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The Retina in Type 5 Hyperlipoproteinemia
T H E RETINA IN TYPE 5 H Y P E R L I P O P R O T E I N E M I A GEORGE H .
KURZ,
M.D.
Flemington, New Jersey MANOUCHER SHAKIB,
M.D.
New York, New York K E N E T T E K.
SOHMER,
M.D.
Flemington, New Jersey AND A L A N H.
FRIEDMAN,
M.D.
Bronx, New York Type 5 hyperlipoproteinemia (Fredrickson) is characterized by increased very low density lipoproteins and chylomicrons in the blood plasma. W e describe the ophthalmoscopic and postmortem changes in one pa tient with this disorder who had lipemia retinalis, multiple retinal hemorrhages, and lipid-containing retinal deposits. A second patient lost vision because lipids occluded many retinal arteries.
a five-day history of dizziness and having vomited bile-stained material the day before admission. On the day of admission she developed a temperature of 38.9°C (102°F), became confused, and semistuporous. Her blood appeared lipemic (Fig. 1). Blood glucose level was 394 mg/100 ml; total lipids, 12,900 mg/100 mi; serum cholesterol, 1770 mg/ 100 ml; triglycérides, 7,400 mg/100 ml; phospho lipids, 3,600 mg/100 ml ; and throat culture showed innumerable colonies of beta type of hemolytic streptococcus. Chest x-ray films showed pulmonary edema. Respiratory obstruction necessitated a tracheotomy. The patient had a rapid downhill course and on the fourth day of hospitalization she died of what was felt to be aspiration pneumonia complicating an underlying viremia. An ophthalmologic consultation was obtained on the day before the patient died. She was comatose and on a respirator. There was marked chemosis of both conjunctivae. Pupils were reactive. Ophthalmoscopic examination revealed lipemia retinalis in both eyes. All vessels had a creamy appearance (Fig. 2). In an area betwen the inferior and superior temporal vessels in the right eye there was a massive extravasation of lipid material into the retina extending from the disk beyond the macula (Fig. 3)· A smaller creamy exudate was present in the same area of the left eye. Lipid ma terial also appeared to have broken out into both vitreous bodies. In addition, both eyes had several prominent retinal hemorrhages ringed by creamy exudate.
C A S E REPORTS
Case 1—The patient was a 34-year-old black woman who died in September 1972. In 1970, she had a positive glucose tolerance test. Total serum cholesterol level was 189 mg/100 ml; triglycérides, 430 mg/100 ml (normal 30 to 135 mg/100 ml) ; and lipoprotein electrophoresis was consistent with type 5 hyperlipoproteinemia. In May 1972, during a hospitalization for obesity and diabetes, an ophthalmologic consulta tion was unremarkable. Visual acuity was 6/6 in both eyes without correction, and there was no evi dence of diabetic retinopathy. Serum cholesterol level was 196 mg/100 ml; triglycérides, 424 mg/ 100 ml; phospholipids, 480 mg/100 ml (normal 150 to 300 mg/100 ml) ; total lipids, 1,030 mg/100 ml (normal 500 to 1,000 mg/100 ml) ; and lipo protein electrophoresis was consistent with Type 4 or 5. In September 1972, she was hospitalized after
P R I N C I P A L AUTOPSY F I N D I N G S — 1 . Severe
bilateral undifferentiated interstitial pneu monia with many hyaline membranes lining alveolar sacs in addition to inflammatory exudate in alveolar spaces and evidence of old organizing foci of pneumonia. 2. Superimposed aspiration pneumonia. 3. Large areas of pancreatic fat necrosis. Sparse islets of Langerhans.
From the Departments of Ophthalmology, New York University Medical Center, New York (Drs. Kurz and Shakib), Hunterdon Medical Center, Flemington, New Jersey (Drs. Kurz and Sohmer), and the Albert Einstein College of Medicine, Bronx, New York (Dr. Friedman). Reprint requests to George H. Kurz, M.D., Hunterdon Medical Center, Flemington, NJ 08822. 32
Fig. 1 (Kurz and associates). Unrefrigerated blood of a 34-year-old woman with hyperlipoproteinemia. Fig. 2 (Kurz and associates). All vessels in the left fundus have a creamy appearance with two retinal hemorrhages near disk.
Fig. 4 (Kurz and associates). Posterior part of enucleated eye shows multiple hemorrhages, some of which are surrounded by white material, and creamy material within retinal vessels and in several prominent spots in the retina.
Fig. 3 (Kurz and associates). Right eye demonstrates lipemia retinalis, hemorrhages, and massive pale exudate adjacent to disk.
Fig. 19 (Kurz and associates). Right fundus of 53-year-old man shows inferior temporal artery filled with creamy material.
Fig. 20 (Kurz and associates). Ischémie infarction above disk.
Fig. 23 (Kurz and associates). Right fundus in July 1970, shows lipid in superior temporal artery.
