Spontaneous isolated convexity subarachnoid hemorrhage: presentation, radiological findings, differential diagnosis, and clinical course

Clinical article

Full access

Object

The clinical characteristics and overall outcome in patients with spontaneous isolated convexity subarachnoid hemorrhage (SAH) are not well described in the literature. The purpose of this study was to examine the mode of presentation, common origins, radiographic findings, and clinical course in a large case series of such patients.

Methods

A retrospective single-center chart review of all patients in whom nontraumatic primary convexity SAH was diagnosed between 2002 and 2007 was performed. Twenty patients were identified and analyzed for presenting symptoms, radiological and laboratory findings, hospital course, and outcome.

Results

There were 15 women and 5 men in our series, and the mean age was 52 years (range 18–86 years). The most common presenting symptom was headache, with 15 patients experiencing it as a chief complaint. Other frequent manifestations included altered mental status (8 patients), focal neurological deficits (7), and seizure (4 patients). An underlying cause of the hemorrhage was identified in 13 cases, whereas the remainder went unresolved. Of the known causes, 5 were due to posterior reversible encephalopathy syndrome, 3 were caused by thrombocytopenia or anticoagulation, and the remainder were isolated cases of lupus vasculitis, drug-induced vasculopathy, postpartum cerebral angiopathy, hypertensive microangiopathy, and Call–Fleming syndrome. All patients with unknown disease origins had favorable outcomes, whereas 8 of 13 patients with an identifiable underlying disorder experienced favorable outcomes.

Conclusions

Spontaneous isolated convexity SAH is rarely caused by aneurysm rupture, has a distinct mode of presentation, and generally carries a more favorable prognosis than that of aneurysmal SAH.

Abbreviations used in this paper: AVF = arteriovenous fistula; AVM = arteriovenous malformation; CSF = cerebrospinal fluid; DS = digital subtraction; PRES = posterior reversible encephalopathy syndrome; SAH = subarachnoid hemorrhage; SCA = superior cerebellar artery.

Abstract

Object

The clinical characteristics and overall outcome in patients with spontaneous isolated convexity subarachnoid hemorrhage (SAH) are not well described in the literature. The purpose of this study was to examine the mode of presentation, common origins, radiographic findings, and clinical course in a large case series of such patients.

Methods

A retrospective single-center chart review of all patients in whom nontraumatic primary convexity SAH was diagnosed between 2002 and 2007 was performed. Twenty patients were identified and analyzed for presenting symptoms, radiological and laboratory findings, hospital course, and outcome.

Results

There were 15 women and 5 men in our series, and the mean age was 52 years (range 18–86 years). The most common presenting symptom was headache, with 15 patients experiencing it as a chief complaint. Other frequent manifestations included altered mental status (8 patients), focal neurological deficits (7), and seizure (4 patients). An underlying cause of the hemorrhage was identified in 13 cases, whereas the remainder went unresolved. Of the known causes, 5 were due to posterior reversible encephalopathy syndrome, 3 were caused by thrombocytopenia or anticoagulation, and the remainder were isolated cases of lupus vasculitis, drug-induced vasculopathy, postpartum cerebral angiopathy, hypertensive microangiopathy, and Call–Fleming syndrome. All patients with unknown disease origins had favorable outcomes, whereas 8 of 13 patients with an identifiable underlying disorder experienced favorable outcomes.

Conclusions

Spontaneous isolated convexity SAH is rarely caused by aneurysm rupture, has a distinct mode of presentation, and generally carries a more favorable prognosis than that of aneurysmal SAH.

The incidence of spontaneous SAH in the general population is approximately 6–8 cases per 100,000 person-years, of which 85% are the result of a ruptured saccular aneurysm.43 In 10% of cases, no specific structural lesion or other underlying condition is identified. This group includes the entity known as benign perimesencephalic SAH.34 The remaining 5% are caused by a variety of conditions, including the following: transmural arterial dissection, cerebral AVM, dural AVF, cavernous malformation, mycotic aneurysm, sinus or cortical venous thrombosis, thrombocytopenia or coagulopathy, vasculitis, cocaine abuse, brain neoplasm, brain abscess, hypertensive microangiopathy, postpartum cerebral angiopathy, and PRES.5,17,33,35–38,40,42

Although distribution of blood is dependent on the specific site of rupture, the majority of patients with spontaneous SAH demonstrate blood within the basal cisterns, which may extend into the sulci along the cerebral convexities. Isolated SAH along the cerebral convexities, on the other hand, is rare, and has been described in the literature mainly in isolated case reports30,38,42 as well as a recent case series.40 Although the underlying cause is varied, spontaneous isolated convexity SAHs as a group share many clinical features and neuroradiological characteristics that differ substantially from those of classical aneurysmal SAH. The purpose of the present study is to define these clinical features better, to examine the underlying causes, and to assess outcome in a large series of patients with this uncommon hemorrhagic disorder.

