in CVST, intracranial infections and space occupying lesions, and pressure is low with SIHProtein and WBC count elevated in CNS inflammation and/or infection.CVST may have a combination of RBC count, protein, lymphocytic pleocytosis, opening pressure, although only elevated opening pressure or maybe completely normal results possible

Additional TestingConflicting opinions regarding the necessity for additional testing when the cause of TCH is not determined following brain CT and lumbar puncture Additional testing often includes brain MRI with and without gadolinium and imaging of the intracranial and cervical arteries via MRA or CTA. Depending upon clinical suspicion, MRV or CTV maybe consideredMRI with gadolinium is particularly helpful for the diagnosis of SIH, ischemic stroke, tumors, pituitary apoplexy, colloid cyst, and edema associated with hypertensive emergencies and reversible posterior leukoencephalopathy (seen in the setting of hypertensive emergencies and RCVS).

Additional TestingConflicting opinions regarding the necessity for additional testing when the cause of TCH is not determined following brain CT and lumbar puncture American College of Emergency Physicians clinical policy guideline that states: patients with a sudden-onset, severe headache who have negative findings on a head CT, normal opening pressure, and negative findings in CSF analysis do not need emergent angiography and can be discharged from the ED with follow-up recommended.Additional testing often includes brain MRI with and without gadolinium and imaging of the intracranial and cervical arteries via MRA or CTA. Depending upon clinical suspicion, MRV or CTV maybe considered

Additional TestingMRI with gadolinium is particularly helpful for the diagnosis of SIH, ischemic stroke, tumors, pituitary apoplexy, colloid cyst, and edema associated with hypertensive emergencies and reversible posterior leukoencephalopathy (+/- hypertensive emergencies and RCVS).Angiography is performed in the evaluation of the SAH patient in order to identify an underlying intracranial aneurysm. Angiography is also useful in evaluating for other causes of TCH, including unruptured intracranial aneurysm, RCVS, CVST, and arterial dissections.However, the risks of catheter angiography need to be considered. Non-invasive angiography via CTA or MRA may be considered in place of catheter angiography

Initial assessment of TCH

SummaryTCHs are severe headaches that reach maximum severity quicklyTCH can be the only presenting symptom of SAH, the patient with TCH must be evaluated emergentlyBrain CT without contrast and lumbar puncture with basic CSF studies and inspection for xanthochromia are probably sufficient for the emergent evaluation of the patient with TCHKnow the changing sensitivity of brain CT and CSF analysis in relation to the interval between symptom onsetIf SAH is detected via CT or lumbar puncture, angiography is performed in search of an underlying aneurysmWhen head CT and lumbar puncture are normal, further testing should be considered in order to evaluate for causes of TCH other than SAH

ReferencesSchwedt, T. et al. Review: Thunderclap headache. Lancet Neurol 2006; 5: 62131Dilli, E. Thunderclap Headache. Curr Neurol Neurosci Rep. 2014; 14: 437Purdy, AR. et al. Dangerous and Thunderclap Headaches. Headache. 2012; 52; S2:56-59Schwedt, TJ. Clinical Review: Thunderclap Headaches A Focus on Etiology and Diagnostic Evaluation. Headache 2013; 563-569

95% of cases have a normal cerebral angiogram and the source of bleeding is not identified; the cause is thought to be a venous bleed.*