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Pediatric cerebral venous sinus thrombosis (CVST) is not an uncommon condition. It is a dreadful condition, which can be easily missed until we suspect on clinical grounds. Here, we present a case of pediatric CVST following kidney transplantation in a child and the challenges in diagnosing the condition.

INTRODUCTION

Pediatric cerebral venous sinus thrombosis (CVST) is not an uncommon condition. Overall incidence is 0.67/100,000 children/year.[1] It is seen frequently after ear problems, coagulation disorders, and acute gastroenteritis with dehydration. It is a dreadful condition, which cannot be easily diagnosed until we suspect on clinical grounds. Here, we present a case of pediatric CVST following kidney transplantation in a child.

An 11-year-old male child, who underwent kidney transplant 3 years ago for renal failure secondary to bilateral congenital renal hypoplasia and currently on immunosuppressants (tablet tacrolimus, mycophenolate, and prednisolone acetate), presented to us with complaints of headache, double vision, and redness in the left eye for 8 days after an episode of fever.

On examination, best-corrected visual acuity in both eyes was 20/20. Near-vision was N6 in both eyes. Color vision tested with Ishihara's chart was normal. A left face turn of 20° was noted. Ocular movements showed −1 limitation of abduction in the left eye. Prism and alternate cover test for distance revealed 12–15 prism diopter esotropia in primary gaze, 20 prism diopter esotropia in levoversion, and 5 prism diopter in dextroversion, and 12–15 prism diopter esotropia for near suggestive of left abducens nerve palsy. On Hertel's exophthalmometry, a 2 mm axial proptosis in the left eye was noted. There was no palpable thrill or bruit. Retropulsion was normal.

Anterior segment of the right eye was unremarkable but of the left eye showed tortuous episcleral vessels in the nasal aspect of the left eye [Figure 1]. Pupils were 3 mm round, regular, and reactive. Corneal sensations were normal. Intraocular pressure with applanation tonometry was 20 mmHg in the right eye and 20 mmHg in the left eye. Ultrasound pachymetry revealed corneal thickness in the right eye to be 524 and 526 μ, respectively. Fundus examination showed disc edema in the right eye and hyperemic disc in the left eye.

Figure 1:

Slit-lamp examination of the left eye showing dilated tortuous episcleral vessels

Magnetic resonance imaging (MRI) brain with contrast was advised, which showed cerebrospinal fluid-filled sella with flattening of the pituitary gland – partial empty sella and vertical tortuosity of both optic nerves with prominent subarachnoid space. Hypoplastic right transverse sinus was also noted. The radiologist suggested possibility of idiopathic intracranial hypertension (IIH). We could not correlate the presence of tortuous episcleral vessels with IIH and hence went ahead to do MR venogram (MRV). MRV showed loss of flow void with filling defect in the left transverse sinus and bilateral sigmoid sinus (left > right) suggestive of thrombosis [Figure 2]. This was a diagnostic finding in MRV. A neurologist's opinion was advised. The child was admitted and treatment began immediately in the form of anticoagulation therapy and antibiotics.

Figure 2:

Magnetic resonance venography coronal section showing right transverse sinus and bilateral sigmoid sinus thrombosis

On subsequent follow-up visits every week, ocular movements gradually recovered. On 1-month follow-up visit, the prism and alternate cover test revealed orthophoria for distance and near. Anterior segment showed reduction in the episcleral venous congestion in the left eye. Fundus examination revealed resolving papilledema in both eyes. Repeat MRV showed recanalization of transverse and sigmoid sinus [Figure 3].

Figure 3:

Two-dimensional time-of-flight magnetic resonance venography image showing recanalization of right transverse sinus and bilateral sigmoid sinuses

DISCUSSION

Pediatric cerebral venous sinus thrombosis (CVST) following kidney transplantation is hitherto unreported. This unique report also highlights the role of clinical acumen in diagnosing this condition.

Dural venous thrombosis mainly involves sagittal sinus (70%–80%) and transverse, sigmoid sinuses (70%) and may extend to the cerebral veins.[2] The signs and symptoms are extremely varied and nonspecific, ranging in severity from mild headache to progressive neurological deficit, deterioration of consciousness, progressive coma, and death related to intracranial hemorrhagic infarction and increased intracranial pressure.[3] The clinical spectrum of CVST closely mimics that of IIH. IIH is mainly a diagnosis of exclusion based on Dandy's criteria.[4]

Risk factors for CVST may not be apparent in all the cases; hence, it is difficult to exclude CVST clinically in these patients. MRI in combination with MRV is recommended to correctly diagnose CVST in these patients.[45]

Steroids and immunosuppressants in kidney transplant can indirectly lead to hypercoagulability and pose a risk factor for sinus thrombosis.[6] Children commonly present with lethargy, focal neurologic signs, papilledema, and headache.[7]

Pediatric CVST usually affects a single sinus. Huisman et al.[2] found that the superficial sagittal sinus or transverse sinuses were involved in 47.5% and 12% of cases, respectively. In the same study, involvement of two sinuses was seen in 30% of the cases. In our case, it is the simultaneous involvement of transverse and sigmoid sinuses.

Purvin et al.[8] suggested that clinical manifestations of CVST may be differentiated from IIH by the abrupt onset and marked severity of symptoms.

In our case, the child had headache and diplopia. Although MRI brain was suggestive of IIH, we suspected an increase in the episcleral venous pressures due to the presence of episcleral congestion and mild proptosis and hence ordered MRV to look for CVST.

It is crucial to differentiate CVST from IIH because the management protocols are entirely different. CVST is typically treated with anticoagulants and IIH with diuretics. CVST is life-threatening as it can cause stroke and death, unlike IIH, which stops with optic atrophy.

The combination of MRI and MRV is the diagnostic modality of choice for CVST. MRV alone may be false positive in cases of sinus aplasia or hypoplasia (seen as a flow gap). It can also mistake T2-weighted hypointense signal of deoxyhemoglobin and intracellular methemoglobin as flow void.[9]

CONCLUSION

Pediatric CVST in a kidney transplant child with elevated episcleral pressure is a rare entity. It needs to be kept in mind while dealing with acute neurological conditions in children. In the absence of correct diagnosis and lack of MRV, these patients might continue to get treated as IIH, resulting in dismal visual prognosis, as well as significant risk of stroke and death. MRV in combination with MRI is recommended to identify this subgroup of patients who present with associated risk factors.

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.