Methods

After obtaining institutional approval from the committee on human research, a search of the radiology database at our medical center for “convexity subarachnoid hemorrhage” yielded 864 patients treated between 2002 and 2007. The radiology reports for these patients were then reviewed. We excluded patients with traumatic causes of SAH (459 individuals), patients having intraparenchymal or intraventricular hemorrhagic components (190), and patients having cisternal or sylvian fissure blood (195). The data for the remaining 20 patients were reviewed for this report. These patients with nontraumatic, isolated convexity SAH were analyzed for presenting symptoms, radiological findings, diagnostic studies, causes, treatment, and outcome.

Results

Clinical Presentation

Fifteen of the 20 patients were female; their ages ranged from 18 to 86 years, with a mean age of 52 years. Tables 1 and 2 provide details of the presenting symptoms, radiological findings, diagnostic studies, causes, treatment, and outcomes for these 20 cases. The most common presenting symptom was headache, with 15 patients experiencing headache as a chief complaint. Of these, only 6 experienced a true thunderclap headache and only 1 had neck stiffness. Eight patients had altered mental status, 7 had focal neurological deficits such as unilateral weakness, numbness, or homonymous hemianopia, and 4 patients had seizures (2 focal motor and 2 generalized tonic–clonic).

TABLE 1

Overview of imaging and laboratory values in 20 patients with isolated convexity SAH*

Case No.Age (yrs), SexPresenting SymptomsCT ScanMRI/MRADSACSF AnalysisBlood Screen
118, Fseizures, AMSrt frontoparietal convexity SAHrt frontoparietal SAH (T2, FLAIR)ND↑RBCs, ↑WBCs, ↑protein, ↑IgG↑WBCs, anemia
274, Fsudden severe HA, nausea, mild nuchal stiffnessrt convexity SAHrt parietal convexity SAH (T2, FLAIR)rt MCA atherosclerosisNDnormal
377, Fchronic HANDrt parietal convexity SAH (T2, FLAIR)NDNDND
428, Fsudden severe HA, nausea, photophobia, vertigolt frontal convexity SAHlt frontoparietal convexity SAH (T1, FLAIR)normalND↑WBCs, anemia
530, FHA, tonic–clonic seizures, AMSlt frontoparietal convexity SAHlt parietal convexity SAH (FLAIR)normalND↑WBCs
663, MAMS, anisocoriart parietal convexity SAHNDNDND↑PT/INR, ↑WBCs, anemia
740, MHA, AMSrt parietal convexity SAHNDNDNDthrombocytopenia
864, Msudden severe HA, AMSlt frontal, temporal, parietal convexity SAH, HCPlt cerebral SAH (T1, FLAIR)narrowing of proximal lt ACA & rt VA↑WBCs, xanthochromia↑WBCs, anemia, ↑ESR
949, Flt side weakness, AMS, HArt frontal convexity SAHrt frontal microhemorrhages (T1, FLAIR)NDND↑WBCs, anemia
1033, Ftonic–clonic seizures, HArt frontal SAH, herniationNDradionuclide angiogram: no effective cerebral perfusion↑WBCs↑WBCs, anemia, ↑D-dimer
1169, Frt arm weaknessnormalrt frontal convexity SAH (T2, STAR)NDND↑WBCs, anemia
1255, Fsudden severe HA, rt leg weaknessbilat frontal convexity SAHNDnormal↑WBCs, xanthochromianormal
1352, Fsudden severe HA, rt homonymous hemianopia, AMSbilat posterior parietal SAHbilat parietooccipital convexity SAH (T2, FLAIR)normal 1st angiogram, 2nd w/ subtle bilat SCA narrowing, 3rd w/ diffuse vasoconstriction↑RBCs, ↑WBCs, ↑proteinantibody screen for vasculitis negative, ↑WBCs, anemia
1446, MAMS, anisocoriart parietal convexity SAHNDNDND↑WBCs, anemia, in- infections
1579, Fseizuresrt frontoparietal SAHNDnormalNDthrombocytopenia, ↑WBCs, anemia
1635, Fsudden severe HA, photophobia, lt numbness & weaknessrt parietal convexity SAHrt parietal convexity SAH (T2, FLAIR)normal↑RBCs, ↑WBCs, ↑proteinanemia
1733, Fgradual-onset severe HAlt frontal convexity SAHNDabnormal caliber changes in major vesselsNDantibody screen for vasculitis negative
1827, Fdaily severe HArt frontal convexity SAHbilat parietal vasogenic edema (T2, FLAIR)normalNDnormal
1986, Mchronic HArt frontal convexity SAHrt frontal lobe SAH (T2, FLAIR), abnormal enhancement on MRANDNDND
2025, FHA, rt weakness, vomitinglt frontotemporal SAHlt cerebral convexity SAH (FLAIR)abnormal caliber changes in major vessels of anterior circulationnormalantibody screen for vasculitis negaative, ↑ESR

* ACA = anterior cerebral artery; AMS = altered mental status; DSA = DS angiography; ESR = erythrocyte sedimentation rate; HA = headache; HCP = hydrocephalus; IgG = immunoglobulin G; MCA = middle cerebral artery; MRA = MR angiography; ND = not done; PT/INR = prothrombin time/international normalized ratio; RBCs = red blood cells; SCA = superior cerebellar artery; STAR = T2* MR imaging sequence; VA = vertebral artery; WBCs = white blood cells; ↑ = elevated.

