Guess the Diagnosis: Case 2 - Episode 4
What is the most likely diagnosis for this patient?
Dr. David Fajgenbaum, Perelman School of Medicine, University of Pennsylvania, says the lymph node biopsy, the absence of other disorders that can lead to similar pathology, and the negative viral studies in the setting of generalized lymphadenopathy suggest that the correct diagnosis is HHV-8 negative (iMCD). iMCD can cause some immune dysregulation, and low positive ANA has been reported in approximately 30% of patients. This can delay diagnosis or even lead to inappropriate therapy. More specific testing for SLE should always be performed to confirm or exclude the diagnosis when a positive ANA is discovered. This patient was found to have a mildly elevated IL-6 level (6 pg/mL, normal range: <5 pg/mL), which may play a role with other cytokines in driving the inflammatory response. Elevated IL-6 can also reduce the production of albumin-causing hypoalbuminemia. Hypoalbuminemia together with high VEGF levels can cause leaky capillaries, which produce marked third spacing, explaining the pleural effusions, ascites, and peripheral edema in this patient. Third spacing can also contribute to circulatory collapse and organ failure. The cause of renal failure in iMCD is not well understood and in cases where kidney biopsy was performed, a variety of pathologies has been reported. IL-6 increases hepcidin production by the liver, which reduces iron absorption, iron release from macrophage, and iron exit from the liver, all contributing to the development of anemia. IL-6 promotes thrombopoiesis, and often increases in platelet counts are seen. Interestingly, most patients with iMCD have low platelet counts.
The etiology of thrombocytopenia in iMCD has not been fully elucidated, but it is especially seen in patients who are severely ill. iMCD can be accompanied by autoimmune phenomena such as autoimmune hemolytic anemia. Disseminated intravascular coagulation (DIC) was ruled out in this patient. It has been proposed, but not validated, that the presence of thrombocytopenia, normal gamma globulin levels, and the presence of bone marrow fibrosis in a patient with iMCD may represent a subentity in the clinical spectrum of iMCD.
Guess the Diagnosis: Case 2
Mark F. is a 25-year-old law school student from Florida with a 3-week history of severe fatigue, night sweats, and weight loss; he has also reported high fevers for the past week. He did not complain of joint pain.
The patient was admitted for further assessment.
Mark’s SLE diagnosis was reviewed and further testing was performed: