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Polyradiculopathy and Multiple Cranial Nerve Palsies - Rare Manifestations of Cerebral Venous Sinus Thrombosis
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.310084
Keywords: Cerebral venous sinus thrombosis, polyradiculopathy, multiple cranial nerve palsies
Isolated intracranial hypertension is one of the important presenting features of intracranial venous sinus thrombosis. In addition to the more classic signs of intracranial hypertension such as headache, vomiting, and papilledema, patients may present with various false localizing signs. The notion of “false localizing signs” was first elucidated by James Collier in 1904. Sixth nerve palsy, either unilateral or bilateral, is the classic example of a false localizing sign. It occurs in the context of raised intracranial pressure of various causes. Neurological signs have been described as “false localizing” if they reflect dysfunction distant or remote from the expected anatomical locus of pathology[1]. Awareness that signs may be false localizing has implications for diagnostic investigation. Radiculopathy as a false localizing sign is very rare.
Case history: A 13-year-old male whose illness started with fever and vomiting of three weeks duration followed by unsteadiness of gait and slurring of speech. MRI taken at that point of time was normal. He was found to be positive for Salmonella typhi O and H (1/400 dilution). He was treated as para infectious cerebellitis. The unsteadiness of gait improved over the next few days and he was discharged. One week later, the patient developed acute onset of headache, vomiting, diplopia, neck pain, and weakness of all four limbs. On examination: Higher mental functions were normal; Cranial nerve examination showed normal visual acuity, peripheral constriction of visual fields with tubular vision, enlargement of the blind spot, bilateral papilledema, convergent squint, and bilateral restriction of abduction. Pupils were normal. Other cranial nerves were normal. Spinomotor examination revealed flaccid areflexic quadriparesis. The patient needed support to get up from squatting posture; proximal weakness (MRC grade: 4-) was more than distal weakness (4+) and lower limbs were weaker than upper limbs. All deep tendon jerks were absent. Bilateral plantar showed flexor response. Sensory examination was normal. No cerebellar signs were found during the second admission. Neck stiffness was present. Investigations: Complete blood count was normal except for mild anemia (Hb: 10.4 gms%). Routine blood biochemistry, renal function tests, serum electrolytes, peripheral blood smear, liver function tests, serum creatinine kinase and coagulation parameters (BT, CT, PT, APTT, INR) were within normal limits. Rheumatological workup (ANA, ACL antibodies, LAC) and hematological workup (protein C and S, antithrombin 3, serum homocysteine) were normal. Blood widal (repeat) was negative. HIV ELISA and HBsAg were negative. USG abdomen and pelvis were normal. CT brain (P & C) showed superior sagittal sinus thrombosis. MRI brain with MRA and MRV showed superior sagittal sinus and right transverse sinus thrombosis [Figure 1]. Nerve Conduction Studies (NCS) on both upper and lower limb nerves showed the total absence of F waves. The patient was treated with antiedema measures, anticoagulants, antibiotics, and acetazolamide. Repeat NCS done 2 weeks later showed re-appearance of F waves in both upper and lower limbs. Repeat assessment of visual fields showed progressive improvement; proximal weakness of both upper and lower limbs improved markedly over the next few weeks.
Case history A 23-year-old male presented with symptoms of headache, vomiting, blurring of vision, and diplopia following an alcohol binge. Two days later, the patient developed severe proximal weakness of all four limbs (upper limbs > lower limbs; right > left). The patient also had neck weakness and masticatory weakness. On examination Higher mental functions were normal. Cranial nerve examination showed normal visual acuity, bilateral peripheral constriction of visual fields, bilateral papilledema, bilateral restriction of abduction (R > L), and right trochlear nerve dysfunction. Pupils were normal. Bilateral masticatory weakness suggestive of the involvement of the motor component of the trigeminal nerve was present. Other cranial nerves were normal. Spinomotor system examination showed profound neck weakness, hypotonia of all four limbs, proximal weakness of all four limbs (upper limbs showed MRC grade of 1 to 2 on the right side and 3 on the left side, and lower limbs showed MRC grade of 3 on the right side and 4- on the left side). All deep tendon jerks were absent. Bilateral plantar showed flexor response. Sensory examination was normal. There were no cerebellar signs. Mild neck stiffness was present. Investigations Complete hemogram, routine blood biochemistry, renal function tests, liver function tests, serum creatinine kinase, serum electrolytes, and coagulation parameters (BT, CT, PT, APTT, INR) were normal. Blood VDRL and HIV ELISA were negative. Rheumatological workup (ANA, ACL antibodies, and LAC) and hematological workup (protein C and S; serum homocysteine) were normal. CT brain and MRI brain with MRA and MRV revealed [Figure 1]. NCS done on all four limbs showed the total absence of F waves [Figure 2] and [Figure 3]. He was treated with antiedema measures, anticoagulants, and acetazolamide. Repeat NCS done two weeks later showed re-appearance of F waves in all four limbs [Figure 4] and [Figure 5]. The patient showed improvement in visual fields and proximal weakness of limbs. He also showed recovery of right trochlear, bilateral trigeminal (motor), and bilateral abducent nerve function.