TABLE 2

Overview of origins, risk factors, treatments, and outcomes in 20 patients with isolated convexity SAH*

Case No.Age (yrs), SexOriginRisk FactorsTreatmentOutcome at Time of Discharge
118, Flupus vasculitissystemic lupus erythematosus, HTNantihypertensives, pulse steroid therapyneurological status at baseline, no further seizures
274, FunknownHTNnimodipine, Keppra, antihyperten sives, analgesicsneurological status at baseline, HAresolved
377, Funknowndiabetesacetaminophenneurological status at baseline, HAwell controlled
428, Fpostpartum PRESnoneKeppra, acetaminophen, antihyper tensivesneurological status at baseline, HAwell controlled
530, Fpostpartum PRESHTNDilantin, nimodipine, diazepam, antihypertensivesneurological status at baseline, no further seizures
663, Manticoagulation therapysepsis, lower-extremity amputation, atrial fibrillationDilantin, steroids, cessation of war- farindied of sepsis
740, Mthrombocytopenia due to end-stage hepatic failureend-stage liver disease, alco holism, diabetesplatelet transfusionneurological status at baseline, HAresolved
864, Munknowndeep venous thrombosisKeppra, nimodipine, IVC filter, hy perdynamic therapy, ventriculos tomyhospital course complicated by vasospasm & HCP; neurological status improved to near baseline (mild cognitive deficits)
949, Fhypertensive micro angiopathyHTNantihypertensives, analgesicsneurological status improved to near base- line (mild cognitive deficits)
1033, Fimmunosuppressive PRES (post lung transplant)cyclosporin treatmentDilantin, Depakotedied of PRES-induced cerebral edema w/ herniation syndrome
1169, Funknownnoneanalgesicsneurological status at baseline
1255, Funknownnoneacetaminophenneurological status at baseline, HAresolved
1352, FCall Fleming syn dromeHTN, diabetessteroids, Topamax, analgesics, brain biopsyworsened neurological condition due to de layed-onset IPH & multiple cerebral in farcts
1446, Mimmunosuppressive PRES (post stem cell transplant)leukemianonedied due to complications of leukemia
1579, Fthrombocytopenia & anticoagulation therapyanticoagulation therapy for mechanical heart valvecessation of warfarinworsened neurological condition secondary to delayed-onset IPH
1635, FunknownHTNDilantin, acetaminophenneurological status at baseline, HAresolved
1733, Fpostpartum cerebral angiopathyperipartumnimodipine, ibuprofenneurological status at baseline, HAresolved
1827, Fpostpartum PRESHTN, amphetamine usenimodipine, Solu-Medrol, predni sone, Topamax, antihyperten sives, ibuprofenneurological status at baseline, HAresolved
1986, Munknownnoneanalgesicsneurological status at baseline, HAresolved
2025, Fdrug-induced vascu lopathydietary supplement (ephedra)Dilantin, analgesics, cessation of dietary supplementneurological status at baseline, HAresolved

* HTN = hypertension; IPH = intraparenchymal hemorrhage; IVC = inferior vena cava.

Radiological Findings

Seven hemorrhages were located over the frontal convexity, 6 over the parietal convexity, and 4 in the frontoparietal region. Two of these 17 patients had bilateral subarachnoid blood. Of the 3 remaining patients, 1 had parietooccipital SAH, 1 had frontotemporal SAH, and 1 had multifocal SAH. Eighteen cases were diagnosed based on CT findings, and 2 were identified via MR imaging. Eleven patients underwent DS angiography as part of their diagnostic workup. No aneurysms, AVMs, dural sinus or cortical venous thromboses were identified by DS angiography, but angiographic evidence of vasculitis or vasculopathy was noted in 3 cases. Seven patients underwent CSF analysis, and all underwent routine blood screening.

Underlying Causes

A cause of the convexity SAH was determined in 13 cases, whereas the remaining seven went unresolved. Five cases were the result of PRES, 3 of which occurred postpartum and 2 of which occurred in the context of immunosuppression. Three cases were caused by thrombocytopenia or coagulopathy: 1 due to thrombocytopenia secondary to end-stage liver failure, 1 due to warfarininduced coagulopathy related to atrial fibrillation therapy, and 1 due to thrombocytopenia and warfarin-induced coagulopathy related to mechanical heart valve therapy. Other causes included 2 cases of angiographically evident vasculopathy (1 ascribed to postpartum cerebral angiopathy and 1 to drug-induced vasculopathy from the dietary supplement ephedra), 1 case of lupus vasculitis, 1 of hypertensive microangiopathy, and 1 related to Call–Fleming syndrome. Other pertinent findings included anemia in 11 (55%) of 20 patients and a history of hypertension in 7 (35%) of 20 patients.

