Pyrexia of Unknown Origin Caused by Non-Hodgkin's Lymphoma: A Diagnostic Challenge for Clinicians

Non-Hodgkin's lymphomas (NHLs) are a group of lymphoproliferative diseases that originate from different cell types, namely B cells, T cells, or natural killer cells. Herein, we report the case of a 69-year-old male patient who presented with a gradual-onset, intermittent, low-grade fever for four months and a right-sided neck lump for two months. On examination, a right-sided enlarged lymph node sized 1 × 1 cm2 was noted, which was mobile, hard in consistency, and non-tender. No other lymphadenopathy was noted in other parts of the body. Imaging and biochemical studies done at the initial stages did not reveal features in favor of any lymphoproliferative disorders, and the two lymph node biopsies done two weeks apart were inconclusive as well. An extended panel of investigations was done in view of excluding other infective and inflammatory pathologies, which was negative, making the patient undiagnosed of any disease state despite being symptomatic for four months. Finally, the third lymph node biopsy tested positive, which paved the way for the diagnosis of NHL. This diagnosis underlines the importance of this case. Following the diagnosis, the patient was initiated on a few chemotherapeutic agents, after which a mild symptomatic improvement was achieved.

Development of a Consensus-Based List of Potential Quality Indicators for Fever and Inflammation of Unknown Origin

With a growing emphasis on value-based reimbursement, developing quality indicators for infectious diseases has gained attention. Quality indicators for fever of unknown origin and inflammation of unknown origin are lacking. An assembled group of international experts developed 12 quality measures for these conditions, which could be validated with additional study.

A Case of Pyrexia of Unknown Origin Diagnosed as Hemophagocytic Lymphohistiocytosis

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease that is even rarer in the adult population. It requires a high degree of suspicion from the treating physician, and if diagnosed early, patients might have a survival benefit from this highly fatal condition. HLH is a disorder of immune regulation where the hyperactivity of cytokines attacks different cells, which leads to multiple organ dysfunctions. Varying presentations and similarities with other diseases make diagnosis difficult. Familial HLH is commonly seen in the pediatric population, while acquired or secondary HLH is seen in adults. Secondary HLH is commonly triggered by neoplasms, infections, rheumatological diseases, and other autoimmune diseases. Here is a case of HLH that presented as chronic undiagnosed fever. In this case report, we have discussed in detail this disease, its presentation, investigations, treatment, and other important information that will help practicing doctors better diagnose and treat HLH patients.

Hemophagocytic Lymphohistiocytosis due to Disseminated Histoplasmosis in a Patient with HIV Infection

Hemophagocytic lymphohistiocytosis is usually considered a rapidly progressive fatal illness with poor outcomes. It is of two types: primary or familial and secondary. In patients with HIV, opportunistic infections are the secondary triggers of HLH. First line of management of infection associated HLH is treatment of the underlying infection. Here, we present a case of HLH in HIV infection due to disseminated histoplasmosis managed with liposomal amphotericin B, who required immunosuppressive therapy with intravenous immunoglobulin and dexamethasone due to nonresponse to primary therapy.

A Rare Presentation of Tuberculosis in Transplanted Kidney on Fluorodeoxyglucose Positron Emission Tomography with Computed Tomography Scan

Tuberculosis (TB) is currently the world's leading cause of infectious mortality. Infective complications are common after renal transplantation. TB is one of the leading infections following renal transplantation; however, TB affecting the transplanted kidney is a rare presentation. Reactivation of the Mycobacterium tuberculosis is the most common mode of infection. The use of immunosuppressive agents such as cyclosporin, azathioprine, and steroids advance the onset of TB to an earlier date which most often presents as a fever or pyrexia of unknown origin (PUO). The use of 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG-PET/CT) scan images of the whole body and provides the metabolic map of the infection as well as also helps in its radiological localization and characterization and selecting the most appropriate site of the biopsy. Currently, the combined FDG-PET/CT scan modality is the investigation of the choice of physicians for the diagnosis of PUO. Not only the diagnosis but 18F-FDG-PET/CT is also very valuable in assessing early disease response to therapy, and plays an important role in cases where conventional microbiological methods are unavailable for monitoring response to the therapy in cases of pulmonary, extrapulmonary, or multidrug resistant TB.

Investigator-Determined Categories for Fever of Unknown Origin (FUO) Compared With International Classification of Diseases-10 Classification of Illness: A Systematic Review and Meta-analysis With a Proposal for Revised FUO Classification

Background

Classifying fever of unknown origin (FUO) into categorical etiologies (ie, infections, noninfectious inflammatory, oncologic, miscellaneous, and undiagnosed disorders) remains unstandardized and subject to discrepancies. As some disease classifications change, a systematic review of studies would help physicians anticipate the frequency of illness types they may encounter that could influence care.

