Central nervous system infections in the tropics

PURPOSE OF REVIEW

Emerging and re-emerging central nervous system (CNS) infections are a major public health concern in the tropics. The reasons for this are myriad; climate change, rainfall, deforestation, increased vector density combined with poverty, poor sanitation and hygiene. This review focuses on pathogens, which have emerged and re-emerged, with the potential for significant morbidity and mortality.

RECENT FINDINGS

In recent years, multiple acute encephalitis outbreaks have been caused by Nipah virus, which carries a high case fatality. Arboviral infections, predominantly dengue, chikungunya and Zika are re-emerging increasingly especially in urban areas due to changing human habitats, vector behaviour and viral evolution. Scrub typhus, another vector borne disease caused by the bacterium Orientia tsutsugamushi , is being established as a leading cause of CNS infections in the tropics.

SUMMARY

A syndromic and epidemiological approach to CNS infections in the tropics is essential to plan appropriate diagnostic tests and management. Rapid diagnostic tests facilitate early diagnosis and thus help prompt initiation and focusing of therapy to prevent adverse outcomes. Vector control, cautious urbanization and deforestation, and reducing disturbance of ecosystems can help prevent spread of vector-borne diseases. Regional diagnostic and treatment approaches and specific vaccines are required to avert morbidity and mortality.

Interventions in cerebrovascular emergencies among patients with Paroxysmal nocturnal haemoglobinuria - A word of caution

INTRODUCTION

Paroxysmal nocturnal haemoglobinuria (PNH) is a clonal hematopoietic disorder, where there is deficiency of glycosylphosphatidylinositol (GPI) anchored proteins in the cell membrane, leading to increased complement sensitivity of red blood cells, intravascular hemolysis and vascular inflammation. Arterial and venous strokes in patients with PNH are a rarity posing significant diagnostic and therapeutic challenges. We report our experience with management of PNH patients with cerebrovascular emergencies.

METHODS

We report 2 patients with PNH, one who was previously diagnosed with PNH and had arterial stroke, the other had an index presentation of cerebral venous sinus thrombosis (CVT) and was subsequently diagnosed with PNH. We also present the systematic review of literature reporting similar cases, highlighting the challenges in management.

RESULTS

Both patients presented to our centre with cerebrovascular emergency. The first patient was a diagnosed with PNH, and presented with left hemispheric infarction caused by thrombosis of middle cerebral artery. He was thrombolysed and underwent mechanical thrombectomy, which was unsuccessful in view of repeated re - thrombosis of the vessel. The patient survived with significant disability. The second patient had severe cerebral venous sinus thrombosis with large right hemispheric hemorrhagic venous infarction. She underwent emergency decompressive hemicraniectomy complicated by massive blood loss and disseminated intravascular coagulation. She subsequently had recurrent life threatening intracranial bleed secondary to platelet transfusions, thrombocytopenia, and use of contrast agents. She progressed to develop Budd Chiari syndrome and was initiated on Eculuzimab. She became transfusion independent, however remained in minimally conscious state and succumbed to sepsis.

CONCLUSIONS

Management of arterial and venous strokes is complex in patients with PNH. Invasive procedures and platelet transfusions are to be avoided in acute thrombosis, till robust evidence is available establishing the safety of the same in patients with PNH. Eculuzimab is a promising option, but far from reach for patients in developing countries.

Cerebral venous sinus thrombosis: changing trends in the incidence, age and gender (findings from the CMC Vellore CVT registry)

BACKGROUND

Multiple cerebral venous sinus thrombosis (CVT) registries from various geographical regions indicate that female gender, the use of contraceptive pills, pregnancy and puerperium are important risk factors. In this study, we report the changes in the epidemiology of patients with CVT managed over the past 26 years.

METHODS

The CMC Vellore CVT registry is a prospectively maintained database at the Christian Medical College, Vellore since January 1995. Stata software was used to analyse the data and assess the changes in the incidence, age and gender distribution over the previous 26 years.

