Roth spot

**Definition:** Oval or round retinal (often flame-shaped/superficial) hemorrhages with a pale white or cream-colored center, located in the retina near the posterior pole. Described by Moritz Roth (1872).

**Pathophysiology:** Historically attributed to septic emboli lodging in retinal vessels. The current understanding is that they are immune-complex–mediated vasculitis/endothelial damage with capillary rupture. The white center was thought to represent a septic focus, but histology shows it is typically fibrin-platelet aggregates, inflammatory cells, or edema/cytoid-body-like ischemic changes (not necessarily organisms). Hemorrhage results from vessel wall damage.

**Clinical significance (USMLE):** - **Infective endocarditis:** Roth spots are an **immunologic phenomenon** under the modified Duke criteria (minor criteria), along with Osler nodes, glomerulonephritis, and positive rheumatoid factor. Vascular phenomena (minor criteria) include Janeway lesions, septic emboli, mycotic aneurysms, conjunctival/splinter hemorrhages, and intracranial hemorrhage. - Mnemonic: **FROM JANE** — Fever, Roth spots, Osler nodes, Murmur, Janeway lesions, Anemia, Nail-bed hemorrhages (splinter), Emboli. - **Pearl:** Osler nodes = painful, immune-mediated (fingers/toes pads); Janeway lesions = painless, septic emboli (palms/soles). Roth spots = immune-mediated, retinal.

**Other causes (nonspecific):** Severe anemia (including pernicious anemia), leukemia and other hematologic malignancies, diabetic retinopathy, hypertensive retinopathy, collagen vascular disease/SLE, HIV retinopathy, hypoxia/high altitude retinopathy, shaken baby syndrome/abusive head trauma, sepsis, and carbon monoxide poisoning.

**Diagnosis/Management:** Found on dilated funduscopic exam. Workup depends on the clinical context: for suspected endocarditis, obtain ≥3 sets of blood cultures before antibiotics, then echocardiography (TTE, followed by TEE if needed). Treat the underlying cause (e.g., prolonged IV antibiotics for endocarditis; correct anemia, etc.). Common organisms in endocarditis: *S. aureus* (acute, IV drug use, tricuspid valve), viridans streptococci (subacute, damaged valves), *S. epidermidis* (prosthetic valves), *S. bovis*/*S. gallolyticus* (colon cancer association), HACEK organisms, *Enterococcus*.