The great masquerader: Kikuchi-Fujimoto disease presenting as fever of unknown origin

IntroductionKikuchi-Fujimoto (KF) disease, also known as necrotizing histiocytic lymphadenitis, is a rare cause of fever of unknown origin. Most commonly seen in Japanese populations, it presents with fever and diffuse lymphadenopathy. KF can present a diagnostic challenge as its presentation can mimic sepsis, autoimmune disease, and/or malignancy. We present a case of KF disease presenting with innumerable pulmonary nodules and suspected sepsis.Case reportA 24-year old African-American male inmate with no past medical history presented to the Emergency Department with two witnessed generalized tonic-clonic seizures. Initial vitals were notable for a fever of 101.5 F, tachycardia, and tachypnea. He was lethargic with a diffuse, erythematous, scaly, necrotic rash. Additionally, cervical, axillary, and inguinal mobile, non-tender lymph nodes were noted. Laboratory studies revealed white blood cells 1.9 × 10 3 cells/μL with 25% bands, hemoglobin 9.4 G/dL, and platelet count of 110 × 10 3 cells/μL. He was subsequently admitted for sepsis due to presumed meningitis and started on broad-spectrum antibiotics. Lumbar puncture revealed no pleocytosis. Peripheral blood smear showed bandemia with Pelger Huet cells. Computed Tomography of chest, abdomen, and pelvis with contrast revealed diffuse pulmonary nodules involving all lobes of the lungs in addition to bulky hilar and retroperitoneal lymphadenopathy. Interventional Radiology performed a retroperitoneal lymph nodes biopsy that revealed lymphoplasmacytic cell infiltrate with extensive necrosis. Otolaryngology performed an excisional biopsy of a lymph node, which showed histiocytic necrotizing lymphadenitis. The final diagnosis was Kikuchi-Fujimoto disease, also known as histiocytic necrotizing lymphadenitis.OutcomeThe patient completed a 7-day course of empiric antibiotics. Workup for infectious etiologies was negative. The patient had a repeat CT of the chest with interval resolution of his pulmonary nodules on outpatient follow-up.ConclusionPatients with innumerable pulmonary nodules and fever of unknown origin should be evaluated early in their hospital course for KF as early diagnosis can reduce excessive testing and shorten hospital stay.     

Inflammatory pseudotumor of lymph nodes presenting as pyrexia of unknown origin

Inflammatory pseudotumor (IPT) is an uncommon benign disorder characterized by proliferation of spindle cells, inflammatory cells, and small vessels. The IPT of lymph nodes is a rare cause of lymphadenopathy that usually affects one or two nodal groups. We describe a 27-year-old male presenting with generalized lymphadenopathy, hepatosplenomegaly and fever for 1 year. Histologic examination of lymph node revealed few remnant lymphoid aggregates with marked sclerosis and numerous anastomosing blood vessels in lymph node parenchyma. Interspersed in between the fibrotic bands was a polymorphic infiltrate composed of lymphocytes, plasma cells, eosinophils, and immunoblasts. Also, many histiocytes, multinucleated giant cells some being Langhan's type and at places forming ill-defined granulomas were observed. The presence of granulomas and Langhan's type of giant cells can lead to a misdiagnosis of tuberculosis as was also done in the present case. It is thus not only important to be aware of this rare benign pathologic entity while dealing with a case of lymphadenopathy, but also consider it in the differential diagnosis of granulomatous disease.     

Bartonella henselae infection as a cause of fever of unknown origin

Fourteen of 41 patients (34%) with a serological diagnosis of Bartonella henselae infection were found to have prolonged fever or fever of unknown origin, suggesting that generalized systemic B. henselae infection is not rare in immunocompetent healthy individuals.     

A case of giant hemangioma of the liver presenting with fever of unknown origin.

A 37 year-old-woman was admitted to the hospital because of 15 days'' duration of continuous fever. Routine studies for detection of fever foci were negative. Imaging studies revealed giant hemangioma of the liver with central thrombosis. The fever persisted for a period of 4 weeks, and subsided after conservative management. We report a case of hepatic hemangioma presenting with fever of unknown origin. The condition is very rare, but should be regarded as one of the causes of fever of unknown origin.     

Comparative microbiological features of Bartonella henselae infection in a dog with fever of unknown origin and granulomatous lymphadenitis

We report the first documented case of Bartonella henselae infection in a dog from France and the first isolation of B. henselae from a dog with fever of unknown origin. This observation contributes to the “One Health” concept focusing on zoonotic pathogens emerging from companion animals. A 1-year-old female German shepherd dog was referred for evaluation of fever of unknown origin of 1 month duration. Diagnostic investigations confirmed diffuse pyogranulomatous lymphadenitis. The dog became afebrile, and lymph node size normalized in response to a 6-week course of doxycycline. Retrospectively, Bartonella DNA was amplified from an EDTA-anticoagulated blood sample obtained before antimicrobial therapy, with the gtlA fragment sharing 99 % identity with the 350-bp gtlA fragment of the B. henselae Houston-1 strain. The same strain was isolated in the blood of three healthy cats from the household. Two months after discontinuation of doxycycline, the dog experienced a febrile relapse. Bartonella DNA was again amplified from blood prior to and immediately after administration of a 6-week course azithromycin therapy. However, without administration of additional medications, PCR was negative 9 months after azithromycin therapy and the dog remains clinically healthy 12 months following the second course of antibiotics. The medical management of this case raises several clinically relevant comparative infectious disease issues, including the extent to which Bartonella spp. contribute to fever of unknown origin and pyogranulomatous inflammatory diseases in dogs and humans, and the potential of doxycycline and azithromycin treatment failures. The possibility that dogs could constitute an underestimated reservoir for B. henselae transmission to people is also discussed.     

Intramammary tuberculous lymphadenitis

A 50-year-old North African woman presented with a painful lump in the left breast. Fine needle aspiration cytology suggested an inflamed lymph node and histology established the diagnosis of intramammary tuberculous lymphadenitis. The case raises the possibility that the nodular type of tuberculous mastitis arises in intramammary lymph nodes.     

Discovery of a novel human picornavirus in a stool sample from a pediatric patient presenting with fever of unknown origin

Fever of unknown origin (FUO) is a serious problem in the United States. An unidentified agent was cultured from the stool of an infant who presented with FUO. This virus showed growth in HFDK cells and suckling mice. Using DNase sequence-independent single-primer amplification, we identified several nucleotide sequences with a high homology to Theiler's murine encephalomyelitis virus. Nearly full-length viral genome sequencing and phylogenetic analysis demonstrate that this virus is a member of the Cardiovirus genus of the Picornaviridae family.