Hemangioma de coroide e o desafio do diagnóstico diferencial / Choroidal hemangioma and the challenge of differential diagnosis

Resumo O hemangioma de coroide é um tumor benigno relativamente raro, que se apresenta de forma circunscrita ou difusa, sendo esta última normalmente associada à Síndrome de Sturge-Weber. Os tumores circunscritos manifestam-se de forma insidiosa, com o diagnóstico realizado comumente após o aparecimento de sintomas secundários. Apresentam como diagnóstico diferencial lesões graves e potencialmente letais, como melanoma de coroide e doença metastática. Neste relato descrevemos o caso de um hemangioma intraocular nodular avançado associado a descolamento hemorrágico da retina, evidenciando o desafio do diagnóstico diferencial devido às semelhanças clínicas e radiológicas compartilhadas pelos tumores.

Abstract Choroidal hemangioma is a fairly rare benign vascular tumor that can manifest in either circumscribed or diffuse type; the latter one is usually related to Sturge-Weber Syndrome. The circumscribed tumors have an insidious presentation and diagnosis is commonly made after the onset of secondary symptoms. Serious and potentially lethal lesions, such as choroidal melanoma and metastatic disease, may represent a differential diagnosis. In this report, we describe an advanced case of nodular hemangioma associated with hemorrhagic retinal detachment. This case highlights the challenge of differential diagnosis in intraocular tumors, due to their similar clinical and radiologic features.

Low-level Chronic Lead Exposure Impairs Neural Control of Blood Pressure and Heart Rate in Rats.

Lead (Pb) induces adverse effects when it chronically accumulates in the body, including effects on the nervous and cardiovascular systems. Wistar rats were exposed to lead acetate for 30 days (first dose 4 µg/100 g followed by 0.05 µg/100 g/day, i.m.) to investigate the cardiovascular system impact on the autonomic control. The femoral artery and vein were catheterised to perform hemodynamic evaluations in awake rats: heart rate variability (HRV), baroreflex sensitivity, cardiopulmonary reflex and hemodynamic responses to vagal and sympathetic pharmacological blockade. Rats exposed to Pb exhibited a higher blood pressure and reduced HRV in the time domain when compared to the saline-injected group. Spectral analysis of the HRV in the frequency-domain showed an augmented low-frequency component of the spectrum. Methylatropine and atenolol administration suggest increased sympathetic tone and reduced vagal tone on the control of heart rate. Chronic Pb exposure decreased the sensitivity of the baroreflex without significantly changing the cardiopulmonary reflex. This study demonstrated for the first time in an animal model of a controlled, low-dose chronic lead exposure that cardiovascular changes, such as arterial hypertension, are accompanied by impaired autonomic control of the cardiovascular system, as characterised by reduced baroreflex sensitivity and a sympathovagal imbalance.

Low-level lead exposure changes endothelial modulation in rat resistance pulmonary arteries.

Lead exposure induces hypertension and endothelial dysfunction. However, the effects on the pulmonary vasculature have not been explored. In this study, rats exposed to lead acetate for seven days (4µg/100g on the 1st day and 0.05µg/100g/day i.m. subsequently) had lead blood level of 3.9±0.7µg/dL and increased right ventricular pressures. There was an increased Pb deposition and superoxide anions production in the pulmonary arteries, associated with reduced vasoconstriction but unchanged endothelium-dependent vasodilatation to acetylcholine (ACh). In both groups, inhibition of the nitric oxide (NO) synthase with L-NAME blocked the response to ACh, while indomethacin (cycloxygenase inhibitor) had no effect. Incubation with nonspecific potassium channel blocker (tetraethylammonium) reduced the ACh-induced vasodilatation only in the Pb group. Apamin (SKCa channel blocker) and 4-aminopyridine (Kv channel blocker), but not iberiotoxin (BKCa channel blocker), also inhibited this response in the Pb group. The vasodilatation to exogenous NO was reduced by Pb, while relaxation to the cGMP analogue was similar between groups. Concordantly, the protein level of soluble guanylate cyclase (sGC) was reduced. In conclusion, short-term and low-level exposure to Pb changes pulmonary haemodynamic and increases oxidative stress. The pulmonary vasculature exhibited increased hyperpolarization by the Kv and SKCa channels, probably as a compensatory mechanism to the decreased responsiveness to NO.