Clinical Course

General treatment measures taken for most patients included the following: 1) transfer to the neurology/neurosurgery intensive care unit for close observation; 2) anticonvulsant administration for seizure prophylaxis or therapy; and 3) analgesic administration for headache management. A minority of patients (5 of 20) were also given oral nimodipine for vasospasm prophylaxis. Further therapy was tailored to the particular clinical scenario, with treatment specific to the disease's cause instituted when possible. Patients with PRES were treated with antihypertensive therapy, anticonvulsants, and steroids if needed. Patients with thrombocytopenia were administered platelets, and patients with coagulopathy were treated via cessation of warfarin therapy and reversal with blood products. Documented hypertension was treated with antihypertensive therapy, lupus vasculitis was treated with steroids, and Call–Fleming syndrome was treated with steroids and analgesic agents.

The hospital course was complicated by SAH-induced hydrocephalus and cerebral vasospasm in only 1 of 20 cases; a 5% incidence rate for either acute hydrocephalus or symptomatic vasospasm. This patient (Case 8) had a large volume of isolated convexity SAH and developed symptomatic hydrocephalus that required ventriculostomy placement, but did not require a permanent shunt. This same patient also developed symptomatic cerebral vasospasm (angiographically proven) in delayed fashion, which was successfully treated with nimodipine and hemodynamic augmentation.

Overall, 15 of 20 patients experienced favorable outcomes, with complete or near-complete resolution of presenting symptoms by the time of discharge (mean hospital stay 16.5 days). The remaining 5 patients had unfavorable outcomes, including 2 with worsened neurological status and 3 deaths. Specifically, 1 patient (Case 15) who had both thrombocytopenia and coagulopathy developed an intraparenchymal hemorrhage leading to a worsened neurological condition. One patient (Case 13) with Call–Fleming syndrome developed intraparenchymal hemorrhage and multiple infarcts leading to a worsened neurological condition. One patient (Case 10) with immunosuppressive PRES developed severe cerebral edema leading to herniation and brain death. The remaining 2 deaths were nonneurological in nature, with 1 patient (Case 14) dying due to complications of leukemia and the other (Case 6) dying of sepsis secondary to a preexisting wound infection. All poor outcomes occurred in patients in whom underlying causative disorders were diagnosed, whereas patients without identifiable underlying causes all had favorable outcomes.

Discussion

Clinical Presentation

Several important observations emerge from this series, which is the largest reported to date. First, patients with spontaneous isolated convexity SAH resembled those with aneurysmal SAH in age and sex distribution,24 but their presenting symptoms were atypical. Only 6 patients (30%) in our series presented with thunderclap headache and 1 (5%) had nuchal rigidity. In contrast, patients with aneurysmal SAH present with thunderclap headache in up to 74% of cases and display nuchal rigidity in 35% of cases.8,9 Conversely, seizures and focal neurological deficits were more frequent after spontaneous convexity SAH. Seizure at presentation was noted in 4 (20%) of 20 patients in our series and in 7 (58%) of 12 patients in the series reported by Spitzer et al.40 Both rates contrast with the 6–7% incidence reported after aneurysmal SAH.3,23,31,43 A high rate of focal neurological deficits was also noted in our study (35%) and that of Spitzer et al. (42%), which is greater than that reported for aneurysmal SAH.43

Several explanations for these differences in presentation may exist. Spitzer and colleagues40 suggested that the lower incidence of thunderclap headache and nuchal rigidity may reflect a smaller volume of subarachnoid blood, its confinement outside the basal cisterns, or a nonarterial source of hemorrhage. It may also relate to inherent differences in the causes of the disease between the 2 populations of patients with SAH. Whereas SAH from a ruptured aneurysm is an isolated event that accounts for the sudden and severe appearance of symptoms, in contrast, many of the disorders leading to isolated convexity SAH (for example, PRES, lupus vasculitis, and cerebral venous thrombosis) cause headaches in the absence of SAH. It is therefore not surprising that headaches associated with convexity SAH have a variable rapidity of onset as well as in overall quality and severity. The higher incidence of seizures and focal neurological deficits associated with convexity SAH probably reflects the more extensive parenchymal involvement of many of the underlying causes. Local cortical irritation by subarachnoid blood may also be a contributing factor.40

Radiological Evaluation

A second observation in this study is the need for a systematic and often multimodal approach toward identifying underlying causative disorders. Head CT scanning without contrast agents continues to be the study of choice for screening acute cerebral hemorrhage. In our series, head CT scanning was diagnostic of convexity SAH in 18 (95%) of the 19 patients initially examined. One patient (Case 11) had normal CT findings, but subsequent MR imaging revealed subacute blood over the right frontal convexity. The sensitivity of CT scanning declines markedly in the subacute setting.35 We therefore recommend MR imaging (which is clearly superior to CT by Day 5),46 as the initial neuroimaging study when patients present in delayed fashion.

