Title of Case(s):

Fever of unknown origin: was it the plane, the parent or the parrot?

Background:

Fever of unknown origin can be a puzzling clinical presentation, especially if signs and symptoms are atypical and if there are multiple potentially relevant exposures.

Case Presentation Summary:

A 10-year-old girl presented with a history of fever for nine days and painful joints. She also reported lower abdominal pain, night sweats and weight loss. A close contact had recently been diagnosed with pulmonary tuberculosis and she had travelled to Suriname prior to presentation. The family history was positive for auto-immune diseases and the patient had a parrot at home.

On physical examination, she was pale and had a temperature of 38.6C, examination was otherwise unremarkable. CRP was 19 mg/L, ESR 35 mm/hr, white cell count 3.5x109/L, haemoglobin 7.0 mmol/L, platelets 201x109/l and ferritin 1209 ug/L. A peripheral blood film showed atypical lymphocytes, no blasts. Abdominal ultrasonography showed enlarged lymph nodes around the aorta and the right iliac artery. Chest X-ray was normal.

Extensive microbiological work-up including testing for tuberculosis did not yield any positive results. A positron emission tomography CT scan showed lymphadenopathy with enhanced fluorine-18-deoxyglucose uptake in both axillae, abdominally and in the left tonsil and mild poly-arthritis in the feet and hands.

A bone marrow biopsy showed normocellular bone marrow with reactive lymphocytosis and hemophagocytosis, but no signs of malignancy. Subsequently, a lymph node from the right axilla was excised for histopathological analysis. This showed a necrotising histiocytic lymphadenitis, typical for Kikuchi disease. She was treated conservatively and recovered swiftly without sequelae.

Key Learning Points:

Kikuchi disease is a rare and generally benign condition of uncertain aetiology that presents with non-specific symptoms including fever and lymphadenopathy. Clinical presentations can vary, and lymph node biopsy is required for definitive diagnosis. When tumour is the rumour, tissue is the issue.