Standardised work-up programme for fever of unknown origin and contribution of magnetic resonance imaging for the diagnosis of hidden systemic vasculitis

Rheumatic disorders among patients with fever of unknown origin: A systematic review and meta-analysis

OBJECTIVES

To conduct a systematic literature review and meta-analysis to estimate the proportion of fever of unknown origin (FUO) and inflammation of unknown origin (IUO) cases that are due to rheumatic disorders and the relative frequency of specific entities associated with FUO/IUO.

METHODS

We searched PubMed and EMBASE between January 1, 2002, and December 31, 2021, for studies with ≥50 patients reporting on causes of FUO/IUO. The primary outcome was the proportion of FUO/IUO patients with rheumatic disease. Secondary outcomes include the association between study and patient characteristics and the proportion of rheumatic disease in addition to the relative frequency of rheumatic disorders within this group. Proportion estimates were calculated using random-effects models.

RESULTS

The included studies represented 16884 patients with FUO/IUO. Rheumatic disease explained 22.2% (95%CI 19.6 - 25.0%) of cases. Adult-onset Still's disease (22.8% [95%CI 18.4-27.9%]), giant cell arteritis (11.4% [95%CI 8.0-16.3%]), and systemic lupus erythematosus (11.1% [95%CI 9.0-13.8%]) were the most frequent disorders. The proportion of rheumatic disorders was significantly higher in high-income countries (25.9% [95%CI 21.5 - 30.8%]) versus middle-income countries (19.5% [95%CI 16.7 - 22.7%]) and in prospective studies (27.0% [95%CI 21.9-32.8%]) versus retrospective studies (20.6% [95%CI 18.1-24.0%]). Multivariable meta-regression analysis demonstrated that rheumatic disease was associated with the fever duration (0.011 [95%CI 0.003-0.021]; P=0.01) and with the fraction of patients with IUO (1.05 [95%CI 0.41-1.68]; P=0.002).

CONCLUSION

Rheumatic disorders are a common cause of FUO/IUO. The care of patients with FUO/IUO should involve physicians who are familiar with the diagnostic workup of rheumatic disease.

Findings in whole body MRI and conventional imaging in patients with fever of unknown origin-a retrospective study

Background

To analyse the influence of whole body (wb)-MRI on patient management compared to routine diagnostic tests in patients with fever of unknown origin (FUO).

Methods

Twenty-four patients with FUO, defined as illness of more than three weeks with fever greater than 38.3 °C, underwent wb-MRI at a 1.5 T MR-system. The MR-protocol consisted of the following sequences: axial T1 VIBE, coronal T2-TIRM and a coronal echoplanar diffusion weighted sequence (overall acquisition time 29:39 min:s). Furthermore, laboratory findings, chest-x-ray, abdominal ultrasound, CT-scans and/or PET-CT scans were evaluated and compared to the wb-MRI findings in regard to treatment changes.

Results

Wb-MRI yielded a correct diagnosis in 70% of the patients. In 46% the inflammatory focus was exclusively detected by wb-MRI. Focus detection by wb-MRI led to a subsequent change of the clinical management in 92% of the patients. In 6 patients both a wb-MRI and a PET-CT were performed yielding the correct diagnosis in the same 4 of 6 patients for both imaging modalities.

Conclusions

Wb-MRI appears to be of value in the evaluation of FUO patients, allowing for optimized treatment by increasing diagnostic certainty. Due to its lack of nephrotoxicity and ionizing radiation it may be preferred over standard imaging techniques and PET-CT in the future. However, given the low number of patients in our trial, further prospective studies have to be performed to confirm our results.

Aortitis Presenting as Fever of Unknown Origin

Patients with aortitis often present with nonspecific constitutional symptoms. Due to the fact that aortitis is associated with inflammatory or infectious courses, patients may manifest fever or fever of unknown origin. Such clinical characteristics of aortitis are unavoidably brought about diagnostic dilemmas and might lead to a series of unnecessary work-ups and maltreatment. Therefore, it is important for the clinical physicians and surgeons to understand aortitis presenting with fever of unknown origin to avoid delayed diagnosis and treatment. In this article, clinical and pathological features of aortitis (giant cell arteritis, Takayasu arteritis and infective aortitis, etc.) with fever of unknown origin are described and the differential diagnosis and management policy are discussed.