Methods

We systematically reviewed prospective FUO studies published across the Medline (PubMed), Embase, Scopus, and Web of Science databases from January 1, 1997, to July 31, 2022. We performed a meta-analysis to estimate associated pooled proportions between the investigator-determined choice of disease category and those determined by the International Classification of Diseases, 10th edition (ICD-10), methodology.

Results

The proportion of patients with a difference between the investigator and ICD-10-adjusted noninfectious inflammatory disorder category was 1.2% (95% CI, 0.005-0.021; P < .001), and the proportion was similar for the miscellaneous category at 1.5% (95% CI, 0.007-0.025; P < .001). The miscellaneous and noninfectious inflammatory disorders categories demonstrated significant across-study heterogeneity in the proportions of patients changing categories, with 52.7% (P = .007) and 51.0% (P = .010) I² , respectively.

Conclusions

Adjusting FUO-associated diagnoses by ICD-10 methodology was associated with a statistically significant risk of over- or underestimation of disease category frequency approximation when using a 5 FUO category system. An FUO diagnostic classification system that better reflects mechanistic understanding would assist future research and enhance comparability across heterogenous populations and different geographic regions. We propose an updated FUO classification scheme that streamlines categorizations, aligns with the current understanding of disease mechanisms, and should facilitate empirical decisions, if necessary.

18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Scan Findings in a Rare Case of Subcutaneous Panniculitis-Like T-Cell Lymphoma

Skin lymphomas are less common and subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a fairly rare subtype of primary cutaneous lymphoma. Skin lymphomas involve subcutaneous adipose tissues with no involvement of lymph nodes. Diagnosis of these cases is generally a challenge to clinicians. These cases present with fever, weight loss, and local discomfort in the region of involvement of subcutaneous tissues and sometime with skin eczema and rashes. Positron emission tomography/computed tomography (PET/CT) scan can guide in determining the extent of involvement being whole-body imaging and can guide the site of biopsy and can help to prevent misdiagnosis. It also helps in correct and early diagnosis and successful treatment. We report a case of a young adult who presented with pyrexia of unknown origin in which PET/CT scan revealed mildly fluorodeoxyglucose-avid diffuse subcutaneous panniculitis involving the whole body, trunk, and extremities. Biopsy was taken from the most appropriate site according to the PET/CT scan report and reported as SPTCL.

Critical illness in the returning traveller

A 70 year old man, who had recently travelled in rural Iraq, presented with fevers, rigors, and developed multiorgan failure. An extensive range of diagnostic tests was undertaken in an attempt to identify the cause. He was treated with multi-organ support and a number of antibiotics. Critical illness in the returning traveller presents a number of challenges on the ICU: obtaining adequate history, the potentially broad differential diagnosis, the requirement for numerous and sometimes specialised investigations and risks of infection transmission to staff and other patients. Travellers are more often elderly, more likely to have comorbidities and immunosuppression whilst global disease patterns are changing. Particular consideration should be given to unusual infections and venous thromboembolic disease from prolonged immobility whilst in transit, alongside more commonly encountered diseases. Antimicrobial resistance may be encountered and appropriate infection control is essential for the protection of patients, staff and others. Specialist support is available in the UK via the Imported Fever Service, especially for High Consequence Infectious Diseases. Consideration of non-infectious causes of fever and critical illness in returning travellers is also warranted. Crucially, a multidisciplinary team approach with thorough information gathering, repeated clinical review and judicious use of investigations are essential for optimal patient care.

Uncommon manifestations in tuberculosis: An expanding clinical spectrum from North India

BACKGROUND

Despite being given the best by the health department to eradicate the disease, an alarming rise of tuberculosis (TB) remains a significant public health concern in India. Recently, highly variable clinical manifestations of TB have been reported. This study highlights the unusual presentations of TB with a comprehensive overview of epidemiology, demography and risk factors in the expended clinical spectrum of TB patients and their outcomes.

METHODS

It is a retrospective study using the records of 503 TB patients of all age groups of either sex from July 2017 to January 2021 at two tertiary care hospitals in North India.

RESULTS

Out of 503 cases, pulmonary, extrapulmonary, and disseminated TB were 77.7%, 19.5%, and 2.8%, respectively. Among all TB cases, 36 (7.2%) had uncommon manifestations, including the most common was pyrexia of unknown origin in 12 (33.3%) cases and liver abscess in 5 (13.9%) cases, followed by pancytopenia in 4 (11.1%) cases and chyluria in 3 (8.3%) cases. Atypical skin nodules and multiple swellings were also noted in three (8.3%) cases. Male sex (58%) and rural area (66.7%) were dominant in TB with uncommon manifestation (TBU) cases. The mean age in TBU cases was 46.92 years, whereas 34.26 years in all TB cases. It was extremely significant. The statistically significant risk factors in the TBU case were low socioeconomic status (24, 66.7%), inadequate nutrition (11, 30.6%), and smoking (19, 52.8%).

