Subarachnoid haemorrhage in ADPKD patients: how to recognize and how to manage?
Nephrology, Dialysis and Transplantation
Epidemiology and demography The association of intracranial aneurysm (ICA) and autosomal dominant polycystic kidney disease (ADPKD) has been established for many years. However, a reliable estimate of its prevalence has been obtained only recently thanks to the development of non-invasive techniques of detection, namely highresolution computerized tomography (CT) and magnetic resonance angiography (MRA). A prevalence of 8% of asymptomatic ICA has been derived from three large prospective series
... prospective series of ADPKD patients, i.e. a rate about five times higher than in the general population (see  for review). The natural history of ICA in ADPKD is largely unknown. Fortunately, not all ICAs do rupture, as evidenced by the intact ICAs found at autopsy . The risk of rupturing an ICA remains actually undefined. Using Rochester demographic data, Schievink estimates the frequency of ICA rupture in the ADPKD population as about 1/2000 person per year , i.e. about five times higher than in the general population. ICA rupture results in subarachnoid haemorrhage (SAH). It is important to remember that the majority of acute neurological events affecting ADPKD patients do not result from ICA rupture, but from primary hypertensive intracranial haemorrhage or ischaemic stroke . In ADPKD patients, ICA rupture entails a 35-55% risk of combined case fatality and morbidity [2, 3] . Early recognition of SAH is crucial, since any delay affects patient outcome. Clinical profile of the ADPKD patient admitted for ICA rupture The identification of characteristics associated with ICA rupture in ADPKD requires the unequivocal demonstration of a ruptured ICA. Three such studies are available: a critical review of 79 cases gathered from the literature , a single-centre American report of 41 cases  and a multicentre European series including 71 cases  . Together, they outline the profile of the ADPKD patient presenting with ICA rupture. ICA rupture occurs at a mean age of 41 years, which, when compared with the general population, is very close to that of the familial form of ICA, but 10 years earlier than that of the sporadic form  . In our series, 10% of the patients were under 21 years old. Occasionally, ICA rupture was the presenting manifestation of ADPKD  . Fifty-four percent of patients still had a normal renal function at the time of rupture . Twenty-six percent had also a normal blood pressure before rupture  . Established hypertension is thus not a prerequisite for the development of ICA, although hypertension remains a recognized risk factor for ICA rupture, at least in the general population. The prevalence of clinical manifestations related to ADPKD is not different in patients with and in patients without ICA rupture  . The only characteristic clearly associated with ICA rupture in ADPKD is a family history of ICA, which is five times more common in patients with an ICA rupture than in a control group without ICA rupture . Suspecting subarachnoid haemorrhage (SAH) The cardinal feature of SAH is sudden headache, often described as a blow on the head or an explosion inside; the pain is incredibly severe, and diffuse rather than local. Headache thereafter radiates into the occipital or cervical region. It should be known that neck stiffness takes 3-12 h to develop  . Other symptoms of SAH include photophobia, nausea, vomiting, lethargy, and confusion. Brief loss of consciousness often occurs. Clinical signs include mild hyperpyrexia, hypertension, intraocular haemorrhage, and cranial nerve palsies. In 20-40% of non-ADPKD patients hospitalized with SAH, the event has been preceded, a few hours up to two weeks, by premonitory headaches (due to a first leak from the ICA), frequently overlooked both by the patient and the doctor  . Obviously, SAH should not be suspected in every ADPKD patient complaining of headache ... Doctors should be alerted by headaches of sudden onset and unusual character or severity. The majority of sentinel headaches are localized rather than generalized, the posterior location being most frequent  .