RESULTS

Among 1701 patients treated during the study period, 908 (53%) were women and 793 (47%) were men. The mean incidence of CVT was 49 per 100 000 admissions before 2010, which increased to 96 per 100 000 after 2010. Male gender had a higher odds of developing CVT (OR - 2.07 (CI 1.68 to 2.55, p<0.001). This could be attributed to the declining incidence of postpartum CVT after 2010 compared with the decade before 2010 (50% vs 20%). The mean age at presentation had increased from 24.5 to 33.2 years in the last decade.

CONCLUSIONS

There was a clear change in the gender pattern from being a condition with female preponderance, to one where equal or more men are being affected. Lower incidence of postpartum CVT cases could be the driving factor. An increase in the overall incidence of CVT cases was noted, probably due to a higher index of clinical suspicion and better diagnostic imaging modalities.

Chronic flaccid quadriparesis from tract specific myelopathy in neurosyphilis

INTRODUCTION

Tract-specific myelopathies with distinctive imaging features are uncommon and typically occur with metabolic or paraneoplastic syndromes. We report a unique case of tract-specific myelopathy with neurosyphilis.

CASE PRESENTATION

A 53-year-old male presented with a four-month history of flaccid quadriparesis, sensory loss, and bladder dysfunction. His MRIs revealed striking symmetric T2-weighted hyperintensities in the lateral corticospinal tracts and dorsal columns of the cervical spinal cord that extended rostrally into the pyramidal decussation and medial lemnisci of the medulla oblongata. Nerve conduction and needle electromyography studies excluded axonal or demyelinating lower motor neuron disorders. The patient reported previous untreated primary syphilis and was seropositive on the T.pallidum hemagglutination assay. Penicillin therapy resulted in substantial clinical improvement.

DISCUSSION

Although syphilitic meningomyelitis is well-reported, our patient was unique because of the persistent flaccidity (possibly suggesting prolonged spinal shock) and striking tract-specific MRI patterns. These features are novel in syphilitic myelitis and suggest unknown mechanisms of tract-specific tropism and neuronal injury.

CONCLUSIONS

"Tract-specific" complete transverse myelopathy with persistent flaccid weakness and areflexia is a novel presentation of neurosyphilis. Early recognition and crystalline penicillin therapy can alleviate morbidity. Our report describes this patient's findings and discusses the differential diagnoses of tract-specific myelopathies.

Management and Outcomes of COVID – 19 Associated Cerebral Venous Sinus Thrombosis

Background

Systemic hyper-coagulabilty leading to micro and macro thrombosis is a known complication of Coronavirus disease – 2019(COVID -19). The postulated mechanism appears to be the viral activation of endothelium, triggering the coagulation pathways. Thrombosis of the cerebral veins and sinuses (CVT), a potentially serious condition, has been increasingly reported with COVID – 19 infection. In this clinical study we attempt to describe the clinical profile, investigations and outcomes of patients with COVID- 19 associated CVT.

Methods

This is a single center prospective observational study from South India. The study included patients (aged >18 years) with concomitant COVID infection and CVT. The clinical, laboratory, imaging characteristics, management and outcomes were described and compared with COVID negative CVT patients.

Results

Out of 97 cases of CVT treated at our center during the first and second waves of the COVID pandemic 11/97 (11%) were COVID related CVT. Among these 11 patients, 9 (81%) had presented with only CVT related symptoms and signs and were tested positive for COVID - 19 infection during the pre-hospitalization screening. Respiratory symptoms were absent in 90% of the patients. Headache (100%) and seizures (90%) were the common presenting symptoms. The median time to diagnosis was 6 hours, from presentation to the emergency department. Transverse sinus was involved 10/11 (90%) and majority of them (9/11) had Haemorrhagic Venous Infarction (HVI). Acute inflammatory markers were elevated in comparison with non COVID CVT patients, with the mean serum D-dimer being 2462.75 ng/ml and the C-reactive protein was 64.5 mg/dl. Three patients (30%) underwent decompressive hemicraniectomy (DHC) because of large hemispheric HVI. All patients survived in the COVID CVT group while the mortality in the non COVID group was 4%. At 6 months follow up excellent outcome (modified Rankin Scale (mRS) score of 0–2) was noted equally in both groups.

Conclusions

Symptoms and signs of CVT may be the only presentation of COVID-19 infection. Prompt recognition and aggressive medical management including DHC offers excellent outcomes.