Thrombotic Storm has been seen in individuals of all ages and races. The initial symptoms of TS present in a similar fashion to the symptoms experienced in deep vein thrombosis. Symptoms of a DVT may include pain, swelling and discoloration of the skin in the affected area. As with DVTs patients with TS may subsequently develop pulmonary emboli. Although the presentation of TS and DVTs are similar, TS typically progresses rapidly, with numerous clots occurring within a short period of time. After the formation of the initial clot a patient with TS typically begins a “clotting storm” with the development of multiple clots throughout the body. Rapid progression within a short period of time is often seen, affecting multiple organs systems. The location of the clot is often unusual or found in a spot in the body that is uncommon such as the dural sinus. Patients tend to respond very well to anticoagulation such as coumadin or low molecular weight heparin but may become symptomatic when treatment is withheld.

While the key clinical characteristics of thrombotic storm are still being investigated, it is believed that the clinical course is triggered by a preexisting condition, known as a hypercoagulable state. These can include such things as pregnancy, trauma or surgery. Hypercoagulable states can be an inherited or acquired risk factor that then serves as a trigger to initiate clot formation. However, in a subset of patient with TS a trigger cannot be identified. Typically people with TS will have no personal or family history of coagulations disorders.

Paget-Schroetter disease is the obstruction of an upper extremity vein (such as the axillary vein or subclavian vein) by a thrombus. The condition usually comes to light after vigorous exercise and usually presents in younger, otherwise healthy people. Men are affected more than women.

Cavernous sinus thrombosis is a specialised form of cerebral venous sinus thrombosis, where there is thrombosis of the cavernous sinus of the basal skull dura, due to the retrograde spread of infection and endothelial damage from the danger triangle of the face. The facial veins in this area anastomose with the superior and inferior ophthalmic veins of the orbit, which drain directly posteriorly into the cavernous sinus through the superior orbital fissure. Staphyloccoal or Streptococcal infections of the face, for example nasal or upper lip pustules may thus spread directly into the cavernous sinus, causing stroke-like symptoms of double vision, squint, as well as spread of infection to cause meningitis.

Currently laboratory testing is not as reliable as observation when it comes to defining the parameters of Thrombotic Storm. Careful evaluation of possible thrombosis in other organ systems is pertinent in expediting treatment to prevent fatality.Preliminary diagnosis consists of evidence documented with proper imaging studies such as CT scan, MRI, or echocardiography, which demonstrate a thromboembolic occlusion in the veins and/or arteries. Vascular occlusions mentioned must include at least two of the clinic events:

- Deep venous thrombosis affecting one (or more) limbs and/or pulmonary embolism.

- Cerebral vein thrombosis.

- Portal vein thrombosis, hepatic vein, or other intra-abdominal thrombotic events.

- Jugular vein thrombosis in the absence of ipsilateral arm vein thrombosis and in the absence of ipsilateral central venous access.

- Peripheral arterial occlusions, in the absence of underlying atherosclerotic vascular disease,

- resulting in extremity ischemia and/or infarction.

- Myocardial infarction, in the absence of severe coronary artery disease

- Stroke and/or transient ischemic attack, in the absence of severe atherosclerotic disease and at an age less than 60 years.

- Central retinal vein and/or central retinal arterial thrombosis.

- Small vessel thrombosis affecting one or more organs, systems, or tissue; must be documented by histopathology.

In addition to the previously noted vascular occlusions, development of different thromboembolic manifestations simultaneously or within one or two weeks must occur and the patient must have an underlying inherited or acquired hypercoagulable state (other than Antiphospholipid syndrome)

The most common conditions associated with thrombophilia are deep vein thrombosis (DVT) and pulmonary embolism (PE), which are referred to collectively as venous thromboembolism (VTE). DVT usually occurs in the legs, and is characterized by pain, swelling and redness of the limb. It may lead to long-term swelling and heaviness due to damage to valves in the veins. The clot may also break off and migrate (embolize) to arteries in the lungs. Depending on the size and the location of the clot, this may lead to sudden-onset shortness of breath, chest pain, palpitations and may be complicated by collapse, shock and cardiac arrest.