Differential Diagnosis and Workup

Following initial diagnosis of convexity SAH, further evaluation is required to identify a potential underlying cause and a direct therapy specific to the origin of the SAH (for example, antihypertensive therapy for PRES, platelet transfusion for thrombocytopenia, anticoagulation for venous thrombosis, and steroids for vasculitis). Because the differential diagnosis is broad, subsequent workup must evaluate for the varied causes. Vital signs should be obtained in all patients, because hypertension is a key feature of PRES (it was the cause in 5 cases in our series). All patients should be tested for the platelet count and prothrombin time to rule out thrombocytopenia or coagulopathy (the cause in 3 cases in our series).

In the absence of clinical or laboratory clues to suggest a definitive origin, we recommend that patients undergo MR imaging, which is sensitive to many causes of convexity SAH including PRES,7 mass lesions,40 vasculitis,2 dural sinus thrombosis,6,27 cortical venous thrombosis,5,28 cerebral AVMs,12 dural AVFs,44 and cavernous malformations.17 In patients with unrevealing MR imaging studies, DS angiography should be considered, because it can demonstrate narrowing of medium-sized arteries (of concern as a sign of vasculitis or vasculopathy), segmental cerebral vasoconstriction (a sign of Call–Fleming syndrome), and aneurysms or other vascular malformations. In our series, DS angiography led to the diagnosis of a specific vasculopathy in 2 patients; vasculitis in one, and Call–Fleming syndrome in the other.

Although not diagnostic, CSF analysis in the appropriate clinical context can provide corroborative information in support of a specific diagnosis. For example, pleocytosis, elevated protein, and increased immunoglobulin G suggest vasculitis (the cause of 1 case in our series). Additional hematological studies, including erythrocyte sedimentation rate, C-reactive protein, and serum antibody screens can often be helpful.

Using the aforementioned diagnostic schema, we identified a definitive underlying cause in 13 of 20 patients. The most common cause was PRES (5 patients, 25%), which is a clinicoradiological entity characterized by acute to subacute onset of headache, seizures, altered mental status, vomiting, and visual symptoms ranging from blurred vision to cortical blindness.13 On radiological evaluation, white and gray matter edema is typically seen in the parietooccipital lobes (Fig. 1), although more anterior involvement may occur.7 Posterior reversible encephalopathy syndrome may result from uncontrolled hypertension, immunosuppression, eclampsia, renal failure, drug overdose, connective tissue disorders, acute intermittent porphyria, and hypercalcemia.13,15,20,21,37,38,40,41 The syndrome is transient if treated early,13 but delayed diagnosis may lead to permanent neurological deficits.1 Four of our 5 patients with PRES had favorable outcomes, but 1 developed severe cerebral edema, resulting in herniation and brain death. Our experience suggests that convexity SAH on initial head CT scans may be the first radiographic clue to PRES. Because MR imaging is more sensitive in demonstrating the associated and often diagnostic parenchymal changes, this imaging modality should be performed in any patient in whom PRES is suspected.

Fig. 1.
Fig. 1.

Case 18. Neuroimages demonstrating convexity SAH associated with PRES. On a head CT scan obtained without contrast material (A), hyperdensity is seen along the right frontal sulci, consistent with SAH (white arrow). There is also a vague focus of hypodensity within the left parietal lobe (black arrow). Further evaluation by FLAIR MR imaging revealed hyperintensity over the right frontal lobe corresponding to the known SAH. Additional FLAIR images revealed hyperintensity predominantly involving the white matter of the left more than the right parietal lobe (B), with no corresponding diffusion restriction to suggest ischemia (C). These changes represent vasogenic edema due to PRES.

Thrombocytopenia or anticoagulant-induced coagulopathy was the identified underlying cause in 3 of our patients. Coagulopathy and thrombocytopenia are known causes of spontaneous SAH in the setting of multisystemic disease.33,36 Management includes cessation of the offending medication, platelet transfusions, fresh-frozen plasma transfusions, and the administration of vitamin K. In the setting of cerebral hemorrhage, therapeutic goals generally include maintaining platelet counts of > 100,000/μl and normalizing the patient's international normalized ratio.

Angiographically evident vasculopathy was noted in 2 of our cases. One patient had postpartum cerebral angiopathy, a known cause of convexity SAH.42 These patients are usually healthy young women who present with acute headache, seizures, neurological deficits, and angiographic findings consistent with vasospasm or vasculitis.42 Drug- induced vasculopathy and SAH have previously been attributed to the dietary supplement ephedra.11 Our case represents the second one in which the temporal association between ephedra consumption, isolated SAH, and angiographic abnormalities suggests a causal relationship. Other dietary supplements such as phenylpropanolamine have also been associated with intracerebral hemorrhage.10,16

Lupus vasculitis was identified in 1 of our patients. Subarachnoid hemorrhage in patients with systemic lupus erythematosus is well described.18,28 Central nervous system vasculitis may be a secondary manifestation of an underlying systemic vasculitis (for example, Wegener granulomatosis, polyarteritis nodosa, or Churg–Strauss syndrome), or connective tissue disorder (for example, systemic lupus erythematosus).25 Alternatively, central nervous system vasculitis may represent a primary condition known as isolated angiitis of the central nervous system.19,29,39 Both DS angiography (assessing for narrowing of medium-sized arteries) and MR imaging (assessing for associated parenchymal abnormalities) should be pursued when the diagnosis of vasculitis is being considered. Additional studies such as serum antibody and CSF analyses can often lead to a definitive diagnosis. However, in some circumstances when diagnosis proves elusive, an open brain biopsy may be required.14

