Varicose veins are more common in women than in men, and are linked with heredity. Other related factors are pregnancy, obesity, menopause, aging, prolonged standing, leg injury and abdominal straining. Varicose veins are unlikely to be caused by crossing the legs or ankles. Less commonly, but not exceptionally, varicose veins can be due to other causes, as post phlebitic obstruction or incontinence, venous and arteriovenous malformations.

It is often caused by venous reflux. More recent research has shown the importance of pelvic vein reflux (PVR) in the development of varicose veins. Hobbs showed varicose veins in the legs could be due to ovarian vein reflux and Lumley and his team showed recurrent varicose veins could be due to ovarian vein reflux. Whiteley and his team reported that both ovarian and internal iliac vein reflux causes leg varicose veins and that this condition affects 14% of women with varicose veins or 20% of women who have had vaginal delivery and have leg varicose veins. In addition, evidence suggests that failing to look for, and treat pelvic vein reflux can be a cause of recurrent varicose veins.

There is increasing evidence for the role of incompetent perforator veins (or "perforators") in the formation of varicose veins. and recurrent varicose veins.

Varicose veins could also be caused by hyperhomocysteinemia in the body, which can degrade and inhibit the formation of the three main structural components of the artery: collagen, elastin and the proteoglycans. Homocysteine permanently degrades cysteine disulfide bridges and lysine amino acid residues in proteins, gradually affecting function and structure. Simply put, homocysteine is a 'corrosive' of long-living proteins, i.e. collagen or elastin, or lifelong proteins, i.e. fibrillin. These long-term effects are difficult to establish in clinical trials focusing on groups with existing artery decline. Klippel-Trenaunay syndrome and Parkes-Weber syndrome are relevant for differential diagnosis.

Another cause is chronic alcohol consumption due to the vasodilatation side effect in relation to gravity and blood viscosity.

This condition is most common after age 50.

It is more prevalent in females.

There is a hereditary role.

It has been seen in smokers, those who have chronic constipation and in people with occupations which necessitate long periods of standing such as lecturers, nurses, conductors (musical and bus), stage actors, umpires (cricket, javelin, etc.), the Queen's guard, lectern orators, security guards, etc.

Dilated submucosal veins are the most prominent histologic feature of esophageal varices. The expansion of the submucosa leads to elevation of the mucosa above the surrounding tissue, which is apparent during endoscopy and is a key diagnostic feature. Evidence of recent variceal hemorrhage includes necrosis and ulceration of the mucosa. Evidence of past variceal hemorrhage includes inflammation and venous thrombosis.

Esophageal varices (sometimes spelled oesophageal varices) are extremely dilated sub-mucosal veins in the lower third of the esophagus. They are most often a consequence of portal hypertension, commonly due to cirrhosis; patients with esophageal varices have a strong tendency to develop bleeding. Esophageal varices are typically diagnosed through an esophagogastroduodenoscopy.

A varix (pl. varices) is an abnormally dilated vessel with a tortuous course. Varices usually occur in the venous system, but may also occur in arterial or lymphatic vessels.

Examples of varices include:

- Varicose veins, large tortuous veins usually found on legs

- Sublingual varices

- Esophageal varices, commonly stemming from cirrhosis of the liver, also known as oesophageal varicose

- Gastric varices, commonly stemming from cirrhosis of the liver

- Intestinal varices

- Scrotal varices

- Vulvar varices

- Pelvic varices

- Vesical varices, varicose veins associated with the urinary bladder

- Rectal varices, which can be similar to external haemorrhoids

Anorectal varices are the dilation of collateral submucosal vessels due to backflow in the veins of the rectum. Typically this occurs due to portal hypertension which shunts venous blood from the portal system through the portosystemic anastomosis present at this site into the systemic venous system. This can also occur in the oesophagus, causing oesophageal varices, and at the level of the umbilicus, causing caput medusae. Between 44% and 78% of patients with portal hypertension get anorectal varices.

Unlike oesophageal varices, rectal varices are less prone to bleeding, are less serious when a bleed does occur, and are easier to treat because of the more accessible location.

