33 Posterior Segment Manifestations of Systemic Trauma
33.1 Purtscher’s Retinopathy
In 1910, Purtscher described a constellation of changes in the posterior pole of two patients with severe head trauma. 1 Angiopathia retinae traumatica, or Purtscher’s retinopathy, as it is now known, consists of multiple patches of superficial retinal whitening and retinal hemorrhages around the optic nerve heads in both eyes. Similar fundus presentations have since been reported with a variety of traumatic and nontraumatic conditions. 2 , 3 , 4 , 5 , 6
33.1.1 Clinical Features
Patients typically notice a marked, sudden loss of vision in one or both eyes. Ophthalmoscopic examination reveals multiple cotton-wool spots and intraretinal hemorrhages, all of which are clustered in the peripapillary region (Fig. 33-1). Purtscher’s flecken, characterized by larger areas of intraretinal whitening with a clear zone within 50 µm on either side of retinal arterioles, venules, and precapillary arterioles, are considered pathognomonic but occur in only about 50% of cases. 7 Some degree of asymmetry may be present. Rarely, a unilateral picture is observed. 8 The optic nerve heads usually appear normal early on, although disc swelling is sometimes noted. Retinal venous engorgement or tortuosity may also be present. The retinal periphery is usually uninvolved.
Optical coherence tomography may, in acute cases, show retinal edema and thickening. Fluorescein angiography demonstrates patchy capillary nonperfusion in the regions of retinal whitening, intraretinal leakage of dye from surrounding small retinal arterioles, and blocked fluorescence from intraretinal blood. 3 , 8 There may or may not be a delay in arteriovenous transit. Fluorescein angiography adds little to establishing the diagnosis and is not necessary in the work-up of patients with the condition.
Purtscher’s retinopathy has been associated with severe head trauma, significant chest compression injury, and extensive long-bone fractures. 2 In such cases, the associated trauma will be obvious and the diagnosis is readily made after fundus examination alone. No further testing is generally needed. However, when the fundus presentation occurs in conjunction with a systemic disease, the underlying cause may not be so easily recognizable. Medical conditions that have been described to produce a Purtscher-like retinopathy include acute pancreatitis, systemic lupus erythematosus, thrombotic thrombocytopenic purpura, chronic renal failure, and other, often autoimmune, systemic disease. With some of these conditions, the ocular symptoms may predominate over systemic symptoms and prompt the patient to present to the ophthalmologist first. 3 Finally, it is important to recognize that a fundus picture similar to that of Purtscher’s retinopathy has also been described as a complication of retrobulbar anesthesia and steroid injection in and around the orbit. 9 , 10
Conditions Associated with Purtscher’s and Purtscher-like Retinopathy
Long-bone fractures (fat embolism syndrome)
Chronic renal failure
Systemic lupus erythematosus
Thrombotic thrombocytopenic purpura
Hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome
Amniotic fluid embolism
Orbital steroid injection
When Purtscher’s retinopathy is associated with a nontraumatic medical condition, the ocular symptoms may sometimes predominate and prompt the patient to present first to the ophthalmologist.
33.1.3 Pathogenesis and Histopathology
The pathogenesis of Purtscher’s retinopathy is not well understood. There is, however, much clinical and experimental evidence to suggest that the underlying systemic condition results in the generation of various intravascular microparticles that occlude the small arterioles in the peripapillary retina and elsewhere. 2 , 3 , 6 , 11 , 12 Fibrin clots, platelet–leukocyte aggregates, fat emboli, air emboli, or other similarly sized particles have been implicated, depending on the nature of underlying systemic problem. Experimentally, injection of fibrin clots of about 0.15 to 1.0 mm in size into the ophthalmic artery of pigs results in a fundus picture identical to that of Purtscher’s retinopathy. 12
Histopathologic analyses show evidence for retinal capillary obliteration and inner retinal atrophy in areas corresponding clinically to retinal whitening. These findings are consistent with cotton-wool spots of a variety of etiologies. 13 Studies also confirm the clinical observation that pathology is confined mainly to the retina posterior to the equator. Recent indocyanine green angiography observations indicate that there may also be localized choroidal microvascular compromise in the posterior pole. 14 Nonspecific optic atrophy is present to various degrees both clinically and histopathologically. Histopathologic studies available to date have failed to reveal emboli or other intravascular particles, but data are limited to globes processed weeks or months after the acute event when such particles are likely to be no longer present.
33.1.4 Management and Course
Purtscher’s retinopathy is essentially an acute ischemic event of the peripapillary retina and optic nerve for which there is no specific treatment. Visual acuity is decreased on the basis of infarction of either the foveal retina or the optic nerve. While corticosteroids have been used in the past, there is no evidence that they alter the visual prognosis. The retinal whitening and hemorrhages slowly disappear during weeks or months, but visual acuity often does not recover significantly. Optic atrophy and surrounding retinal pigment epithelial alterations are late findings. Therapy directed at the underlying systemic condition may help to reduce or eliminate ongoing embolic phenomena and the risk for additional retinal or optic nerve damage.
