Journal of Neurology, Neurosurgery, and Psychiatry, 1976, 39, 381-384

'Sneeze syncope,' basilar invagination and Arnold-Chiari type I malformation

J. J. CORBETT, A. B. BUTLER, AND B. KAUFMAN

From the Departments of Neurology and Neurosurgery, Naval Hospital, Portsmouth, Virginia,and Department of Radiology, University Hospitals of Cleveland, Case- Western Reserve University,

Cleveland, Ohio, USA

SYNOPSIS Syncope precipitated by sneezing in an adult male associated with an Arnold-Chiaritype I malformation and basilar invagination presents a clinical problem in the differential diagnosisand pathological anatomy of Valsalva-related syncope. An abnormally acute clivoaxial angle, smallforamen magnum, and type I Arnold-Chiari malformation appear to be a combination of featuresintolerant of Valsalva-induced changes in cerebral volume, brain-stem position, CSF fluid dy-namics, or blood vessel relationships. Proposed mechanisms of pressure transmission to the area ofintracranial pathology are discussed.

Sneezing, or any other brief Valsalva manoeuvremay, in rare instances, result in syncope (Engel,1962). 'Sneeze syncope' was the presentingsymptom of an adult male who had both basilarinvagination and type I Arnold-Chiari mal-formation. The relationship between thesecraniovertebral structural anomalies and thephysiological events of the Valsalva manoeuvreis the subject of this report.

1 Reprint requests: Dr Albert B. Butler, Department of NeurologicalSurgery, Univessity ofVirginia, Charlottesville, Virginia 22901, U.S.A.

(Accepted 4 December 1975.)

120'

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CASE REPORT

A 29 year old man (PNH221862) was seen in con-sultation at the Naval Hospital, Portsmouth, Vir-ginia, with the chief complaint of dizziness associ-ated with sneezes, which had been occurring for thepreceding 15 years. Each episode was essentiallyidentical, beginning with a sneeze (although not allsneezes produced the dizziness) and followed im-mediately by a 'crick' sensation in the back of theneck (the patient could not characterize this sen-sation more specifically). Severe vertigo then oc-curred lasting 45 to 60 seconds, followed by nauseawhich would persist for up to 15 minutes. Nausea,

FIG 1 Line drawingof the skull andupper cervical spineshowing the clivo-axial angle (theangle formed bythe plane of theclivus and theaxis ofthe odontoid)to be 120 degrees.Basilar invaginationis present with Bull'sangle being 27degrees and Cham-berlain's line passesthrough the body ofC2 vertebra.

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FIG. 2 Lateral laminagram ofthe skull and cervical spineshows the unfused anteriorneural arch (right side) of Clbeneath the basioccipital bone(arrow). The posterior edgeof the foramen magnum(opisthion) is indicated by thearrowhead (F).

FIG. 3 Lateral laminagramshows the classical appearanceof 'occipitalization' of the leftside of the posterior neuralarch of Cl vertebra (arrows).The anterior neural arch of Clvertebra, occipital condyle,and lateral mass of Clvertebra present as a non-segmented mass

present for only the last three years, was a relativelynew feature of the symptom complex. In addition tosneezing, more recently the patient noted thatstraining during bowel movements and isometricexer-cises could produce an identical sequence of events.The symptoms were sequentially invariable but thecomplex occurred unpredictably, in a ratio of aboutone sneeze (or other Valsalva manoeuvre) in three.Two weeks before his hospitalization while shavingone morning, he sneezed and suffered a typicalattack which progressed rapidly from the 'sneeze-and-vertigo phase' to an abrupt, brief loss of con-

sciousness of three to four seconds. For 15 minutesafter this episode, any attempt at walking was attend-ed by a tendency to drift to the right 'as thoughdrunk'. Headache, diplopia, dysphagia, hoarseness,weakness of arms or legs were not present then orlater. A history was elicited of occasional brief'electric shock sensations' radiating into both armson flexion of his head consistent with Lhermitte'sphenomenon.

