Movement Disorders in Brain Sagging Syndrome Due To Spontaneous Intracranial Hypotension: A Review

Gait unsteadiness

The most common phenomenology reported in BSS is gait unsteadiness. Gait unsteadiness frequently emerges in the backdrop of one or several cardinal symptoms of SIH/BSS. Nowak and colleagues were the first to report paroxysmal ataxia along with visual blurring in a 50-year-old man with CSF leak at T12–L1 level [12]. Patient’s gait improved substantially after EBP. Subsequently, several other publications (Table 1) reported gait unsteadiness as a major presenting symptom along with the classic symptoms of SIH/BSS [13, 14, 15, 16, 17]. All these reports are on middle aged patients who improved substantially after EBP or only with conservative therapy [16]. Our literature search revealed only one article that reported ataxia related to SIH/BSS in a child [18]. Uysal and colleagues reported gait ataxia in a five-year-old girl along with chronic headache and hearing loss. Imaging revealed enlargement of cervical venous plexus and a dural leak at L3–L4. Similar to majority of the case reports summarized in Table 1, the child in Uysal et al.’s report improved substantially after EBP [18]. Although gait dysfunction usually co-exists with the classic symptoms/signs of SIH/BSS, rarely, patients may present with isolated gait dysfunction. Sasikumar and colleagues reported isolated gait dysfunction in a 64-year-old man and an 80-year-old woman [19]. In the 64-year-old man, objective gait assessment revealed reduced stride length and velocity along with a broad-based stance and frequent swaying. There were subjective as well as objective improvement in gait after multiple non-targeted blood patch. Gait unsteadiness of the 80-year-old woman improved spontaneously in 6 months [19].

In addition to the aforementioned reports, several case series have reported gait unsteadiness in patients with SIH/BSS. Six out of eight patients in the study by Wicklund et al., 19 out of 29 patients in the study by Schievink et al. and five out of eight patients in the study by Capizzano et al. had gait unsteadiness at presentation [20, 21, 22]. Radiological evidence of brain sagging was the common finding in all these studies. There were variations in the extent and duration of improvement in the symptoms after EBP [20, 21, 22].

It is important to note that, due to involvement of the common neuroanatomical substrates, gait dysfunction in SIH/BSS frequently co-exists with other movement disorders. For example, the patient described in the reports by Devin et al., [16] and Domínguez et al., [17] had postural tremor and kinetic tremor of the arms, respectively.

Tremor

Tremor is the second most commonly reported movement disorder in SIH/BSS (Table 2). It usually co-exists with gait dysfunction of varying severity. In the case series by Schievink et al., 15 out of 29 patients had tremor; however, the exact phenomenology of tremor was not mentioned [21]. In several case reports, the tremor phenomenology was documented as postural and/or kinetic involving both arms [16, 17, 23, 24]. In a case series of five patients, Mokri described two patients with tremor [25]. While one patient had right hand rest and action tremor (without bradykinesia), other had dystonic head tremor (with torticollis). The former experienced partial improvement with EBP and intravenous normal saline infusions. In an interesting report, Iyer and colleagues described a 23-year-old patient with Holmes tremor in the context of SIH/BSS [26]. In addition to Holmes tremor of right hand, the patient had several other clinical signs such as somnolence, upgaze restriction, and pupillary light near dissociation. With conservative measures (increased hydration and rest in Trendelenburg position), the patient had excellent recovery.

In summary, patients with SIH/BSS may present with various tremor phenomenologies (rest, postural, kinetic, dystonic). The most commonly reported phenomenology is postural and kinetic tremor of the arms. Isolated tremor has not been reported as a feature of SIH/BSS. Any patient presenting with subacute onset of tremor in the backdrop of chronic headache, memory issues, or gait unsteadiness should be investigated in detail to explore SIH/BSS.

Parkinsonism

Several authors have reported subacute parkinsonism in patients with BSS (Table 3). Pakiam and colleagues were the first to publish a report on parkinsonism in a 55-year-old woman with BSS [27]. The patient had asymmetric rest tremor and bradykinesia along with soft speech and gait unsteadiness. The patient had some of the commonly observed radiological signs that include downward displacement of posterior fossa structures and elongation of the brainstem in the anterior-posterior plane. The patient had complete recovery 5-weeks after having EBP. Mokri reported a 78-year-old man with rest tremor along with gait unsteadiness, memory problem, and slowness in thinking [25]. Examination revealed some of the core features of parkinsonism such as rigidity and walking with short steps. The patient had imaging evidence of brain sagging and improved spontaneously in a few months. Parkinsonism may emerge with bulbar symptoms, as reported by Cochran and colleagues in a 64-year-old woman [28]. The patient had parkinsonism in the form of rest and postural tremor of right arm, lip tremor, and bilateral upper extremity bradykinesia along with nasal speech, swallowing difficulty, and dysarthria. Patient was suspected to have a leak at T7 level, and the symptoms improved a few months after the surgical repair. Gupta and colleagues described a patient with parkinsonism in the context of SIH due to a CSF venous fistula at T9–T10 level and the patient improved substantially after ligating of the fistula [29]. Recently, Frachet and colleagues reported post-coma hemiparkinsonism in a patient with SIH/BSS caused by lumbar puncture for intrathecal chemotherapy [30]. The patient had gradual resolution of symptoms after EBP. As SIH usually does not lead to strikingly asymmetric symptoms/signs, it is unclear how the patient presented with hemiparkinsonism. A trial of levodopa, serial imaging of the dopamine transporter and longitudinal clinical evaluation would be valuable in such cases to see if the laterality of symptoms is due to asymmetric mechanical distortion of basal ganglia or due to transient unmasking of underlying dopaminergic deficit.

