Swollen calf - red flag symptoms

Refresh your knowledge of red flag symptoms to look out for in presentations of swollen calf.

The most acutely sinister cause is DVT (Photo: Dr P. Marazzi/Science Photo Library)
The most acutely sinister cause is DVT (Photo: Dr P. Marazzi/Science Photo Library)

Red flag symptoms

  • Recent immobility or surgery
  • 3cm discrepancy compared to the other calf
  • Unilateral swelling
  • Calf pain/tightness/redness

Calf swelling can be unilateral or bilateral. The most acutely sinister cause for this symptom is a deep vein thrombosis (DVT) and it is important to identify or exclude this potentially dangerous condition.

History

There are many causes for calf swelling. In exploring this condition, it is important to establish if the calf swelling is unilateral or bilateral. Also, one should find out whether the symptom is acute or chronic.

There may be a history of trauma, and this may guide you towards a possible fracture, ruptured muscle or potential compartment syndrome. A history of a chronic medical condition, such as diabetes or congestive heart failure, may predispose to conditions such as cellulitis.

Risk factors for a DVT include smoking, taking the oral contraceptive pill, obesity, and thrombophilic states such as factor V Leiden, as well as pregnancy and increasing age.

Examination

The patient may not be able to bear weight or may be walking with a limp. The patient may be tachycardic and possibly febrile.

Examination of the calf may show features of inflammation including redness, warmth, tenderness and enlargement compared with the contralateral calf at a fixed point. Homan's test demonstrates pain on dorsiflexion of the foot, but this should be done with caution as it may trigger fragmentation of a clot.

Peripheral pulses should be assessed, as the dorsalis pedis pulse may be absent in a deep vein thrombosis, but this sign may also be suggestive of compartment syndrome. Bilateral calf swelling and peripheral oedema can suggest conditions such as congestive heart failure.

Investigations

Investigations will be directly guided by the clinician's assessment of the calf swelling. Well’s score can further stratify the risk of a deep vein thrombosis and a score greater than one should warrant further investigations within secondary care.

These include blood tests such as a d-dimer, full blood count, clotting screen, renal and liver function tests. Doppler ultrasound should also be considered. If other conditions are suspected, consider tests such as a limb x-ray, knee ultrasound and even magnetic resonance imaging. If a deep vein thrombosis is suspected, urgent referral to the nearest secondary care centre is vital.

Possible causes

  • Calf trauma
  • DVT
  • Thrombophlebitis
  • Cellulitis
  • Ruptured gastrocnemius muscle
  • Bone tumour
  • Ruptured Baker's cyst
  • Fracture
  • Compartment syndrome
  • Lymphoedema

Dr Anish Kotecha is a GP in Gwent, Wales. This article, originally by Dr Mehul Mathukia, first appeared on 9 July 2010 and was updated in November 2019.

Visit MIMS Learning for an interactive version of this article and a CPD certificate

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