Cerebral ischemia probably related to isotretinoin

A Young Patient Presenting with Dilated Cardiomyopathy and Renal Infarction during Treatment with Isotretinoin: Mere Coincidence or Serious Side Effect of a Drug Commonly Used in Adolescence?

Isotretinoin or 13-cis-retinoic acid (RA) is one of the most effective and widely used drugs for the treatment of severe acne vulgaris. Despite being deemed safe, no definite consensus has been reached on the cardiovascular risk of RA derivatives. We report a case of heart failure due to dilated cardiomyopathy (DCM) and concomitant renal infarction occurring after 5 months of isotretinoin use in a previously healthy 18-year-old male. The patient, with a history of acne vulgaris, presented to our emergency department with left iliac fossa pain and effort dyspnea. A trans-thoracic echocardiogram showed DCM and severely reduced left ventricle ejection fraction (LVEF: 29%). During hospitalization, a total body computed tomography (CT) showed an ischemic lesion in the left kidney. Ischemic, autoimmune, infective, and heritable causes of DCM were ruled out. Cardiac magnetic resonance (CMR) evidenced LV circumferential mid-wall late gadolinium enhancement. Heart failure therapy was promptly started and up-titrated, but only poor LVEF improvement was detected overtime. Our case aims to raise awareness on rare life-threatening cardiovascular events possibly associated with isotretinoin use. To the best of our knowledge, this is the first described case of renal thromboembolism and severe DCM leading to implantable cardioverter-defibrillator (ICD) implantation occurring during isotretinoin treatment.

13-cis-Retinoic Acid Affects Brain Perfusion and Function: In Vivo Study

Purpose. Study the effects of 13-cis-retinoic acid (13-RA), a synthetic analogue of a vitamin A used for the treatment of severe acne, on the blood flow in the rat brain using technetium-99m hexamethyl propylene amine oxime (99mTc-HMPAO) imaging. Methods. A total of 30 adult male Wistar rats were divided into the control (C), low-dose (L), and high-dose (H) groups. The L and H rats were exposed subcutaneously to 0.3 and 0.5 mg, respectively, of 13-RA per kg of body weight for seven days. Brain blood flow imaging was performed using a gamma camera. Then, a region of interest (ROI) around the brain (target, T), a whole-body region (WB), and a background region (BG) was selected and delimited. The net 99mTc-HMPAO brain counts were calculated as the net target counts, $\text{NTC}=\left(\text{T}-\text{BG}\right)/\left(\text{WB}-\text{BG}\right)$ in all groups. At the end of the 99mTc-HMPAO brain blood flow imaging, the brain, heart, kidney, lung, and liver were rapidly removed, and their uptake was determined. Brain histopathological analysis was performed using hematoxylin and eosin stains. In addition, the plasma fatty acids were studied using gas chromatography/mass spectrometry. Results. There were highly significant differences between L and H in comparison to C and across the groups. The 99mTc-HMPAO radioactivity in the brain showed increased uptake in a dose-dependent manner. There were also significant changes in the brain tissues and decreased free fatty acids among the groups compared to C. Conclusion. 13-RA increases 99mTcHMPAO brain perfusion, uptake, and function and reduces fatty acids.

Rubella Virus Infection, the Congenital Rubella Syndrome, and the Link to Autism

Rubella is a systemic virus infection that is usually mild. It can, however, cause severe birth defects known as the congenital rubella syndrome (CRS) when infection occurs early in pregnancy. As many as 8%-13% of children with CRS developed autism during the rubella epidemic of the 1960s compared to the background rate of about 1 new case per 5000 children. Rubella infection and CRS are now rare in the U.S. and in Europe due to widespread vaccination. However, autism rates have risen dramatically in recent decades to about 3% of children today, with many cases appearing after a period of normal development ('regressive autism'). Evidence is reviewed here suggesting that the signs and symptoms of rubella may be due to alterations in the hepatic metabolism of vitamin A (retinoids), precipitated by the acute phase of the infection. The infection causes mild liver dysfunction and the spillage of stored vitamin A compounds into the circulation, resulting in an endogenous form of hypervitaminosis A. Given that vitamin A is a known teratogen, it is suggested that rubella infection occurring in the early weeks of pregnancy causes CRS through maternal liver dysfunction and exposure of the developing fetus to excessive vitamin A. On this view, the multiple manifestations of CRS and associated autism represent endogenous forms of hypervitaminosis A. It is further proposed that regressive autism results primarily from post-natal influences of a liver-damaging nature and exposure to excess vitamin A, inducing CRS-like features as a function of vitamin A toxicity, but without the associated dysmorphogenesis. A number of environmental factors are discussed that may plausibly be candidates for this role, and suggestions are offered for testing the model. The model also suggests a number of measures that may be effective both in reducing the risk of fetal CRS in women who acquire rubella in their first trimester and in reversing or minimizing regressive autism among children in whom the diagnosis is suspected or confirmed.