These two patients with intracranial venous sinus thrombosis presented with flaccid areflexic quadriparesis and transient cranial nerve dysfunction. Isolated intracranial hypertension being a common manifestation of intracranial venous sinus thrombosis may present with false localizing signs. Among the various false localizing signs described in patients with intracranial hypertension, radiculopathy is an important manifestation, which is probably under recognized. MRI brain of both of these patients showed no parenchymal lesions but MRV showed evidence of venous sinus thrombosis [Figure 5] and [Figure 6]. NCS revealed radiculopathy in both of these patients in the form of the absence of F waves [Figure 2], [Figure 3], [Figure 4] and [Figure 7]. Both of the patients showed bilateral constriction of visual fields and bilateral abducent nerve dysfunction. The second patient showed bilateral trigeminal (motor part) nerve and right trochlear nerve dysfunction in addition. All of the aforementioned symptoms were transient. Raised intracranial pressure was found to be the sole cause for all the clinical manifestations as evidenced by the resolution of symptoms and signs of cranial neuropathies and polyradiculopathy after the management of CVT. The re-appearance of F waves establishes a cause and effect relationship between elevated intracranial pressure and polyradiculopathy.
Moosa et al.[2],[3] discussed two female patients with blindness, ophthalmoplegia, and extensive radiculopathy in the presence of elevated intracranial pressure (ICP) resulting from idiopathic intracranial hypertension in one, and cerebral venous sinus thrombosis (CVT) in the other, the radiculopathy improving with thecoperitoneal shunt. Obeid et al.[4] reported two patients with polyradiculopathy and impending visual loss due to intracranial hypertension, which responded to thecoperitoneal shunt. Motor roots appear to be particularly vulnerable as weakness was the major deficit in cases reported by Obeid. Kuchnen et al.[6] described cases of transverse and sigmoid sinus thrombosis with raised intracranial pressure causing distortion or displacement of brainstem structures and/or pontine and medullary veins. Dysfunction of the fifth and seventh cranial nerves has been reported with raised intracranial pressure which may cause trigeminal neuropathy or trigeminal neuralgia or hemifacial spasm.[5] Most of these cases of flaccid areflexic quadriparesis are initially diagnosed as GBS. Though it is well known that papilledema rarely does occur in GBS, careful assessment of the evolution of the disease, MRV and electrophysiology may be useful in distinguishing GBS with papilledema from polyradiculopathy due to raised ICP. The mechanism of radicular dysfunction in elevated ICP might be due to distension and distortion of the subarachnoid space around the nerve roots. Documented enlargement of spinal subarachnoid space and distended root pouches in a patient with radicular pain and areflexia due to idiopathic intracranial hypertension supports this view. Radiculopathy secondary to intracranial hypertension has been reported almost exclusively in patients with IIH or cerebral venous sinus thrombosis. Other causes of intracranial hypertension may not induce a diffuse increase in pressure in both intracranial and intraspinal compartments, and are unlikely to manifest as radiculopathy. Venous ischemia of the nerve roots secondary to impaired venous outflow through the thin-walled radicular veins might have a role. A marked rise in ICP produces a potentially reversible dysfunction of the cranial nerves and spinal nerve roots. Timely recognition of this syndrome is necessary with regard to the preservation of vision and restoration of the power of the proximal muscles. Few of the unique features in our patients were that both the patients were young males in contrast to reports available in literature which are mostly about female patients. In addition, our patients showed marked improvement in symptoms with medical management of CVT in contrast to other reports which state improvement in radiculopathy only after thecoperitoneal shunt procedure. The initial manifestation of cerebellar ataxia in the first patient raises the possibility of ataxia being yet another false localizing sign of intracranial hypertension. The factors which predispose a small fraction of patients to develop these false localizing signs such as polyradiculopathy and multiple cranial nerve palsies in the presence of raised intracranial hypertension has to be investigated further. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]
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