Venous thrombosis may also occur in more unusual places: in the veins of the brain, liver (portal vein thrombosis and hepatic vein thrombosis), mesenteric vein, kidney (renal vein thrombosis) and the veins of the arms. Whether thrombophilia also increases the risk of arterial thrombosis (which is the underlying cause of heart attacks and strokes) is less well established.

Thrombophilia has been linked to recurrent miscarriage, and possibly various complications of pregnancy such as intrauterine growth restriction, stillbirth, severe pre-eclampsia and abruptio placentae.

Protein C deficiency may cause purpura fulminans, a severe clotting disorder in the newborn that leads to both tissue death and bleeding into the skin and other organs. The condition has also been described in adults. Protein C and protein S deficiency have also been associated with an increased risk of skin necrosis on commencing anticoagulant treatment with warfarin or related drugs.

Common signs and symptoms of DVT include pain or tenderness, swelling, warmth, redness or discoloration, and distention of surface veins, although about half of those with the condition have no symptoms. Signs and symptoms alone are not sufficiently sensitive or specific to make a diagnosis, but when considered in conjunction with known risk factors, can help determine the likelihood of DVT. In most suspected cases, DVT is ruled out after evaluation, and symptoms are more often due to other causes, such as cellulitis, Baker's cyst, musculoskeletal injury, or lymphedema. Other differential diagnoses include hematoma, tumors, venous or arterial aneurysms, and connective tissue disorders.

Phlegmasia cerulea dolens is a very large and dangerous type of DVT. It is characterized by an acute and almost total venous occlusion of the entire extremity outflow, including the iliac and femoral veins. The leg is usually painful, tinged blue in color, and swollen, which may result in venous gangrene.

Thrombophilia (sometimes hypercoagulability or a prothrombotic state) is an abnormality of blood coagulation that increases the risk of thrombosis (blood clots in blood vessels). Such abnormalities can be identified in 50% of people who have an episode of thrombosis (such as deep vein thrombosis in the leg) that was not provoked by other causes. A significant proportion of the population has a detectable abnormality, but most of these only develop thrombosis in the presence of an additional risk factor.

There is no specific treatment for most thrombophilias, but recurrent episodes of thrombosis may be an indication for long-term preventative anticoagulation. The first major form of thrombophilia, antithrombin deficiency, was identified in 1965, while the most common abnormalities (including factor V Leiden) were described in the 1990s.

Deep vein thrombosis (DVT), is the formation of a blood clot in a deep vein, most commonly the legs. Symptoms may include pain, swelling, redness, or warmth of the affected area. About half of cases have no symptoms. Complications may include pulmonary embolism, as a result of detachment of a clot which travels to the lungs, and post-thrombotic syndrome.

Risk factors include recent surgery, cancer, trauma, lack of movement, obesity, smoking, hormonal birth control, pregnancy and the period following birth, antiphospholipid syndrome, and certain genetic conditions. Genetic factors include deficiencies of antithrombin, protein C, and protein S, and factor V Leiden mutation. The underlying mechanism typically involves some combination of decreased blood flow rate, increased tendency to clot, and injury to the blood vessel wall.

Individuals suspected of having DVT may be assessed using a clinical prediction rule such as the Wells score. A D-dimer test may also be used to assist with excluding the diagnosis or to signal a need for further testing. Diagnosis is most commonly confirmed by ultrasound of the suspected veins. Together, DVT and pulmonary embolism are known as venous thromboembolism (VTE).

