Supplementary Case #2

Clinical summary: A 35-y-old man with sickle cell disease was admitted to the hospital in January with dyspnea. He had had a cold with moderate cough and sputum for about a week. He had also had many hospitalizations for painful crises, pneumonia, and priapism, and had received blood transfusions. One and a half years before admission, cor pulmonale and heart failure were diagnosed, and he was treated with digitalis, diuretics, and exchange transfusions to keep Hb A at 30-40% and Hb at 12-14 g/dl. He had been able to work loading trucks until a short time before admission. He was afebrile with a respiratory rate of 36/min. P2 was greater than A2. Laboratory values showed a WBC of 22.9 k/µl, hematocrit 31%, and platelets 660 k/µl. Arterial blood gases on air were pH 7.51, PaCO2 18 mm Hg, and PaO2 35 mm Hg. He was treated with oxygen, morphine, lasix, and digitalis but died 6 h later after 1 hr of CPR.

Gross autopsy findings: The heart weighed 500 g (normal 300 g) and showed right ventricular hypertrophy and dilation. Lungs weighed 500 g (right) and 450 g (left). Multiple thrombi, 1-4 mm in diameter, were present in arteries of all lobes. There were small foci of subpleural fibrosis posteriorly in the lower lobes. The spleen weighed 4 g.

Histologic findings: Elastic-van Gieson stains showed widespread narrowing of arterioles and venules (A). Arterioles (left) showed muscularization of the media as well as intimal thickening. The venules (right) showed intimal fibrosis (red).

A

Muscular arteries (B) showed a sieve-like pattern of recanalized thrombi, as well as a concentric pattern of intimal fibrosis (artery at lower middle). The medias are thin. Some of the intimal proliferation may result from release of inflammatory mediators generated by sickle RBC-endothelial interactions (see discussion). Recent thrombi were also present in this case. Capillaries (not shown) contained several megakaryocytes per high power field, a marked increase in number, but of unknown significance.

B

C. A branch (arrows) of a muscular artery (MA) with intimal proliferation shows a plexiform lesion in two parts separated because of the plane of section. The proximal portion between the arrows is probably devoid of media and elastic layers except at the bottom arrow. The plexus itself (P) is clearly devoid of a media even with H&E stain. It leads into a dilation lesion (D). A stain for elastic tissue can be helpful to confirm the destructive nature of plexiform lesions, which have been described in the thrombotic pulmonary hypertension of sickle cell disease.

C

Diagnosis: Chronic sickle cell lung disease with thrombotic pulmonary hypertension and cor pulmonale

Discussion

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