Cardiovascular for PLAB 1

A 58 year old woman has a swollen, painful left calf four days after a long-haul flight. The calf is 4 cm larger than the right, warm and tender along the deep veins, with pitting oedema. She has no erythematous advancing edge and is afebrile. Her Wells score is 3. What is the SINGLE most likely diagnosis?

1. Deep vein thrombosis correct Correct. Swelling in one calf that is more than 3 cm bigger than the other side, tenderness along the deep veins, swelling that dents when pressed, and a recent risk factor for not moving around. No fever and no spreading red edge argues against cellulitis, the condition most often mistaken for this.
2. Chronic venous insufficiency Poor vein return from the legs. Affects both legs, long-standing, with brown skin staining from old blood (haemosiderin) and hardened, tightened skin. But a Wells score of 3 with swelling in one leg that dents when pressed does not point to it.
3. Lymphoedema Swelling from a blocked lymph system. It does not leave a dent when pressed, is long-standing, involves the toes, and gives a positive Stemmer sign, where a fold of skin at the base of the toe cannot be pinched up. It does not fit a Wells score of 3 with swelling in one leg that dents when pressed.
4. Calf muscle tear Sudden pain during exercise with bruising, and a clear story of how it happened. Here, a Wells score of 3 with swelling in one leg that dents when pressed points elsewhere.
5. Cellulitis A skin infection. Spreading redness with a clear moving edge, fever and a break in the skin where the infection got in. This is the condition most often confused with DVT. That does not match a Wells score of 3 with swelling in one leg that dents when pressed.

The point: Work out the Wells score first. A score of two or more means a blood clot in the leg (DVT) is LIKELY: get an ultrasound scan of the deep leg veins within 4 hours, or give a blood thinner while waiting and scan within 24 hours. A score of one or less means it is UNLIKELY: do a blood test called a D-dimer, and if it is negative, DVT is ruled out. A D-dimer taken without working out the Wells score first cannot be read properly. It is good at picking up a clot if one is there, but it is not specific to DVT, and it also rises with infection, cancer, pregnancy and old age.

Source: NICE NG158 — Venous thromboembolic diseases: diagnosis, management and thrombophilia testing NICE · tier 1, national regulator or guidance

A 58 year old woman has a swollen, painful left calf four days after a long-haul flight. The calf is 4 cm larger than the right, warm and tender along the deep veins, with pitting oedema. She has no erythematous advancing edge and is afebrile. Her Wells score is 3. What is the SINGLE most appropriate initial investigation?

1. D-dimer A blood test. Only useful when the Wells score says DVT is UNLIKELY, to rule it out. Even in that group, a positive result still needs a scan, because the test cannot confirm DVT on its own. Here, a Wells score of 3 with swelling in one leg that dents when pressed points elsewhere.
2. CT pulmonary angiogram A CT scan with dye that looks at the lung arteries. Used for a suspected blood clot in the lung, not for a swollen leg on its own. It does not fit a Wells score of 3 with swelling in one leg that dents when pressed.
3. Proximal leg vein ultrasound correct Correct. A Wells score of 2 or more makes DVT LIKELY, and in that group ultrasound is the test to do. A D-dimer adds nothing here, because even a negative result would not be enough to rule DVT out. The scan should happen within 4 hours, or she gets a blood thinner while waiting and a scan within 24 hours.
4. Thrombophilia screen A blood test for clotting disorders. Used for a blood clot with no clear trigger, when stopping the blood thinner is being considered, and never during the acute clot or while still on the blood thinner. But a Wells score of 3 with swelling in one leg that dents when pressed does not point to it.
5. Wells score A scoring system that decides which test to do next and makes the D-dimer result meaningful. It comes before anything else, and it is the step people often skip. That does not match a Wells score of 3 with swelling in one leg that dents when pressed.

The point: Work out the Wells score first. A score of two or more means a blood clot in the leg (DVT) is LIKELY: get an ultrasound scan of the deep leg veins within 4 hours, or give a blood thinner while waiting and scan within 24 hours. A score of one or less means it is UNLIKELY: do a blood test called a D-dimer, and if it is negative, DVT is ruled out. A D-dimer taken without working out the Wells score first cannot be read properly. It is good at picking up a clot if one is there, but it is not specific to DVT, and it also rises with infection, cancer, pregnancy and old age.

Source: NICE NG158 — Venous thromboembolic diseases: diagnosis, management and thrombophilia testing NICE · tier 1, national regulator or guidance

A 58 year old woman has a swollen, painful left calf four days after a long-haul flight. The calf is 4 cm larger than the right, warm and tender along the deep veins, with pitting oedema. She has no erythematous advancing edge and is afebrile. Her Wells score is 3. What is the SINGLE most appropriate immediate management?

1. Low molecular weight heparin A blood thinner given by injection. The choice in pregnancy, where DOACs and warfarin must not be used, and in some clots linked to cancer. But a Wells score of 3 with swelling in one leg that dents when pressed does not point to it.
2. Direct oral anticoagulant correct Correct. Apixaban or rivaroxaban started straight away once confirmed, for at least three months. Neither drug needs an extra heparin injection to start with, which is the change from the older warfarin days that exams like to test.
3. Reassure and review in one week Telling the patient it is fine and reviewing in a week. Unsafe whenever DVT is possible, because the risk is a fatal blood clot in the lung before the review happens. It does not fit a Wells score of 3 with swelling in one leg that dents when pressed.
4. Compression stockings Tight stockings. Not routinely recommended to prevent long-term swelling after a clot, though they are used to ease symptoms. Here, a Wells score of 3 with swelling in one leg that dents when pressed points elsewhere.
5. Interim anticoagulation pending the scan Giving a blood thinner while waiting for the scan, used when DVT is likely and the ultrasound cannot be done within 4 hours. That does not match a Wells score of 3 with swelling in one leg that dents when pressed.

The point: Work out the Wells score first. A score of two or more means a blood clot in the leg (DVT) is LIKELY: get an ultrasound scan of the deep leg veins within 4 hours, or give a blood thinner while waiting and scan within 24 hours. A score of one or less means it is UNLIKELY: do a blood test called a D-dimer, and if it is negative, DVT is ruled out. A D-dimer taken without working out the Wells score first cannot be read properly. It is good at picking up a clot if one is there, but it is not specific to DVT, and it also rises with infection, cancer, pregnancy and old age.

Source: NICE NG158 — Venous thromboembolic diseases: diagnosis, management and thrombophilia testing NICE · tier 1, national regulator or guidance