Anticoagulation (blood thinners) is the standard treatment. Typical medications include low-molecular-weight heparin, warfarin, or a direct oral anticoagulant. Wearing graduated compression stockings may reduce the risk of post-thrombotic syndrome. Prevention may include early and frequent walking, calf exercises, aspirin, anticoagulants, graduated compression stockings, or intermittent pneumatic compression. The rate of DVTs increases from childhood to old age; in adulthood, about one in 1000 adults are affected per year. About 5% of people are affected by a VTE at some point in time.

Catastrophic antiphospholipid syndrome (CAPS), also known as Asherson's syndrome, is an acute and complex biological process that leads to occlusion of small vessels of various organs. It was first described by Ronald Asherson in 1992. The syndrome exhibits thrombotic microangiopathy, multiple organ thrombosis, and in some cases tissue necrosis and is considered an extreme or catastrophic variant of the antiphospholipid syndrome.

CAPS has a mortality rate of about 50%. With the establishment of a CAPS-Registry more has been learned about this syndrome, but its cause remains unknown. Infection, trauma, medication, and/or surgery can be identified in about half the cases as a "trigger". It is thought that cytokines are activated leading to a cytokine storm with the potentially fatal consequences of organ failure. A low platelet count is a common finding. Individuals with CAPS often exhibit a positive test to antilipid antibodies, typically IgG, and may or may not have a history of lupus or another connective tissue disease. Association with another disease such as lupus is called a secondary APS unless it includes the defining criteria for CAPS.

Clinically, the syndrome affects at least three organs and may affect many organs systems. Peripheral thrombosis may be encountered affecting veins and arteries. Intraabdominal thrombosis may lead to pain. Cardiovascular, nervous, kidney, and lung system complications are common. The affected individual may exhibit skin purpura and necrosis. Cerebral manifestations may lead to encephalopathy and seizures. Myocardial infarctions may occur. Strokes may occur due to the arterial clotting involvement. Death may result from multiple organ failure.

Treatments may involve the following steps:

- Prevention includes the use of antibiotics for infection and parenteral anticoagulation for susceptible patients.

- Specific therapy includes the use of intravenous heparin and corticosteroids, and possibly plasma exchanges, intravenous immunoglobulin.

- Additional steps may have to be taken to manage circulatory problems, kidney failure, and respiratory distress.

- When maintaining survival of the disease treatments also include high doses of Rituxan (Rituximab) to maintain stability.

It can be diagnosed by histomorphologic examination of the placenta and is characterized by fetal vessel thrombosis and clustered fibrotic chorionic villi without blood vessels.

Post-thrombotic syndrome (PTS), also called postphlebitic syndrome and venous stress disorder is a medical condition that may occur as a long-term complication of deep vein thrombosis (DVT).

Signs and symptoms of PTS in the leg may include:

- pain (aching or cramping)

- heaviness

- itching or tingling

- swelling (edema)

- varicose veins

- brownish or reddish skin discoloration

- ulcer

These signs and symptoms may vary among patients and over time. With PTS, these symptoms typically are worse after walking or standing for long periods of time and improve with resting or elevating the leg.

PTS lowers a person's quality of life after DVT, specifically with regards to physical and psychological symptoms and limitations in daily activities.

Phlegmasia cerulea dolens (literally: "painful blue edema") is an uncommon severe form of deep venous thrombosis which results from extensive thrombotic occlusion (blockage by a thrombus) of the major and the collateral veins of an extremity. It is characterized by sudden severe pain, swelling, cyanosis and edema of the affected limb. There is a high risk of massive pulmonary embolism, even under anticoagulation. Foot gangrene may also occur. An underlying malignancy is found in 50% of cases. Usually, it occurs in those afflicted by a life-threatening illness.

This phenomenon was discovered by Jonathan Towne, a vascular surgeon in Milwaukee, who was also the first to report the "white clot syndrome" (now called heparin induced thrombocytopenia [HIT]). Two of their HIT patients developed phlegmasia cerulea dolens that went on to become gangrenous.

Treatment by Catheter directed thrombolytic therapy.

