Key distinguishing features of the most common diagnoses
|Worse at Night||Yes||No||No||No||No|
|Worse with Exercise||Possible||Yes||Possible||Yes||Yes|
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.
- 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.
- 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.