The incidence of cerebral venous sinus thrombosis (CVST) is low, ranging from 0.02 to 0.2 per 1,000 [1]. Due to the lack of specificity in the clinical presentation of this disease, the misdiagnosis rate, disability rate and mortality rate are high, and the prognosis is often poor [2]. 1. Summary of medical history Primigravida, 23 years old. She was admitted to the hospital with progressive worsening of postpartum headache for 20 days. The patient was transferred to our hospital because she developed headache two days after cesarean delivery and was treated with neuropathic headache at the local hospital without significant effect, and gradually developed numbness of both upper limbs and face, vomiting several times, memory loss, and blurred vision two days before admission. After admission, a lumbar puncture was performed to check the pressure of 400 mmH2O, the cerebrospinal fluid was normal, the blood count showed that the platelets were 440×109/L, and the coagulation index was within the normal range (APTT 33.7s, PT 12.6s). MR examination of the head was performed and the results are shown in Figure 1. The imaging showed that the sagittal sinus and bilateral transverse sinuses were not visualized, and the cortical veins were draining downward to the cavernous sinus (Figure 2A and B). The above symptoms disappeared after one week, and the repeat blood test showed platelets 249×109/L, coagulation index APTT56.7s, PT25s, lumbar puncture pressure In March, the outpatient recheck of head CT was normalized (Figure 3). 2, Discussion 2.1, Overview The intracranial venous sinuses are divided into superior sagittal sinus, transverse sinus, sigmoid sinus, inferior sagittal sinus, straight sinus, occipital sinus, superior (inferior) rock sinus, cavernous sinus, etc. The first three of them are the main channels of cortical venous return, which may cause venous sinus thrombosis during local inflammation, trauma, hypercoagulable state, dehydration, allergy, oral contraceptives, pregnancy and puerperium [3]. The main causes of postpartum venous sinus thrombosis are: (1) maternal blood loss, sweating hemoconcentration resulting in a hypercoagulable state of blood, increased coagulation factors, hyperactivation of platelets [4], increased adhesion and aggregation, resulting in changes in blood coagulation and hemodynamic changes, combined with the special anatomical structure of the venous sinus, resulting in intracranial venous sinus thrombosis. (2) Postpartum infection, maternal weakness during the puerperium, prone to infection or recurrence of the original foci of infection, inducing thrombosis. When venous sinus thrombosis is formed, the venous sinus pressure gradually rises, and then significantly higher than the subarachnoid pressure, the cerebrospinal fluid reflux is obstructed, developing into traffic hydrocephalus, the ventricular system is enlarged, and the intracranial pressure continues to increase. MRI of this patient showed high signal in the right mastoid, probably due to the aggravation of the pre-existing mastoid inflammation in the postpartum period, coupled with postpartum blood loss that caused platelet reactive increase in aggregation, resulting in thrombosis of the right transverse sinus, which gradually expanded to thrombosis of the superior sagittal sinus and a gradual increase in intracranial pressure. 2.2, diagnosis 2.2.1, clinical manifestations The clinical manifestations of postpartum CVST are variable, usually with acute or subacute onset and gradual aggravation. The most important clinical manifestation is increased intracranial pressure, often with persistent and severe headache, nausea, jet vomiting, and optic papilledema. It may also manifest as convulsions, limited neurological deficits, partial seizures, and movement disorders. Disorders of consciousness are more common, with blurred consciousness or drowsiness in mild cases and coma in severe cases. In this case, the patient mainly presented with symptoms of increased intracranial pressure such as headache, vomiting and blurred vision, and later neurological symptoms such as facial and limb numbness appeared. Any postpartum patient with the above symptoms should consider the possibility of intracranial venous sinus thrombosis, and should routinely perform lumbar puncture to check the intracranial pressure, routine cerebrospinal fluid, blood routine, and coagulation index. The head CT examination and DSA or MRV examination should be considered if necessary. 2.2.2, imaging characteristics 2.2.2.1, head CT The CT manifestations of CVST are various, and its direct signs include cord sign, dense triangle sign and empty triangle sign or Delta sign [5-6]. Cord sign is a sign of fresh thrombus in the cortical veins and venous sinuses on CT scan, and the cord sign appears as a cord-like or band-like high-density shadow. The high-density triangular sign is a sign of fresh thrombus in the superior sagittal sinus in its cross-sectional view. These two signs are mostly seen in the acute thrombotic phase and are rarely seen in the subacute and chronic phases, so their occurrence is low. The hollow triangle sign is a sign of venous sinus thrombosis in the cross-section of the venous sinus itself on CT-enhanced scan, which shows a “hollow triangle” image with high density in and around the dural sinus wall and low density in the intraluminal thrombus, commonly seen in the posterior superior sagittal sinus thrombosis. The hollow triangle sign is the best and most direct sign for the diagnosis of CVST by CT, but be aware of false positives [7]. Indirect signs of CVST include limited or extensive hypodensity in the brain parenchyma, partially symmetrical on both sides, for cerebral edema or cerebral infarct changes; mixed density in the brain parenchyma, for hemorrhagic cerebral infarcts, mostly located at the subapical level; and superficial single or multiple high density in the brain, for cerebral hemorrhage changes. There may be cerebral gyrus-like enhancement after intensification. [8] Because CVST was considered upon admission in this case, MR was performed directly without CT. 2.2.2.2, MRI MRI can reflect the pathophysiological evolution of thrombus in different periods; it can directly reflect the lesions of brain tissue, detect venous cerebral edema, cerebral infarction and hemorrhage without the