A 54-year-old man was admitted to the Department of Intensive Care Medicine of the First Affiliated Hospital, Sun Yat-sen University, on June 30th, 2021, due to headache and fatigue for 2 days.
The patient developed a headache on June 28th, 2021, without obvious inducement, and gradually had drowsiness, accompanied by fatigue, anorexia, and occasional cough, which could not be relieved after rest. No other abnormal symptoms were detected. The patient had a history of hypertension and gout for more than 10 years. He since had been diagnosed with sepsis and multiple organ failure in the ICU of a local hospital due to fever with upper abdominal pain. Metagenomic next-generation sequencing (mNGS) of blood on May 8th showed negative. After treatment of mepem 1 g every 6 h (Q6H), the patient was cured and was discharged 2 months ago. He did not take immunosuppressive drugs regularly for a long time and had no history of exposure to poisons, chemical agents, or animals. Personal and family histories were unremarkable.
Physical examination on admission showed body temperature of 36.0 C, pulse at 94 beats/min, respiratory rate of 14 breaths/min, blood pressure at 69/37 mmHg, drowsiness, chemosis, coarse breath sounds, and a small number of moist rales heard in both lower lungs. Cardio abdominal physical examination was unremarkable. Extremities were moderate edema. The movement of both upper limbs was good, and the movement of both lower limbs was limited. Auxiliary examination was also performed. Blood gas analysis showed metabolic acidosis, pH of 7.25, BE -16 mmol/L, and oxygenation >300. Elevated infection indicators analysis showed CRP of 234.75 mg/L, PCT of 5.06 ng/mL, and WBC of 41.84 x 109/L. The patient was detected with mild anemia (RBC of 3.26 x 1012/L and Hb 93 g/L), prolonged coagulation time (APTT of 58.2 s), renal insufficiency (urea of 19.5 mmol/L and CREA 357 mumol/L), and acute heart failure (TnT-T of 0.130 ng/mL and NT-proBNP of 20813.0 pg/mL). In addition, the patient had elevated liver metabolic total bilirubin (TBIL of 79.6 mumol/L) and predominantly elevated direct bilirubin (DBIL of 55.9 mumol/L). Immunosuppressive status revealed a lower immunoglobulin M (0.49 g/L) and immunoglobulin G (7.37 g/L), B lymphocytes (CD3-CD19 +) % of 0.48%, B lymphocytes (CD3-CD19 +) count of 2.41 cells/mul, regulatory T-cells (Treg) of 18.75%, interleukin 6 of 1508.65 pg/mL, and interleukin of 10 5.57 pg/mL. Bacteriology, mycology, and tuberculosis tests of blood, sputum, urine, and stool showed no pathogens. HIV, syphilis, and Hepatitis virus tests were negative. Radiography of the pulmonary showed worsening infiltrate (Figure 1). Septic shock was considered. The patient was given Sulperazone 3 g, Q8H for anti-infection, fluid infusion, correction of acidosis, acid suppression, stomach protection, and prothrombin complex supplement on June 30th. After 7-day treatment, the infection indicators were significantly lower than before, with PCT of 1.19 ng/mL, CRP of 49.41 mg/L, WBC of 8.08 x 109/L, NEUT of 6.94 x 109/L. The conditions were under control.
On July 7th, the patient had a sudden light coma with repeated generalized tonic-clonic seizures, with the most extended duration lasting for about 90 s. He was transferred to the neurological ICU for treatment with a GCS score of 5. Twenty-four-hour bedside quantitative EEG monitoring was immediately performed, which showed simultaneous epileptic discharges in both cerebral hemispheres during convulsive seizures. Sodium valproate 1,200 mg QD (from July 7th to July 10th), and Oxcarbazepine 300 mg Q12H combined Levetiracetam 1 g Q12H (from July 9th to August 16th) were then used. The epilepsy did not recur.
On July 8th, a lumbar puncture was performed to measure the initial pressure of 210 cmH2O and the final pressure of 135 cmH2O. CSF was collected and submitted for examination. Biochemical combination of CSF revealed glucose of 3.0 mmol/L, CSF chloride (Cl) of 131 mmol/L, CSF protein (PROT) of 734.7 mg/L, synchronous blood glucose of 5.9 mmol/L, and blood chloride of 117 mmol/L.