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4. Severe passive congestion and fatty metamorphosis of the liver. 5. Red pulp of spleen packed with foamy lipid-containing cells. 6. Many petechiae in gastric mucosa. 7. Congestion of vascular channels and focal areas of edema throughout cerebrum and cerebellum. Permission was obtained for a post mortem examination of only one eye. It was enucleated and placed in formalin within two hours of the patient's death. GROSS EXAMINATION—The
specimen, a
firm left eye, measured 24.5 X 24.5 X 24 mm with the optic nerve cut flush with the sciera. The anterior segment was unremark able. The eye was opened horizontally. Retinal blood vessels contained much white material and there were dozens of hemorrhagic patches of varying size scattered throughout the retina, each surrounded by a halo of white, finely granular material (Fig. 4). Only a few segments of the retinal vessels contained blood. The optic nerve head appeared to be slightly edematous. MICROSCOPIC
EXAMINATION—The
an
terior segment showed several small cystic spaces in the iris pigment epithelium and an intraepithelial cyst of the ciliary pigment epithelium. In the retina on the nasal side there were several large hemorrhages be tween the internal limiting membrane and the nerve fiber layer (Fig. 5). In the region of some of these hemorrhages the outer
35
plexiform layer was marked by multiple cys tic spaces. These spaces contained a fine fibrillar material and occasional neutrophils (Fig. 6). In some areas the hemorrhage ex tended into the nerve fiber and ganglion cell layers. Some of the cystic spaces in the outer plexiform layer also contained blood, and in some sections, blood broke through the outer nuclear layer and external limit ing membrane into the subretinal space. The cystic spaces in the outer plexiform layer in most instances were present, not beneath the main body of the hemorrhages, but at the sides of the hemorrhages. On the temporal side there were larger empty spaces in the outer plexiform layer, elon gated in the plane of the retina (Fig. 7). These extended from the optic nerve head well beyond the macula. The nerve fiber layer was unusually thin on the temporal side. In the temporal periphery there were small retinal hemorrhages, principally be neath the internal limiting membrane, in areas not associated with cystic spaces in the outer plexiform layer (Fig. 8). FROZEN SECTIONS—Frozen sections were prepared by immersing a calotte in water soluble wax (O.C.T.) and freezing in a dry ice-isopentane mixture. Tissue was sectioned at 8 μ on a cryostat and stained with Sudan black B and carmalum. Deposition of sudanophilic material was seen in all retinal layers. It was most marked in the outer plexiform layer where lipid de-
Fig. 5 (Kurz and associates). Large preretinal hemorrhage is seen on nasal side of left eye (hematoxylin and eosin, X35).
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and stained with Sudan black B and carmalum. Two types of lesions were apparent. First, there was deposition of lipid within capil lary, artery, and vein walls (Fig. 12). This deposition was not uniform. Some segments showed heavy deposition of sudanophilic ma terial, others only droplets. Secondly, there were large pools of lipid approximately 1 mm in diameter (Fig. 13). ELECTRON MICROSCOPY·—Pieces of retina measuring about 2 mm X 2 mm showing brownish patches surrounded by white granular material were dissected from the choroid and postfixed in chilled 2% osmium tetroxide in 0.1 M phosphate buffer for one hour. The specimens were dehydrated in graded alcohols and embedded in Epon 812. One-micron thick sections were stained with toluidine blue and observed with the light microscope. Thin sections cut from selected areas were double stained with uranyl ace tate and lead citrate and observed and photo graphed with the Zeiss 9A electron micro scope.
Fig. 6 (Kurz and associates). Cystic spaces in outer plexiform layer at edge of hemorrhage, seen in Figure 5, contain a fine fibrillar material and occasional neutrophils and erythrocytes (hematoxylin and eosin, χ88 top; XS60 bottom). posits lay as large puddles on each side of one of the hemorrhages in the inner part of the retina (Fig. 9). Smaller droplets were present in the outer and inner nuclear layers as well as in the inner plexiform layer. Retinal vessel walls were thickened by the deposition of lipid material resulting in mild narrowing of the lumen in some areas (Fig. 10). Walls of large and small vessels within the choroid contained lipid (Fig. 11). TRYPSIN DIGEST—The retina was dis sected free from the other calotte and di gested with pepsin 1:10,000 and then trypsin 1:250. It was mounted and dried on a slide
As this was postmortem material which had been stored for several days in formalin at room temperature, there were many post mortem changes. These alterations, however, did not obscure the basic pathology. Our interest in the electron microscopic study was mainly directed toward the patho logic findings in the retinal vessels and sur rounding tissue. In the vessels the endo thelial cells had large globules that contained homogeneous material resembling more satu rated droplets of lipid. There was a more electron-dense line at the interface between the globules and surrounding cytoplasm (Fig. 14). Dense irregular masses of differ ent size and shape, without surrounding membranes, were found adjacent to the pre sumed lipid globules (Fig. 15). The endoplasmic reticulum of the endothelial cells showed no enlargement and contained no material resembling lipid. The junctional complexes between the endothelial cells ap peared unchanged.
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Fig. 7 (Kurz and associates). Large empty spaces in outer plexiform layer are seen temporal to the optic nerve head (hematoxylin and eosin, X3S).
The basement membrane of the vessels was thicker than normal and showed empty areas containing bizarrely shaped masses with high electron density (Fig. 16). Some of these were similar to those found in the endothelial cells and were presumably lipid material. In the pericytes, electron-lucent vacuoles with a dense peripheral zone were also seen (Fig. 17). Numerous vacuoles similar to those found in the pericytes were seen in the retinal tissue and around the blood vessels.
These masses found free in the retina, as well as those in the basement membrane, and in the cytoplasm of the endothelial cells and pericytes had characteristics of lipid parti cles. Some fibrin, blood cells, and empty spaces were also observed in the retinal tissue (Fig. 18). Case 2—A 53-year-old white man seen in March 1970 had had diabetes and type 5 hyperlipoproteinemia since 1962. He had not been following his diet carefully. Serum lipids recently had been markedly elevated. Three days after an episode of left-sided numbness and transient weakness, he
Fig. 8 (Kurz and as sociates). Two preretinal hemorrhages on temporal side are not associated with cystic spaces in outer plexiform layer (hematoxylin and eosln, X3S).
