Scintigraphic functional hyposplenism in amyloidosis

Functional asplenia or hyposplenism may predispose patients to spontaneous splenic rupture and potentially increase the risk of serious infection. In addition, hyposplenism may be a marker of more extensive systemic amyloidosis and has been correlated to a reduction in survival. Decreased splenic function is generally diagnosed by the presence of abnormal red blood cell morphology and decreased splenic uptake on 99mTc-sulfur colloid or microlite scans. We compared liver spleen scans with red cell morphology and anatomic imaging results in all patients with biopsy-proven amyloidosis who presented to the nuclear medicine department over a 12-yr period. Patients were referred from a center for amyloid disease for work-up of suspected hepatic involvement.

Between 1983 and 1995, 23 liver spleen scans from 21 patients (one patient had three scans) with known amyloidosis were referred for the assessment of degree of hepatic involvement with amyloid. All scans were retrospectively reviewed, and the degree of splenic uptake was graded. Medical records were reviewed for evidence of splenomegaly on physical exam. Extent of splenic involvement also was assessed by anatomical imaging (CT or MRI) in 45% of cases. Peripheral smear reports were reviewed for the presence of abnormal red cell morphology consistent with hyposplenism.

Splenic activity was moderately or markedly reduced in 22 of 23 liver spleen scans (21 patients). Eight of these scans had correlative anatomic splenic imaging: four were abnormal and four were normal. Forty-one percent of available peripheral smears contained abnormal red cell morphology. Nine patients had palpable splenomegaly at the time of the liver spleen scan. Splenic pathologic studies were available for three patients (two autopsy, one surgical) and demonstrated diffuse splenic infiltration with amyloidosis. One patient had spontaneous splenic rupture. Fourteen patients died, four of overwhelming infection.

Reduced splenic uptake on liver spleen scans for patients with suspected hepatic infiltration with amyloid is a common finding. Liver spleen scanning appears to be a more sensitive marker of splenic amyloidosis than clinical parameters or anatomical imaging.