a formula for the diagnostic assessment of thunderclap headache ( tch ) should be established . the management of this type of headache is controversial the established diagnostic assessment of tch includes a computer tomography ( ct ) of the head and cerebrospinal fluid ( csf ) examination in order to exclude a subarachnoid haemorrhage . in patients whose ct scans and csf analyses are normal , further testing is rarely considered to be indicated by most clinicians . however , others suggest that in circumstances where ct and csf are normal , further diagnostic assessment with magnetic resonance imaging ( mri ) , magnetic resonance angiography ( mra ) of the brain and neck , and magnetic resonance venography is necessary . thunderclap headache is described as a sudden , unusually severe headache which reaches its maximum intensity within a split second or , at most , a few minutes . the term was first used by day and raskin , in a case of sudden headache , where investigations revealed an unruptured cerebral aneurysm . about 25% of tchs a number of other disorders are known to be present with tch , e.g. cerebral venous thrombosis , cervical artery dissection and spontaneous intracranial hypotension . tch can also be a manifestation of primary headache , and it is now also recognised as an idiopathic headache . headache is not uncommon in ischaemic stroke , but is usually overshadowed by other manifestations such as aphasia and neglect . prospective studies of the occurrence of headache in patients with ischaemic strokes reveal a frequency of 834% . we describe a patient who experienced a tch as the primary clinical feature of a supratentorial cerebral infarct . our patient underwent mri and mra that revealed a cerebral infarct . we suggest that an expanded assessment with mri should be performed in similar cases even when the neurological examination , csf analysis , and ct are normal . a 73-year - old man appeared in the emergency department following an acute and sudden onset of severe headache . the pain was located in the frontal region , it reached its maximum intensity in < 1  min and lasted for about 3  h. there were no additional symptoms . he took 500  mg of aspirin and was later taken to hospital . at the time of admission , the patient reported that the headache had resolved . csf examination revealed a normal opening pressure ( 180  mmh2o ) , a normal closing pressure , a normal cell count and protein . an mri of the brain revealed an acute ischaemic lesion in the right semiovale region ( fig .  1 ) . an mra was performed to exclude possible intracranial aneurysms , cerebral venous thrombosis , cervical artery dissection , and vasospasm . a brain ct was performed 3  days after the mri and demonstrated a definitive cerebral infarct . further investigations with ecg telemetry , mra of the cervical arteries , and echocardiography were normal . further measures were taken to improve the medical treatment of his hypertension and diabetes mellitus . the patient could be discharged and remains well . at follow - up after 3- and 6  months , he reported no headache . 1mri , diffusion - weighted imaging ( dwi ) ( a ) , adc map ( b ) demonstrating an acute ischemic lesion in the right periventricular white matter ( centrum semiovale region ) mri , diffusion - weighted imaging ( dwi ) ( a ) , adc map ( b ) demonstrating an acute ischemic lesion in the right periventricular white matter ( centrum semiovale region ) our case shows that the assessment of tch might have to be expanded with mri to rule out a cerebral infarct . tch is a rare manifestation of cerebral infarct . in the year 2006 , a case report was published where tch was the presenting feature of embolic cerebellar infarcts , in the absence of neurological findings . presented a similar case ( cerebellar infarct ) in 2008 . to our knowledge , this is the first report of a tch as the presenting feature of an otherwise asymptomatic supratentorial cerebral infarct . the severity of the headache is not related to the size of the infarct or the location of the lesion . it is likely that an activation of the trigeminovascular system in intracranial vessels seems to be essential for the production of headache in ischaemic stroke . headache is more common when stroke occurs in the area of the posterior circulation than in the anterior circulation . the posterior circulation is more densely innervated by the trigeminal system , which may explain the frequency of headache in posterior circulation infarcts . this reaction may in turn result in an increased nociceptive input into the nervous system and head pain . one hypothesis is that excessive sympathetic activity or an abnormal vascular response to circulating catecholamines may be involved . this would explain the occurrence of tch during physical activity , and in patients with pheocromocytoma . we suggest that when a patient presents with a tch an expanded assessment with mri of the brain should be ordered to rule out a cerebral infarct , even when neurological examination , brain ct , and csf examination are normal as in our case . it is also obvious that angiographic studies are necessary in some cases to rule out other secondary causes of tch .
a 73-year - old man presented with a thunderclap headache ( tch ) , suggesting a subarachnoid haemorrhage . neurological examination , 
 computer tomography of the head , and cerebrospinal fluid examination were normal . 
 magnetic resonance imaging of the brain revealed a supratentorial cerebral infarct . 
 no cerebral aneurysm could be detected . 
 a tch can be the presenting feature of many conditions . 
 a formula for the diagnostic assessment of tch should be established . 
 the management of this type of headache is controversial . 
 articles differ in their conclusions and recommendations . 
 an expansion of routine investigations should be performed in cases where the neurological examination , cerebrospinal fluid analysis , and computer tomography are normal . 
 a tch can be the primary clinical feature of a supratentorial cerebral infarct .