Another case of convexity SAH in our series was ascribed to hypertensive microangiopathy. In patients with chronic uncontrolled hypertension, microangiopathic changes to the cerebral vasculature can result in intracranial bleeding. Diagnosis is made based on MR imaging results in the context of chronic hypertension, with characteristic microhemorrhages and lacunae in the corticosubcortical region and deep gray matter.22

The final case of this series was attributed to Call– Fleming syndrome.4 This syndrome is characterized by thunderclap headache and reversible cerebral vasoconstriction. The vasoconstriction may last days or weeks and cause infarction. It has been associated with the postpartum period, migraines, use of cocaine or amphetamines, and the abrupt cessation of selective serotonergic receptor inhibitors.26 In the present study we report on a 52-yearold woman presenting with thunderclap headache and right homonymous hemianopia. Initial head CT studies demonstrated SAH in the bilateral parietal lobes, and brain MR imaging revealed bilateral parietooccipital SAH. The initial DS angiography study was negative for vascular abnormality. A second session of DS angiography performed at 7 days showed subtle new narrowing of the proximal SCAs bilaterally (Fig. 2A). Approximately 10 days later, the patient developed new left upper-extremity weakness and worsening visual complaints. The MR imaging demonstrated small acute infarctions primarily in the right parietooccipital convexity and an associated left occipital lobe hematoma. The patient was then taken to the operating room, where clot evacuation and parietal brain biopsy were accomplished. The biopsy was inconclusive for vasculitis but did demonstrate thickening of cortical blood vessels. Repeated angiography showed diffuse segmental narrowing of bilateral internal carotid and vertebrobasilar arteries (Fig. 2B). She was treated with calcium channel blockers and ultimately discharged to inpatient rehabilitation with improved left upper-extremity strength and vision. A final angiogram obtained 2 weeks later showed complete resolution of the vasculopathy. Because the patient's initial presentation resembled that described by Call et al.,4 and subsequent DS angiography showed segmental vasoconstriction, we considered her condition to be Call– Fleming syndrome. It is the first such case to be associated with SAH.

Fig. 2.
Fig. 2.

Case 13. Angiograms demonstrating convexity SAH associated with Call–Fleming syndrome. A: Right vertebral angiogram, anteroposterior injection. Subtle mild irregularity of both SCAs is present, a change from the initial study obtained on admission. B: A third angiogram obtained 10 days later, following clinical deterioration and an MR imaging study showing multiple small acute infarcts in the right parietooccipital convexity with an associated left occipital hematoma (MR image not shown). The cerebral angiogram depicted multiple new severe arterial narrowings, which were worst in the posterior circulation, but also involved both intracranial carotid artery territories.

Other possible causes of convexity SAH reported in the literature, but not seen in our case series, include mycotic aneurysm,33,43 superficial AVM,43 dural AVF,44 transmural arterial dissection,35 cavernous malformation,40,45 dural sinus/cortical vein thrombosis,5,27,28 brain abscess,32 and brain neoplasm.40 All of these potential causes of spontaneous isolated convexity SAH should be pursued with rigorous diagnostic workup, as detailed earlier.

Clinical Course

A final observation involves the generally benign clinical course of patients with isolated convexity SAH, compared with aneurysmal SAH. The majority of patients in our series (75%) had complete or near-complete return to their premorbid condition by the time of discharge (mean hospital stay 16.5 days). The clinical course, however, was highly dependent on the underlying origin of the disease. For example, all patients without an underlying causative disorder had a favorable outcome, whereas only 8 of 13 patients with a definitive underlying diagnosis fared as well. Hydrocephalus and symptomatic cerebral vasospasm were rare, with only 1 patient (who experienced the largest volume of subarachnoid blood in our series) developing such complications, neither of which led to long-term clinical sequelae.

Conclusions

Spontaneous isolated SAH over the cerebral convexity is rare. Compared with aneurysmal SAH, patients present less commonly with thunderclap headache and nuchal rigidity and more commonly with seizures and focal neurological deficits. Spontaneous convexity SAH carries a broad differential diagnosis. The most common cause in our series was PRES, which accounted for 22% of cases. Diagnostic workup should include head CT scans obtained without contrast agent as well as platelet count and prothrombin time. Most patients also require brain MR imaging, and selected individuals may benefit from diagnostic catheter angiography. A CSF evaluation and certain hematological studies are indicated in the case of suspected vasculitis. General treatment measures include serial neurological evaluations, seizure prophylaxis, and analgesics. Prophylactic use of nimodipine may be reserved for those patients with the largest volume of subarachnoid blood. Treatment directed toward the underlying condition (when identified) is paramount. Finally, although complications specific to the underlying disorder can occur, the overall prognosis for this patient population is generally favorable.