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Fig. 9 (Kurz and associates). Sudanophilic ma terial (S) is in outer plexiform layer on sides of a hemorrhage (H) in inner retinal layers. Large black circle is artifactitious air bubble beneath cover slip (Sudan black B, X88). noted a "cloud" covering the upper part of the field of vision of his right eye. On examination the uncorrected visual acuity was R.E. : 6/7.5, L.E. : 6/6—. Ophthalmoscopically the inferior temporal retinal artery of the right eye was filled with opaque white material extending from the bifurcation of the central retinal artery well out into the periphery (Fig. 19). In the far periphery there were glistening white plaques in an arteriole. A small amount of opaque white ma terial filled the beginning of the inferior nasal
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artery. The retina above the inferior temporal artery had a slightly gray edematous appearance that did not reach the macula. Just above and slightly temporal to the disk there was a fluffy white zone interpreted as an area of ischémie in farction (Fig. 20). There were no xanthomas or other skin lesions. The patient was hospitalized, given anticoagulants, and placed on an appropriate diet. The serum tri glycérides level changed from 2,100 on admission to 206 mg/100 ml, and serum cholesterol changed from 708 to 370 mg/100 ml 12 days later. Subse quently hemorrhages were noted near the disk and dense scotomas were demonstrated in the visual field superiorly and inferiorly (Fig. 21). Four weeks after initial examination the in ferior temporal arteriole remained filled with white material and a previously uninvolved arteriole in the upper temporal quadrant contained lipid. Addi tional visual field defects were noted in May 1970 (Fig. 22). In July 1970, the right superior temporal artery was largely filled with lipid and a new area of retinal infarction was noted above the disk (Fig. 23). The patient described the vision of the right eye as seeing "through a peephole" between scotomas. One year after the initial examination the ap pearance of the right inferior temporal arteriole was unchanged. Pallor of the optic disk and several dot and blot hemorrhages and fine, hard, white exudates were noted in the right fundus. In May 1971, the patient developed a right hemi-
Fig. 10 (Kurz and associates). Retinal vessel has lipid in wall and lumen (Sudan black B, X224).
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Fig. 11 (Kurz and associates). Choroidal vessel contains lipid in wall and lumen (Sudan black B, X224). paresis. He reported that, during an arteriogram in March 1972, he lost vision in his good eye, and at the same time lost additional vision in his right eye. Examination revealed a right homonymous hemianopsia superimposed on the previous defects (Fig. 24). Ophthalmoscopic examination of the left eye was normal on all examinations. Visual acuity
Fig. 13 (Kurz and associates). Large pool of lipid and blood (retinal digest preparation; Sudan black B, x35). when last examined was R.E.: hand movements, and L.E.: 6/7.5. COMMENT—The outstanding feature of this case was the progressive obstruction of retinal vessels with lipid, resulting in visual field defects. These findings persisted over the two-year period of observation and were confined to his right eye. Lipemia retinalis was never observed. In addition to loss of vision in his right eye, the hyperlipoproteinemia was undoubtedly a contributing factor to his generalized arteriosclerosis and ischémie attacks. DISCUSSION
Fig. 12 (Kurz and associates). Patchy deposi tion of lipid in walls of retinal vessels of all sizes (digest preparation; Sudan black B, χ35 top; χ224 bottom).
The plasma lipoproteins are macromolecular complexes of specific lipids and pro teins in relatively fixed proportions. They represent the vehicles whereby water-insolu ble lipids are maintained in a stable colloidal form and are transported in the blood.1 These compounds may be categorized on the basis of particle size and charge, electrophoretic migration, density, and flotation by techniques such as analytic ultracentrifugation or polyacrylamide gel electrophoresis, paper or agar-agarose gel electrophoresis. Four families of lipoproteins are differenti ated: chylomicrons, low-density lipoproteins (beta lipoproteins), very low-density lipo-
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Fig. 14 (Kurz and associates). Electron micrograph of an endo thelial cell (E) of a retinal vessel shows a globule (G) within the cytoplasm containing material pre sumed to be lipid. The junctional complex between the two adjacent endothelial cells appears closed (arrow) (uranyl acetate-lead ci trate, X 17,000).
proteins (pre-beta lipoproteins), and highdensity lipoproteins. The first three families serve as determinants of the five recognized abnormal lipoprotein patterns by which nearly all patients with hereditable hyperlipoproteinemia may be classified.2 Other known diseases, such as insulinopenic dia betes, can result in secondary hyperlipoproteinemia manifesting itself in any of the five types of lipoprotein patterns. Type 4 may be defined as the presence of increased very low-density (pre-beta) lipo proteins without chylomicronemia. Serum triglycérides are increased. Serum choles terol is normal or increased. After standing unfrozen in a refrigerator for 18 to 24 hours, plasma may be clear or turbid. In type 5, in addition to increased very
Fig. IS (Kurz and associates). A globule in an endothelial cell contains homogenous material with dense irregular masses (arrow) (uranyl acetate-lead citrate, X 36,000).
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Fig. 16 (Kurz and associates). The basement membrane (BM) of a blood vessel appears thicker than normal and shows irregular masses resembling lipid (arrows) (uranyl acetate-lead citrate, X36,000). low-density lipoproteins, chylomicrons are present. Serum cholesterol levels a r e in creased as well as triglycérides. T h e plasma is creamy on top, turbid below. The distinction between " n o " chylomi-
Fig. 17 (Kurz and associates). Electron micro graph shows a vacuole (V) with a dense pe ripheral zone within the cytoplasm of an intra mural pericyte (uranyl acetate-lead citrate, X36.000).
Fig. 18 (Kurz and associates). Electron micro graph of retinal tissue adjacent to a blood vessel shows empty spaces and bundles of fibrin (arrows) (uranyl acetate-lead citrate, X 14,000).
