Diagnostic use of serum ferritin levels to differentiate infectious and noninfectious diseases in patients with fever of unknown origin

Diagnostic utility of clinical characteristics, laboratory tests, and serum ferritin in diagnosis of adult-onset Still disease

The diagnosis of adult-onset Still disease (AOSD) is challenging with ambiguous clinical presentation and no specific serological markers. We aim to evaluate the diagnostic utility of clinical, laboratory and serum ferritin features in established AOSD patients. We included all patients >18 years who were admitted to 2 tertiary medical centers (2003-2019) with serum ferritin above 1000 ng/mL. AOSD patients and non-AOSD controls were matched in 1:4 ratio for age and sex. The primary outcomes were sensitivity, specificity, positive/negative likelihood ratio and area under the curve (AUC) using clinical and laboratory characteristics based on the Yamaguchi classification criteria, in addition to serum ferritin. We identified 2658 patients with serum ferritin above 1000 ng/m, of whom 36 diagnosed with AOSD and 144 non-AOSD matched controls. Presence of arthralgia/arthritis showed the highest sensitivity (0.74), specificity (0.93), positive likelihood ratio (10.69), negative likelihood ratio (0.27) and AUC (0.83, 95% confidence interval 0.74-0.92) to the diagnosis of AOSD. On the other hand, serum ferritin showed variation and poorer results, depends on the chosen ferritin cutoff. Joint involvement showed the best diagnostic utility to establish the diagnosis of AOSD. Although clinicians use often elevated ferritin levels as an anchor to AOSD, the final diagnosis should be based on thorough clinical evaluation.

Fever of Unknown Origin: The Workup and Diagnosis of Pel-Ebstein Fever

The clinical and diagnostic workup of fever of unknown origin (FUO) is key in the treatment of patients on the internal medicine service. In this article, the authors present a case of fever of unknown origin, walk through the differential diagnosis, explain the laboratory testing ordered in the workup of the patient as well as the resulting values of said testing, and discuss the pathophysiology and diagnostic criteria for the diagnosis of Pel-Ebstein fever. The authors also discuss a clinical pearl when working with electronic health records to ensure that the needs of the patient in question are met.

Listeria monocytogenes Ankle Osteomyelitis in a Patient with Rheumatoid Arthritis on Adalimumab: A Report and Literature Review of Listeria monocytogenes Osteomyelitis

Localized Listeria infection predominantly occurs in the prosthetic and hip joints. We herein report a case of Listeria monocytogenes ankle osteomyelitis in a 73-year-old man receiving adalimumab who was transferred to our hospital because of suspected rheumatoid arthritis (RA) flare. He reported a four-month history of left ankle swelling. A surgical biopsy revealed L. monocytogenes osteomyelitis in the left tibia and talus bones. The patient was successfully treated with antibiotics and surgical debridement. Thus, infection due to L. monocytogenes can present as ankle osteomyelitis in immunocompromised patients and may mimic an RA flare.

Fever with persistent flagellate erythema in a primigravida: a rare presentation of adult-onset Still's disease

We describe a case of a 25-year-old primigravida, who presented to the emergency department with fever, arthralgia and erythematous maculopapular eruption. There was confluent violaceous macular erythema on the arms, v-area of the neck and upper back with periorbital oedema, mimicking dermatomyositis. There was flagellate erythema on the back. Skin biopsy and systemic investigations helped to rule out dermatomyositis. A final diagnosis of adult-onset Still's disease with atypical cutaneous manifestations was made. This atypical variant is associated with a worse prognosis. Early recognition of this clinical variant can be life-saving for the patient.

Marked elevation of serum ferritin associated with Anaplasma phagocytophilum infection

Human granulocytic anaplasmosis (HGA) is a tick-borne disease caused by the intracellular bacterial pathogen Anaplasma phagocytophilum. Patients typically present with non-specific symptoms, including high fever, headache, malaise, and myalgias. Laboratory investigations often reveal leukopenia, thrombocytopenia, and an elevation in serum hepatic aminotransferases. A marked elevation in ferritin with or without other features of hemophagocytic/macrophage activation syndrome has been occasionally reported in patients with A. phagocytophilum infection. A case of HGA is described in which the patient had an elevated ferritin of 1964 μg/L. For patients presenting with features of hemophagocytic syndrome including a markedly elevated ferritin, infection with A. phagocytophilum should be considered in the differential diagnosis in the appropriate clinical context (i.e., at-risk geographic location, season, tick exposure) as this distinction has management implications.

Establishment of a Predictive Model Related to Pathogen Invasion for Infectious Diseases and Its Diagnostic Value in Fever of Unknown Origin

The present study aimed to establish a list of parameters indicative of pathogen invasion and develop a predictive model to distinguish the etiologies of fever of unknown origin (FUO) into infectious and non-infectious causes. From January 2014 to September 2017, 431 patients with FUO were prospectively enrolled in the study population. This study established a list of 26 variables from the following 4 aspects: host factors, epidemiological factors, behavioral factors, and iatrogenic factors. Predefined predicted variables were included in a multivariate logistic regression analysis to develop a predictive model. The predictive model and the corresponding scoring system were developed using data from the confirmed diagnoses and 9 variables were eventually identified. These factors were incorporated into the predictive model. This model discriminated between infectious and non-infectious causes of FUO with an AUC of 0.72, sensitivity of 0.71, and specificity of 0.63. The predictive model and corresponding scoring system based on factors concerning pathogen invasion appear to be reliable screening tools to discriminate between infectious and non-infectious causes of FUO.

Serum ferritin and primary lung cancer

Existing research yields conflicting results regarding the relation between iron deficiency and high serum ferritin (SF) levels in primary lung cancer patients. We investigated the concentrations of SF, hemoglobin (Hb) and transferrin (TRF) in 569 male primary lung cancer patients and 252 female primary lung cancer patients. We grouped the subjects according to gender, smoking status, menopausal status, pathological type, stage, and TNM stage. The levels of SF and TRF were correlated with T stage in male patients (p<0.01). The levels of SF and TRF were correlated with menopausal status in female patients (p<0.01). Hb was correlated with smoking status, pathological type, stage, and TNM stages in male patients(p<0.01), but in female patients, Hb was not correlated with these grouping factors(p>0.05). The levels of SF may be regulated by different mechanisms and may be of different physiological significance in different populations.

Hyperferritinemia as a Diagnostic Marker for Severe Fever with Thrombocytopenia Syndrome

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral disease in East Asia with high mortality. Few studies have examined markers that suggest SFTS in febrile patients. To determine useful biochemical markers for SFTS, patients aged 18 years or older with SFTS or microbiologically confirmed community-onset bacteremia with thrombocytopenia (BT) at presentation between June 2013 and December 2015 were included from two tertiary university hospitals in Republic of Korea retrospectively. Eleven patients with SFTS and 62 patients with bacteremia and thrombocytopenia were identified in the study period. Age and sex did not show significant difference among two groups. Fever was more commonly observed but comorbidities were less common in SFTS than in BT (P < 0.05, each). The areas under the curves of serum ferritin, C-reactive protein, white blood cell count, serum procalcitonin, and fibrinogen were above 0.9, indicating the discriminative power of these biomarkers (1.000, 0.991, 0.963, 0.931, and 0.934, resp., all P < 0.05). The optimal cutoff value of serum ferritin was 3,822 ng/mL in this study. These results suggest that hyperferritinemia is a typical laboratory feature of SFTS, and the serum ferritin level can be used as a marker for clinicians suspecting SFTS.