Disclaimer

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

References

Article Information

Address correspondence to: Daniel Refai, M.D., Department of Neurosurgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8057, Saint Louis, Missouri 63110. email: refaid@nsurg.wustl.edu.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Case 18. Neuroimages demonstrating convexity SAH associated with PRES. On a head CT scan obtained without contrast material (A), hyperdensity is seen along the right frontal sulci, consistent with SAH (white arrow). There is also a vague focus of hypodensity within the left parietal lobe (black arrow). Further evaluation by FLAIR MR imaging revealed hyperintensity over the right frontal lobe corresponding to the known SAH. Additional FLAIR images revealed hyperintensity predominantly involving the white matter of the left more than the right parietal lobe (B), with no corresponding diffusion restriction to suggest ischemia (C). These changes represent vasogenic edema due to PRES.

  • View in gallery

    Case 13. Angiograms demonstrating convexity SAH associated with Call–Fleming syndrome. A: Right vertebral angiogram, anteroposterior injection. Subtle mild irregularity of both SCAs is present, a change from the initial study obtained on admission. B: A third angiogram obtained 10 days later, following clinical deterioration and an MR imaging study showing multiple small acute infarcts in the right parietooccipital convexity with an associated left occipital hematoma (MR image not shown). The cerebral angiogram depicted multiple new severe arterial narrowings, which were worst in the posterior circulation, but also involved both intracranial carotid artery territories.

References

1

Antunes NLSmall TNGeorge DBoulad FLis E: Posterior leukoencephalopathy syndrome may not be reversible. Pediatr Neurol 20:2412431999

2

Aviv RIBenseler SMDeVeber GSilverman EDTyrrell PNTsang LM: Angiography of primary central nervous system angiitis of childhood: conventional angiography versus magnetic resonance angiography at presentation. AJNR Am J Neuroradiol 28:9152007

3

Butzkueven HEvans AHPitman ALeopold CJolley DJKaye AH: Onset seizures independently predict poor outcome after subarachnoid hemorrhage. Neurology 55:1315 13202000

4

Call GKFleming MCSealfon SLevine HKistler JPFisher CM: Reversible cerebral segmental vasoconstriction. Stroke 19:115911701988

5

Chang RFriedman DP: Isolated cortical venous thrombosis presenting as subarachnoid hemorrhage: a report of three cases. AJNR Am J Neuroradiol 25:167616792004

6

Ciccone ACitterio ISantilli ISterzi R: Subarachnoid haemorrhage treated with anticoagulants. Lancet 356:18182000

7

Covarrubias DJLuetmer PHCampeau NG: Posterior reversible encephalopathy syndrome: prognostic utility of quantitative diffusion-weighted MR images. AJNR Am J Neuroradiol 23:103810482002

8

de Falco FA: Sentinel headache. Neurol Sci 25:3 SupplS215 S2172004

9

Fontanarosa PB: Recognition of subarachnoid hemorrhage. Ann Emerg Med 18:119912051989

10

Glick RHoying JCerullo LPerlman S: Phenylpropanolamine: an over-the-counter drug causing central nervous system vasculitis and intracerebral hemorrhage. Case report and review. Neurosurgery 20:9699741987

11

Haller CABenowitz NL: Adverse cardiovascular and central nervous system events associated with dietary supplements containing ephedra alkaloids. N Engl J Med 343:183318382000

12

Hartmann AMast HMohr JPKoennecke HCOsipov APile-Spellman J: Morbidity of intracranial hemorrhage in patients with cerebral arteriovenous malformation. Stroke 29:9319341998

13

Hinchey JChaves CAppignani BBreen JPao LWang A: A reversible posterior leukoencephalopathy syndrome. N Engl J Med 334:4945001996

14

Josephson SAPapanastassiou AMBerger MSBarbaro NMMcDermott MWHilton JF: The diagnostic utility of brain biopsy procedures in patients with rapidly deteriorating neurological conditions or dementia. J Neurosurg 106:72 752007

15

Kastrup OMaschke MWanke IDiener H: Posterior reversible encephalopathy syndrome due to severe hypercalcemia. J Neurol 249:156315662002

16

Kernan WNViscoli CMBrass LMBroderick JPBrott TFeldmann E: Phenylpropanolamine and the risk of hemorrhagic stroke. N Engl J Med 343:182618322000

17

Kim CHKim HJ: Cervical subarachnoid floating cavernous malformation presenting with recurrent subarachnoid haemorrhage. J Neurol Neurosurg Psychiatry 72:6682002

18

Krishnan E: Stroke subtypes among young patients with systemic lupus erythematosus. Am J Med 118:14152005

19

Kumar RWijdicks EFBrown RDJParisi JEHammond CA: Isolated angiitis of the CNS presenting as subarachnoid haemorrhage. J Neurol Neurosurg Psychiatry 62:6496511997

20

Kupferschmidt HBont ASchnorf HLandis TWalter EPeter J: Transient cortical blindness and bioccipital brain lesions in two patients with acute intermittent porphyria. Ann Intern Med 123:5986001995