Fetal thrombotic vasculopathy is a chronic disorder characterized by thrombosis in the fetus leading to vascular obliteration and hypoperfusion.

It is associated with cerebral palsy and stillbirth.

In medicine, May-Thurner syndrome (MTS), also known as the iliac vein compression syndrome, is a rare condition in which compression of the common venous outflow tract of the left lower extremity may cause discomfort, swelling, pain or blood clots, called deep venous thrombosis (DVT), in the iliofemoral vein.

The specific problem is compression of the left common iliac vein by the overlying right common iliac artery. This leads to pooling or stasis of blood, predisposing the individual to the formation of blood clots. Uncommon variations of MTS have been described, such as the right common iliac vein getting compressed by the right common iliac artery.

In the 21st century the May-Thurner syndrome definition has been expanded to a broader disease profile known as nonthrombotic iliac vein lesions (NIVL) which can involve both the right and left iliac veins as well as multiple other named venous segments. This syndrome frequently manifests as pain when the limb is dependent (hanging down the edge of a bed/chair) and/or significant swelling of the whole limb.

Three or more of the following six criteria must be met:

- Age when disease starts is under 50

- Decreased brachial artery pulse

- Systolic blood pressure differs by more than 10mmHg between arms

- Cramping caused by exercise in the extremities

- Abnormal sounds (through stethoscope) over subclavian arteries or abdominal aorta

- A narrowing or blockage in the aorta, its primary branches, or large arteries as seen through a radiograph of the arteries.

May-Thurner syndrome (MTS) is thought to represent between two and five percent of lower-extremity venous disorders. May-Thurner syndrome is often unrecognized; however, current estimates are that this condition is three times more common in women than in men. The classic syndrome typically presents in the second to fourth decades of life. In the 21st century in a broader disease profile, the syndrome acts as a permissive lesion and becomes symptomatic when something else happens such as, following trauma, a change in functional status such as swelling following orthopaedic joint replacement.

It is important to consider May-Thurner syndrome in patients who have no other obvious reason for hypercoagulability and who present with left lower extremity thrombosis. To rule out other causes for hypercoagulation, it may be appropriate to check the antithrombin, protein C, protein S, factor V Leiden, and prothrombin G20210A.

Venography will demonstrate the classical syndrome when causing deep venous thrombosis.

May-Thurner syndrome in the broader disease profile known as nonthrombotic iliac vein lesions (NIVLs) exists in the symptomatic ambulatory patient and these lesions are usually not seen by venography. Morphologically, intravascular ultrasound (IVUS) has emerged as the best current tool in the broader sense. Functional testing such as duplex ultrasound, venous and interstitial pressure measurement and plethysmography may sometimes be beneficial. Compression of the left common iliac vein may be seen on pelvic CT.

Starts with nonspecific symptoms such as:

- Localized joint pain

- Fever

- Fatigue

- Headaches

- Rashes

- Weight loss

- Diagnosis usually does not happen until the blockage causes deficient blood flow to the extremities or to a stroke.

Thrombotic microangiopathy (TMA) is a pathology that results in thrombosis in capillaries and arterioles, due to an endothelial injury. It may be seen in association with thrombocytopenia, anemia, purpura and renal failure.

The classic TMAs are hemolytic uremic syndrome and thrombotic thrombocytopenic purpura. Other conditions with TMA include atypical hemolytic uremic syndrome, disseminated intravascular coagulation, scleroderma renal crisis, malignant hypertension,

antiphospholipid antibody syndrome, and drug toxicities, e.g. calcineurin inhibitor toxicity.

The clinical presentation of TMA, although dependent on the type, typically includes: fever, microangiopathic hemolytic anemia (see schistocytes in a blood smear), renal failure, thrombocytopenia and neurological manifestations. Generally, renal complications are particularly predominant with Shiga-toxin-associated hemolytic uremic syndrome (STx-HUS) and atypical HUS, whereas neurologic complications are more likely with TTP. Individuals with milder forms of TTP may have recurrent symptomatic episodes, including seizures and vision loss. With more threatening cases of TMA, and also as the condition progresses without treatment, multi-organ failure or injury is also possible, as the hyaline thrombi can spread to and affect the brain, kidneys, heart, liver, and other major organs.

