Bile acids, in particular chenodeoxycholic acid (CDCA) and cholic acid (CA), can regulate the expression of genes involved in their synthesis, thereby, creating a feed-back loop. The elucidation of this regulatory pathway came about as a consequence of the isolation of a class of receptors called the farnesoid X receptors, FXRs . The FXRs belong to the superfamily of nuclear receptors that includes the steroid/thyroid hormone receptor family as well as the liver X receptors (LXRs) , retinoid X receptors (RXRs), and the peroxisome proliferator-activated receptors (PPARs) .
The most common side effect of topical corticosteroid use is skin atrophy. All topical steroids can induce atrophy, but higher potency steroids, occlusion, thinner skin, and older patient age increase the risk. The face, the backs of the hands, and intertriginous areas are particularly susceptible. Resolution often occurs after discontinuing use of these agents, but it may take months. Concurrent use of topical tretinoin (Retin-A) % may reduce the incidence of atrophy from chronic steroid applications. 30 Other side effects from topical steroids include permanent dermal atrophy, telangiectasia, and striae.
A 14-year-old boy, without any preceding history of trauma, meningoencephalitis or seizures, was admitted in a comatose state. A similar episode of loss of consciousness 2 months prior with normal neuroimaging and electroencephalogram (EEG) had been followed by behavioral alterations. A year previously, during evaluation for increased appetite and poor weight gain, he was noted to have small goitre with thyroid-stimulating hormone (TSH) mIU/L, T3 nmol/L, and T4 nmol/L. Routine hemogram, blood biochemistry, thyroid function tests including free hormone levels, ultrasonography thyroid and magnetic resonance imaging were normal. EEG showed diffuse slowing of all waves. Cerebrospinal fluid showed no pleocytosis and electrophoresis showed oligoclonal band. Viral studies and serum N-methyl-D-aspartate receptor antibody levels were negative. Anti-thyroid peroxidase (Anti-TPO) antibodies were raised. Intervention was with intravenous dexamethasone 4 mg every 6 h for 1 week followed by tapering schedule of oral prednisolone over 6 months.