In recent years, the annual incidence of syphilis has been on the rise, from 6.43/100,000 in 2000 to 32.86/100,000 in 2013, with an average annual increase of 13.37% [1]. According to WHO, more than 1 million pregnant women worldwide are infected with syphilis every year, of which 460,000 have miscarriage or stillbirth, about 270,000 have preterm delivery, and about 270,000 newborns are infected with congenital syphilis [2]. In this paper, we analyze and summarize the experience and treatment of a recent case of congenital syphilis combined with diffuse intravascular hemorrhage (DIC) in a premature infant. 1 Data and methods 1.1 Maternal history G2P2, 29+4 w. The baby was delivered spontaneously in our obstetrics department due to a small amount of vaginal bleeding in the mother. After clearing the airway, stimulating breathing and administering oxygen, the baby was admitted to the NICU with an Apgar score of 8 at 5 minutes. The mother of the child had delivered a male child at 32 weeks of gestation 1 year ago in an outside hospital and died of “DIC” on the second day after birth (specific information is lacking). The mother was admitted to the hospital with a prenatal syphilis confirmatory test (syphilis spirochete hemagglutination test (TPHA): (+) and a serological test (rapid plasma reactin:RPR test) 1:64 (+). 1.2 Admission examination The child was admitted with a physical examination, T 36.5 ℃, P 65 times/min, HR 140 times/min, BP 58/38 mmHg, and a simple gestational age score of 29 weeks. There was no skin rash, yellow stain or bleeding spots on the whole body; fontanelle was flat and soft, bilateral pupils were equal in size and round, and light reflex was sensitive; there were no obvious abnormal signs in the heart, lungs and abdomen. Myotonia was slightly hypotonic, and the primitive reflex was incomplete. Blood gas analysis PH: 7.11; BE:-9.2 mmol/L; PaCO2:64 mmHg; PO2:52 mmHg, HCO3-:23 mmol/L. Blood count: WBC 18×109/L, Hb 147 g/L, absolute neutrophil count (ANC) 11×109/L, Plt 140×109/L. Calcitoninogen (PCT):0.69 ng/ml, blood glucose 3.2 mmol/L, cardiac enzyme profile, liver and kidney function, and electrolytes were all in the normal range. Chest radiograph: the translucency of both lungs was generally reduced, and bronchial ventilation signs were seen. The above clinical manifestations, blood gas analysis and chest X-ray results were all suggestive of neonatal respiratory distress syndrome (NRDS). 1.3 Diagnosis and treatment The child was given bovine pulmonary surfactant (PS) 140 mg intratracheally 1 h after birth and CPAP-assisted ventilation at a pressure of 5 cmH2O and an oxygen concentration of 40%, in addition to acid correction with sodium bicarbonate (SB) and stimulation of the respiratory center with doxorubicin. Because the child’s mother had a history of syphilis, she was treated with penicillin at the same time, and syphilis-related tests were completed. After the above treatment, the child’s respiration improved significantly, and the results of blood gas analysis gradually improved to return to normal. L; PaCO2:42 mmHg, PO2:65 mmHg, HCO3-:21 mmol/L, all suggesting that NRDS-induced respiratory acidosis and hypoxemia were corrected. The child’s vital signs were stable, and he passed meconium and urine at 6h and 11h postnatally, respectively. However, the child’s percutaneous oxygen saturation (SPO2) decreased several times to a minimum of 65% at 28h after birth, and the heart rate was normal. Hypoxic shortness of breath was still obvious in the hyperoxic condition, and a small amount of bright red blood was found in the left nasal cavity. Since the nasal plug used was moderate in size and elastic, it was very unlikely that the nasal mucosa would rupture and bleed simply due to the friction of the plug. The chest X-ray was immediately repeated, showing that the translucency of both lungs was significantly higher than before, and no hyperdense shadow was seen. Coagulation and DIC tests showed: PLT 48×109/L, APTT 81.9 s (70 s±), D-dimer 9.62 mg/L (0-0.5 mg/L), FDP 27.0 ug/ml (0-5 ug/ml), fisetin coagulation test (+), PT 