33.2 Terson’s Syndrome
At the turn of the 20th century, the French ophthalmologist Albert Terson described the finding of vitreous hemorrhage associated with an acute subarachnoid hemorrhage. 15 The term Terson’s syndrome is now used to refer to any intraocular hemorrhage present after either spontaneous or trauma-induced intracranial bleeding.
Some degree of intraocular hemorrhage is seen in approximately 20 to 40% of patients with various types of acute intracranial bleeds. 16 , 17 , 18 A smaller percentage of patients, around 3 to 5%, present with frank vitreous hemorrhage. 16 , 18 , 19 The intracranial hemorrhage is usually subarachnoid in location, and the most common reported cause is spontaneous rupture of an anterior communicating artery aneurysm. 17 , 18
33.2.1 Clinical Features
At presentation, the most common ocular manifestation of Terson’s syndrome is multiple retinal hemorrhages (Fig. 33-2). 11 , 16 The hemorrhages are almost always bilateral and tend to be concentrated in the posterior pole. The amount of intraocular hemorrhage is often, but not consistently, proportional to the amount of intracranial hemorrhage. 17 Patients have varying degrees of decreased visual acuity, typically related to the extent of ocular hemorrhage. However, sparse hemorrhage that involves the fovea may sometimes cause a significant loss of acuity. Although the hemorrhages are occasionally subretinal, they are usually more superficial, being either just under the internal limiting membrane (ILM) or preretinal (subhyaloid) in location. There is some controversy as to which location is more common, as it can be difficult to distinguish between the two ophthalmoscopically. Significant vitreous hemorrhage also occurs and is thought to result from blood breaking through the ILM or posterior hyaloid face into the vitreous gel. This breakthrough bleeding can occur at any point in the clinical course and may be a cause for further worsening of visual acuity during follow-up.
Late-appearing sequelae include epiretinal membrane formation, macular holes, and, rarely, traction or rhegmatogenous retinal detachments. 20 , 21 , 22 , 23 , 24 Perimacular retinal folds, similar to what has been described in the shaken baby syndrome (SBS), have also been reported. 25 All these changes have the potential to limit visual recovery.
Because the primary intracranial event typically dominates the clinical picture at presentation, the ophthalmologist is usually already aware that a significant intracranial hemorrhage has taken place. Therefore, the diagnosis is generally readily apparent at the initial ophthalmoscopic examination. Establishing the diagnosis of Terson’s syndrome by documenting the presence of intraocular hemorrhage may have systemic prognostic significance, as some series suggest that cases of intracranial hemorrhaging associated with intraocular bleeding have a higher mortality than those that do not have eye involvement. 16 In rare cases where patients present primarily to the ophthalmologist with fundus features suggestive of this diagnosis, emergency neuroimaging is essential.
A similar fundus appearance to that of Terson’s syndrome can be seen after Valsalva maneuvers and with the SBS (Fig. 33-3 and Fig. 33-4). In trauma cases, the findings of cotton-wool spots or retinal edema associated with the retinal hemorrhages are more consistent with Purtscher’s retinopathy than with Terson’s syndrome.
33.2.3 Pathogenesis and Histopathology
The mechanism of the intraocular hemorrhage has been the subject of debate for many years. Early on, it was thought that the subarachnoid hemorrhage tracked down within the optic nerve sheath and dissected directly into the eye. 11 This is an unlikely explanation for several reasons. First, there are no known communications between the subarachnoid space and the optic nerve. Second, the vitreous and retinal hemorrhages are not often contiguous with the optic nerve. Third, histopathologic studies indicate that, in many cases, the blood around the intraorbital optic nerve is actually subdural rather than subarachnoid and that the nerve sheath blood does not extend to the globe. 23 , 25 , 26
Most investigators now believe that the intraocular hemorrhage is somehow related to the sudden rise in intracranial pressure that occurs at the time of the intracranial bleed. 17 It has been shown that the rapidity and magnitude of increase in intracranial pressure are directly correlated with the amount of ocular hemorrhage. The increased intracranial pressure either directly increases orbital venous pressure through its effects on the cavernous sinus or causes compression of both the ophthalmic vein and retinochoroidal anastomoses from a rapid effusion of cerebrospinal fluid or blood into the optic nerve sheath. 11 , 17 With either mechanism, there would be an acute obstruction to retinal outflow and this, in turn, is thought to result in rupture of epipapillary or retinal postcapillary venules.
Although the exact mechanism remains unclear, most investigators believe that the intraocular hemorrhage is related to the sudden rise in intracranial pressure that occurs at the time of the acute intracranial bleed.