CONCLUSIONS

Early recognition of uncommon presentations is imperative to respond better.

Retinal Detachment and Temporal Artery Dissection: An Elusive Case of Giant Cell Arteritis

Giant cell arteritis (GCA), also known as temporal arteritis, is the most common systemic inflammatory vasculitis occurring in the elderly. Patients usually present with vision loss, headache, jaw claudication, diplopia, myalgia and constitutional symptoms. The most common ocular manifestations are anterior ischemic optic neuropathy (AION), choroidal ischemia and central retinal artery occlusion. Here we describe a case of GCA presenting with vision changes secondary to retinal detachment and vitreous hemorrhage. Upon temporal artery biopsy, GCA was confirmed and it was found to be accompanied by temporal artery dissection as well. Patient was treated with pulse dose intravenous steroids after which her symptoms improved. Based on our literature review, this is the first reported case of GCA presenting in this manner.

Can Subacute Thyroiditis Be a Cause of Fever of Unknown Origin?

Subacute thyroiditis (SAT) is a self-limiting, painful, non-suppurative thyroid gland inflammation, which usually develops two to eight weeks after viral upper respiratory tract infections, accompanied by pain and fever. The thyroid gland is large, painful, and tender. It presents with fever, myalgia, arthralgia, weakness, and sore throat.

A 37-year-old male presented to medical ward with a history of fever for three weeks along with swelling of neck and difficulty in swallowing. The patient had features of hyperthyroidism. High-resolution ultrasonography (HRUSG) and thyroid scan were suggestive of thyroiditis. Later on, on follow-up, the patient developed hypothyroidism. He was managed with antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), and glucocorticoids, and he responded well to the above treatment. The index patient presented as a case of fever which on workup was found to be secondary to subacute thyroiditis (SAT).

Primary Small Cell Neuroendocrine Tumour of Gallbladder Presenting as Pyrexia of Unknown Origin

Herein, we report a case of primary small cell neuroendocrine tumor (NET) of the gallbladder in a 45-year-old female who presented with complaints of fever accompanied by abdominal pain on the right upper quadrant for one month. Contrast-enhanced computed tomography abdomen showed a large gallbladder mass. It was infiltrating the segments IVa, IVb, and V of the liver. Ultrasound-guided fine-needle-aspiration-cytology was performed. Based on preoperative pathological and immunohistochemical investigations, it was diagnosed to be a primary small cell NET of the gallbladder. The patient underwent radical cholecystectomy after three cycles of cisplatin-based neoadjuvant chemotherapy. She had an uneventful recovery and received adjuvant chemo-radiotherapy. The patient was well at the 18-month follow-up.

Antibiotic-Resistant Pyrexia of Unknown Origin: An Unusual Presentation of Myelodysplastic Syndrome

A 74-year-old male presented to the emergency department (ED) with complaints of high-grade fever, productive cough, and difficulty breathing for three weeks, and a significant weight loss in the past six months. Despite a detailed investigation, diagnosis could not be achieved. Multiple empiric regimens were tried but no response was observed. Bone marrow biopsy was conducted after suspicious peripheral film result, which concluded that the patient was having myelodysplastic syndrome. Although pyrexia of unknown origin has a diverse group of diseases to evaluate for, and rare entities are difficult to diagnose, meticulous evaluation may give significant evidence for targeted diagnostic workup.

Habitual Hyperthermia: An Interpretive Paradigm of the 20th Century? Not Really

Prolonged and unexplained fevers in young adults are uncommon, especially when access to diagnostic tests is simplified. Therefore, the definition of unexplained fever depends on the volume of tests performed. However, low-grade fever has not been a priority in research. Management of low-grade fever [eg, an oral temperature of ≥37.8°C (100°F) and <38.3°C (101°F) at any time of the day] is not codified. The presented case of a 37-year-old nurse with an intermittent fever for three months, with no clear diagnostic evidence and no elevated markers of inflammation, illustrates “habitual hyperthermia” (HH)—retained after ordering tests sequentially in town and at the hospital. HH was made known by Prof. H.A. Reimann (1897–1986) an American virologist, although the diagnostic criteria are fallible. The article reviews the criteria and then discusses how to select diagnostic tests in family practice for prolonged fever in young adults without clinical signs of orientation. Given the polymorphism of febrile illnesses, the principle of parsimony must be transgressed, and in the event of an early suspicion of HH, surveillance is a rule to be further amended.

