Based on the history and examination findings, the correct diagnosis is false aneurysm of the femoral artery. It may occur following arterial trauma in intravenous drug users.

A false aneurysm, or pseudoaneurysm of the vessels, occurs when a blood vessel wall is injured and the leaking blood collects in the surrounding tissue. It is not an enlargement of any of the layers of the vessel wall. Pseudoaneurysms usually present as a painful, tender, pulsatile mass. Diagnostic options include duplex scan, and CT angiogram or a conventional angiogram.

In a true aneurysm, the artery or vessel weakens and bulges, usually forming a blood-filled sac.

Lymphatic filariasis, commonly known as elephantiasis, is a painful and profoundly disfiguring disease. In communities where filariasis is transmitted, all ages are affected. While the infection may be acquired during childhood its visible manifestations may occur later in life, causing temporary or permanent disability. The disease is caused by three species of thread-like nematode worms, known as filariae – Wuchereria bancrofti, Brugia malayi and Brugia timori. Male worms are about 3–4 centimetres in length, and female worms 8–10 centimetres. The male and female worms together form “nests” in the human lymphatic system.

Filarial infection can cause a variety of clinical manifestations, including lymphoedema of the limbs, genital disease (hydrocele, chylocele, and swelling of the scrotum and penis) and recurrent acute attacks, which are extremely painful and are accompanied by fever. The vast majority of infected people are asymptomatic, but virtually all of them have subclinical lymphatic damage and as many as 40% have kidney damage, with proteinuria and haematuria.

Catheter-directed thrombolysis (CDT) is recommended as the next step of management for patients with proximal upper-extremity deep vein thrombosis (UEDVT) of recent onset or severe symptoms.

Primary UEDVT is less common than secondary forms. The most common primary form is effort-related thrombosis, also called Paget-Schroetter syndrome. It usually occurs in otherwise healthy young men who report, before the onset of thrombosis, vigorous arm exercise such as lifting weights, playing badminton, pitching a baseball, or performing repetitive overhead activities, such as painting or car repair. Most patients with effort-related UEDVT have an underlying venous thoracic outlet syndrome (VTOS). Secondary causes of UEDVT include central line insertion, malignancy, or pacemakers.

Patients with UEDVT typically present with heaviness, discomfort, pain, paraesthesia, and swelling of the affected arm. Physical examination may reveal pitting oedema, redness, or cyanosis of the involved extremity; visible collateral veins at the shoulder or upper arm; and fever.

Diagnosis is made by:
1. FBC: platelet function
2. Coagulation profile
3. Liver function tests
4. Duplex scan: investigation of choice
5. D-dimer testing
6. CT scan: for VTOS

Treatment options for primary UEDVT are as follows:
1. Anticoagulation therapy should be undertaken with a once-daily regimen of LMWH or fondaparinux for at least five days, followed by vitamin K antagonists for at least three months. Unfractionated heparin instead of LMWH is recommended for patients with renal failure or for those treated with CDT.

2. Early thrombus removal and restoration of venous patency should be done immediately after starting the patient on heparin. Catheter-based therapy is recommended for patients with proximal UEDVT of recent onset and severe symptoms, low risk for bleeding complications, and good functional status.

This patient has an axillary vein thrombosis. It classically presents with pain and swelling of the affected limb. Venous duplex scan is needed to exclude a thrombus.

Primary proximal upper-extremity deep vein thrombosis (UEDVT) is less common than its secondary forms. The most common primary form is effort-related thrombosis, also called Paget-Schroetter syndrome. It usually occurs in, otherwise, healthy young men who report, before the onset of thrombosis, vigorous arm exercise such as lifting weights, playing badminton/tennis, pitching a baseball, or performing repetitive overhead activities, such as painting or car repair. Most patients with effort-related UEDVT have an underlying venous thoracic outlet syndrome (VTOS). Secondary causes of UEDVT include central line insertion, malignancy, or pacemakers.

Patients with UEDVT typically present with heaviness, discomfort, pain, paraesthesia, and swelling of the affected arm. Physical examination may reveal pitting oedema, redness, or cyanosis of the involved extremity; visible collateral veins at the shoulder or upper arm; and fever.

Diagnosis is made by:
1. FBC: platelet function
2. Coagulation profile
3. Liver function tests
4. Venous duplex scan: investigation of choice, provides information relating to flow and characteristics of the vessels.
5. D-dimer testing
6. CT scan: for VTOS

Treatment options for primary UEDVT are as follows:
1. Anticoagulation therapy should be undertaken with a once-daily regimen of LMWH or fondaparinux for at least five days, followed by vitamin K antagonists for at least three months. Unfractionated heparin instead of LMWH is recommended for patients with renal failure or for those treated with CDT.

2. Early thrombus removal and restoration of venous patency aim should be done immediately after starting the patient on heparin. Catheter-based therapy is recommended for patients with proximal UEDVT of recent onset and severe symptoms, low risk for bleeding complications, and good functional status.

Intravenous drug users are at a high risk of right-sided cardiac valvular endocarditis. The character of the murmur described in the scenario fits with the diagnosis of tricuspid valve endocarditis.