influence of cranial artifacts in multi-directional imaging in the plane, and it is one of the main methods to diagnose CVST. In the acute phase (within 1 week), venous sinus thrombosis shows iso-signal in T1WI and low signal in T2WI; in the subacute phase (within 1 month), both T1WI and T2WI show high signal; in the chronic phase (1 month to several years), the thrombus signal is reduced and inhomogeneous in all pulse sequences, and the venous sinus is recanalized and re-appears as a flow space signal. MRV is a non-invasive, convenient and stereoscopic visualization of the structure of cerebral veins.MRV of CVST shows the following: (i) absence of venous sinus flow signal; (ii) thin and uneven blood flow signal; (iii) compensatory collateral circulation is seen in the late stage. [9] In this case, MRI and MRV examinations were performed to show that the superior sagittal sinus, the right transverse sinus, and the sigmoid sinus were not visualized, and the T2WI sagittal sinus did not show flow space and showed triangular high signal shadow, and venous sinus thrombosis could be diagnosed according to the clinical special. 2.2.2.3, digital subtraction angiography (DSA) DSA is the current “gold standard” for the diagnosis of venous sinus thrombosis, and the extent and degree of intracranial venous sinus thrombosis can be determined according to the degree of prolonged arterial venous circulation time, whether the cortical veins, deep veins, guiding veins, scalp venous dilatation, and the filling of the venous sinus trunk. The extent and degree of intracranial venous sinus thrombosis can be determined by mechanical intravenous fragmentation and contact thrombolytic therapy [10]. 2.2.3 Diagnostic basis 1) Causes such as childbirth, bleeding, infection, dehydration, etc.; 2) symptoms of increased intracranial pressure such as persistent headache, vomiting, blurred vision (optic papilledema), etc.; 3) localized signs such as protruding eyes, visual impairment, epilepsy, limb hypesthesia, focal neurological dysfunction, etc.; 4) significantly increased intracranial pressure (>200 mmH2O) on lumbar puncture, increased platelets on laboratory tests, and increased blood clotting. (5) imaging is consistent with the above features; 2.3. Treatment Postpartum CVST is treated with early administration of heparin intravenous drip, streptokinase or urokinase, tissue-type fibrinolytic plasminogen activator (rtPA) is also widely used, and is now mostly used for contact thrombolysis. Because of the low concentration of local drugs in the venous sinus of systemic intravenous thrombolysis and the tendency to cause intracranial hemorrhage, they are rarely used. With the development of neurointerventional techniques, catheter injection of drug thrombolysis for CVST has become a common method, in which a microcatheter and umbrella are delivered retrograde to the thrombus site in the internal jugular vein according to the preoperative diagnosis, a guide wire is inserted to perform several pumping and rotational movements, and then streptokinase, urokinase, or t-PA is injected directly into the thrombus. The study of treatment of superior sagittal sinus thrombosis suggested that local thrombolysis was more effective than the latter. Embolectomy and intravenous bypass can be used in cases where drug therapy alone is ineffective, but they are rarely used with the development of interventional therapy. 2.4. Differential diagnosis This disease should be differentiated from the following cases: (1) Hypertensive headache: Some patients have gestational hypertension before delivery, often have headache and increased blood pressure, and the combined venous thrombosis after delivery is easily misdiagnosed as exacerbation of hyperemesis, but the headache is accompanied by increased blood pressure in hyperemesis, and it can be improved quickly with antihypertensive treatment. (2) Eclampsia: At a certain stage of development of hyperemesis, neurological symptoms such as headache and dizziness, and in severe cases, loss of consciousness and convulsions can be easily confused with this disease, which can be differentiated by history of hyperemesis and head CT. (3) Subarachnoid hemorrhage: Some mothers have headache, vomiting, and even impaired consciousness due to rupture of the aneurysm caused by the force during labor because of the combined intracranial aneurysm, but the onset is sudden. (4) Postpartum cold: The mother is weak and sweats easily, so it is easy to catch a cold with headache, anorexia and vomiting. But often accompanied by runny nose, cough and other cold symptoms. (5) Nervous headache: Postpartum depression easily leads to headache, accompanied by individual vomiting and anorexia. However, the onset is slow, the headache symptoms are mild, and accompanied by personality or temperament changes. (6) It still needs to be distinguished from pregnancy combined with cranial occupational lesions, meningitis and other infectious diseases, but it is extremely rare to see such coincidence, and head CT and MRI can be distinguished. 2.5, easy to misdiagnose the causes and prevention of postpartum CVST because of the low incidence, diverse and non-specific clinical manifestations, not easy to be considered the emergence of this disease. Most of them are severe headache, vomiting, and disturbance of consciousness. Because some patients have gestational hypertension syndrome, they are easily misdiagnosed as pre-eclampsia, eclampsia, subarachnoid hemorrhage, etc. Postpartum patients with physical weakness are also prone to cold and headache, and some patients have neurogenic headache due to postpartum depression, which are easily confused with subacute venous thrombosis. In this case, the patient was treated with neuropathic headache for more than 20 days in an outside hospital, and came to our hospital only when it was progressively aggravated, which missed the early treatment time. Therefore, this disease should be considered when the mother has continuously worsening headache symptoms or cranial hypertension manifestations such as vomiting and visual impairment, and early lumbar puncture should be performed to check the cranial pressure and head CT examination, and if venous sinus thrombosis is suspected, MRV or DSA examination is recommended to make a clear diagnosis and strive for early treatment.