Imaging a Fever-Redefining the Role of 2-deoxy-2-[18F]Fluoro-D-Glucose-Positron Emission Tomography/Computed Tomography in Fever of Unknown Origin Investigations

Growing evidence suggests that 2-deoxy-2-[18F]fluoro-D-glucose (18FDG)-positron emission tomography/computed tomography (PET/CT) is a useful imaging technique for the evaluation of fever of unknown origin (FUO). This imaging technique allows for accurate localization of foci of hypermetabolism based on 18FDG uptake in glycolytically active cells that may represent inflammation, infection, or neoplasia. The presence of abnormal uptake can help direct further investigation that may yield a final diagnosis. A lack of abnormal uptake can be reasonably reassuring that these conditions are not present, thereby avoiding unnecessary additional testing. Insurers have not routinely covered outpatient 18FDG-PET/CT for the indication of FUO in the United States. However, data published since 2007 suggest early use in FUO diagnostic evaluations improves diagnostic efficiency and reduces costs. Clinicians and insurers should consider 18FDG-PET/CT as a useful tool when preliminary studies are unrevealing.

First Report of Candidatus Mycoplasma haemohominis Infection in Australia Causing Persistent Fever in an Animal Carer

BACKGROUND

Hemotropic mycoplasmas (hemoplasmas) infect animals and humans and can lead to clinical syndromes mainly characterized by hemolytic anemia. A novel pathogen, Candidatus Mycoplasma haemohominis, was recently associated with a case of human hemoplasmosis in Europe. Here we report the first detection of this pathogen in an Australian patient exhibiting persistent fever, hemolytic anemia, and pancytopenia over a 10-month period.

METHODS

After exhaustive negative testing for human infectious diseases, whole genome sequencing (WGS) was performed on the patient's bone marrow aspirate, using an Illumina NextSeq500 platform. Conventional polymerase chain reaction (PCR), followed by Sanger sequencing, was then performed on blood samples using novel Mycoplasma-specific primers targeting the 16S ribosomal RNA gene. In addition, a Mycoplasma-specific fluorescence in situ hybridization (FISH) assay was developed to differentiate Mycoplasma cells from other erythrocyte inclusions (eg, Pappenheimer and Howell-Jolly bodies) which are morphologically similar to bacterial cocci by light microscopy.

RESULTS

WGS analysis revealed that approximately 0.04% of the total number of unmapped reads to human genome corresponded to Mycoplasma species. A 1-kb Mycoplasma 16S fragment was successfully amplified by conventional PCR, and sequence analyses revealed 100% identity with Candidatus Mycoplasma haemohominis. FISH confirmed that several (approximately 2%) epierythrocytic inclusions initially observed by light microscopy corresponded to Mycoplasma cells.

CONCLUSIONS

This represents the second report of hemolytic anemia associated with hemoplasma infection in a human, and the first report of human hemoplasmosis in Australia. This study highlights the importance of new and emerging diagnostic approaches and need for further investigations on the epidemiology of Candidatus Mycoplasma haemohominis in Australia.

Isolated Splenic Tuberculosis: A Diagnostic Conundrum

Tuberculosis is an established cause of pyrexia of unknown origin and can implicate practically any human organ system. Splenic involvement is common in disseminated or miliary tuberculosis following hematogenous spread, but isolated splenic involvement is a very rare phenomenon. We report the case of a 30-year-old immunocompetent female who presented with high-grade fever and dull aching pain in the left hypochondrium for three months. Laboratory data provided no diagnostic information. Abdominal ultrasonography revealed an enlarged spleen with multiple small hypoechoic lesions that were corroborated on computed tomography. No pulmonary involvement or primary focus of infection was discernible elsewhere. Splenic fine needle aspiration cytology helped clinch a histopathological diagnosis of isolated splenic tuberculosis. Administration of anti-tubercular therapy resulted in resolution of the disease and an excellent outcome in our patient.

Post kidney transplant histoplasmosis: An under-recognized diagnosis in India

Histoplasmosis is an invasive mycosis caused by fungus Histoplasma capsulatum. Clinical features of histoplasmosis are often nonspecific, but patients with disseminated infection may present with severe manifestations posing an increasing threat to patients with various immunocompromised conditions. It is often misdiagnosed as tuberculosis in endemic regions leading to high mortality. There is under-reporting of histoplasmosis in solid organ transplant from India undermining its actual incidence and impact. As a result of the potentially fatal nature of the disease, careful evaluation with tissue diagnosis is recommended. We present a series of five cases of disseminated histoplasmosis in renal transplant recipients from our centre, highlighting its significance as differential diagnosis in this population. To our knowledge, this is the largest case series reported from India in renal transplant patients.