Fig. 21 (Kurz and associates). Central visual field of right eye 16 days after initial examination, 9/1000 white.
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Fig. 22 (Kurz and associates). Central visual field of right eye two months after initial ex amination, 9/1000 white.
crons and a "few"—the difference between types 4 and 5—is a fine one. A type 4 pattern can be converted into type 5 under certain dietary conditions. Types 4 and 5 may appear in the same family. Both pat terns are undoubtedly nonspecific and ap pear secondary to a variety of diseases.
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Nonketotic diabetes and a history of pan creatitis are each present in about three fourths of patients with type 5.2 Lipemia retinalis and palpebral eruptive xanthomas are the recognized ocular findings that may appear in both types 4 and 5.3 The appearance of lipemia retinalis is believed to be directly correlated with the level of serum triglycérides.3·4 Lipemia retinalis is first recognizable when triglycéride levels reach 2,500 mg/100 ml. In severe lipemia, when all arteries and veins are cream colored and their differentiation is difficult even at the disk, triglycéride levels are above 5,000 mg/100 ml. Lipemia retinalis disappears as triglycér ide levels decrease and is usually considered to have no effect on retinal function. Eyes with lipemia rarely become available for his tologie examination. According to DukeElder,5 pathologic examinations have shown consistently that retinal tissues are normal. The unique features of Case 1 are the prominent retinal hemorrhages surrounded by a ring of lipid material and the electron microscopic studies confirming the presence of lipid in the vessel walls.
Fig. 24 (Kurz and associates). Right homonymous hemianopsia superimposed on previous visual field defects, 9/1000 white.
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Rapid large alterations in venous pressure transmitted from the intrathoracic pressure were undoubtedly caused by the respirator. This may provide an explanation for the bi lateral retinal hemorrhages as well as the marked chemosis. The lipid seen in rings surrounding the retinal hemorrhages was in each instance separated from the erythrocytes by several retinal layers. The hemor rhages were located largely just beneath the internal limiting membrane, while lipid-filled spaces were largely confined to the outer plexiform layer. Thus the lipid appears to have seeped toward the outer retinal layers (for which we do not have an explanation), becoming separated from the erythrocytes that were held in the inner retinal layers. In the case report of Blodi8 similarities are present. There were a few large yellow ish deposits in the periphery of the fundus and some of them contained a central hemor rhage. His case was complicated by retinal detachment for which two operations had been performed. When total detachment en sued and the eye became blind and painful, it was removed and studied histologically. In one photomicrograph, there is a small hemorrhage beneath the internal limiting membrane in an area with cystic spaces in the outer retinal layers containing fat. Clinically, retinal vessels regain a normal appearance as neutral fat levels fall below those necessary to produce lipemia retinalis. One would thus expect to find no lipid in the vessel walls or in the perivascular retinal tissue. The histopathologic study of Blodi's case,6 however, included the demonstration of fat within the retinal vessel walls as well as in the lumen. Duke-Elder5 stated that in the vessels the plasma is loaded with fat which permeates into the perivascular area. Our case confirms by electron microscopy the possibility of lipid penetrating the wall of the retinal vessels. Lipid may reach the peri vascular retinal tissue by transport through the endothelial cells, intramural pericytes, and
43
basement membranes rather than through spaces between adjacent endothelial cells. Junctional complexes7 appeared to be closed and fat vacuoles were demonstrated in the endothelial cells, intramural pericytes, and basement membranes. The presence of fibrin and blood cells in areas of lipid deposition indicates that some of the lipid is accounted for by rupture of blood vessels and hemor rhage. SUMMARY
Of two patients with type 5 hyperlipoproteinemia, one exhibited lipemia retinalis with multiple retinal hemorrhages and intraretinal lipid extravasations. Postmortem ex amination showed hemorrhages in the inner retinal layers and lipid deposits largely in the outer plexiform layer. Lipid within the walls of the retinal vessels was demonstrated by light and electron microscopy. The sec ond patient exhibited visual loss due to pro gressive obstruction of retinal vessels with white material presumed to be lipid. Find ings were confined to one eye. REFERENCES
1. Fredrickson, D. S., Gotto, A. M., and Levy, R. I. : Familial lipoprotein deficiency. In Stanbury, J. B., Wyngaarden, J. B., and Fredrickson, D. S. (eds.) : The Metabolic Basis of Inherited Disease. New York, McGraw-Hill, 1972, p. 493. 2. Fredrickson, D. S., and Levy, R. I.: Familial hyperlipoproteinemia. In Stanbury, J. B., Wyn gaarden, J. B., and Fredrickson, D. S. (eds.) : The Metabolic Basis of Inherited Disease. New York, McGraw-Hill, 1972, pp. 54S-SS0; 592-604. 3. Vinger, P. F., and Sachs, B. A. : Ocular manifestations of hyperlipoproteinemia. Am. J. Ophthalmol. 70:563, 1970. 4. Dunphy, E. G. : Ocular conditions associated with idiopathic hyperlipemia. Am. J. Ophthalmol. 33:1579, 1950. 5. Duke-Elder, S., and Dobree, J. H.: Diseases of the Retina. In Duke-Elder, S. (ed.) : System of Ophthalmology, vol. 10. St. Louis, C. V. Mosby, 1967, pp. 454, 555. 6. Blodi, F. C. : Retinal involvement in idiopathic hyperlipemia. Trans. Am. Acad. Ophthalmol. Otolaryngol. 64:720, 1960. 7. Shakib, M., and Cunha-Vaz, J. G. : Studies on the permeability of the blood retinal barrier. 4. Junctional complexes of the retinal vessels and their role in the permeability of the blood retinal barrier. Exp. Eye Res. 5:229, 1966.