18F-fluorodeoxyglucose positron emission tomography in elderly patients with an elevated erythrocyte sedimentation rate of unknown origin

Patients with an elevated erythrocyte sedimentation rate (ESR) and non-specific symptoms often pose a diagnostic dilemma. PET/CT visualises infection, inflammation and malignancy, all of which may cause elevated ESR. The objective of this study was to determine the contribution of 18F-fluorodeoxglucose positron emission tomography (PET/CT) in the diagnostic work-up of referred patients with an elevated ESR, in whom initial routine evaluation did not reveal a diagnosis. We conducted a combined retrospective (A) and prospective (B) study in elderly (>50 years) patients with a significantly elevated ESR of≥50 mm/h and non-specific complaints. In study A, 30 patients were included. Malignancy (8 patients), auto-inflammatory disease (8 patients, including 5 with large-vessel vasculitis) and infection (3 patients) were suggested by PET/CT. Two scans showed non-specific abnormalities and 9 scans were normal. Of the 21 abnormal PET/CT results, 12 diagnoses were independently confirmed and two alternative diagnosis were made. Two diagnoses were established in patients with a normal scan. In study B, 58 patients in whom a prior protocolised work-up was non-diagnostic, were included. Of these, 25 PET/CT-scans showed suspected auto-inflammatory disease, particularly large-vessel vasculitis (14 cases). Infection and malignancy was suspected in 5 and 3 cases, respectively. Seven scans demonstrated non-specific abnormalities, 20 were normal. Of the 40 abnormal PET/CT results, 22 diagnoses were confirmed, 3 alternative diagnoses were established. Only one diagnosis was established in the 20 patients with a normal scan. In both studies, the final diagnosis was based on histology, clinical follow-up, response to therapy or additional imaging. In conclusion, PET/CT may be of potential value in the diagnostic work-up of patients with elevated ESR if routine evaluation reveals no diagnosis. In particular, large-vessel vasculitis appears to be a common finding. A normal PET/CT scan in these patients suggests that it is safe to follow a wait-and-see policy.

More than meets the eye

A 27-year-old woman was hospitalized with fever and visual changes. She had been well until nine months earlier when she developed unilateral blurry vision in the left eye. Ophthalmologic examination revealed bilateral acute anterior uveitis. She was treated with topical steroids and her vision returned to baseline. However, over the next few months, she developed debilitating fatigue and experienced an unintentional fifteen pound weight loss. One month prior to presentation, she noted the onset of daily low grade fevers and chills. On the day of admission, she developed a temperature of 103°F and a severe frontal headache. Here we describe a case where the overlap of clinical features led to an initially broad differential diagnosis of seemingly unrelated diseases. Ultimately, the discovery of a key radiographic finding allowed us to more clearly define the diagnosis.

Fever of unknown origin: discrimination between infectious and non-infectious causes

OBJECTIVE

The present study aimed to develop and evaluate a simple diagnostic model that could aid physicians to discriminate between infectious and non-infectious causes of fever of unknown origin (FUO).

DESIGN/SETTING/SUBJECTS

Patients with classical FUO were studied in two distinct, prospective, observational phases. In the derivation phase that lasted from 1992 to 2000, 33 variables regarding demographic characteristics, history, symptoms, signs, and laboratory profile were recorded and considered in a logistic regression analysis using the diagnosis of infection as a dependent variable. In the validation phase, the discriminatory capacity of a score based on the derived predictors of infection was calculated for FUO patients assessed from 2001 to 2007.

RESULTS

Data from 112 individuals (mean age 56.5+/-11.2 years) were analyzed in the derivation cohort. The final diagnoses included infections, malignancies, non-infectious inflammatory diseases, and miscellaneous conditions in 30.4%, 10.7%, 33% and 5.4% of subjects, whereas 20.5% of cases remained undiagnosed. C-reactive protein>60 mg/L (odds ratio 6.0 [95% confidence intervals 2.5, 9.8]), eosinophils<40/mm(3) (4.1 [2.0, 7.3]) and ferritin<500 microg/L (2.5 [1.3, 5.2]) were independently associated with diagnosis of infection. Among the 100 patients of the validation cohort, the presence of > or =2 of the above factors predicted infection with sensitivity, specificity, and positive and negative predictive values of 91.4%, 92.3%, 86.5%, and 95.2%, respectively.

CONCLUSIONS

The combination of C-reactive protein, ferritin and eosinophil count may be useful in discriminating infectious from non-infectious causes in patients hospitalised for classical FUO.