21

Kwon SKoo JLee S: Clinical spectrum of reversible posterior leukoencephalopathy syndrome. Pediatr Neurol 24:361 3642001

22

Lee SHBae HJKo SBKim HYoon BWRoh JK: Comparative analysis of the spatial distribution and severity of cerebral microbleeds and old lacunes. J Neurol Neurosurg Psychiatry 75:4234272004

23

Linn FHRinkel GJAlgra Avan Gijn J: Headache characteristics in subarachnoid haemorrhage and benign thunderclap headache. J Neurol Neurosurg Psychiatry 65:7917931998

24

Longstreth WT JrNelson LMKoepsell TDvan Belle G: Clinical course of spontaneous subarachnoid hemorrhage: a population-based study in King County, Washington. Neurology 43:7127181993

25

Moore PMRichardson B: Neurology of the vasculitides and connective tissue diseases. J Neurol Neurosurg Psychiatry 65:10221998

26

Noskin OJafarimojarrad ELibman RNelson J: Diffuse cerebral vasoconstriction (Call-Fleming syndrome) and stroke associated with antidepressants. Neurology 67:1591602006

27

Oppenheim CDomigo VGauvrit JLamy CMackowiak-Cordoliani MPruvo J: Subarachnoid hemorrhage as the initial presentation of dural sinus thrombosis. AJNR Am J Neuroradiol 26:6146172005

28

Oshiro SMotomura KFukushima T: Systemic lupus erythematosus manifesting as subarachnoid hemorrhage induced by cortical venous thrombosis and followed by medial medullary infarction. No To Shinkei 55:7917952003

29

Ozawa TSasaki OSorimachi TTanaka R: Primary angiitis of the central nervous system: report of two cases and review of the literature. Neurosurgery 36:1731791995

30

Patel KCFinelli PF: Nonaneurysmal convexity subarachnoid hemorrhage. Neurocrit Care 4:2292332006

31

Pinto ANCanhao PFerro JM: Seizures at the onset of subarachnoid haemorrhage. J Neurol 243:1611641996

32

Rhode Vvan Oosterhout AMull MGilsbach J: Subarachnoid haemorrhage as initial symptom of multiple brain abscesses. Acta Neurochir (Wien) 142:2052082000

33

Rinkel GJvan Gijn JWijdicks EF: Subarachnoid hemorrhage without detectable aneurysm. A review of the causes. Stroke 24:140314091993

34

Ruigrok YMRinkel GJBuskens EVelthuis BKvan Gijn J: Perimesencephalic hemorrhage and CT angiography: A decision analysis. Stroke 31:297629832000

35

Schwedt TJMatharu MSDodick DW: Thunderclap headache. Lancet Neurol 5:6216312006

36

Segura TFiguerola ALeón TVivancos J: [Subarachnoid hemorrhage as a form of onset of systemic lupus erythematosus.]. Rev Neurol 27:9849851998. (Spn)

37

Servillo GStriano PStriano STortora FBoccella PDe Robertis E: Posterior reversible encephalopathy syndrome (PRES) in critically ill obstetric patients. Intensive Care Med 29:232323262003

38

Shah AK: Non-aneurysmal primary subarachnoid hemorrhage in pregnancy-induced hypertension and eclampsia. Neurology 61:1171202003

39

Siva A: Vasculitis of the nervous system. J Neurol 248:451 4682001

40

Spitzer CMull MRohde VKosinski C: Non-traumatic cortical subarachnoid haemorrhage: diagnostic work-up and aetiological background. Neuroradiology 47:5255312005

41

Teksam MCasey SMichel ETruwit C: Subarachnoid hemorrhage associated with cyclosporine A neurotoxicity in a bone-marrow transplant recipient. Neuroradiology 43:242 2452001

42

Ursell MRMarras CLFarb RRowed DWBlack SEPerry JR: Recurrent intracranial hemorrhage due to postpartum cerebral angiopathy: implications for management. Stroke 29:199519981998

43

van Gijn JRinkel GJ: Subarachnoid haemorrhage: diagnosis, causes and management. Brain 124:2492782001

44

van Rooij WJSluzewski MBeute GN: Dural arteriovenous fistulas with cortical venous drainage: incidence, clinical presentation, and treatment. AJNR Am J Neuroradiol 28:6516552007

45

Voigt KYaºargil MG: Cerebral cavernous haemangiomas or cavernomas. Incidence, pathology, localisation, diagnosis, clinical features and treatment Review of the literature and report of an unusual case. Neurochirurgia (Stuttg) 19:59681976

46

Wiesmann MBrückmann H: [Magnetic resonance imaging of subarachnoid hemorrhage.]. Rofo 176:5005052004. (Ger)

TrendMD

Metrics

Metrics

All Time Past Year Past 30 Days
Abstract Views 12 12 12
Full Text Views 172 172 84
PDF Downloads 112 112 63
EPUB Downloads 0 0 0

PubMed

Google Scholar