Typically, treatment consists of addressing the underlying portal hypertension. Some treatments include portosystemic shunting, ligation, and under-running suturing. Insertion of a transjugular intrahepatic portosystemic shunt (TIPS) has been shown to alleviate varices caused by portal hypertension. Successful treatment of portal hypertension that subsequently reduces anorectal varices provides a confirmation of the initial diagnosis, allowing for a distinction between varices and hemorrhoids, which would not have been alleviated by reduction of portal hypertension.

Population studies from numerous areas in the world have shown that HHT occurs at roughly the same rate in almost all populations: somewhere around 1 in 5000. In some areas, it is much more common; for instance, in the French region of Haut Jura the rate is 1:2351 - twice as common as in other populations. This has been attributed to a founder effect, in which a population descending from a small number of ancestors has a high rate of a particular genetic trait because one of these ancestors harbored this trait. In Haut Jura, this has been shown to be the result of a particular "ACVRL1" mutation (named c.1112dupG or c.1112_1113insG). The highest rate of HHT is 1:1331, reported in Bonaire and Curaçao, two islands in the Caribbean belonging to the Netherlands Antilles.

Most people with HHT have a normal lifespan. The skin lesions and nosebleeds tend to develop during childhood. AVMs are probably present from birth, but don't necessarily cause any symptoms. Frequent nosebleeds are the most common symptom and can significantly affect quality of life.

Several factors may increase the tendency for clot formation, such as specific infections (such as infectious mononucleosis, cytomegalovirus infection, malaria, or babesiosis), inherited clotting disorders (thrombophilia, such as Factor V Leiden, antiphospholipid syndrome), malignancy (such as pancreatic cancer) or metastasis, or a combination of these factors.

In some conditions, blood clots form in one part of the circulatory system and then dislodge and travel to another part of the body, which could include the spleen. These emboligenic disorders include atrial fibrillation, patent foramen ovale, endocarditis or cholesterol embolism.

Splenic infarction is also more common in hematological disorders with associated splenomegaly, such as the myeloproliferative disorders. Other causes of splenomegaly (for example, Gaucher disease or hemoglobinopathies) can also predispose to infarction. Splenic infarction can also result from a sickle cell crisis in patients with sickle cell anemia. Both splenomegaly and a tendency towards clot formation feature in this condition. In sickle cell disease, repeated splenic infarctions lead to a non-functional spleen (autosplenectomy).

Any factor that directly compromises the splenic artery can cause infarction. Examples include abdominal traumas, aortic dissection, torsion of the splenic artery (for example, in wandering spleen) or external compression on the artery by a tumor. It can also be a complication of vascular procedures.

Splenic infarction can be due to vasculitis or disseminated intravascular coagulation. Various other conditions have been associated with splenic infarction in case reporters, for example granulomatosis with polyangiitis or treatment with medications that predispose to vasospasm or blood clot formation, such as vasoconstrictors used to treat esophageal varices, sumatriptan or bevacizumab.

Splenic infarction can be induced for the treatment of such conditions as portal hypertension or splenic injury. It can also be used prior to splenectomy for the prevention of blood loss.

Several anti-angiogenesis drugs approved for other conditions, such as cancer, have been investigated in small clinical trials. The anti-VEGF antibody bevacizumab, for instance, has been used off-label in several studies. In the largest study conducted so far, bevacizumab infusion was associated with a decrease in cardiac output and reduced duration and number of episodes of epistaxis in treated HHT patients. Thalidomide, another anti-angiogenesis drug, was also reported to have beneficial effects in HHT patients. Thalidomide treatment was found to induce vessel maturation in an experimental mouse model of HHT and to reduce the severity and frequency of nosebleeds in the majority of a small group of HHT patients. The blood hemoglobin levels of these treated patients rose as a result of reduced hemorrhage and enhanced blood vessel stabilization.

