What is the reason for a hard lump on the calf?

If you find a protruding lump on your calf, you should pay attention to it. The most common cause of this situation is the venous cluster or the venous sinus. You should check in time to see if you have varicose veins in your calf. You should take medication in time and pay more attention to health care in your daily life. Let us learn about this aspect.

Clinical features of venous sinus thrombosis

Cerebral venous sinus thrombosis is a special type of vascular disease, which is divided into two categories: non-infectious and infectious. The former is mostly caused by trauma, wasting diseases, certain blood diseases, pregnancy, severe dehydration, oral contraceptives, etc., and the latter is mostly secondary to infections of the head and face, as well as purulent meningitis, brain abscess, sepsis and other diseases. The main clinical manifestations are intracranial hypertension, such as headache, vomiting, decreased vision, papilledema, hemiplegia, and hemiplegia.

Pathogenesis

The pathogenesis and pathological changes of this disease are different from those of arterial thrombosis, with cerebral venous return disorder and cerebrospinal fluid absorption disorder being the main changes. If the venous sinus is completely blocked and involves a large number of collateral veins, or if the thrombus extends to the cerebral cortical veins, increased intracranial pressure and cerebral venous and cerebrospinal fluid circulation disorders will occur, leading to cerebral edema, hemorrhage, and necrosis. In the late stage of the disease, severe venous blood stasis and intracranial hypertension will slow down the secondary arterial blood flow, leading to cerebral ischemia, hypoxia, and even infarction. Therefore, the diversity of clinical manifestations is the result of different causes and stages of the disease, different ranges and locations of thrombosis, and secondary brain lesions.

CT findings

Direct signs of cerebral venous thrombosis are those that can directly reflect thrombosis in the venous sinus, including: band sign, high-density triangle sign, and Delta or empty triangle sign.

1) Band sign: This sign can be seen on CT plain scan and is a high-density thrombus image running along the cortical veins. A positive sign suggests fresh cortical vein thrombosis, but this sign is rarely seen.

2) High-density triangle sign: This sign can also be shown on plain scan CT images, indicating fresh thrombosis in the posterior part of the superior sagittal sinus. The incidence rate is less than 2%, and it manifests as a triangular high density, which is difficult to distinguish from the slightly higher density of the superior sagittal sinus and sinus confluence under normal circumstances. Abnormal high density can also be seen in other venous sinuses, such as the transverse sinus and straight sinus. However, this sign should be determined with caution because venous sinuses can spontaneously have high density, especially in children or dehydrated patients.