Intensive care management of a rare case of pyrexia of unknown origin (Kikuchi-Fujimoto disease)

Kikuchi-Fujimoto disease is a rare, benign cause of necrotising lymphadenitis often presenting with fever. We describe a case of a 17-year-old boy with non-verbal autism presenting to our intensive care unit with prolonged fever of unknown cause. This case highlights the role of the intensive care unit in cases of diagnostic dilemma. The critical care community should be aware of Kikuchi-Fujimoto disease as although it is usually benign, it can rarely lead to acute airway compromise.

Disseminated bacillus Calmette-Guérin (BCG): a cause of delirium in an older adult

Intra-vesical Bacillus Calmette-Guérin (BCG) immunotherapy is an effective treatment for high-risk bladder cancer. Less well known is that fewer than 1% of patients receiving BCG treatment can develop disseminated BCG. The reaction can range from a mild flu-like illness to a systemic disorder with a fulminant course which in the most severe cases can lead to death. The diagnostic yield is low and diagnosis is often made after a comprehensive exclusion of more common causes of pyrexia of unknown origin. A high level of suspicion is therefore required in those who may be at risk. We report a case of disseminated BCG in an older patient for whom early involvement of his family was pertinent to determining the precipitant for delirium.

Fever and Fever of Unknown Origin: Review, Recent Advances, and Lingering Dogma

Fever has preoccupied physicians since the earliest days of clinical medicine. It has been the subject of scrutiny in recent decades. Historical convention has mostly determined that 37.0°C (98.6°F) should be regarded as normal body temperature, and more modern evidence suggests that fever is a complex physiological response involving the innate immune system and should not be characterized merely as a temperature above this threshold. Fever of unknown origin (FUO) was first defined in 1961 by Petersdorf and Beeson and continues to be a clinical challenge for physicians. Although clinicians may have some understanding of the history of clinical thermometry, how average body temperatures were established, thermoregulation, and pathophysiology of fever, new concepts are emerging. While FUO subgroups and etiologic classifications have remained unchanged since 1991 revisions, the spectrum of diseases, clinical approach to diagnosis, and management are changing. This review considers how newer data should influence both definitions and lingering dogmatic principles. Despite recent advances and newer imaging techniques such as 18-fluorodeoxyglucose-positron emission tomography, clinical judgment remains an essential component of care.

Pyrexia of unknown origin in HIV-negative adults from Himachal Pradesh (India): will you suspect disseminated histoplasmosis?

Histoplasmosis is usually clinically suspected only in people who reside in, are migrants from or are travelling to endemic areas such as North America. Immunocompetent patients with a low level of exposure typically have either subclinical or mild and self-limiting infection. The most common risk for the development of progressive disseminated form is HIV infection. We recently managed two patients with disseminated histoplasmosis, presenting with prolonged fever, significant weight loss, pallor and hepatosplenomegaly. Both were HIV-negative and lived in Himachal Pradesh (India), a region that was considered "Histoplasma-free" until recently.

Primary Adrenal Angiomatoid Fibrous Histiocytoma With Novel EWSR1-ATF1 Gene Fusion Exon-Exon Breakpoint

We describe the clinical, pathological, and molecular features of a primary adrenal angiomatoid fibrous histiocytoma (AFH) in an 11-year-old girl presenting with pyrexia of unknown origin. We performed next-generation sequencing-based anchored multiplex polymerase chain reaction (Archer® FusionPlex® sarcoma assay), which revealed an EWSR1-ATF1 gene fusion with novel breakpoints in exon 11 of EWSR1 and exon 3 of ATF1. The pyrexia resolved fully after surgical resection, and the patient was disease-free on follow-up at 1 year and 6 months. This case exemplifies the value of molecular testing of pediatric neoplasms presenting at unusual sites for diagnosis and identification of novel gene fusion breakpoints.

Seroprevalence of brucellosis in Western Rajasthan: A study from a tertiary care centre

Brucellosis is a significant bacterial zoonotic disease with a high seroprevalence in low-to-middle-income countries where there is a significant contact of humans with animals. This prospective study was conducted to observe the seroprevalence of brucellosis in 75 symptomatic patients with pyrexia of unknown origin (PUO) and 75 high-risk individuals (10 veterinarians, 15 milkmen and 50 healthy contacts of symptomatic patients) with possible exposure to brucellosis. Serum samples collected from these patients and individuals were subjected to rose Bengal test (RBT) and ELISA for the detection of IgM and IgG antibodies. RBT was positive in 50 samples (40 PUO and 10 high risk), of which 25 (33.3%) PUO cases had detectable IgM antibodies, whereas IgG antibodies were detected in 20 patients. None of samples from high-risk individuals was reactive for IgM/IgG antibodies by ELISA. The overall seroprevalence in this study was 16.7% (33.3% in PUO patients). Being a predominantly livestock rearing area, brucellosis is a significant health-care problem in this part of India with this entity being linked to 33% of PUO cases.