24.8 s (14-21 s), fibrinogen 2.58 g/l (2-4.5 g/l). According to the DIC diagnostic score [2], platelet count was evaluated as 2 points, fibrinogen-related markers were evaluated as 3 points, and PT prolongation >3s but <6s was evaluated as 1 point, totaling 6 points. Heparin 15 U/(kg/h) was immediately pumped for 1h, and fresh frozen plasma 10 ml/kg and low molecular dextrose 5 ml/kg were infused to improve microcirculation. After 12 h of application of the above treatment, PLT 80×109/L, APTT 70 s, D-dimer 0.4 mg/L, FDP 4 ug/ml, fisetin coagulation test (-), PT 17.6 s, fibrinogen 3.02 g/l were rechecked and bleeding stopped. After that, we applied low molecular heparin 10 U/kg subcutaneously for 3 consecutive days, and dynamically monitored PLT fluctuated from 120-156×109, APTT 55-72 s, D-dimer 0.18-0.39 mg/L, FDP 2-8 ug/ml, fisetin coagulation test (-), PT 13-19 s, fibrinogen 2.04-3.15 g/L, suggesting DIC was effectively controlled. We were discharged from CPAP at 48 h postnatally and oxygen was discontinued after hood transition. The child's syphilis serology test was 1:32 and the confirmatory test (+), combined with the medical history of the mother, the child was diagnosed with congenital syphilis and treated with penicillin for a total of 3 weeks. There were no significant abnormalities in hearing, cardiac ultrasound and retinal screening during hospitalization, and there were no other complications. The discharge diagnosis: prematurity, congenital syphilis, neonatal respiratory distress syndrome (NRDS), and DIC were recovered. 2 Discussion Neonatal congenital syphilis is a fetal systemic infection caused by syphilis spirochetes transmitted to the fetus through the placenta by the bloodstream of the pregnant woman during fetal life, which can lead to other complications and a high mortality rate. According to WHO, there are 1.36-2×106 pregnant women infected with syphilis every year, 50-80% of which are not treated effectively in time and lead to serious consequences. Congenital syphilis can be divided into 3 main categories according to clinical manifestations: ① stillbirth, which is rare. ②hepatosplenomegaly, rash, jaundice, anemia and other symptoms at birth or within 4 weeks of birth, with a high mortality rate. ③Symptoms related to syphilis appear several months to years after birth. Congenital syphilis has increased significantly in recent years and can lead to multiple organ damage such as heart, lung, liver, kidney, bone and brain. Because most children lack typical clinical manifestations, it is very easy to be misdiagnosed and missed [3]. This child was born prematurely at 29 weeks of gestation, and after effective postnatal treatment of NRDS, DIC occurred, which was rapidly controlled with low-dose heparin, supplementation of coagulation factors and improvement of microcirculation. Although NRDS may be secondary to DIC, the child's NRDS was effectively controlled after 5 h of endotracheal PS, assisted ventilation and systemic medication, and the hypoxemia and respiratory acidosis were promptly corrected with normal blood gas analysis results on multiple reviews. In contrast, DIC occurred about 24 hours after NRDS control, and the pregnant mother was syphilis-infected, and there was a history of DIC-related death of the first 32W preterm infant, who was positive for syphilis. Recent foreign literature reports that syphilis spirochete infection can lead to a large number of perivascular lymphocyte and mesenchymal cell infiltration, causing endothelial congestion and edema, fibrosis, and eventually coagulation dysfunction and secondary DIC [4-5]. Therefore, DIC in this child was induced by congenital syphilis. Therefore, at a time when the rate of syphilis infection in pregnant women is gradually increasing, it is necessary to be alert to the possibility of secondary DIC while paying great attention to the diagnosis and treatment of congenital syphilis in newborns, and timely treatment with appropriate amounts of heparin and supplemental coagulation substances may help to effectively control DIC caused by congenital syphilis.