Hemolytic Uremic Syndrome Associated With Purtscher-like Retinopathy

Purtscher reported the findings of cotton-wool spots, hemorrhages, and edema in the posterior fundus of 2 patients who experienced severe head trauma. Later, angiopathica retinae traumatica,¹ or Purtscher retinopathy, was described following long-bone fractures, rapid deceleration injuries, and compressive injuries to the trunk. Subsequently, Purtscher-like retinopathy was observed in atraumatic cases such as pancreatitis, collagen vascular disease, amniotic fluid embolism, retrobulbar anesthesia, chronic renal failure, and thrombotic thrombocytopenia purpura.² We report a case of Purtscher-like retinopathy in a patient with hemolytic uremic syndrome (HUS).

A 31-month-old boy was admitted to a hospital with a history of pallor, lethargy, and oliguria preceded by gastroenteritis. After experiencing 2 brief tonic-clonic seizures, he was transferred to the pediatric intensive care unit where examination revealed a lethargic child with scattered petechiae and periorbital and peripheral edema. The child was anuric. Computed tomography of his brain was normal on admission. Laboratory findings revealed microcytic hemolytic anemia (hemoglobin, 68 g/L; mean corpuscular volume, 72.5 mm³), thrombocytopenia (platelets, 33×10⁹/L), and acute renal failure (creatinine, 407 µmol/L [4.6 mg/dL]). Stool culture yielded Escherichia coli (0157:H7). Diagnosed as having HUS, the patient underwent plasmapheresis and hemodialysis. Three days after admission to the pediatric intensive care unit, a repeated computed tomographic scan revealed bilateral infarctions of the basal ganglia (Figure 1). The patient had not experienced any trauma, cardiopulmonary resuscitation, assisted ventilation, or further seizures. On the fourth day of his intensive care admission, an ophthalmic evaluation disclosed sluggishly reacting pupils without relative afferent pupillary defect and moderate conjunctival chemosis. Funduscopic examination revealed ischemic retinal whitening in both posterior poles, most prominently in the peripapillary area. Retinal arteriolar attenuation and scattered intraretinal hemorrhages were also present bilaterally. Additionally, a preretinal hemorrhage and peripapillary nerve fiber layer hemorrhage were noted in the left eye (Figure 2).

The patient experienced cardiovascular and neurologic decline despite intensive management and died. He was thought to have had multiple thrombotic infarcts to the central nervous system and myocardium; the request for autopsy was denied.

Hemolytic uremic syndrome is the most common cause of acute renal failure in young children and is marked by a prodrome of gastroenteritis followed in 5 to 10 days by pallor, irritability, weakness, lethargy, and oliguria. Laboratory findings include microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure of severity varying from mild insufficiency to renal shutdown. Central nervous system manifestations occur in a minority of patients and portend a poorer prognosis. Stool culture frequently yields enterohemorrhagic E coli (0157:H7).³

The gastroenteritis, hematologic abnormalities, and renal failure in HUS result from thrombotic microangiopathy. Escherichia coli (0157:H7) initiates a pathogenic cascade by elaborating verocytotoxin. This Shigalike exotoxin targets glycolipid GB₃ expressed on the endothelial surface of intestinal, renal, and central nervous system arterioles of predisposed individuals. Once internalized by receptor-mediated endocytosis, a toxin subunit inhibits protein synthesis and damages the endothelium. Platelet aggregation and ensuing thrombotic microangiopathy result in target organ ischemia. Erythrocytes suffer mechanical damage as they transit altered vasculature, resulting in hemolytic anemia, while intraluminal platelet damage and aggregation result in thrombocytopenia.³

Purtscher retinopathy and Purtscher-like retinopathy are characterized by multiple patches of retinal whitening, hemorrhages, and arteriolar attenuation in the posterior pole. Siegler et al⁴ first reported retinal involvement in HUS with features compatible with sequelae of the acute manifestation of retinal infarction seen in our case. The basal ganglia infarcts in our patient and that of Siegler et al are a similarity suggesting Purtscher-like retinopathy in HUS could indicate concurrent ischemia elsewhere in the central nervous system.

The pathogenesis of Purtscher retinopathy remains controversial. Hypotheses have implicated reflux hydrostatic injury, vasospasm, and microembolism of fat, air, fibrin, amniotic fluid, or granulocyte aggregates in retinal arterioles.² The pathogenesis of HUS suggests the Purtscher-like changes in our patient are a result of thrombotic retinal microangiopathy caused by exotoxin-induced endothelial injury.

Purtscher-like retinopathy in HUS is reported infrequently and its diagnosis in the acute phase is overshadowed by the grave systemic complications of HUS. Awareness of this entity may help explain visual loss in children who recover from acute HUS.

Supported by an unrestricted fund from the Research to Prevent Blindness Inc, New York, NY.

Corresponding author: Michael L. Klein, MD, 3375 Terwilliger Blvd, Casey Eye Institute, Oregon Health Sciences University, Portland, OR 97201-4197.