Our case presented a 34 year old lady with known sickle cell disease to the A&E department complaining of shortness of breath and chest pain. The case starts by reminding us of the basic management of a patient with sickle cell disease.
- chest x-ray
- Physiotherapy – incentive spirometry
- Involvement of HDU/ITU team
- FBC, Basic biochemistry, group and screen, blood cultures
- sputum culture
- Consideration of top up transfusion or exchange
Whilst treating the patient for ACS, suspicion was raised of a possible PE. VTE in adults with sickle cell disease is a recognised important clinical complication and is likely in part to be related to the hypercoagable state. Pulmonary embolism may present with chest pain, dyspnoea and hypoxia. If there is a high clinical suspicion of pulmonary embolism (i.e. sudden onset unilateral pleuritic pain that is not typical of sickle pain) treat for both conditions pending imaging. ACS may be complicated by pulmonary embolism or may occur secondary to pulmonary embolism and treatment will be required for both conditions simultaneously.
Risk factors for VTE in sickle (reference 1)
- Sickle cell disease is an ongoing risk factor for VTE.
- Genotype with HbSS and HbSbeta0 having the highest risk compared to HbSC or SBeta+.
- Gender – women are at higher risk
- Number of crises – > 3 admissions per year
- Hospitalisation within 90 days
- elevated tricuspid regurgitant jet velocity on cardiac ECHO
- Indwelling catheter
Use of d-dimer levels at diagnosis are uncertain, as baseline levels in patient with sickle cell disease who are clinically well, are often elvated. Therefore performing a d-dimer is unlikely to be helpful.
Imaging (reference 1)
- CTPA – results may be confounded in SCD disease patient experiencing ACS due to high prevalence of in situ pulmonary thrombosis. There can also be small subsegmental filling defects secondary to sicklingnin the absence of ACS
- CTPA may lead to contrast induced kidney damage
- V/Q – minimises radiation exposure, and there is no risk of kidney damage, however it may be less useful in patients exhibiting abnormalities on chest x-ray
Treatment options for sickle patients are no different to that of the general population but thought must be given to the higher risk of recurrence in this population and their bleeding risk. Data has suggested a high bleeding risk in patients with sickle after a VTE, with a rate of 2.9% at 6 months and 5 % at one year. (Reference 3). This is in line with patients treated for cancer related thrombosis on anticoagulation.
Risk of recurrence of VTE in sickle patients is similar to those individuals in the general population who have had a unprovoked VTE. Individuals factors need to be considered. Patients with >3 admissions per year had a recurrence rate of 37%. Therefore a careful balance is required between bleeding risk and risk of recurrence.
In this case the patient was female of child bearing age which may add further complications to the treatment plan. This simply highlights the importance of an individualised plan for each patient, which considering the impact of the underlying sickle cell disease.
‘How I treat and diagnose thromboembolism in sickle disease’ provides an excellent resource. Here is a summary of diagnosis and treatment from this document available in blood journal.
1. How I treat and diagnose thromboembolism in sickle cell disease. Shet, A and Wun, T. Blood 2018.
2. Sickle cell disease: an inherited thrombophilia. Wun, T, Brunson, A. Haematology Am Soc Hematol edut program 2016
3. Increased incidence of VTE in sickle cell disease patients: risk factors, recurrence and impact on mortality. Brunson A et al. British journal of haematology 2017