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Quiz Feedback: Thrombophilia, CRP & Fungal Infections
This quiz feedback provides an opportunity to revisit Best Tests, March 2011
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Question:
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1. Which of the following most increases an individual’s risk of venous thromboembolism (VTE)? |
Your peers |
Answer |
Major trauma |
96% |
|
Varicose veins |
8% |
|
Air travel |
12% |
|
Inherited thrombophilia |
22% |
|
Question 1 comments
The strongest risk factors for VTE are; fracture (hip or leg), hip or knee replacement, major general surgery, major
trauma and spinal cord injury. Inherited thrombophilia is considered to be a moderate risk factor, while air travel
and varicose veins are weak risk factors. The assessment of risk can help to determine if the event was provoked (i.e.
exacerbated by external risk factors), or unprovoked (i.e. occurred for no apparent reason).
2.In which of the following situations is thrombophilia testing indicated? |
Your peers |
Answer |
A person under the age of 40 years, presenting with unprovoked VTE, and no known family history
of VTE |
72% |
|
A person on chemotherapy presenting with VTE |
6% |
|
A woman on oral contraceptives, worried about the risk of VTE |
3% |
|
All people presenting with VTE |
4% |
|
Question 2 comments
Thrombophilia testing should only be performed when the test results will alter management and is therefore only recommended
in situations such as:
- A patient presenting with unprovoked venous thrombosis at an early age (<40 years) with a family history of thrombosis
(more than two other symptomatic first degree family members)
- Children with purpura fulminans
- Pregnant women at risk of venous thrombosis, e.g. pregnant women who have had a previous VTE due to a minor provoking
factor
Thrombophilia testing is not indicated in any of the scenarios presented in Question 2. In hindsight this may have
caused confusion. In the first option, testing would have been indicated if “a positive family history of thrombosis” was
added to the scenario. Malignancy and oestrogen containing oral contraceptives are both moderate risk factors for VTE
but are not considered indications for testing. In addition, testing is not recommended when patients present in the
acute phase of a thrombotic event.
3.What is the purpose of the D-dimer test, when investigating a possible deep vein thrombosis (DVT)? |
Your peers |
Answer |
An elevated test is a specific marker for DVT |
1% |
|
Is a useful test for helping to exclude DVT |
86% |
|
Is useful for differentiating between a superficial and deep vein thrombosis |
2% |
|
Should be used in conjunction with a clinical probability rule for determining referral to ultrasound |
73% |
|
Question 3 comments
The D-dimer test can be elevated in nearly all patients with VTE, but can also be elevated in patients with infection,
malignancy or recent surgery so is therefore not specific. Its key diagnostic role is as a negative predictor of VTE,
i.e. a low level makes VTE an unlikely diagnosis. D-dimer can be used in conjunction with the Wells Rule or the Primary
Care Rule to determine the probability of a DVT.
Differentiating between superficial and deep thrombosis is best done with ultrasound.
4.If a patient wants to start the combined oral contraceptive (COC), which of the following are
correct? |
Your peers |
Answer |
The patient should have thrombophilia testing performed |
<1% |
|
Ask about any known inherited thrombophilias |
89% |
|
Do not prescribe the COC if there is any first degree relative with a history of VTE |
47% |
+/- |
COC are a moderate risk factor for VTE |
80% |
|
Question 4 comments
The use of oestrogen-containing oral contraceptives is a moderate risk factor for VTE but this is not considered an
indication for testing.
It is important to ask about a family history of thrombophilia, to determine if a first degree relative aged less
than 45 years has had a VTE. If this is the case, the use of oestrogen-containing oral contraceptives is not recommended
unless other methods are unacceptable or not available. For patients with known thrombogenic mutations, oestrogen-containing
oral contraceptives should be avoided.
5.Your patient reports a positive family history of VTE ( her elderly mother had a DVT following
a hip fracture). What is the role of thrombophilia testing in your patient? |
Your peers |
Answer |
Testing is indicated |
6% |
|
Family members should be tested |
1% |
|
She should be advised to avoid long-distance flights |
5% |
|
It would be useful to test for just the more common mutations (Factor V Leiden and Prothrombin
gene mutations) |
32% |
|
Question 5 comments
As previously discussed, one of the strongest risk factors for VTE is fracture (hip or leg) so in this scenario no
testing is indicated for either your patient or for her mother.
Factor V Leiden and Prothrombin gene mutation are considered low risk thrombophilias, and case finding in asymptomatic
relatives is not indicated.
6. What next steps are recommended in a person suspected of temporal arteritis with an elevated
CRP, but normal ESR? |
Your peers |
Answer |
Repeat ESR |
2% |
|
Repeat CRP |
3% |
|
The ESR and CRP should both be elevated to support diagnosis |
<1% |
|
Biopsy or empirical treatment should be initiated, irrespective of results |
98% |
|
Question 6 comments
In most cases, temporal arteritis is characterised by a normal ESR with an elevated CRP, however, although unusual,
an elevated ESR and a normal CRP can also be suggestive of temporal arteritis. Traditionally, both ESR and CRP have
been used to investigate temporal arteritis, but the role of ESR as a routine test for this has now been questioned.
Some consider the additional 1.7% sensitivity that is gained by using both ESR and CRP together, encourages increased
use of tests, but for minimal clinical gain. Particularly, as any patient with a strong clinical history should have
a temporal artery biopsy or empirical treatment irrespective of the results of laboratory tests.
7. In which of the following scenarios is fungal testing indicated? |
Your peers |
Answer |
In suspected fungal infection of the hair where the diagnosis is uncertain |
80% |
|
In all patients with suspected athletes foot |
2% |
|
To allow targeted treatment |
86% |
|
In all patients with thick, crumbly toenails |
15% |
|
Question 7 comments
Most minor fungal infections, e.g. athletes foot, do not require testing and can be treated topically. Laboratory
fungal testing is useful to confirm disease when it is chronic, severe or when considering systemic therapy, and when
the fungal infection involves the hair, palms of the hands or soles of the feet. Sometimes testing can be useful to
determine the species of fungus to allow targeted oral treatment.
Thick, crumbly toenails can be the result of various conditions, not just fungal infection. Laboratory testing might
not be useful in cases where patients are not willing to take oral antifungal therapy, even if a fungal infection was
confirmed.
8. Which of the following may be reasons for a negative fungal result? |
Your peers |
Answer |
Use of antifungal medication prior to collection |
98% |
|
Lack of viable fungal elements in sample |
95% |
|
The lesion is a discoid eczema |
88% |
|
Cleaning the area with alcohol prior to collection |
9% |
|
Question 8 comments
When collecting specimens for fungal testing, preparation of the skin or nails with an alcohol swab is useful to remove
any traces of skin products or medications.
Negative culture results may arise due to a number of problems including; antifungal treatment used prior to collection
of the specimen, the presence of non-viable hyphae elements (as can occur in the distal region of a nail) and an incorrect
clinical diagnosis, such as the skin condition actually being a skin cancer or form of eczema.
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