[Imaging techniques in the evaluation of primary large vessel vasculitides: Part 2: duplex ultrasound, positron emission tomography, computed tomography, and ophthalmological methods]

This article focuses on the clinical application and technical aspects of imaging methods which are used alternatively or additionally to angiography or magnetic resonance imaging in patients with Takayasu's arteritis or giant cell arteritis. Providing a high spatial resolution, duplex ultrasound is particularly suitable for the evaluation of peripheral arteries. With the exception of cranial arteries, positron emission tomography as a whole body examination is the best imaging modality for the assessment of inflammatory activity. Computed tomography is used for angiographic examinations and enables evaluation of wall thickening in large arteries. It is the method of choice in the case of emergencies due to aortic aneurysm or dissection. In addition to angiographic and ultrasound techniques, ophthalmological methods comprise biomicroscopy, including funduscopy and optical coherence tomography.

[Large-vessel vasculitis. Imaging and interventional therapy]

Giant cell arteritis and Takayasu's arteritis are classified as primary large-vessel vasculitides. Inflammatory cell infiltrates and cytokines induce destruction and hyperplasia of the vessel wall, leading to stenoses or aneurysms. When extracranial large arteries are involved, there is often a similar clinical and radiologic disease pattern of an inflammatory aortic arch syndrome. Rare causes of large-vessel vasculitis include Behçet's disease, association with other autoimmune diseases, and infection. Depending on the localization, imaging is usually performed by means of duplex ultrasound, magnetic resonance imaging, computed tomography, or positron emission tomography. These imaging modalities are used not only to establish the diagnosis but also to determine the disease extent and activity and to perform follow-up in the course of medical therapy. Angiography offers the option to perform interventional therapy for vascular stenoses and occlusions.

Follow-up CT evaluation of the mural changes in active Takayasu arteritis

Objective

We wanted to evaluate the mural changes by CT on the follow-up examination of patients with active Takayasu arteritis.

Materials and Methods

The study included 18 patients, (4 males and 14 females), with active Takayasu arteritis. A total of 44 CT examinations were done during the follow-up period (mean: 55.6 months). At the time of the last follow-up CT, the disease, on the basis of the erythrocyte sedimentation rate (ESR), was found to be inactive in five patients and the disease was active and persistent in 13 patients. The thickness and CT attenuation of the aortic wall on the precontrast, arterial and venous phases were measured on the initial and the follow-up CT examinations. The ratio of the mural attenuation over that of the back muscle on the initial CT was compared with the ratio found on the follow-up CT.

Results

The initial CT findings included high density and calcifications of the aortic wall in the precontrast images and a thickened wall with enhancements in the arterial and the venous phases. A low-attenuation ring was demonstrated in the venous phase in 15 patients (83%). On the follow-up evaluation, the mean mural thickness decreased significantly from 4.1 mm to 2.4 mm. The mean mural attenuation ratio in the venous phase decreased significantly from 1.9 to 1.3 (p = 0.001). The low attenuation ring was identified in seven patients (39%) who had only with active, persistent Takayasu arteritis.

Conclusion

The mural changes demonstrated by the follow-up CT evaluations for the patients with active Takayasu arteritis included a decrease of the mural thickness and enhancement, disappearance of the low-attenuation ring on the venous phase, and an increase of the mural attenuation and calcification on the precontrast phase.

Outpatient assessment of systemic vasculitis

The vasculitides are complex, multisystem diseases, the natural history of which has been transformed by the use of immunosuppressive therapy. In many cases, survival is characterized by the presence of ongoing low-grade disease activity and, now that patients can survive acute, life-threatening manifestations of vasculitis, the new challenge is to provide accurate descriptions of these problems so as to plan appropriate changes in therapy to ensure optimal control of disease, with minimal toxicity, damage, and impairment of function. To achieve these aims, it is necessary to undertake structured evaluation of patients, with a significant dependence on careful clinical observation, supported by appropriate laboratory investigation at all stages from diagnosis to long-term care of these patients. This chapter reviews the important aspects of disease assessment and recommends a strategy for managing these complex patients. We can make use of standardized disease assessment instruments, such as the Birmingham Vasculitis Assessment Score and the Vasculitis Damage Index, to serve as an aide memoire in documenting the clinical features of disease. Routine monitoring for drug toxicity in the short-term and long-term is essential. Above all, however, it is very important to review these patients regularly and see them urgently in case of flares or complications, which are a common problem in most forms of vasculitis.