Swollen Calf Flashcards
What are the main factors to consider when coming up with a differential diagnosis for calf swelling?
Is it acute or chronic?
Is it in one leg or both legs?
Construct a differential diagnosis for a single acutely swollen calf.
Vascular:
DVT
Compartment syndrome
Knee joint:
Baker cyst
septic arthritis
Skin changes:
Cellulitis
Allergy insect bite
Muscle strain
Construct a differential diagnosis for bilateral calf swelling.
Right heart failure Lymphoedema Venous insufficiency Pregnancy Vasodilators (e.g. CCBs) Hypoalbuminaemia Pelvic tumour
List some key features of the history that you should ask the patient about.
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
List some risk factors for DVT.
Trauma Surgery Bed rest Long-haul travel Cancer Pregnancy OCP and HRT
List the main symptoms of PE.
Breathlessness
Pleuritic chest pain
Haemoptysis
Which cause of calf swelling is associated with a rapidly growing swelling along the affected limb?
Cellulitis
Why should you ask about symptoms of GI, ovarian and uterine malignancy (e.g. PR bleeding, unusual vaginal bleeding, weight loss)?
A pelvic mass (e.g. a tumour) could compress the iliac veins or IVC leading to leg swelling
Why should you ask a patient about previous radiotherapy and surgery to the affected leg?
Increases risk of lymphedema
List how, on examination, the nature of the swelling is different in:
Septic Arthritis
Compartment Syndrome
Baker’s Cyst
- Septic Arthritis
Swelling around the joint - Compartment Syndrome
Swelling/inflammation is confined to the compartment but spares the joints - Baker’s Cyst
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
Why is it important to palpate for abdominal masses?
Abdominal masses could compress the IVC or iliac veins leading to leg swelling
Why is it important to assess the neurovascular status of the affected limb?
The high pressure within the compartment in compartment syndrome can lead to compromise of neurovascular status
Describe how the pain on passive movement is different in:
Septic Arthritis
Compartment Syndrome
- Septic Arthritis
Pain in the joint - Compartment Syndrome
Pain in the calf
Describe how the Wells’ score is interpreted.
< 4 = D-dimer to rule out PE
4+ = CTPA
What the most sensitive, rapid and non-invasive method of visualising a DVT?
Doppler ultrasound of proximal leg veins
NOTE: this can also help distinguish DVTs from Baker’s cysts
Why might FBC and Clotting Screen be useful in a patient with a swollen calf?
FBC – may show high WCC (infection), high RBC (polycythaemia –> hypercoagulability)
Deranged coagulation – increased risk of clots forming
Outline the management of DVT.
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)
Describe the typical features of compartment syndrome.
Tense, shiny, swollen limb that is painful to passive movement
What is the most common cause of compartment syndrome?
Trauma
What can the high pressures within the compartment in compartment syndrome lead to?
Neurovascular compromise –> ischaemia and necrosis
What can compartment syndrome of the anterior compartment of the forearm lead to?
Volkmann’s contracture – permanent flexion of the wrist due to ischaemia and necrosis of the anterior forearm compartment muscles
How is acute compartment syndrome managed surgically?
Emergency fasciotomy
Outline the management of cellulitis.
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)
What is a Baker’s cyst?
Swelling of a synovial bursa (usually the semimembranosus bursa) around the knee joint
NOTE: also known as a popliteal cyst
Rupture of a Baker’s cyst can be clinically indistinguishable from which other cause of calf swelling?
DVT
Outline the treatment of a ruptured Baker’s cyst.
Elevation of affected limb
Aspiration of fluid
Corticosteroid injection
List some congenital mutations that cause hypercoagulability.
Factor V leiden
Antithrombin III deficiency
Protein C deficiency
Protein S deficiency
List some diseases that cause hypercoagulability.
Any malignancy
DIC
Antiphospholipid syndrome
Polycythaemia
List some drugs that cause hypercoagulability.
COCP
HRT
Procoagulant/antifibrinolytic drugs
Describe the mechanism of action of warfarin.
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
List some contraindications for warfarin.
Pregnancy (teratogenic)
Severe hypertension (risk of haemorrhagic stroke)
Peptic ulcer disease
Under what circumstance can a DVT lead to a stroke rather than a PE?
Patent foramen ovale (PFO)
