27. Swollen Calf

Question 1

What are the main factors to consider when coming up with a differential diagnosis for calf swelling?

Answer 1

Is it acute or chronic?

Is it in one leg or both legs?

Question 2

Construct a differential diagnosis for a single acutely swollen calf.

Answer 2

DVT 
Cellulitis 
Ruptured Baker’s cyst 
Muscle strain 
Septic arthritis 
Allergic response (e.g. to an insect bite) 
Compartment syndrome

Question 3

Construct a differential diagnosis for bilateral calf swelling.

Answer 3

Right heart failure 
Lymphoedema 
Venous insufficiency
Pregnancy
Vasodilators (e.g. CCBs)
Hypoalbuminaemia
Pelvic tumour

Question 4

List some key features of the history that you should ask the patient about.

Answer 4

Risk factors for DVT
Symptoms of PE
Cuts/wounds/insect bites on affected limb
Is the swelling getting any bigger?
Signs of pelvic malignancy (e.g. PR bleeding, unusual vaginal bleeding, abdominal pain)
Radiotherapy and surgery to affected leg

Question 5

List some risk factors for DVT.

Answer 5

Trauma 
Surgery
Bed rest
Long-haul travel
Cancer
Pregnancy
OCP and HRT

Question 6

List the main symptoms of PE.

Answer 6

Breathlessness
Pleuritic chest pain
Haemoptysis

Question 7

Which cause of calf swelling is associated with a rapidly growing swelling along the affected limb?

Answer 7

Cellulitis

Question 8

Why should you ask about symptoms of GI, ovarian and uterine malignancy (e.g. PR bleeding, unusual vaginal bleeding, weight loss)?

Answer 8

A pelvic mass (e.g. a tumour) could compress the iliac veins or IVC leading to leg swelling

Question 9

Why should you ask a patient about previous radiotherapy and surgery to the affected leg?

Answer 9

Increases risk of lymphedema

Question 10

List how, on examination, the nature of the swelling is in septic arthritis

Answer 10

Swelling around the joint

Question 11

List how, on examination, the nature of the swelling is in Compartment Syndrome

Answer 11

Swelling/inflammation is confined to the compartment but spares the joints

Question 12

List how, on examination, the nature of the swelling is in Baker’s Cyst

Answer 12

Swelling protrudes backwards from the knee joint into the popliteal fossa
NOTE: rupture of the Baker’s cyst can make the swelling run down into the calf

Question 13

Why is it important to palpate for abdominal masses?

Answer 13

Abdominal masses could compress the IVC or iliac veins leading to leg swelling

Question 14

Why is it important to assess the neurovascular status of the affected limb?

Answer 14

The high pressure within the compartment in compartment syndrome can lead to compromise of neurovascular status

Question 15

Describe how the pain on passive movement is different in septic arthritis and compartment syndrome

Answer 15

Septic Arthritis = Pain in the joint

Compartment Syndrome = Pain in the calf

Question 16

Describe how the Wells’ score is interpreted.

Answer 16

< 4 = D-dimer to rule out PE

4+ = CTPA

Question 17

What the most sensitive, rapid and non-invasive method of visualising a DVT?

Answer 17

Doppler ultrasound of proximal leg veins

NOTE: this can also help distinguish DVTs from Baker’s cysts

Question 18

Why might FBC and Clotting Screen be useful in a patient with a swollen calf?

Answer 18

FBC – may show high WCC (infection), high RBC (polycythaemia -> hypercoagulability)
Deranged coagulation – increased risk of clots forming

Question 19

Outline the management of DVT.

Answer 19

Anticoagulation (with LMWH or fondaparinux, then ongoing anticoagulation is achieved with warfarin or rivaroxaban)
Compression stockings 
Lifestyle advice (e.g. stop HRT/COCP, lose weight)

Question 20

Describe the typical features of compartment syndrome.

Answer 20

Tense, shiny, swollen limb that is painful to passive movement

Question 21

What is the most common cause of compartment syndrome?

Answer 21

Trauma

Question 22

What can the high pressures within the compartment in compartment syndrome lead to?

Answer 22

Neurovascular compromise  ischaemia and necrosis

Question 23

What can compartment syndrome of the anterior compartment of the forearm lead to?

Answer 23

Volkmann’s contracture – permanent flexion of the wrist due to ischaemia and necrosis of the anterior forearm compartment muscles

Question 24

How is acute compartment syndrome managed surgically?

Answer 24

Emergency fasciotomy

Question 25

Outline the management of cellulitis.

Answer 25

Antibiotics
Demarcation of erythematous region to monitor progress
Elevation – helps reduce the swelling and reduce pain
Topical steroids and oral antihistamines – in the case of an inflammatory reaction to an insect bite (may present similarly to cellulitis)

Question 26

What is a Baker’s cyst?

Answer 26

Swelling of a synovial bursa (usually the semimembranosus bursa) around the knee joint
NOTE: also known as a popliteal cyst

Question 27

Rupture of a Baker’s cyst can be clinically indistinguishable from which other cause of calf swelling?

Answer 27

DVT

Question 28

Outline the treatment of a ruptured Baker’s cyst.

Answer 28

Elevation of affected limb
Aspiration of fluid
Corticosteroid injection

Question 29

List some congenital mutations that cause hypercoagulability.

Answer 29

Factor V leiden
Antithrombin III deficiency
Protein C deficiency
Protein S deficiency

Question 30

List some diseases that cause hypercoagulability.

Answer 30

Any malignancy
DIC
Antiphospholipid syndrome
Polycythaemia

Question 31

List some drugs that cause hypercoagulability.

Answer 31

COCP
HRT
Procoagulant/antifibrinolytic drugs

Question 32

Describe the mechanism of action of warfarin.

Answer 32

Vitamin K epoxide reductase inhibitor
Inhibits the gamma-carboxylation of factors 2, 7, 9 and 10
Also inhibits the production of protein C and protein S (thus causing an transient hypercoagulable stage)
This is why warfarin is started with LMWH until the INR has remained within the target range for > 24 hrs

Question 33

List some contraindications for warfarin.

Answer 33

Pregnancy (teratogenic)
Severe hypertension (risk of haemorrhagic stroke)
Peptic ulcer disease

Question 34

Under what circumstance can a DVT lead to a stroke rather than a PE?

Answer 34

Patent foramen ovale (PFO)