Abstract
Chikungunya virus (CHIKV) typically causes febrile illness and arthralgia. However, severe complications such as encephalitis, rhabdomyolysis, and multiorgan dysfunction are increasingly recognised, particularly during epidemics in endemic regions. We report a case of a 61-year old male presenting with progressive flaccid paraparesis and respiratory failure following febrile illness. Magnetic resonance imaging (MRI) revealed white matter hyperintense foci with restricted diffusion in the periventricular, deep white matter, cerebellum, and middle cerebellar peduncles, consistent with encephalitis. Laboratory findings indicated rhabdomyolysis and acute kidney injury. Serological confirmation of CHIKV highlighted the diagnosis of CHIKV encephalitis complicated by rhabdomyolysis. Despite intensive care, the patient succumbed to refractory shock and hyperkalaemia. This case underscores the importance of early recognition of atypical manifestations of CHIKV, particularly MRI findings, to facilitate timely diagnosis and multidisciplinary management in severe cases.
Case description
A 61-year old male presented with progressive bilateral flaccid paraparesis for four days, accompanied by bowel and bladder incontinence. Ten days prior, he had developed high-grade fever with chills and arthralgia, resolving in four days with antipyretics. Two days after defervescence, he developed paraparesis, without sensory, bulbar, or upper limb involvement.
On admission, he was drowsy but responsive. Vital signs showed tachycardia (108/min), tachypnoea (38/min), oxygen saturation of 88% on ambient air, with paradoxical chest movements. He was intubated and mechanically ventilated. Neurological examination revealed bilateral lower limb power of 1/5 with absent knee and ankle reflexes. Upper limb power and reflexes, as well as sensory examination, were normal. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis (98 cells, 80% lymphocytes), elevated protein (1100 mg/L), and normal glucose (4.9 mmol/L).
Laboratory evaluation revealed leucocytosis (12.3 × 109/L), hyperkalaemia (5.5 mmol/L), worsening renal function (urea 71 mmol/L and creatinine 884 µmol/L), and elevated aspartate and alanine transaminases (20.7 µkat/L and 4.6 µkat/L, respectively). Markedly elevated creatine kinase (91.2 µkat /L), lactate dehydrogenase (20.4 µkat/L), and urine myoglobin (21 μg/L) confirmed rhabdomyolysis.
Given the acute febrile illness with multiorgan involvement in an endemic setting, a tropical infection was suspected. Serological tests for leptospirosis, dengue, malaria, scrub typhus, and enteric fever were negative. Blood, urine, CSF, and endotracheal aspirate cultures were sterile. CSF polymerase chain reaction for herpes simplex virus (HSV), enterovirus, adenovirus, rabies virus, and Mycobacterium tuberculosis was negative. Echocardiography did not show any vegetation or thrombus. HIV was nonreactive.
Magnetic resonance imaging (MRI) of the brain revealed multiple diffusion-restricting lesions in the periventricular and deep white matter, medulla, cerebellum, and middle cerebellar peduncles, consistent with encephalitis (Fig. 1). Spinal MRI was normal. A positive chikungunya virus (CHIKV) IgM antibody confirmed the diagnosis of CHIKV infection complicated by encephalitis and rhabdomyolysis. Despite intensive care, including mechanical ventilation and haemodialysis, the patient deteriorated and succumbed to refractory shock and hyperkalaemia (7.7 mmol/L).
MRI brain findings. Axial T2-weighted images (A and B) and FLAIR images (C and D) demonstrate multiple confluent hyperintense foci (white arrows) involving the centrum semiovale (A and B), periventricular regions (B and C), and cerebellum and middle cerebellar peduncles (D). Axial diffusion-weighted images (E to H) reveal diffusion restriction in these lesions (black arrows).
Discussion
CHIKV, an arbovirus transmitted by Aedes mosquitoes, usually causes febrile illness and arthralgia. Severe atypical complications such as encephalitis, rhabdomyolysis and multiorgan dysfunction are increasingly recognised in endemic regions, particularly during epidemics and in vulnerable groups such as the elderly, neonates, and those with comorbidityy 1
Encephalitis is a major cause of intensive care unit admission and can be difficult to diagnose without high clinical or radiological suspicion.1,2 Although generally considered non-specific, the presence of focal or confluent white matter hyperintense foci with restricted diffusion on MRI in patients presenting with fever and neurological symptoms is diagnostically valuable for CHIKV encephalitis in endemic regions.3,4 These lesions usually involve supra-tentorial white matter but may extend to infra-tentorial regions, as in this case. Patho-physiologically, diffusion restriction reflects cytotoxic oedema, likely caused by immune-mediated plasma leakage and perivascular lymphocytic infiltrates, consistent with the immune hyperactivation seen in viral encephalitis. 3 Unlike HSV (temporal lobe haemorrhagic lesions) or dengue (bilateral thalamic ‘double doughnut’), CHIKV encephalitis lacks post-contrast enhancement, haemorrhage, or distinctive topographic predilections. 5
Rhabdomyolysis, though less commonly reported, is a serious complication of CHIKV, contributing to morbidity and mortality.1,6 The mechanism is not fully understood but may involve virus-induced myonecrosis and immune-mediated muscle injury.
Early recognition of atypical complications is critical. This case highlights the importance of heightened clinical awareness in endemic regions and underscores the necessity of multidisciplinary approaches in managing severe CHIKV complications. Nevertheless, the prognosis remains poor in severe cases, particularly in older patients, those with comorbidity, or multiorgan involvement.1,2
Patient's consent
Written informed consent is present. The patient's son was informed about confidentiality, and the case information will be used for educational purposes only.
Footnotes
Authors’ contributions
PJ: collected patient data, drafted the manuscript, patient management. RD, DA, VB and MK: collected patient data, drafted the manuscript, and managed patient management. AKP: conceived the idea, collected patient data, drafted and revised the manuscript, patient management.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
