Calf Pain
Calf pain is usually innocent, except when accompanied by swelling. It is often caused by cramp, which is especially common in the elderly. In this group it can cause significant distress, through the havoc wreaked on sleep. Some of the less likely diagnoses, such as peripheral vascular disease, have important implications, so careful assessment is necessary.
Differential diagnosis
Common Diagnoses
- Idiopathic (Simple) Cramp (Including Night Cramps)
- Muscle Stiffness (Unaccustomed Exercise)
- Cellulitis
- Peripheral Vascular Disease (PVD; Intermittent Claudication)
- Muscle Injury (e.g. Strain)
Occasional Diagnoses
- Referred Back Pain (L4 and 5)
- Referred Knee Pain (Arthropathy, Infection)
- Alcoholic or Diabetic Neuropathy
- Cramps Caused by Underlying Hypocalcaemia or Electrolyte Imbalance
- Ruptured Baker’s Cyst
- Deep Vein Thrombosis (DVT)
- Thrombophlebitis
- Growing Pains in Children
Rare Diagnoses
- Motor Neurone Disease
- Multiple Sclerosis
- Muscle Enzyme Deficiency
- Psychological: Muscle Tension
- Lead and Strychnine Poisoning
- Ruptured Achilles Tendon
Ready reckoner
Key distinguishing features of the most common diagnoses
| Cramp | Stiffness | Cellulitis | Muscle Injury | PVD | |
|---|---|---|---|---|---|
| Worse at Night | Yes | No | No | No | No |
| Systemically Unwell | No | No | Possible | No | No |
| Worse with Exercise | Possible | Yes | Possible | Yes | Yes |
| Calf Swelling | No | No | Yes | Possible | No |
| Cool Peripheries | No | No | No | No | Yes |
Possible investigations
Likely: None.
Possible: Urinalysis, WCC, ESR/CRP, U&E, calcium, LFT, blood glucose or HbA1c, D-dimer.
Small Print: Ultrasound, venogram, angiography.
- Urinalysis: Check specific gravity, glucose and protein (over and under-hydration, diabetes, renal failure as occasional causes of ‘simple’ cramp).
- WCC and ESR/CRP: Both raised in infection. ESR/CRP raised in arthropathy.
- U&E and calcium: Check renal function and electrolyte imbalance (e.g. from diuretics; hypocalcaemia).
- LFT and blood glucose or HbA1c: If suspect alcoholism or diabetes resulting in a neuropathy.
- D-dimer (usually in hospital): A raised level suggests a DVT, but is not conclusive.
- Ultrasound/venogram: Further tests to diagnose DVT, performed in secondary care.
- Angiography will be arranged by the specialist if peripheral vascular disease is suspected.
Top Tips
- Bear in mind that many patients will be anxious about the possibility of DVT – reassure them about this if the diagnosis clearly lies elsewhere
- Save the patient unnecessary investigation and possible anticoagulation by taking a careful history. A muscle tear and a DVT can both produce calf swelling and warmth. The former, though, is preceded by a dramatic and sudden pain in the calf, sometimes described as being like a kick or a gunshot.
- It can be difficult to distinguish a simple muscle strain from claudication. Muscular pains tend to produce discomfort as soon as the patient stands; claudication usually starts after the patient has walked a predictable distance.
- Patients with superficial phlebitis will fear the more serious DVT. Explain the difference to them.
Red Flags
- Consider investigating the adult patient with recent onset of apparently simple cramps if associated with general malaise (these will be in the minority).
- Claudication accompanied by nocturnal pain in the ball of the foot suggests critical ischaemia – refer urgently.
- If the clinical picture suggests a DVT then refer urgently either to A&E or according to your local DVT pathway.
- Do not overlook Achilles rupture. The presentation may sometimes be less dramatic than you would expect. Use the calf squeeze test to ensure that the tendon is intact.