Several studies have attempted to predict the survival of patients with Budd–Chiari syndrome. In general, nearly 2/3 of patients with Budd–Chiari are alive at 10 years. Important negative prognostic indicators include ascites, encephalopathy, elevated Child-Pugh scores, elevated prothrombin time, and altered serum levels of various substances (sodium, creatinine, albumin, and bilirubin). Survival is also highly dependent on the underlying cause of the Budd–Chiari syndrome. For example, a patient with an underlying myeloproliferative disorder may progress to acute leukemia, independently of Budd–Chiari syndrome.

The cause can be found in more than 80% of patients.

- Primary Budd–Chiari syndrome (75%): thrombosis of the hepatic vein

- Hepatic vein thrombosis is associated with the following in decreasing order of frequency:

2. Polycythemia vera

1. Pregnancy

2. Postpartum state

3. Use of oral contraceptives

4. Paroxysmal nocturnal hemoglobinuria

5. Hepatocellular carcinoma

6. Lupus anticoagulants

- Secondary Budd–Chiari syndrome (25%): compression of the hepatic vein by an outside structure (e.g. a tumor)

Budd–Chiari syndrome is also seen in infections such as tuberculosis, congenital venous webs and occasionally in inferior vena caval stenosis.

Often, the patient is known to have a tendency towards thrombosis, although Budd–Chiari syndrome can also be the first symptom of such a tendency. Examples of genetic tendencies include protein C deficiency, protein S deficiency, the Factor V Leiden mutation, hereditary anti-thrombin deficiency and prothrombin mutation G20210A. An important non-genetic risk factor is the use of estrogen-containing (combined) forms of hormonal contraception. Other risk factors include the antiphospholipid syndrome, aspergillosis, Behçet's disease, dacarbazine, pregnancy, and trauma.

Many patients have Budd–Chiari syndrome as a complication of polycythemia vera (myeloproliferative disease of red blood cells). Patients suffering from paroxysmal nocturnal hemoglobinuria (PNH) appear to be especially at risk for Budd–Chiari syndrome, more than other forms of thrombophilia: up to 39% develop venous thromboses and 12% may acquire Budd-Chiari.

A related condition is veno-occlusive disease, which occurs in recipients of bone marrow transplants as a complication of their medication. Although its mechanism is similar, it is not considered a form of Budd–Chiari syndrome.

Other toxicologic causes of veno-occlusive disease include plant & herbal sources of pyrrolizidine alkaloids such as Borage, Boneset, Coltsfoot, T'u-san-chi, Comfrey, Heliotrope (sunflower seeds), Gordolobo, Germander, and Chaparral.

Spider angiomas form due to failure of the sphincteric muscle surrounding a cutaneous arteriole. The central red dot is the dilated arteriole and the red "spider legs" are small veins carrying away the freely flowing blood. If momentary pressure is applied, it is possible to see the emptied veins refilling from the centre. No other angiomas show this phenomenon.

The dilation, in turn, is caused by increased estrogen levels in the blood. Many pregnant women, or women using hormonal contraception, have spider angiomas, due to high estrogen levels in their blood. Individuals with significant hepatic disease also show many spider angiomas, as their liver cannot metabolize circulating estrogens, specifically estrone, which derives from the androgen androstenedione. About 33% of patients with cirrhosis have spider angiomas. As such, microhemorrhages may be observed as spider angiomas.

10-15% of intracranial AV malformations are DAVFs. There is a higher preponderance in females (61-66%), and typically patients are in their fourth or fifth generation of life. DAVFs are rarer in children.

Following diagnosis, mean survival of patients with PPH is 15 months. The survival of those with cirrhosis is sharply curtailed by PPH but can be significantly extended by both medical therapy and liver transplantation, provided the patient remains eligible.

Eligibility for transplantation is generally related to mean pulmonary artery pressure (PAP). Given the fear that those PPH patients with high PAP will suffer right heart failure following the stress of post-transplant reperfusion or in the immediate perioperative period, patients are typically risk-stratified based on mean PAP. Indeed, the operation-related mortality rate is greater than 50% when pre-operative mean PAP values lie between 35 and 50 mm Hg; if mean PAP exceeds 40-45, transplantation is associated with a perioperative mortality of 70-80% (in those cases without preoperative medical therapy). Patients, then, are considered to have a high risk of perioperative death once their mean PAP exceeds 35 mm_Hg.

