Fever of unknown origin (FUO): CMV infectious mononucleosis or lymphoma?

Cytomegalovirus Pulmonary Involvement in an Immunocompetent Adult

Introduction

Cytomegalovirus (CMV) is a linear double-stranded DNA virus that may cause severe and potentially fatal infection in immunocompromised hosts. In immunocompetent individuals, the infection is typically mild or asymptomatic. However, in the last years, some cases of severe cytomegalovirus infection in immunocompetent individuals have been described. Clinical Presentation. The authors present a male patient aged 42 years, without specific medical history, who presented a 15-day history of fever, headache, night sweats, odynophagia, and bilateral otalgia, without improvement after four days of therapy with amoxicillin/clavulanic acid. Blood count and biochemistry were performed with liver cytolysis pattern. Chest teleradiography showed diffuse interstitial infiltrate. Thoracic CT scan revealed areas in a ground glass with a cross-linking component in the left and right upper lung lobes compatible with an inflammatory/infectious process. Blood serology was positive for CMV IgG and IgM. The detection on blood and bronchoalveolar lavage of CMV DNA by polymerase chain reaction (PCR) was also positive. Ganciclovir was started based on the clinical features and the result of CMV serology. After 48 hours, there was a significant clinical improvement, with remission of fever, and he was discharged on the 13th day of hospitalization with oral valganciclovir, completing a 21-day antiviral course at home.

Conclusion

With this clinical case, the authors highlight the importance of considering CMV infection in evaluating patients with pneumonia, even in immunocompetent ones, particularly in those with no clinical improvement with antibiotics instituted for bacterial pneumonia, and when other causes have been ruled out.

Infectious Mononucleosis: diagnosis and clinical interpretation

EBV is the sole causative agent of the acute illness in humans described either as infectious mononucleosis (IM), or glandular fever. IM, when not clinically silent, can present in patients with at least two of the classic triad of symptoms of fever, pharyngitis, and lymphadenopathy. Challenges for the clinician arise when atypical cases present. Early, accurate and informed laboratory test results are vital for diagnosis, appropriate treatment, and management. A key challenge for the practitioner, particularly in cases where the illness can present atypically, is distinguishing bacterial tonsillitis infections from early acute IM. The ability to draw on timely, clear, and insightful laboratory results to distinguish viral from bacterial infection is vital. Correct and prompt diagnosis of IM can help prevent the unnecessary administration of antibiotics and mitigate the need for other expensive exploratory tests in cases of IM that present with splenomegaly, lymphadenopathy, or suspect haematological conditions. Good communication between the requesting clinician and those carrying out the investigative process, and between the different laboratory departments involved, is good practice and would ultimately benefit the patient. This communication will comprehensively review the aetiology, clinical presentation, and laboratory findings in IM with a view to promoting further research and so derive a standard diagnostic algorithm of the condition.

Retrospective analysis of 1,641 cases of classic fever of unknown origin

Background

Fever of unknown origin (FUO) is commonly defined as fever higher than 38.3 °C on several occasions during at least 3 weeks with uncertain diagnosis after a number of obligatory investigations. It is a special type of fever and a common disease in internal medicine. However, due to its complex etiology, lack of characteristic clinical manifestations, and insufficient laboratory examination indicators, it often baffles clinicians in diagnosis. We herein present a study of the etiological factors and clinical features of classic fever of unknown origin (FUO) to provide help for related clinical diagnosis and treatment.

Methods

A total of 1,641 cases of patients with classic FUO hospitalized in West China Hospital of Sichuan University between January 1, 2011 and December 31, 2017, were collected, and the etiological factors of classic FUO were analyzed. A special effort was made to explore and screen the laboratory indicators related to infectious diseases, and the above data were compared with the clinical features of tuberculosis and lymphoma, which are difficult to diagnose.

Results

Among the 1,641 patients, 1,504 were finally diagnosed through various types of examination or diagnostic methods, and the diagnosis rate was 91.65%. Among all the causes of the 1,641 cases of FUO, 48.69% [799] were infectious diseases, of which tuberculosis was the most common, accounting for 19.50% [320]. Connective tissue diseases were responsible for 19.26% [316] of cases, of which adult-onset Still's disease (AOSD) was the most common, comprising 89 (5.42%) of the cases; 16.94% [278] were neoplastic diseases, and lymphoma (143, 8.71%) cases, was the most common malignant tumor; 6.76% [111] were other diseases; and in 8.35% [137] of cases, the cause was unclear. Through comparative analysis of tuberculosis and lymphoma, no significant differences were found between the symptoms, signs, and non-specific routine examination results of the two diseases. The diagnosis of these diseases was more dependent on tuberculosis-related examinations and pathological examinations.

Conclusions

Infectious diseases are the principal cause of classic FUO, in which tuberculosis accounts for a large proportion. Non-infectious diseases that cause FUO are mainly connective tissue diseases and malignant tumors. Of the various causes of classic FUO, tuberculosis and lymphoma are relatively difficult to diagnose. In most cases, the causes of classic FUO can be ascertained.

Correlations between the Maximum Standard Uptake Value of Positron Emission Tomography/Computed Tomography and Laboratory Parameters before and after Treatment in Patients with Lymphoma

Background:

After the first examination of patients with lymphoma diagnosis, important laboratory tests such as complete blood count; albumin, kidney and liver function tests; uric acid; β2-microglobulin; C-reactive protein (CRP); erythrocyte sedimentation rate (ESR); and lactate dehydrogenase (LDH) examinations are recommended. In this study, our aim was to find the relationship between laboratory parameters and the maximum standard uptake value (SUV_max) of positron emission tomography/computed tomography (PET/CT) in patients with lymphoma at the diagnosis and after treatment.

Methods:

Thirty-four lymphoma patients treated at Mustafa Kemal University Internal Medicine Clinic between 2014 and 2017 were included in this retrospective study. Results of CRP, ESR, LDH, albumin, and white blood cell (WBC) count were recorded before each PET scan test, and each parameter was analyzed for correlation with SUV_max measurements.

Results:

Spearman's correlation test showed that the after-treatment SUV_max values were significantly correlated with the after-treatment LDH, ESR, and CRP values (for LDH, ESR, and CRP, R²: 0.453, 0.426, and 0.351; P = 0.007, 0.012, and 0.042, respectively). On the other hand, albumin and WBC count did not show a significant correlation with the after-treatment SUV_max values (all P > 0.05).

Conclusions:

CRP, ESR, and LDH values may also be good predictors in patients for whom PET/CT imaging cannot be performed.