Factor V Leiden (rs6025) is a variant (mutated form) of human factor V (one of several substances that helps blood clot), which causes an increase in blood clotting (hypercoagulability). With this mutation, the anticoagulant protein secreted (which normally inhibits the pro-clotting activity of factor V) is not able to bind normally to Factor V, leading to a hypercoagulable state, i.e., an increased tendency for the patient to form abnormal and potentially harmful blood clots. Factor V Leiden is the most common hereditary hypercoagulability (prone to clotting) disorder amongst ethnic Europeans. It is named after the Dutch city Leiden, where it was first identified in 1994 by Prof R. Bertina "et al."

The signs and symptoms of TTP may at first be subtle and nonspecific. Many people experience an influenza-like or diarrheal illness before developing TTP. Neurological symptoms are very common and vary greatly in severity. Frequently reported symptoms include feeling very tired, confusion, and headaches. Seizures and symptoms similar to those of a stroke can also be seen.

As TTP progresses, blood clots form within small blood vessels (microvasculature), and platelets (clotting cells) are consumed. As a result, bruising, and rarely bleeding can occur. The bruising often takes the form of purpura, while the most common site of bleeding, if it occurs, is from the nose or gums. Larger bruises (ecchymoses) may also develop.

The classic presentation of TTP includes a constellation of five medical signs which classically support the clinical diagnosis of TTP, although it is unusual for patients to present with all 5 symptoms. The pentad includes:

- Fever

- Changes in mental status

- Thrombocytopenia

- Reduced kidney function

- Haemolytic anaemia (microangiopathic hemolytic anemia).

High blood pressure (hypertension) may be found on examination.

In DIC, the underlying cause usually leads to symptoms and signs, and DIC is discovered on laboratory testing. The onset of DIC can be sudden, as in endotoxic shock or amniotic fluid embolism, or it may be insidious and chronic, as in cancer. DIC can lead to multiorgan failure and widespread bleeding.

Symptoms of cerebral infarction are determined by the parts of the brain affected. If the infarct is located in primary motor cortex, contralateral hemiparesis is said to occur. With brainstem localization, brainstem syndromes are typical: Wallenberg's syndrome, Weber's syndrome, Millard-Gubler syndrome, Benedikt syndrome or others.

Infarctions will result in weakness and loss of sensation on the opposite side of the body. Physical examination of the head area will reveal abnormal pupil dilation, light reaction and lack of eye movement on opposite side. If the infarction occurs on the left side brain, speech will be slurred. Reflexes may be aggravated as well.

Disseminated intravascular coagulation (DIC) is a condition in which blood clots form throughout the body blocking small blood vessels. Symptoms may include chest pain, shortness of breath, leg pain, problems speaking, or problems moving parts of the body. As clotting factors and platelets are used up, bleeding may occur. This may include blood in the urine, blood in the stool, or bleeding into the skin. Complications may include organ failure.

Relatively common causes include sepsis, surgery, major trauma, cancer, and complications of pregnancy. Less common causes include snake bites, frostbite, and burns. There are two main types acute (rapid onset) and chronic (slow onset). Diagnosis is typically based on blood tests. Findings may include low platelets, low fibrinogen, high INR, or high D-dimer.

Treatment is mainly directed towards the underlying condition. Other measures may include giving platelets, cryoprecipitate, or fresh frozen plasma. Evidence to support these treatments, however, is poor. Heparin may be useful in the chronic form. About 1% of people admitted to hospital are affected by the condition. In those with sepsis rates are between 20% and 50%. The risk of death among those affected varies from 20 to 50%.