Under the radar: upper limb DVT

Continuing our series on diagnoses that may be missed in a primary care setting, Dr Ahmed Mostafa describes a case of upper limb DVT that was initially misdiagnosed

Note details of cases in this series have been altered to protect individuals’ identities

A 39-year-old female patient presented with ongoing right arm pain and swelling lasting 1.5 months. She explained it had started when she was on holiday overseas – her arm had become red and swollen, so she had consulted a local clinician who advised it was likely an infected spider bite and prescribed a course of oral antibiotics. She did not recall being bitten, but took the antibiotics.

Once back in the UK, she called 111 and she was advised to go to A&E. After waiting a few hours, she was streamed to the Urgent Treatment Centre where she was diagnosed with cellulitis and soft tissue infection secondary to an insect bite. She was given another course of oral antibiotics and advised to see her GP for follow up.

A week later, there was still no improvement. The patient was seen by another healthcare practitioner at the GP practice who told her to continue the oral antibiotics.

She re-attended A&E again a week later after she had finished the antibiotics as the pain was getting worse. The problem was this time diagnosed as tenosynovitis and she was again discharged home to follow-up with her GP.

It was at this point she presented to me, and explained her arm had become even more swollen, and that it got worse at work when using her arm. I took a detailed history; of note she denied pain anywhere else, and was on an oral contraceptive pill. On clinical examination the affected arm was discoloured, as seen in this report,[1] and showing prominent veins on the arm and chest as in the image in this paper.[2]

The outcome

I considered the diagnosis was likely to be upper limb DVT, so prescribed an oral DOAC and referred the patient to same day emergency care, where a D-dimer test was performed. The result was negative and the patient was discharged home as negative for DVT. One week later, she did not feel any better and attended a different A&E where she underwent an ultrasound (US) scan which confirmed upper limb DVT, with further investigations requested.

How is upper limb DVT diagnosed?

Diagnosis of upper limb DVT, also known as upper extremity DVT (UEDVT), is based initially on clinical presentation, specifically the presence of prominent veins on the shoulder and anterior chest wall, known as Urschel’s sign, associated with whole arm redness, warmth and swelling.

However, a red swollen upper arm can be misdiagnosed and treated as cellulitis, as happened in this case.
In addition to upper extremity swelling and pain, upper limb DVT can initially present as symptomatic or asymptomatic pulmonary embolism.

Confirmation of upper limb DVT is by imaging with colour doppler and duplex US or venography (either computed tomographic (CT) or magnetic resonance (MR) venography, if available) – all done in secondary care. Venography is the gold standard for diagnosis but less frequently performed due to its invasive nature.

Blood tests can be used such as D-dimer, but be aware that timing can affect a D-dimer result: for example, if blood samples are taken after receiving an anticoagulant, or done too early during the formation of the clot, or once the clot has formed, it can lead to a false negative result.

How is upper limb DVT managed?

Recommended treatment of UEDVT is as for lower limb DVT; the patient should be started on oral anticoagulation – usually a DOAC – and then reviewed after 3-6 months, to consider stopping the anticoagulant or continuing treatment long term, depending on the underlying cause and risk of recurrence versus risk of bleeding.

It is important to establish the underlying cause for UEDVT. It may be of primary UEDVT/Paget–von Schrötter syndrome, an effort-induced thrombosis in the axillary and subclavian veins that is rare (estimated annual incidence of 1 to 2 cases per 100,000 population).

However, the majority of cases are secondary, which may be related to central venous cannulation, a pacemaker, prothrombotic states (eg, thrombophilia, malignancy) or oral contraception.

In this case, investigations ruled out other potential causes, so the UEDVT was considered to be secondary to oral contraception. The patient was advised to stop taking the contraception as she was unwilling to continue on concomitant anticoagulation long term. She was booked for another appointment to discuss switching to another method of contraception carrying a lower risk of DVT.

Learning points for GPs

DVT of the upper extremity is becoming increasingly common, reportedly due to increased intravenous catheter use, though it is still much less common than DVT of the lower extremity.

A negative D-dimer test does not exclude upper limb DVT; clinical presentation consistent with Urschel’s sign is strongly suggestive of UEDVT, which should be further investigated through appropriate imaging.
The treatment of choice is anticoagulation, which is given analogously to that for DVT of the lower extremity.

Dr Ahmed Mostafa is a GP registrar in the West Midlands

References

1. Seeger M, Bewig B. Paget–Schroetter Syndrome. N Engl J Med 2010;363: e4
2. Lawless S, Samson R. Urschel’s Sign in Paget Schroetter Syndrome. Am J Med 2017; 130(12): e537