Prevalence of scrub typhus in pyrexia of unknown origin and assessment of interleukin-8, tumor necrosis factor-alpha, and interferon-gamma levels in scrub typhus-positive patients

Background

Scrub typhus is lesser known cause of fever of unknown origin in India. Even if there have been reports documenting the prevalence of scrub typhus in different parts of India, it is still an unknown entity, and clinicians usually do not consider it as differential diagnosis. The present study was performed to document the prevalence of scrub typhus among febrile patients in western part of Uttar Pradesh and to assess the clinical profile of infected patients on the one hand and knowledge, attitude, and practices among clinicians on the other.

Materials and Methods

A total of 357 adult patients with fever of more than 5-day duration were recruited. All patients underwent complete physical examination, and detailed clinical history was elicited as per predesigned pro forma. After primary screening to rule out malaria, enteric fever, and leptospirosis infection, secondary screening for scrub typhus was done by rapid screen test and IgM ELISA.

Results

Scrub typhus infection was positive in 91 (25.5%) cases. The most common symptoms among the patients were fever (100%), pain in abdomen (79.1%), pedal edema 56 (61.5%), rash 44 (48.3%), headache 44 (48.3%), vomiting 42 (46.1%), constipation 33 (36.2%), cough 28 (30.7%), and lymphadenopathy 20 (21.9%). The median values of interleukin-8, interferon-gamma, and tumor necrosis factor-alpha in healthy controls were 15.54 pg/ml, 7.77 pg/ml, and 54.1 pg/ml, respectively, while the median values of these cytokines in scrub typhus-positive patients were 21.04 pg/ml, 8.74 pg/ml, and 73.8 pg/ml, respectively.

Conclusion

Our results highlight that scrub typhus infection is an important cause of pyrexia of unknown origin, and active surveillance is necessary to assess the exact magnitude and distribution of the disease.

Bartonella henselae infection in diverse clinical conditions in a tertiary care hospital in north India

Background & objectives:

Bartonella henselae causes infections which closely resemble febrile illness and chronic diseases such as tuberculosis and haematological malignancies. There are not many studies on Bartonella infections from India. The present study was undertaken to diagnose B. henselae infection in diverse clinical conditions in a tertiary care hospital in north India.

Methods:

A total of 145 patients including those with fever and lymphadenopathy, infective endocarditis and neuroretinitis were enrolled in the study. Whole blood, serum and lymph node aspirate and valvular vegetations if available, were obtained. Samples were plated on chocolate agar and brain-heart infusion agar containing five per cent fresh rabbit blood and were incubated at 35°C for at least four weeks in five per cent CO₂ with high humidity. Immunofluorescent antibody assay (IFA) was done for the detection of IgM antibodies in the serum using a commercial kit. Whole blood was used to perform polymerase chain reaction (PCR) for the citrate synthase gene (gltA).

Results:

IFA was positive in 11 of 140 (7.85%) patients and PCR was positive in 3 of 140 (2.14%) patients. Culture was negative in all the cases. A higher incidence of Bartonella infection was seen in patients with fever and lymphadenopathy (n=30), seven of whom were children. In ophthalmological conditions, four cases were IFA positive.

Interpretation & conclusions:

The present study shows that the threat of Bartonella infection is a reality in India. It is also an important treatable cause of fever and lymphadenopathy in children. Serology and PCR are useful tests for its diagnosis. Clinicians should consider Bartonella infection in the differential diagnosis of febrile illnesses and chronic diseases.

Adult-onset Still's disease with prominent polyserositis

Adult-onset Still's disease is a systemic autoinflammatory disease the presentation of which can often mimic infection. As a consequence, there is often a delay in diagnosis. Serositis is a recognised but less common clinical feature that can result in complications including cardiac tamponade and constrictive pericarditis. We describe a case of adult-onset Still's disease without the hallmark rash or significant arthritis, presenting with polyserositis that showed a good response to initial steroid treatment and sustained remission with anakinra. An elevated procalcitonin level was due to active adult-onset Still's disease, not bacterial infection.