Survival is best inferred from published institutional experiences. At one institution, without treatment, 1-year survival was 46% and 5-year survival was 14%. With medical therapy, 1-year survival was 88% and 5-year survival was 55%. Survival at 5 years with medical therapy followed by liver transplantation was 67%. At another institution, of the 67 patients with PPH from 1652 total cirrhotics evaluated for transplant, half (34) were placed on the waiting list. Of these, 16 (48%) were transplanted at a time when 25% of all patients who underwent full evaluation received new livers, meaning the diagnosis of PPH made a patient twice as likely to be transplanted, once on the waiting list. Of those listed for transplant with PPH, 11 (33%) were eventually removed because of PPH, and 5 (15%) died on the waitlist. Of the 16 transplanted patients with PPH, 11 (69%) survived for more than a year after transplant, at a time when overall one-year survival in that center was 86.4%. The three year post-transplant survival for patients with PPH was 62.5% when it was 81.02% overall at this institution.

Spider angiomas are asymptomatic and usually resolve spontaneously. This is common in the case of children, although they may take several years to disappear. If the spider angiomas are associated with pregnancy, they may resolve after childbirth. In women taking oral contraceptives, they may resolve after stopping these contraceptives. The spider angiomas associated with liver disease may resolve when liver function increases or when a liver transplant is performed.

For spider angiomas on the face, techniques such as electrodesiccation and laser treatment can be used to remove the lesion. There is a small risk of a scar, although the results are generally good. Spider angiomas can recur after treatment.

Congestion of the mucosa in other parts of the gastrointestinal tract can also be seen in portal hypertension. When the condition involves the colon, it is termed "portal hypertensive colopathy".

It is difficult to determine how common hemorrhoids are as many people with the condition do not see a healthcare provider. However, symptomatic hemorrhoids are thought to affect at least 50% of the US population at some time during their lives, and around 5% of the population is affected at any given time. Both sexes experience about the same incidence of the condition, with rates peaking between 45 and 65 years. They are more common in Caucasians and those of higher socioeconomic status.

Long-term outcomes are generally good, though some people may have recurrent symptomatic episodes. Only a small proportion of persons end up needing surgery.

Portal hypertensive gastropathy refers to changes in the mucosa of the stomach in patients with portal hypertension; by far the most common cause of this is cirrhosis of the liver. These changes in the mucosa include friability of the mucosa and the presence of ectatic blood vessels at the surface. Patients with portal hypertensive gastropathy may experience bleeding from the stomach, which may uncommonly manifest itself in vomiting blood or melena; however, portal hypertension may cause several other more common sources of upper gastrointestinal bleeding, such as esophageal varices and gastric varices. On endoscopic evaluation of the stomach, this condition shows a characteristic mosaic or "snake-skin" appearance to the mucosa of the stomach.

Manual carotid self compression is a controversial treatment for DAVF. Patients using this method are told to compress the carotid with the opposite hand for approximately 10 minutes daily, and gradually increasing the frequency and duration of compression. Currently, it is unclear whether this method is an effective therapy.

Caviar tongue (also termed sublingual varicosities or sublingual varices), is a condition characterized by purplish venous ectasias commonly found on the ventral (undersurface) of the tongue after the age of fifty. It is normal for there to be veins visible underneath the tongue, partly because the mucous membrane is so thin and translucent in this region, but where these vessels become dilated and tortuous, they may appear round and black like caviar.

Normally, the ovarian vein crosses over the ureter at the level of the fourth or fifth lumbar vertebral bone. The ureter itself courses over the external iliac artery and vein. Thus, these vessels can impinge on the ureter causing obstruction. The left ovarian vein ends in the renal vein whereas the right ovarian vein normally enters into the inferior vena cava. In the case of right ovarian vein syndrome, the vein often ends in the renal vein. This is thought to contribute to venous engorgement, in analogy to what is seen in varicoceles, which arise more commonly on the left side. The straight angle between the ovarian vein (or testicular vein in males in the case of varicocoele) and the renal vein has been proposed as a cause of decreased blood return.