KURZ,
M.D.
Flemington, New Jersey MANOUCHER SHAKIB,
M.D.
New York, New York K E N E T T E K.
SOHMER,
M.D.
Flemington, New Jersey AND A L A N H.
FRIEDMAN,
M.D.
Bronx, New York Type 5 hyperlipoproteinemia (Fredrickson) is characterized by increased very low density lipoproteins and chylomicrons in the blood plasma. W e describe the ophthalmoscopic and postmortem changes in one pa tient with this disorder who had lipemia retinalis, multiple retinal hemorrhages, and lipid-containing retinal deposits. A second patient lost vision because lipids occluded many retinal arteries.
a five-day history of dizziness and having vomited bile-stained material the day before admission. On the day of admission she developed a temperature of 38.9°C (102°F), became confused, and semistuporous. Her blood appeared lipemic (Fig. 1). Blood glucose level was 394 mg/100 ml; total lipids, 12,900 mg/100 mi; serum cholesterol, 1770 mg/ 100 ml; triglycérides, 7,400 mg/100 ml; phospho lipids, 3,600 mg/100 ml ; and throat culture showed innumerable colonies of beta type of hemolytic streptococcus. Chest x-ray films showed pulmonary edema. Respiratory obstruction necessitated a tracheotomy. The patient had a rapid downhill course and on the fourth day of hospitalization she died of what was felt to be aspiration pneumonia complicating an underlying viremia. An ophthalmologic consultation was obtained on the day before the patient died. She was comatose and on a respirator. There was marked chemosis of both conjunctivae. Pupils were reactive. Ophthalmoscopic examination revealed lipemia retinalis in both eyes. All vessels had a creamy appearance (Fig. 2). In an area betwen the inferior and superior temporal vessels in the right eye there was a massive extravasation of lipid material into the retina extending from the disk beyond the macula (Fig. 3)· A smaller creamy exudate was present in the same area of the left eye. Lipid ma terial also appeared to have broken out into both vitreous bodies. In addition, both eyes had several prominent retinal hemorrhages ringed by creamy exudate.
C A S E REPORTS
Case 1—The patient was a 34-year-old black woman who died in September 1972. In 1970, she had a positive glucose tolerance test. Total serum cholesterol level was 189 mg/100 ml; triglycérides, 430 mg/100 ml (normal 30 to 135 mg/100 ml) ; and lipoprotein electrophoresis was consistent with type 5 hyperlipoproteinemia. In May 1972, during a hospitalization for obesity and diabetes, an ophthalmologic consulta tion was unremarkable. Visual acuity was 6/6 in both eyes without correction, and there was no evi dence of diabetic retinopathy. Serum cholesterol level was 196 mg/100 ml; triglycérides, 424 mg/ 100 ml; phospholipids, 480 mg/100 ml (normal 150 to 300 mg/100 ml) ; total lipids, 1,030 mg/100 ml (normal 500 to 1,000 mg/100 ml) ; and lipo protein electrophoresis was consistent with Type 4 or 5. In September 1972, she was hospitalized after
P R I N C I P A L AUTOPSY F I N D I N G S — 1 . Severe
bilateral undifferentiated interstitial pneu monia with many hyaline membranes lining alveolar sacs in addition to inflammatory exudate in alveolar spaces and evidence of old organizing foci of pneumonia. 2. Superimposed aspiration pneumonia. 3. Large areas of pancreatic fat necrosis. Sparse islets of Langerhans.
From the Departments of Ophthalmology, New York University Medical Center, New York (Drs. Kurz and Shakib), Hunterdon Medical Center, Flemington, New Jersey (Drs. Kurz and Sohmer), and the Albert Einstein College of Medicine, Bronx, New York (Dr. Friedman). Reprint requests to George H. Kurz, M.D., Hunterdon Medical Center, Flemington, NJ 08822. 32
Fig. 1 (Kurz and associates). Unrefrigerated blood of a 34-year-old woman with hyperlipoproteinemia. Fig. 2 (Kurz and associates). All vessels in the left fundus have a creamy appearance with two retinal hemorrhages near disk.
Fig. 4 (Kurz and associates). Posterior part of enucleated eye shows multiple hemorrhages, some of which are surrounded by white material, and creamy material within retinal vessels and in several prominent spots in the retina.
Fig. 3 (Kurz and associates). Right eye demonstrates lipemia retinalis, hemorrhages, and massive pale exudate adjacent to disk.
Fig. 19 (Kurz and associates). Right fundus of 53-year-old man shows inferior temporal artery filled with creamy material.
Fig. 20 (Kurz and associates). Ischémie infarction above disk.
Fig. 23 (Kurz and associates). Right fundus in July 1970, shows lipid in superior temporal artery.