Pyrexia of unknown origin

The syndrome of pyrexia of unknown origin (PUO) was first defined in 1961 but remains a clinical challenge for many physicians. Different subgroups with PUO have been suggested, each requiring different investigative strategies: classical, nosocomial, neutropenic and HIV-related. This could be expanded to include the elderly as a fifth group. The causes are broadly divided into four groups: infective, inflammatory, neoplastic and miscellaneous. Increasing early use of positron emission tomography-computed tomography (PET-CT) and the development of new molecular and serological tests for infection have improved diagnostic capability, but up to 50% of patients still have no cause found despite adequate investigations. Reassuringly, the cohort of undiagnosed patients has a good prognosis. In this article we review the possible aetiologies of PUO and present a systematic clinical approach to investigation and management of patients, recommending potential second-line investigations when the aetiology is unclear.

Refractory Adult Onset Still's Disease

It is often a challenge and a dilemma for clinicians encountering patients with pyrexia of unknown origin. Numerous tests performed to determine the underlying cause often give inconclusive results. We present a 52-year-old man with undulating fever for more than 10 months with persistent hyperferritinaemia, and negative immunological and serological markers. Despite corticosteroids, disease modifying anti-rheumatic agents and immune-modulator therapy, he succumbed to the illness. A diagnosis of refractory Adult onset Still’s disease complicated by haemophagocytic lymphohistiocytosis was made.

Pyrexia of unknown origin: causes, investigation and management

Pyrexia of unknown origin (PUO) is a syndrome that has long tested the skills of physicians to achieve a diagnosis in affected patients. By definition, patients included in this syndrome will be more difficult to diagnose as they have already resisted classification during baseline investigations. Furthermore, investigation of PUO requires knowledge of many diseases across a range of clinical specialties, as well as knowledge of less commonly used investigative tools. As both society and medicine continue to change, the aetiology and epidemiology of the diseases that cause PUO also change. For these reasons, it is important for physicians to approach PUO in a logical manner, and for the causes and approach to PUO to be continuously reviewed. In this article, we review the aetiology of PUO and the diagnostic strategies that may be used to investigate it.

A Microbial Old Friend with a New Face: A Rare Case of Pyrexia of Unknown Origin and Leukemoid Reaction

We present a case of a young male, who presented to us with high-grade fever for more than four weeks, refractory seizures, multiple subcutaneous palpable lumps, and evidence of leukocytosis with predominant left shift on the peripheral smear. The classic "starry-sky" appearance on imaging, generalized muscular uptake on positron emission tomography-computerized tomography scan, and positive serology led to a diagnosis of disseminated cysticercosis. He responded to oral steroids. To the best of our knowledge, disseminated cysticercosis presenting as pyrexia of unknown origin and with a leukemoid reaction has never been reported in literature.

Lesson of the month 1: Autoinflammatory syndromes - an unusual cause of pyrexia of unknown origin

Autoinflammatory diseases are disorders of innate immunity and are characterised by recurring and unprovoked episodes of inflammation. We present a case of episodic pyrexia, associated with a significant inflammatory response, in a young man in whom the cause had remained unexplained since infancy. He was eventually diagnosed with hyperimmunoglobulinaemia D syndrome (HIDS); one of the autoinflammatory syndromes.

A Rare Presentation of Leishmaniasis

Leishmaniasis or kala-azar is a protozoan disease that can present as cutaneous, mucocutaneous, visceral, and disseminated disease. In India, it is usually localized in distinct areas of Bihar, Jharkhand, West Bengal, and parts of Eastern Uttar Pradesh. Visceral leishmaniasis (VL) involves the visceral organs, mainly the liver, the spleen and bone marrow. VL is characterized by prolonged fever, massive splenomegaly, weight loss, progressive anemia, pancytopenia, and hypergammaglobulinemia, and can be complicated by serious infections. In most of the patient the diagnosis is made on bone marrow biopsy or splenic aspirate. We hereby present an unusual case of kala-azar in a 52-year-old patient non-resident of endemic area presenting with pyrexia of unknown origin, in whom bone marrow biopsy was negative for Leishmanin Donovan (LD) bodies, and diagnosis was made by liver biopsy in which LD bodies were seen.

An Unusual Cause of Fever in a Patient with Total Hip Replacement

Pyrexia of unknown origin (PUO) in a patient with acquired immunodeficiency syndrome (AIDS) is a challenging clinical problem despite recent advances in the diagnostic modalities. The diagnosis of the cause of fever is especially difficult in the postoperative period as the focus remains on the operative site. We present an unusual cause of PUO in a patient with advanced HIV disease during an immediate postoperative period following total hip arthroplasty (THA) for osteoarthritis (OA) of the left hip. The fever started on the eighth postoperative day, and after an extensive workup to rule out infection it was found that the patient was allergic to sulfa drugs. The fever subsided after discontinuation of trimethoprim/sulfamethoxazole. Fever in an immunocompromised patient should not be attributed only to infection. A high index of suspicion along with careful history making is required to diagnose drug fever. An early diagnosis of drug fever can reduce hospital stay and the costs of investigations and treatment.

