Kikuchi Lymphadenitis: The Febrile Illness That Cannot Go Unnodeiced

Introduction: Kikuchi-Fujimoto Disease is a rare diagnosis which presents with a constellation of symptoms including fevers, malaise, weight loss, and cervical lymphadenopathy. Because the disease process is uncommon and the symptoms are non-specific, the diagnostic process can be lengthy and challenging.

Case Description: A 14 year old female with no known past medical history presented with 5 days of fever, nausea, vomiting and recently resolved migraines. Initial physical exam was significant for an uncomfortable appearing teenage female with fever (Tmax 104.5) and rigors, however otherwise unremarkable. Family history was significant for a maternal diagnosis of multiple sclerosis controlled on immunomodulators. Lab work was significant for elevations in ferritin, d-dimer, LDH, CRP, and ESR without leukocytosis or signs of systemic infection. Initial differential included an array of etiologies including acute infection vs post-infectious inflammation (MISC/Kawasaki) vs a rheumatologic cause (SLE) vs a hematologic cause (HLH/malignancy). Patient continued to fever with no changes in physical exam or infectious workup, however she had acute increases in troponin and BNP suggestive of pericarditis. Blood and urine cultures remained negative, though she was initially on broad spectrum empiric antibiotics without defervescence or symptomatic improvement. Due to continued fever without identified source, a full body CT scan was done, remarkable for a 9x3x7cm nodal mass under the right sternocleidomastoid muscle (non-palpable on exam). Patient underwent a biopsy of the mass which showed Kikuchi Fujimoto Lymphadenitis. She was treated with high dose steroids with resolution of her symptoms and discharged with Rheumatology and Cardiology follow up.

Discussion: Kikuchi-Fujimoto Disease, otherwise known as Histiocytic Necrotizing Lymphadenitis or Kikuchi’s Disease, presents with subacute fevers, malaise, weight loss, and cervical lymphadenopathy. The disease is a benign and self-limiting inflammatory lymphadenitis and confirmed by characteristic immunochemistry findings on lymph node biopsy. While definitive etiology is unknown, it is theorized to be of viral or autoimmune origin. Incidence of this disease is unknown although it typically presents in patients under 30 years old. Treatment is primarily supportive with NSAIDs and steroids. The most common identified long term sequelae is systemic lupus erythematosus, therefore patients should have follow up with Rheumatology.

Conclusion: The clinical picture of Kikuchi disease is non-specific with fever, elevated inflammatory markers, and lymphadenitis. As the initial differential is broad and encompasses infectious, hematologic, and rheumatologic processes, many with time-sensitive treatments and more dismal prognoses, we present this case as an alternative, rare, and relatively benign cause of fever and inflammation in young patients. Due to the nature of the presenting symptoms, collaboration in care with consultants is important for effective elimination of alternative etiologies and timely diagnosis. While Kikuchi tends to self-resolve and treatment is primarily supportive, continued surveillance after resolution of symptoms is important given the increased probability of rheumatic disease sequelae.