Physical examination revealed a short (170.1 cm),stocky (79.5 kg) man with a thick, short neck. Noabnormalities of any of the cranial nerves, strength,

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Snteeze syncope

FIG. 4 The AP laninlagram of the craniovertebraljunctioni documentis the seginentation error, 'occipitali-zation', of Cl vertebra on the left side (arrow). Theodontoidprocess is seen in the centre (*).

tone or reflexes, cerebellar or sensory function were

found on repeated examinations.Radiographic examination of the skull and cervi-

cal spine revealed partial occipitalization of Clvertebra, a clivoaxial angle of 120 degrees, andbasilar invagination (impression) (Fig. 1). Lamino-graphy showed the unfused neural arch of Clvertebra on the right to be closely applied under thebasioccipital bone anteriorly (Fig. 2). On the leftside, the lateral mass and neural arch had not seg-mented from the occipital bone, giving the classicalappearance of 'occipitalization of C I ' (Figs 3 and 4).A pneumoencephalogram showed only slight filling ofthe lateral ventricles. A complete evaluation of theposterior fossa was not accomplished. Arteriographywas not performed because of a prior anaphylaticreaction to iodized contrast material.At operation an Arnold-Chiari type I malfor-

mation with herniation of the cerebellar tonsils tothe level of C3 vertebra was found. A suboccipitalcraniectomy and decompressive laminectomy of thefirst and second cervical vertebrae was performedwith alleviation of all symptoms.

DISCUSSION

This patient presents a clinical problem in thedifferential diagnosis of Valsalva-related syncope(Engel, 1962). The Valsalva manoeuvre, a forcibleexpiration of air against closed glottis, has dif-ferent effects on cerebrospinal fluid, venous, andarterial pressures. Sudden increase in intra-thoracic and intra-abdominal pressure with theValsalva manoeuvre causes an instantaneous

increase in cerebrospinal fluid pressure equal tothe intrathoric pressure. This increased pressureis due to engorgement of valveless veins in theepidural Batson's plexus and invagination ofspinal sleeves into the intervertebral foramina(Hamilton et al., 1944; Martins et al., 1972).Jugular venous pressure increases more slowlyand never quite equals intrathoracic or CSFpressure (Hamilton et al., 1944). The sequenceof events in the arterial system consists of abrief increase in systolic blood pressure begin-ning immediately at the onset of increased air-way pressure. Mean blood pressure then dropsrapidly to very low levels and rises slowly witha narrow pulse pressure until the glottis opens.Once the manoeuvre ends, the pulse pressuresuddenly increases and a mild bradycardiaensues (Gorlin et al., 1957).True Valsalva-related 'sneeze syncope' is rare

and is said to require several sneezes in rapidsequence (Engel, 1962). The multiple rapid dropsin arterial pressure associated with decreasedblood return to the right ventricle, decreasedeffective cardiac filling pressure, as well as adrop in stroke volume output and mean arterialpressure produce temporary cerebral ischaemiaand at times loss of consciousness. This is trulya cardiovascular event. In contrast, our patientnever needed to sneeze in rapid succession toproduce the symptom complex. In addition, hewas able to produce identical symptoms withother rather modest Valsalva manoeuvres. Itthen appears that some other mechanism maybe related to his loss of consciousness.