Diagnostic utility of fluorodeoxyglucose positron emission tomography/computed tomography in pyrexia of unknown origin

Purpose of the Study:

The present study was undertaken to evaluate the diagnostic utility of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18 FDG PET/CT) in patients presenting as pyrexia of unknown origin (PUO).

Materials and Methods:

Forty-seven patients (31 males and 16 females; mean age of 42.7 ± 19.96 years) presenting as PUO to the Department of Medicine at the All India Institute of Medical Sciences, New Delhi over a period of 2 years underwent F-18 FDG PET/CT. PET ⁄ CT was considered supportive when its results correlated with the final definitive diagnosis. Final diagnosis was made on the basis of combined evaluation of history, clinical findings, investigations, and response to treatment.

Results:

Thirty-five PET/CT studies (74.5%) were positive. However, only 18 (38.3%) were supportive of the final diagnosis. In three patients (6.4%), PET/CT was considered diagnostic as none of the other investigations including contrast-enhanced computed tomography of chest and abdomen, and directed tissue sampling could lead to the final diagnosis. All these three patients were diagnosed as aortoarteritis.

Conclusion:

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography is an important emerging modality in the workup of PUO. It supported the final diagnosis in 38% of our patients and was diagnostic in 6.4% of patients. Thus, PET/CT should only be considered as second-line investigation for the diagnostic evaluation of PUO; especially in suspected noninfectious inflammatory disorders.

Isolated native Tricuspid Valve Endocarditis Presenting as PUO in a Young Adult Male Without Any Risk Factors

A 28-year-old male presented to our hospital with high-grade fever and weight loss for 4 months. Clinical examination was non-contributory and there was no history of any high-risk behavior or prolonged skin or dental infections. Native tricuspid-valve endocarditis may rarely present in these settings and high index of suspicion is essential for early diagnosis.

Megaloblastic anemia: A common but often neglected cause of pyrexia of unknown origin

Objective

The objective was to study megaloblastic anemia as a cause of pyrexia of unknown origin (PUO).

Materials and Methods

We conducted a study on 15 patients of megaloblastic anemia associated with fever, attending our hospital clinics over a period of 6 months.

Results

While 11 patients had symptoms suggesting foci of infection and responded well to intravenous antibiotics, 4 patients had neither any evidence of infection nor responded with empirical broad spectrum antibiotic treatment. They were treated with vitamin B12/folate therapy which led to marked improvement in fever within 48 h. Presenting complaints of the patients and severity/duration of fever along with other epidemiological data were also studied in each case.

Conclusion

The present study led us to conclude that megaloblastic anemia forms an important and reversible cause of fever and should be ruled out in all patients presenting with PUO. This knowledge would help the physicians in adequate and timely management of these patients.

Liver tuberculosis presenting as an uncommon cause of pyrexia of unknown origin: positron emission tomography/computed tomography identifies the correct site for biopsy

OBJECTIVE

To identify the correct site to biopsy in a case of pyrexia of unknown origin (PUO) caused by hepatic tuberculosis (TB).

CLINICAL PRESENTATION AND INTERVENTION

A 58-year-old man who developed hepatic TB presented with PUO. Ultrasonography (US) and computed tomography (CT) of the abdomen showed only calcifications in the liver, and positron emission tomography (PET)/CT showed diffuse increased metabolic activity in addition to focal areas of increased activity. A diagnosis of hepatic TB was confirmed by histological examination of liver tissues and interferon-γ release assays (IGRAs of T-SPOT/TB). The patient was treated with 4 anti-tubercular therapies (rifampicin, isoniazid, ethambutol and pyrazinamide). At the 3-month follow-up, the patient was disease free as confirmed by abdominal US.

CONCLUSION

PET/CT was helpful in identifying a site to biopsy that led to the correct diagnosis.

A rare case of seronegative culture--proven infection with Brucella suis

Brucellosis is a chronic infection produced by members of the Brucella family. Diagnosis of this condition requires either isolation of the organism in culture or positive serological tests.We describe a 27-year-old male admitted as a case of pyrexia of unknown origin (PUO), who tested negative for Brucella IgM ELISA test on preliminary evaluation but was subsequently diagnosed on the strength of positive blood and bone marrow cultures to be a case of brucellosis secondary to Brucella suis infection. In addition to highlighting the pathogenic potential of an unusual organism, this case demonstrates the unreliability of standard serological tests based on the Brucella melitensis antigen for infection with other species of Brucella.