In the absence of chronic orthostatic or Valsalva headache, or any behavioral symptoms, clinical features mentioned above will be concerning for parkinsonism, either Parkinson’s disease (PD) or atypical forms. Although never reported, a patient with PD can also develop SIH/BSS and manifest with the additional cognitive, behavioral, and gait symptoms associated with the latter. Therefore, subacute worsening of parkinsonism in a patient with PD along with the emergence of new symptoms should not be attributed to natural progression of PD and should warrant detailed investigations to rule out or rule in treatable conditions such as SIH and BSS.

Chorea

There are a few case reports on chorea in patients with SIH/BSS. Mokri and colleagues reported generalized chorea (face, trunk, extremities) along with the classic symptoms of SIH/BSS in a 59-year-old man who was found to have CSF leak at cervicothoracic level [31]. Chorea used to be pronounced while walking. The patient recovered completely 4 months after having EBP. Upper limb chorea was reported in studies by Wicklund et al. and Capizzano et al., [20, 22]. Mulroy and colleagues reported chorea-athetosis in two cases of SIH/BSS [32]. These authors documented orofacial, lingual, and limb choreoathetosis in both cases. While epidural blood patch did not result in any improvement one patient, other had partial improvement for a short period. Although extremely rare, hemichorea may be a presenting sign of SIH/BSS [33]. However, similar to the patient with hemiparkinsonism mentioned above, it is unclear how SIH/BSS leads to asymmetric chorea and more studies are needed to obtain better insights.

SIH/BSS patients with chorea, who also have memory disturbance and several behavioral symptoms such as apathy, impulsivity, and disinhibition, can be easily mistaken for Huntington’s disease (HD), although the lack of positive family history should raise the suspicion of a different condition. BSS can be differentiated from HD also by the presence of postural/exertional headache. As described in the context of PD above, rapid worsening of chorea or neuropsychiatric symptoms in HD should not be attributed to the natural progression of HD and secondary etiologies should always be explored. For instance, Figueroa and colleagues reported a case of HD wherein rapid clinical worsening was found out to be secondary to BSS (due to CSF leak at C1–C2 level) [34]. The patient returned to baseline after epidural blood patch. In fact, patients with neurological conditions are often prone to falling and related trauma can contribute to CSF leakage.

Compulsive repetitive flexion with breath holding

In a recently published study, Schmahmann and Scheivink reported a specific sign that could be pathognomonic of BSS [35]. The study involved 51 patients with clinical and radiological features of BSS and reported repetitive flexion with breath-holding in 13 patients at presentation, and in 5 patients in whom these specific symptoms resolved prior to presentation. These repetitive movements were intermittent truncal and hip flexion, with a frequency of once in every 1–2 minutes and each episode lasted for 15–20 seconds. The authors hypothesized that those movements probably conferred some clinical benefit by decreasing the CSF-to-venous pressure gradient with breath holding (which would increase venous pressure), hence minimizing the loss of CSF from the arachnoid system. While the exact phenomenology has not been mentioned in other reports, the tendency to lean forward with hip flexion has been described [21, 36]. In the case report by Park and Kim, there was an acute onset truncal flexion, diagnosed as “camptocormia”, in a patient with SIH [36]. As the truncal flexion is presumed to be a compensatory strategy to reduce severe orthostatic headache, it is likely that the pathophysiology of this postural abnormality is different than what is seen in PD, multiple system atrophy or axial myopathies [37, 38, 39].

Other movement disorders

Another hyperkinetic phenomenology reported in BSS is orofacial dyskinesia, which was present in 6 out 29 patients reported by Schievink et al., [21]. The authors noted that the orofacial dyskinesia was associated with downward displacement of the corners of the mouth in 5 patients. A case of hemifacial spasm, in conjunction with headaches, was also reported by Chow et al., which subsequently improved on repeat epidural blood patches (and thereafter resolved on treatment with botulinum toxin) [40]. As mentioned above, in the case series by Mokri, one patient presented with spasmodic torticollis to the right (and side-to-side head tremor) that began after 5 years of exertional-Valsalva headaches with only partial benefit to 3 cervical EBPs [25].