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What is Post-thrombotic syndrome and explain in detail?
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
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
ulcerThese 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 persons quality of life after DVT, specifically with regards to physical and psychological symptoms and limitations in daily activities.

Cause
Despite outgoing research, the cause of PTS is not entirely clear. Inflammation is thought to play a role as well as damage to the venous valves from the thrombus itself. This valvular incompetence combined with persistent venous obstruction from thrombus increases the pressure in veins and capillaries. Venous hypertension induces a rupture of small superficial veins, subcutaneous hemorrhage and an increase of tissue permeability. That is manifested by pain, swelling, discoloration, and even ulceration.

Risk factors
The following factors increase the risk of developing PTS:
age > 65
proximal DVT
a second DVT in same leg as first DVT (recurrent ipsilateral DVT)
persistent DVT symptoms 1  month after DVT diagnosis
obesity
poor quality of anticoagulation control (i.e. dose too low) during the first 3 months of treatment

Diagnosis
When physicians find a DVT in the clinical history of their patients, a postthrombotic syndrome is possible if the patients have suggestive symptoms. Ultrasonography for deep venous thrombosis must be performed to evaluate the situation: the degree of obstruction by clots, the location of these clots, and the detection of deep and/or superficial venous insufficiency. Since signs and symptoms of DVT and PTS may be quite similar, a diagnosis of PTS should be delayed for 3–6 months after DVT diagnosis so an appropriate diagnosis can be made.

Prevention
Prevention of PTS begins with prevention of initial and recurrent DVT