Williams (1972) has measured the CSF pres-sure in both spinal canal and ventricles ofpatients with Arnold-Chiari malformation. Hefound a definite time differential between thepressure increase in the lumbar sac and thepressure increase in the ventricles during Val-salva manoeuvres. The CSF pressure wave in thelumbar theca is generated by increased intra-thoracic and intra-abdominal pressure. This isreflected instantaneously in dilatation of thevalveless Batson's plexus. The increase in venouspressure around the lumbar theca is then re-flected in the raised cerebrospinal (CSF) pres-sure. The resulting pulse pressure generatedpropagates upward in a wave through the fora-men magnum and increases pressure in theposterior fossa. The pressure is then distributed

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within the intracranial compartment. In thepatient with Arnold-Chiari malformation, thispressure increase presumably results in furtherherniation of the cerebellar tonsils (Williams,1972). This phenomenon has been observedduring surgery on patients with Arnold-Chiarimalformation when cough has produced furtherherniation of the cerebellar tonsils (Mullan andRaimondi, 1962). Williams's hypothesis, al-though appealing, was not verified in studiesperformed by Martins et al. (1972). Patientsundergoing myelography were asked to performa Valsalva manoeuvre when the dye column wasat the craniocervical junction and the dye failedto move into the intracranial vault.

Larson et al. (1974) have reported two patientswith cough syncope and herniated cerebellartonsils who were studied with CSF pressurerecordings. The authors concluded from limitedstudies of CSF lumbar pressures that cerebellarherniation was secondary to expansion of cere-bral blood volume during cough. Evoked soma-tosensory potentials were performed before andafter coughing. Amplitude suppression duringcough and recovery of amplitude after return ofCSF pressure to normal suggests that compres-sion of the medulla by herniated tonsils mayalso contribute to syncope.The possibility of a strictly mechanical ana-

tomical explanation should also be considered.It has been reported that flexion of the neck inpatients with Arnold-Chiari malformation atthe time of surgery may result in respiratoryarrest (List, 1941; Mullan and Raimondi, 1962).Perhaps other cardiovascular events resulting insyncope could be produced as the result ofpercussion of the ventral medulla on the clivusor temporary vascular occlusion causing brain-stem ischaemia. An abnormally acute clivo-

axial angle, small foramen magnum, and type IArnold-Chiari malformation in concert appearto be anatomical features intolerant of briefValsalva-induced changes in cerebral volume,brain-stem position, CSF fluid mechanics, orblood vessel relationships.

It is not possible to say with certainty whethermechanical percussion of brain-stem against theanterior lip of the foramen magnum, temporaryocclusion of ventral brain-stem vessels, increasein cerebral volume with the Valsalva manoeuvre,or the succussion of a CSF pressure wave into asmall posterior fossa was responsible for ourpatient's symptoms. Any or all of these mechan-isms may have been operative.

The opinions expressed are those of the authors and notnecessarily those of the Department of the Navy.

REFERENCES

Engel, G. L. (1962) Fainting. Thomas: Springfield, Ill.Gorlin, R., Knowles, J. H., and Storey, C. F. (1957). The

Valsalva maneuver as a test of cardiac function. AmericanJournal of Medicine, 22, 197-212.

Hamilton, W. F., Woodbury, R. A., and Harper, H. T. (1944).Arterial, cerebrospinal and venous pressures in manduring cough and strain. American Journal of Physiology,141, 42-50.

Larson, S. J., Sances, A., Baker, J. B., and Reigel, D. H.(1974). Herniated cerebellar tonsils and cough syncope.Journal of Neurosurgery, 40, 524-528.

List, C. F. (1941). Neurologic syndromes accompanyingdevelopmental anomalies of occipital bone, atlas and axis.Archives of Neurology and Psychiatry, 45, 577-616.

Martins, A. N., Wiley, J. K., and Myers, P. W. (1972). Dy-namics of the cerebrospinal fluid and the spinal dura mater.Journal of Neurology, Neurosurgery, and Psychiatry, 35,468-474.

Mullan, S., and Raimondi, A. J. (1962). Respiratory hazardsof the surgical treatment of the Arnold-Chiari malforma-tions. Journal of Neurosurgery, 27, 675-678.

Williams, B. (1972). The valvular action of the Arnold-Chiarimalformation. In Intracranial Pressure, pp. 338-442.Edited by M. Brock and H. Dietz. Springer: Berlin.

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