A related diagnosis is "Nutcraker Syndrome" where the left renal vein is described as being compressed between the aorta and the superior mesenteric artery. This is reported to cause collateral flow paths to open up to drain the left kidney i.e. reversed flow (reflux caudally) in the left renal vein. Pelvic Congestion Syndrome, vaginal and vulval varices, lower limb varices are clinical sequelae. Virtually all such patient are female and have been pregnant, often multiply.

The ovarian vein often displays incompetent valves. This has been observed more often in women with a higher number of previous pregnancies. Pressure from the baby might hinder the return of blood through the ovarian vein. It has to be noted however that dilation of the urinary tract is a normal observation in pregnancy, due to mechanical compression and the hormonal action of progesterone. Ovarian vein dilatation might also follow venous thrombosis (clotting inside the vein).

Another proposed mechanism of obstruction is when the ovarian vein and ureter both run through a sheath of fibrous tissue, following a local inflammation. This could be seen as a localised form of retroperitoneal fibrosis.

Following obstruction, the ureter displays an abnormal peristalsis (contractions) towards the kidney instead of towards the bladder. This is thought to cause the colicky pain (similar to renal colic), and it is relieved after surgical decompression.

Treatment consists of painkillers and surgical ablation of the dilated vein. This can be accomplished with open abdominal surgery (laparotomy) or keyhole surgery (laparoscopy). Recently, the first robot-assisted surgery was described.

Another approach to treatment involves catheter-based embolisation, often preceded by phlebography to visualise the vein on X-ray fluoroscopy.

Ovarian vein coil embolisation is an effective and safe treatment for pelvic congestion syndrome and lower limb varices of pelvic origin. Many patients with lower limb varices of pelvic origin respond to local treatment i.e. ultrasound guided sclerotherapy. In those cases, ovarian vein coil embolisation should be considered second line treatment to be used if veins recur in a short time period i.e. 1–3 years. This approach allows further pregnancies to proceed if desired. Coil embolisation is not appropriate if a future pregnancy is possible. This treatment has largely superseded operative options.

Coil embolisation requires exclusion of other pelvic pathology, expertise in endovascular surgery, correct placement of appropriate sized coils in the pelvis and also in the upper left ovarian vein, careful pre- and post-procedure specialist vascular ultrasound imaging, a full discussion of the procedure with the patient i.e. informed consent. Complications, such as coil migration, are rare but reported. Their sequelae are usually minor.

If a Nutcracker compression (see below) is discovered, stenting of the renal vein should be considered before embolization of the ovarian vein. Reducing outflow obstruction should always be the main objective.

Gastric varices are dilated submucosal veins in the stomach, which can be a life-threatening cause of bleeding in the upper gastrointestinal tract. They are most commonly found in patients with portal hypertension, or elevated pressure in the portal vein system, which may be a complication of cirrhosis. Gastric varices may also be found in patients with thrombosis of the splenic vein, into which the short gastric veins which drain the fundus of the stomach flow. The latter may be a complication of acute pancreatitis, pancreatic cancer, or other abdominal tumours, as well as hepatitis C. Gastric varices and associated bleeding are a potential complication of schistosomiasis resulting from portal hypertension.

Patients with bleeding gastric varices can present with bloody vomiting (hematemesis), dark, tarry stools (melena), or rectal bleeding. The bleeding may be brisk, and patients may soon develop shock. Treatment of gastric varices can include injection of the varices with cyanoacrylate glue, or a radiological procedure to decrease the pressure in the portal vein, termed transjugular intrahepatic portosystemic shunt or TIPS. Treatment with intravenous octreotide is also useful to shunt blood flow away from the stomach's circulation. More aggressive treatment including splenectomy (or surgical removal of the spleen) or liver transplantation may be required in some cases.