Samples were also sent for PACEseq mNGS (Hugobiotech, Beijing, China). QIAamp DNA Micro Kit (QIAGEN, Germany) was used for DNA extraction, and the libraries were then constructed using QIAseq  Ultralow Input Library Kit for Illumina (QIAGEN, Germany). The quality of libraries was assessed by Qubit (Thermo Fisher) and Agilent 2100 Bioanalyzer (Agilent Technologies). The qualified DNA libraries were finally sequenced on Nextseq 550 platform (Illumina). Adapter, short, low-quality, and low-complexity reads were removed from the raw data. The human DNA was filtered out by mapping to human reference database (hg38). The remaining reads were finally aligned to the Microbial Genome Databases (http://ftp.ncbi.nlm.nih.gov/genomes/). B19V DNA (2 specific reads) in CSF was detected. Polymerase chain reaction (PCR) was then performed using B19V Q-PCR Detection Kit (ZJ Bio-Tech, Shanghai, China) and confirmed the mNGS results. CSF cytology showed a lymphocyte-monocyte reaction pattern. CSF routine, bacterial culture, autoimmune encephalitis antibody detection, and oligoclonal bands (OB) were unremarkable. Determination of CSF B19V DNA on July 9th showed 1.0 x 10  copies/mL. B19V caused encephalitis was considered.
After transfer, the patient's pneumonia was gradually aggravated, with type I respiratory failure and oxygenation index <200 on July 11th. Chest radiography showed inflammatory infiltration in bilateral lungs with bilateral pleural effusion. Brain plain MRI + enhancement MRI + DWI showed only scattered ischemic lesions in bilateral cerebral hemispheres. Echocardiography and color Doppler ultrasound of liver, gallbladder, pancreas, and spleen were unremarkable. Determination of B19V DNA in blood on July 11st showed 2.96 x 105 copies/mL; B19V DNA and Enterococcus faecium was detected by PACEseq mNGS on July 13th, with the specific reads number of 1,430 and 22, respectively. Blood B19V IgM was negative, and IgG was positive. The reexamination of EEG on July 14th showed no epileptic discharges. Determination of B19V DNA in pleural fluid on July 15th showed the DNA determination of 1.36 x 105 copies/mL; mNGS detected B19V in BALF on July 15th, with the specific reads number of 11, Corynebacterium striatum, with the particular reads number of 250, Acinetobacter baumannii, with the particular reads number of 17, Enterococcus faecium, with the specific reads number of 13, Staphylococcus aureus, with the particular reads number of 11, Pseudomonas aeruginosa, with the particular reads number of 11. In addition to the symptoms of the central nervous system, the patient's anemia was progressively aggravated. After multiple blood transfusions and platelet therapy, the lowest hemoglobin was 58 g/L on August 8th, the proportion of reticulocytes was 0.0026, the reticulocyte count was 0.0089 x 1012/L, the lowest platelet count was 60 x 109/L, red blood cells and platelets were inhibited, and red blood cell morphology examination showed shrinkage and acanthocytes. The patient was finally diagnosed with encephalitis caused by B19V, secondary epilepsy, severe anemia, and bilateral pneumonia.
The patient was given mepem 1 g, Q8H on July 10th, and then switched to vancomycin 1 g, Q12H on July 18th, intravenous gamma globulin 0.4 g/Kg body weight for 5 days from July 15th for symptomatic treatment of heart failure, renal failure, and other symptoms of organ damage. The patient did not have any more seizures. He gradually became conscious, opened and closed his eyes when instructed, made eye contact when called, GCS score increased to 10 points, oxygenation index was more significant than 300, and anemia was improved. On July 20th, reexamination showed the proportion of reticulocytes was 0.0702, and reticulocyte count was 0.2078 x 1012/L. On July 27th, reexamination showed that blood B19V DNA was <1,000 copies/ml. The number of mNGS specific reads and viral DNA quantification in the different specimens are showed in Table 1, while mNGS outcomes belong to the patient are showed in Figure 2. Afterment treatment, the patient had clear consciousness and could simply communicate with his family. He was finally discharged on August 16th. There was no sequelae or relapse of this patient after 4-month follow-up. The patient could take care of himself and communicate with his family normally. The timeline of this case was shown in Figure 3.