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4. Severe passive congestion and fatty metamorphosis of the liver. 5. Red pulp of spleen packed with foamy lipid-containing cells. 6. Many petechiae in gastric mucosa. 7. Congestion of vascular channels and focal areas of edema throughout cerebrum and cerebellum. Permission was obtained for a post mortem examination of only one eye. It was enucleated and placed in formalin within two hours of the patient's death. GROSS EXAMINATION—The
specimen, a
firm left eye, measured 24.5 X 24.5 X 24 mm with the optic nerve cut flush with the sciera. The anterior segment was unremark able. The eye was opened horizontally. Retinal blood vessels contained much white material and there were dozens of hemorrhagic patches of varying size scattered throughout the retina, each surrounded by a halo of white, finely granular material (Fig. 4). Only a few segments of the retinal vessels contained blood. The optic nerve head appeared to be slightly edematous. MICROSCOPIC
EXAMINATION—The
an
terior segment showed several small cystic spaces in the iris pigment epithelium and an intraepithelial cyst of the ciliary pigment epithelium. In the retina on the nasal side there were several large hemorrhages be tween the internal limiting membrane and the nerve fiber layer (Fig. 5). In the region of some of these hemorrhages the outer
35
plexiform layer was marked by multiple cys tic spaces. These spaces contained a fine fibrillar material and occasional neutrophils (Fig. 6). In some areas the hemorrhage ex tended into the nerve fiber and ganglion cell layers. Some of the cystic spaces in the outer plexiform layer also contained blood, and in some sections, blood broke through the outer nuclear layer and external limit ing membrane into the subretinal space. The cystic spaces in the outer plexiform layer in most instances were present, not beneath the main body of the hemorrhages, but at the sides of the hemorrhages. On the temporal side there were larger empty spaces in the outer plexiform layer, elon gated in the plane of the retina (Fig. 7). These extended from the optic nerve head well beyond the macula. The nerve fiber layer was unusually thin on the temporal side. In the temporal periphery there were small retinal hemorrhages, principally be neath the internal limiting membrane, in areas not associated with cystic spaces in the outer plexiform layer (Fig. 8). FROZEN SECTIONS—Frozen sections were prepared by immersing a calotte in water soluble wax (O.C.T.) and freezing in a dry ice-isopentane mixture. Tissue was sectioned at 8 μ on a cryostat and stained with Sudan black B and carmalum. Deposition of sudanophilic material was seen in all retinal layers. It was most marked in the outer plexiform layer where lipid de-
Fig. 5 (Kurz and associates). Large preretinal hemorrhage is seen on nasal side of left eye (hematoxylin and eosin, X35).
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and stained with Sudan black B and carmalum. Two types of lesions were apparent. First, there was deposition of lipid within capil lary, artery, and vein walls (Fig. 12). This deposition was not uniform. Some segments showed heavy deposition of sudanophilic ma terial, others only droplets. Secondly, there were large pools of lipid approximately 1 mm in diameter (Fig. 13). ELECTRON MICROSCOPY·—Pieces of retina measuring about 2 mm X 2 mm showing brownish patches surrounded by white granular material were dissected from the choroid and postfixed in chilled 2% osmium tetroxide in 0.1 M phosphate buffer for one hour. The specimens were dehydrated in graded alcohols and embedded in Epon 812. One-micron thick sections were stained with toluidine blue and observed with the light microscope. Thin sections cut from selected areas were double stained with uranyl ace tate and lead citrate and observed and photo graphed with the Zeiss 9A electron micro scope.
Fig. 6 (Kurz and associates). Cystic spaces in outer plexiform layer at edge of hemorrhage, seen in Figure 5, contain a fine fibrillar material and occasional neutrophils and erythrocytes (hematoxylin and eosin, χ88 top; XS60 bottom). posits lay as large puddles on each side of one of the hemorrhages in the inner part of the retina (Fig. 9). Smaller droplets were present in the outer and inner nuclear layers as well as in the inner plexiform layer. Retinal vessel walls were thickened by the deposition of lipid material resulting in mild narrowing of the lumen in some areas (Fig. 10). Walls of large and small vessels within the choroid contained lipid (Fig. 11). TRYPSIN DIGEST—The retina was dis sected free from the other calotte and di gested with pepsin 1:10,000 and then trypsin 1:250. It was mounted and dried on a slide
As this was postmortem material which had been stored for several days in formalin at room temperature, there were many post mortem changes. These alterations, however, did not obscure the basic pathology. Our interest in the electron microscopic study was mainly directed toward the patho logic findings in the retinal vessels and sur rounding tissue. In the vessels the endo thelial cells had large globules that contained homogeneous material resembling more satu rated droplets of lipid. There was a more electron-dense line at the interface between the globules and surrounding cytoplasm (Fig. 14). Dense irregular masses of differ ent size and shape, without surrounding membranes, were found adjacent to the pre sumed lipid globules (Fig. 15). The endoplasmic reticulum of the endothelial cells showed no enlargement and contained no material resembling lipid. The junctional complexes between the endothelial cells ap peared unchanged.
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Fig. 7 (Kurz and associates). Large empty spaces in outer plexiform layer are seen temporal to the optic nerve head (hematoxylin and eosin, X3S).
The basement membrane of the vessels was thicker than normal and showed empty areas containing bizarrely shaped masses with high electron density (Fig. 16). Some of these were similar to those found in the endothelial cells and were presumably lipid material. In the pericytes, electron-lucent vacuoles with a dense peripheral zone were also seen (Fig. 17). Numerous vacuoles similar to those found in the pericytes were seen in the retinal tissue and around the blood vessels.
These masses found free in the retina, as well as those in the basement membrane, and in the cytoplasm of the endothelial cells and pericytes had characteristics of lipid parti cles. Some fibrin, blood cells, and empty spaces were also observed in the retinal tissue (Fig. 18). Case 2—A 53-year-old white man seen in March 1970 had had diabetes and type 5 hyperlipoproteinemia since 1962. He had not been following his diet carefully. Serum lipids recently had been markedly elevated. Three days after an episode of left-sided numbness and transient weakness, he
Fig. 8 (Kurz and as sociates). Two preretinal hemorrhages on temporal side are not associated with cystic spaces in outer plexiform layer (hematoxylin and eosln, X3S).
