Retinopathy, Purtscher & Still's disease

http://emedicine.medscape.com/article/1225431-overview
Purtscher retinopathy is a hemorrhagic and vasoocclusive vasculopathy, which, in 1912, was first described as a syndrome of sudden blindness associated with severe head trauma. These patients had findings of multiple white retinal patches and retinal hemorrhages that were associated with severe vision loss. Since its original description, Purtscher retinopathy has been associated with traumatic injury, primarily blunt thoracic trauma and head trauma, and numerous nontraumatic diseases. Characteristic fundus findings of Purtscher retinopathy. Multiple cotton-wool spots surround the optic nerve after blunt thoracic trauma. Purtscher-like retinopathy is seen in diverse conditions, including acute pancreatitis; fat embolization; amniotic fluid embolization; preeclampsia; hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome; and vasculitic diseases, such as lupus.

The original findings of white lesions in the retina associated with intraretinal and preretinal hemorrhages and papillitis were believed to be caused by lymphatic extravasation from trauma. These lesions are known as Purtscher flecken (larger infarcts of the retinal capillary bed) and cotton-wool spots (small retinal microinfarcts at the level of the nerve fiber layer). Fluorescein leakage in Purtscher retinopathy suggests that an acute endothelial cell injury is caused by trauma, possibly predisposing the retinal vessels to occlusion.

The exact pathophysiology remains somewhat controversial, and different mechanisms have been proposed. The most accepted mechanism is leukoembolization that causes arterial occlusion and infarction of the microvascular bed. Leukocyte aggregation, which is induced by complement C5a, is believed to be the most likely mechanism of embolization because of its known association with trauma, acute pancreatitis, and vasculitic diseases.

Other possible sources of emboli include fat emboli in cases of long bone fractures and perhaps pancreatitis from enzymatic digestion of omental fat, amniotic fluid embolization during childbirth and postpartum, air emboli from traumatic chest compression, and granulocyte aggregation resulting from complement activation.

Other proposed mechanisms of vascular occlusion include angiospasm resulting from an acute rise in venous pressure from compressive chest injuries or possibly acute head injuries and endothelial cell damage resulting from acutely increased intraluminal pressure.

Presentation:
1. Patients with traumatic Purtscher retinopathy present with a recent history of blunt chest trauma or head trauma. The severity of chest trauma is not correlated directly with the incidence or severity of retinopathy, which is observed in these patients.
2. Patients may present with unilateral or bilateral vision loss (possibly severe) generally within 2 days.
M3. acular cotton-wool spots and intraretinal hemorrhages in patients with this history of trauma are diagnostic of the condition. Larger capillary bed infarcts (Purtscher flecken) are also seen in the macula and region surrounding the optic nerve. Typically, there is sparing of the retina whitening immediately adjacent to the larger retinal vessels.
4. Patients also may present with a Purtscher-like retinopathy in the absence of trauma. Various systemic conditions have been associated with developing the following characteristic retinal findings:
- Patients with acute pancreatitis are at risk for developing Purtscher-like retinopathy.
- Patients with long bone fractures are at risk for developing fat embolization and Purtscher-like retinopathy.
-Childbirth
i. Purtscher-like retinopathy may be seen in the postpartum period.
ii. Purtscher-like retinopathy may be due to amniotic fluid embolization with a catastrophic presentation, including shock and disseminated intravascular coagulopathy (DIC).
iii. Retinal arterial occlusions with microvascular infarcts and labor-associated hemorrhage have been reported in patients with preeclampsia and Purtscher-like retinopathy.
iv. Protein C and protein S deficiency have been reported.
-Purtscher-like retinopathy has been observed in patients with certain types of systemic vasculitides.
i. The most likely etiology is microvascular infarction due to complement C5a-induced leukocyte aggregation.
ii. Unexplained vision loss in patients with these conditions (eg, systemic lupus erythematosus, dermatomyositis, scleroderma) should raise the possibility of Purtscher-like retinopathy.

Regarding relationship of Purtscher retinopathy and Still's disease
Adult-onset Still’s disease (AOSD) is a rare systemic inflammatory disorder of unknown etiology. It is characterized by daily high spiking fevers associated with an evanescent rash, arthritis, and multiorgan involvement. Here we report a patient with AOSD-associated thrombotic microangiopathy (TMA) combining central nervous system and renal involvement, associated with 2 severe and unusual complications: Purtscher-like retinopathy and extremity gangrene. Interestingly, renal biopsy showed decreased expression of glomerular vascular endothelial growth factor (VEGF), which could have triggered the TMA and may represent a new pathophysiologic mechanism in human TMA
http://onlinelibrary.wiley.com/doi/10.1002/art.24826/pdf