Other listed options are ruled out because:
1. Aortic regurgitation—Early diastolic murmur
2. Mitral regurgitation—Pansystolic murmur
3. Aortic valve stenosis—Ejection systolic murmur
4. Tricuspid valve stenosis—Mid-diastolic murmur

Lymphovenous anastomosis – Identifiable lymphatics are anastomosed to sub dermal venules. Usually indicated in 2% of patients with proximal lymphatic obstruction and normal distal lymphatics.

Causes of lymphoedema:
Primary:
Sporadic, Milroy’s disease, Meige’s disease
Secondary:
Bacterial/fungal/parasitic infection (filariasis)
Lymphatic malignancy
Radiotherapy to lymph nodes
Surgical resection of lymph nodes
DVT
Thrombophlebitis

Other options given:
Homans operation – Reduction procedure with preservation of overlying skin (which must be in good condition). Skin flaps are raised and the underlying tissue excised. Limb circumference typically reduced by a third.

Charles operation – All skin and subcutaneous tissue around the calf are excised down to the deep fascia. Split skin grafts are placed over the site. May be performed if overlying skin is not in good condition. Larger reduction in size than with Homans procedure.

Lymphadenitis is the inflammation or enlargement of a lymph node. Lymph nodes are small, ovoid nodules normally ranging in size from a few millimetres to 2 cm. They are distributed in clusters along the course of lymphatic vessels located throughout the body. The primary function of lymph nodes is to filter out microorganisms and abnormal cells that have collected in lymph fluid. Lymph node enlargement is a common feature in a variety of diseases and may serve as a focal point for subsequent clinical investigation of diseases of the reticuloendothelial system or regional infection. The majority of cases represent a benign response to localized or systemic infection. The red streaks that are noted along the line of lymphatics are indicative of lymphadenitis.

Groin masses are common and include:
Herniae
Lipomas
Lymph nodes
Undescended testis
Femoral aneurysm
Saphena varix

Klippel-Trenaunay syndrome is a condition that affects the development of blood vessels, soft tissues (such as skin and muscles), and bones. The disorder has three characteristic features: a red birthmark called a port-wine stain, abnormal overgrowth of soft tissues and bones, and vein malformations.

Most people with Klippel-Trenaunay syndrome are born with a port-wine stain. This type of birthmark is caused by swelling of small blood vessels near the surface of the skin. Port-wine stains are typically flat and can vary from pale pink to deep maroon in colour.

Klippel-Trenaunay syndrome is also associated with overgrowth of bones and soft tissues beginning in infancy. Usually this abnormal growth is limited to one limb, most often one leg. However, overgrowth can also affect the arms or, rarely, the torso.

Malformations of veins are the third major feature of Klippel-Trenaunay syndrome. These abnormalities include varicose veins and deep veins in the limbs. Malformations of deep veins increase the risk of a deep vein thrombosis (DVT).

Other complications of Klippel-Trenaunay syndrome can include cellulitis, lymphedema, and internal bleeding from abnormal blood vessels. Less commonly, this condition is also associated with fusion of certain fingers or toes (syndactyly) or the presence of extra digits (polydactyly).

Mesenteric venous thrombosis (MVT) is a blood clot in one or more of the major veins that drain blood from the intestine. The superior mesenteric vein is most commonly involved. The exact cause of MVT is unknown. However, there are many diseases that can lead to MVT. Many of the diseases cause swelling (inflammation) of the tissues surrounding the veins, and include:
Appendicitis
Cancer of the abdomen
Diverticulitis
Liver disease with cirrhosis
High blood pressure in the blood vessels of the liver
Abdominal surgery or trauma
Pancreatitis
Inflammatory bowel disorders
Heart failure
Protein C or S deficiencies
Polycythaemia vera
Essential thrombocythemia
People who have disorders that make the blood more likely to stick together (clot) have a higher risk for MVT. Birth control pills and oestrogen medicines also increase risk.

MVT is more common in men than women. It mainly affects middle aged or older adults. Symptoms may include any of the following:
Abdominal pain, which may get worse after eating and over time; Bloating; Constipation; Bloody diarrhoea; Fever; Septic shock; Lower gastrointestinal bleeding; Vomiting and nausea.
Blood thinners (most commonly heparin or related medicines) are used to treat MVT when there is no associated bleeding. In some cases, medicine can be delivered directly into the clot to dissolve it. This procedure is called thrombolysis. Less often, the clot is removed by thrombectomy.

Deep vein thrombosis (DVT) is the formation of a blood clot in a deep vein of the legs, thigh, or pelvis. Thrombosis is most often seen in individuals with a history of immobilization, obesity, malignancy, or hereditary thrombophilia. Vascular endothelial damage, venous stasis, and hypercoagulability, collectively referred to as the Virchow triad, are the main factors contributing to the development of DVT.
Symptoms usually occur unilaterally and include swelling, tenderness, and redness or discoloration. Pulmonary embolism (PE), a severe complication of DVT, should be suspected in patients with dizziness, dyspnoea, and fever. The diagnostic test of choice for DVT is compression ultrasound. In most cases, a negative D-dimer test allows thrombosis or PE to be ruled out, but a positive test is nonspecific.
Initial acute treatment of DVT consists of anticoagulation with heparin and, if the thrombus is large or unresponsive to anticoagulation, may also include thrombolysis or thrombectomy. Secondary prophylaxis is achieved with oral warfarin or direct factor Xa inhibitors and supportive measures such as regular exercise and compression stockings.