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Fig. 9 (Kurz and associates). Sudanophilic ma terial (S) is in outer plexiform layer on sides of a hemorrhage (H) in inner retinal layers. Large black circle is artifactitious air bubble beneath cover slip (Sudan black B, X88). noted a "cloud" covering the upper part of the field of vision of his right eye. On examination the uncorrected visual acuity was R.E. : 6/7.5, L.E. : 6/6—. Ophthalmoscopically the inferior temporal retinal artery of the right eye was filled with opaque white material extending from the bifurcation of the central retinal artery well out into the periphery (Fig. 19). In the far periphery there were glistening white plaques in an arteriole. A small amount of opaque white ma terial filled the beginning of the inferior nasal
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artery. The retina above the inferior temporal artery had a slightly gray edematous appearance that did not reach the macula. Just above and slightly temporal to the disk there was a fluffy white zone interpreted as an area of ischémie in farction (Fig. 20). There were no xanthomas or other skin lesions. The patient was hospitalized, given anticoagulants, and placed on an appropriate diet. The serum tri glycérides level changed from 2,100 on admission to 206 mg/100 ml, and serum cholesterol changed from 708 to 370 mg/100 ml 12 days later. Subse quently hemorrhages were noted near the disk and dense scotomas were demonstrated in the visual field superiorly and inferiorly (Fig. 21). Four weeks after initial examination the in ferior temporal arteriole remained filled with white material and a previously uninvolved arteriole in the upper temporal quadrant contained lipid. Addi tional visual field defects were noted in May 1970 (Fig. 22). In July 1970, the right superior temporal artery was largely filled with lipid and a new area of retinal infarction was noted above the disk (Fig. 23). The patient described the vision of the right eye as seeing "through a peephole" between scotomas. One year after the initial examination the ap pearance of the right inferior temporal arteriole was unchanged. Pallor of the optic disk and several dot and blot hemorrhages and fine, hard, white exudates were noted in the right fundus. In May 1971, the patient developed a right hemi-
Fig. 10 (Kurz and associates). Retinal vessel has lipid in wall and lumen (Sudan black B, X224).
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Fig. 11 (Kurz and associates). Choroidal vessel contains lipid in wall and lumen (Sudan black B, X224). paresis. He reported that, during an arteriogram in March 1972, he lost vision in his good eye, and at the same time lost additional vision in his right eye. Examination revealed a right homonymous hemianopsia superimposed on the previous defects (Fig. 24). Ophthalmoscopic examination of the left eye was normal on all examinations. Visual acuity
Fig. 13 (Kurz and associates). Large pool of lipid and blood (retinal digest preparation; Sudan black B, x35). when last examined was R.E.: hand movements, and L.E.: 6/7.5. COMMENT—The outstanding feature of this case was the progressive obstruction of retinal vessels with lipid, resulting in visual field defects. These findings persisted over the two-year period of observation and were confined to his right eye. Lipemia retinalis was never observed. In addition to loss of vision in his right eye, the hyperlipoproteinemia was undoubtedly a contributing factor to his generalized arteriosclerosis and ischémie attacks. DISCUSSION
Fig. 12 (Kurz and associates). Patchy deposi tion of lipid in walls of retinal vessels of all sizes (digest preparation; Sudan black B, χ35 top; χ224 bottom).
The plasma lipoproteins are macromolecular complexes of specific lipids and pro teins in relatively fixed proportions. They represent the vehicles whereby water-insolu ble lipids are maintained in a stable colloidal form and are transported in the blood.1 These compounds may be categorized on the basis of particle size and charge, electrophoretic migration, density, and flotation by techniques such as analytic ultracentrifugation or polyacrylamide gel electrophoresis, paper or agar-agarose gel electrophoresis. Four families of lipoproteins are differenti ated: chylomicrons, low-density lipoproteins (beta lipoproteins), very low-density lipo-
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Fig. 14 (Kurz and associates). Electron micrograph of an endo thelial cell (E) of a retinal vessel shows a globule (G) within the cytoplasm containing material pre sumed to be lipid. The junctional complex between the two adjacent endothelial cells appears closed (arrow) (uranyl acetate-lead ci trate, X 17,000).
proteins (pre-beta lipoproteins), and highdensity lipoproteins. The first three families serve as determinants of the five recognized abnormal lipoprotein patterns by which nearly all patients with hereditable hyperlipoproteinemia may be classified.2 Other known diseases, such as insulinopenic dia betes, can result in secondary hyperlipoproteinemia manifesting itself in any of the five types of lipoprotein patterns. Type 4 may be defined as the presence of increased very low-density (pre-beta) lipo proteins without chylomicronemia. Serum triglycérides are increased. Serum choles terol is normal or increased. After standing unfrozen in a refrigerator for 18 to 24 hours, plasma may be clear or turbid. In type 5, in addition to increased very
Fig. IS (Kurz and associates). A globule in an endothelial cell contains homogenous material with dense irregular masses (arrow) (uranyl acetate-lead citrate, X 36,000).
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Fig. 16 (Kurz and associates). The basement membrane (BM) of a blood vessel appears thicker than normal and shows irregular masses resembling lipid (arrows) (uranyl acetate-lead citrate, X36,000). low-density lipoproteins, chylomicrons are present. Serum cholesterol levels a r e in creased as well as triglycérides. T h e plasma is creamy on top, turbid below. The distinction between " n o " chylomi-
Fig. 17 (Kurz and associates). Electron micro graph shows a vacuole (V) with a dense pe ripheral zone within the cytoplasm of an intra mural pericyte (uranyl acetate-lead citrate, X36.000).
Fig. 18 (Kurz and associates). Electron micro graph of retinal tissue adjacent to a blood vessel shows empty spaces and bundles of fibrin (arrows) (uranyl acetate-lead citrate, X 14,000).
