Acute Tubulointerstitial Nephritis due to Human Papillomavirus Vaccination

Acute tubulointerstitial nephritis (ATIN), a rare cause of acute kidney injury in children, is caused by various factors such as drugs, infection, and systemic inflammation. We herein present a case of ATIN with mild encephalitis/encephalopathy with reversible splenial lesion (MERS)-like findings on head magnetic resonance imaging (MRI), which was associated with human papillomavirus (HPV) vaccination. A 14-year-old girl presented to our hospital with a high fever for 5 days. Results of common laboratory tests were normal except for increased C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR). Antibiotics were administered, and the fever promptly resolved after admission. After 7 weeks, she was readmitted due to a high fever for 4 days. In addition to increased CRP levels and ESR, urine test revealed high urine N-acetyl-β-D-glucosaminidase and β-2-microglobulin levels, and a renal scintigram showed mild bilateral uptake of 67Ga-citrate, consistent with the pathology of ATIN. Furthermore, head MRI, which was performed because the patient experienced prolonged headaches, revealed MERS-like lesions, although she did not have other neurological symptoms. Detailed examination of her medical records revealed that she had developed high fever 10 days after the third HPV vaccination and another previous episode of high fever 12 weeks after the second HPV vaccination. Based on these findings, we concluded that the ATIN and MERS-like lesions could have been associated with HPV vaccination. Although HPV vaccination is important for preventing uterine cancer, physicians must be vigilant about its various potential adverse effects, including ATIN.

Neuroimaging in acute infection-triggered encephalopathy syndromes

Acute encephalopathy associated with infectious diseases occurs frequently in Japanese children (400-700 children/year) and is the most common in infants aged 0-3 years. Acute encephalopathy is classified into several clinicoradiological syndromes; acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is the most common subtype, followed by clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) and acute necrotizing encephalopathy (ANE). Neuroimaging, especially magnetic resonance imaging (MRI), is useful for the diagnosis, assessment of treatment efficacy, and evaluation of the pathophysiology of encephalopathy syndromes. MRI findings essential for diagnosis include delayed subcortical reduced diffusion (bright tree appearance) for AESD, reversible splenial lesions with homogeneously reduced diffusion for MERS, and symmetric hemorrhagic thalamic lesions for ANE. We reviewed several MRI techniques that have been applied in recent years, including diffusion-weighted imaging for the characterization of cerebral edema, arterial spin labeling for evaluating cerebral perfusion, and magnetic resonance spectroscopy for evaluating metabolic abnormality.

Effective therapy with infliximab for clinically mild encephalitis/encephalopathy with a reversible splenial lesion in an infant with Kawasaki disease

Kawasaki disease (KD) is a systemic vasculitis in infants. In KD, encephalopathy is rarely (0.1%) associated, however, clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) has previously been reported in some pediatric patients. Here, we report on a 2-year-old girl who had KD complicated with MERS. The patient experienced generalized clonic convulsion and prolonged consciousness disturbance with fever for 2 days. Her head MRI showed a high signal intensity lesion in the splenium of the corpus callosum in diffusion-weighted images, and low apparent diffusion coefficient (ADC) values on day 3. An electroencephalogram showed high voltage slow waves on the occipital and parietal head. On the same day, it was confirmed that the patient showed all the main symptoms of KD. Based on these findings, we diagnosed her with MERS-complicated KD. Even though she was treated with immunoglobulin (total 4 g/kg) and pulsed-dose methylprednisolone, her fever and consciousness disturbance continued, and blood tests showed that inflammation markers remained high. We then treated the patient with infliximab on day 9, and within a few hours of the treatment her fever dropped and all symptoms of KD and consciousness disturbance disappeared. No recurrence of KD or other complications of KD occurred, and she was discharged on day 23. We propose that infliximab is an effective optional treatment for immunoglobulin/glucocorticoid-resistant KD with MERS. To clarify this possibility, further case accumulation is warranted.

Kleine-Levin syndrome elicited by encephalopathy with reversible splenial lesion

Kleine-Levin syndrome is a rare sleep disorder of unknown etiology characterized by repetitive episodes of hypersomnia between asymptomatic periods. We report the case of a 13-year-old girl who presented with drowsiness triggered by influenza A as the first episode. Magnetic resonance imaging (MRI) on day 6 showed transient reduction of diffusion in the corpus callosum splenium. The patient was diagnosed with encephalopathy with a reversible splenial lesion. The symptoms resolved after 10 days, but additional episodes of hypersomnia lasting 5-10 days occurred 1, 5, 6, 11, 13, and 25 months after the first episode. MRI during hypersomnia indicated no lesions, and sleep duration and cognition were normal between episodes. The patient was diagnosed with Kleine-Levin syndrome. Electroencephalographic and clinical findings during the first episode were similar to those during the other episodes. Encephalopathy with a splenial lesion and Kleine-Levin syndrome may have similar pathological mechanisms causing a disturbance in consciousness.