Pathogenesis of Zika Virus-Associated Embryopathy

A strong causal association has become evident between Zika virus (ZIKV) infection during pregnancy and the occurrence of fetal growth restriction, microcephaly and eye defects. Circumstantial evidence is presented in this paper in support of the hypothesis that these effects, as well as the Guillain-Barré syndrome, are due to an endogenous form of hypervitaminosis A resulting from ZIKV infection-induced damage to the liver and the spillage of stored vitamin A compounds ("retinoids") into the maternal and fetal circulation in toxic concentrations. Retinoids are mainly stored in the liver (about 80%) and are essential for numerous biological functions. In higher concentration, retinoids are potentially cytotoxic, pro-oxidant, mutagenic and teratogenic, especially if sudden shifts occur in their bodily distribution. Although liver involvement has not been mentioned specifically in recent reports, conventional liver enzyme tests underestimate the true extent of liver dysfunction. The proposed model could be tested by comparing retinoid concentration and expression profiles in microcephalic newborns of ZIKV-infected mothers and nonmicrocephalic newborn controls, and by correlating these profiles with measures of clinical severity.

Effects of isotretinoin on the platelet counts and the mean platelet volume in patients with acne vulgaris

Aim. The aim of this study was to evaluate the platelet counts and the mean platelet volume in patients who received isotretinoin for the treatment of acne vulgaris. Method. A total of 110 patients were included in this retrospective study. Complete blood count parameters were recorded prior to and three-months following the treatment. Results. Both platelet counts and the mean platelet volume were significantly decreased following the treatment. No significant differences were noted on the levels of hemoglobin, hematocrit, and white blood cell count. Conclusion. Platelet counts and mean platelet volume significantly decreased following isotretinoin treatment. Since the decrease of platelet counts and the mean platelet volume was seen concomitantly, it is concluded that the effect of isotretinoin was through the suppression of bone marrow.

Retinoids, race and the pathogenesis of dengue hemorrhagic fever

Dengue hemorrhagic fever (DHF) is the most significant mosquito-borne viral disease worldwide in terms of illness, mortality and economic cost, but the pathogenesis of DHF is not well understood and there is no specific treatment or vaccine. Based on evidence of liver involvement, it is proposed that dengue virus and retinoids interact to cause cholestatic liver damage, resulting in the spillage of stored retinoids into the circulation and in an endogenous form of hypervitaminosisis A manifested by the signs and symptoms of the disease, including: fever, severe joint and bone pain, capillary leakage, thrombocytopenia, headache, and gastrointestinal symptoms. While retinoids in low concentration are essential for numerous biological functions, they are prooxidant, cytotoxic, mutagenic and teratogenic in higher concentration, especially when unbound to protein, and an endogenous form of vitamin A intoxication is recognized in cholestasis. The model tentatively explains the observations that 1) repeat infections are more severe than initial dengue virus infections; 2) the incidence of denue has increased dramatically worldwide in recent decades; 3) DHF is less prevalent in people of African ancestry than those of other racial backgrounds; and 4) infants are protected from dengue. The retinoid toxicity hypothesis of DHF predicts the co-existence of low serum concentrations of retinol coupled with high concentrations of retinoic acid and an increased percentage of retinyl esters to total vitamin A. Subject to such tests, it may be possible to treat DHF effectively using drugs that target the metabolism and expression of retinoids.

Fatal Pulmonary Embolism following Achilles Tendon Repair: A Case Report and a Review of the Literature

Deep venous thrombosis (DVT) is a significant source of morbidity in orthopaedic surgery. It can progress to a pulmonary embolism, a significant source of mortality. Up to date, patients with Achilles tendon rupture routinely do not receive DVT chemical prophylaxis. We are presenting a case of fatal pulmonary embolism after a surgically treated Achilles tendon rupture in a forty-two-year-old male healthy patient. In the current body of the literature, the reported incidence of DVT after Achilles tendon rupture is highly variable ranging from less than 1% to 34%, and there is a disagreement in the international guidelines regarding the need of chemical DVT prophylaxis with this type of injury. Further research needs to be conducted to investigate the risks and benefits of chemical DVT prophylaxis following Achilles tendon rupture. For low-risk patients, the use of milder forms of prophylaxis such as aspirin should also be explored.

Association between isotretinoin use and central retinal vein occlusion in an adolescent with minor predisposition for thrombotic incidents: a case report

Introduction

We report an adolescent boy with minimal pre-existing risk for thromboses who suffered central retinal vein occlusion associated with isotretinoin use for acne. To the best of our knowledge, this is the first well documented case of this association.

Case presentation

An otherwise healthy 17-year-old white man who was treated with systemic isotretinoin for recalcitrant acne was referred with central retinal vein occlusion in one eye. Although a detailed investigation was negative, DNA testing revealed that the patient was a heterozygous carrier of the G20210A mutation of the prothrombin gene. Despite the fact that this particular mutation is thought to represent only a minor risk factor for thromboses, it is probable that isotretinoin treatment greatly increased the risk of a vaso-occlusive incident in this patient.

Conclusion

Isotretinoin use may be associated with sight- and life-threatening thrombotic adverse effects even in young patients with otherwise minimal thrombophilic risk. Physicians should be aware of such potential dangers.