Fig. 21 (Kurz and associates). Central visual field of right eye 16 days after initial examination, 9/1000 white.
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Fig. 22 (Kurz and associates). Central visual field of right eye two months after initial ex amination, 9/1000 white.
crons and a "few"—the difference between types 4 and 5—is a fine one. A type 4 pattern can be converted into type 5 under certain dietary conditions. Types 4 and 5 may appear in the same family. Both pat terns are undoubtedly nonspecific and ap pear secondary to a variety of diseases.
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Nonketotic diabetes and a history of pan creatitis are each present in about three fourths of patients with type 5.2 Lipemia retinalis and palpebral eruptive xanthomas are the recognized ocular findings that may appear in both types 4 and 5.3 The appearance of lipemia retinalis is believed to be directly correlated with the level of serum triglycérides.3·4 Lipemia retinalis is first recognizable when triglycéride levels reach 2,500 mg/100 ml. In severe lipemia, when all arteries and veins are cream colored and their differentiation is difficult even at the disk, triglycéride levels are above 5,000 mg/100 ml. Lipemia retinalis disappears as triglycér ide levels decrease and is usually considered to have no effect on retinal function. Eyes with lipemia rarely become available for his tologie examination. According to DukeElder,5 pathologic examinations have shown consistently that retinal tissues are normal. The unique features of Case 1 are the prominent retinal hemorrhages surrounded by a ring of lipid material and the electron microscopic studies confirming the presence of lipid in the vessel walls.
Fig. 24 (Kurz and associates). Right homonymous hemianopsia superimposed on previous visual field defects, 9/1000 white.
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Rapid large alterations in venous pressure transmitted from the intrathoracic pressure were undoubtedly caused by the respirator. This may provide an explanation for the bi lateral retinal hemorrhages as well as the marked chemosis. The lipid seen in rings surrounding the retinal hemorrhages was in each instance separated from the erythrocytes by several retinal layers. The hemor rhages were located largely just beneath the internal limiting membrane, while lipid-filled spaces were largely confined to the outer plexiform layer. Thus the lipid appears to have seeped toward the outer retinal layers (for which we do not have an explanation), becoming separated from the erythrocytes that were held in the inner retinal layers. In the case report of Blodi8 similarities are present. There were a few large yellow ish deposits in the periphery of the fundus and some of them contained a central hemor rhage. His case was complicated by retinal detachment for which two operations had been performed. When total detachment en sued and the eye became blind and painful, it was removed and studied histologically. In one photomicrograph, there is a small hemorrhage beneath the internal limiting membrane in an area with cystic spaces in the outer retinal layers containing fat. Clinically, retinal vessels regain a normal appearance as neutral fat levels fall below those necessary to produce lipemia retinalis. One would thus expect to find no lipid in the vessel walls or in the perivascular retinal tissue. The histopathologic study of Blodi's case,6 however, included the demonstration of fat within the retinal vessel walls as well as in the lumen. Duke-Elder5 stated that in the vessels the plasma is loaded with fat which permeates into the perivascular area. Our case confirms by electron microscopy the possibility of lipid penetrating the wall of the retinal vessels. Lipid may reach the peri vascular retinal tissue by transport through the endothelial cells, intramural pericytes, and
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basement membranes rather than through spaces between adjacent endothelial cells. Junctional complexes7 appeared to be closed and fat vacuoles were demonstrated in the endothelial cells, intramural pericytes, and basement membranes. The presence of fibrin and blood cells in areas of lipid deposition indicates that some of the lipid is accounted for by rupture of blood vessels and hemor rhage. SUMMARY
Of two patients with type 5 hyperlipoproteinemia, one exhibited lipemia retinalis with multiple retinal hemorrhages and intraretinal lipid extravasations. Postmortem ex amination showed hemorrhages in the inner retinal layers and lipid deposits largely in the outer plexiform layer. Lipid within the walls of the retinal vessels was demonstrated by light and electron microscopy. The sec ond patient exhibited visual loss due to pro gressive obstruction of retinal vessels with white material presumed to be lipid. Find ings were confined to one eye. REFERENCES
1. Fredrickson, D. S., Gotto, A. M., and Levy, R. I. : Familial lipoprotein deficiency. In Stanbury, J. B., Wyngaarden, J. B., and Fredrickson, D. S. (eds.) : The Metabolic Basis of Inherited Disease. New York, McGraw-Hill, 1972, p. 493. 2. Fredrickson, D. S., and Levy, R. I.: Familial hyperlipoproteinemia. In Stanbury, J. B., Wyn gaarden, J. B., and Fredrickson, D. S. (eds.) : The Metabolic Basis of Inherited Disease. New York, McGraw-Hill, 1972, pp. 54S-SS0; 592-604. 3. Vinger, P. F., and Sachs, B. A. : Ocular manifestations of hyperlipoproteinemia. Am. J. Ophthalmol. 70:563, 1970. 4. Dunphy, E. G. : Ocular conditions associated with idiopathic hyperlipemia. Am. J. Ophthalmol. 33:1579, 1950. 5. Duke-Elder, S., and Dobree, J. H.: Diseases of the Retina. In Duke-Elder, S. (ed.) : System of Ophthalmology, vol. 10. St. Louis, C. V. Mosby, 1967, pp. 454, 555. 6. Blodi, F. C. : Retinal involvement in idiopathic hyperlipemia. Trans. Am. Acad. Ophthalmol. Otolaryngol. 64:720, 1960. 7. Shakib, M., and Cunha-Vaz, J. G. : Studies on the permeability of the blood retinal barrier. 4. Junctional complexes of the retinal vessels and their role in the permeability of the blood retinal barrier. Exp. Eye Res. 5:229, 1966.