Calf Pain
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.