VR Medicos

 Arteriovenous Fistula (AVF)   AVF is a communication between an artery and a vein that may be either congenital or acquired (trauma or surgical).   Structurally, they are arterialised (become dilated, tortuous and thick-walled).   Physiologically, there is an increase in venous return (as blood starts flowing from arteries to veins, which causes an increase in cardiac output, which in turn results in an increase in systolic BP, leading to cardiac failure.   On examination, there is a presence of pulsatile swelling, a thrill and auscultation reveals machinery murmur (buzzing continuous murmur).   Nicoladoni's / Branham's sign is observed in AVF: On pressing the artery proximal to the fistula, there is a decrease in the size of the pulsatile mass, disappearance of palpable thrill and decrease in heart rate. Surgically created Arterio-Venous fistula: It is commonly used for patients with end-stage renal disease who require hemodialys...

 The presentation of primary amenorrhea with virilisation, clitoromegaly, blind-ended vagina, and Tanner stage 2 pubic hair development, alongside a 46 XY genotype, suggests 5-alpha reductase deficiency.   Definition:   5-alpha reductase deficiency is a condition with a deficiency in the enzyme 5-alpha reductase, which converts testosterone to dihydrotestosterone (DHT).   Features:   DHT is crucial for the development of male external genitalia.   Individuals with this deficiency typically have normal testosterone levels because the enzyme defect doesn't affect testosterone production.   At birth, they are often assigned female because they have ambiguous genitalia or appear female externally.  ​During puberty, testosterone levels increase, leading to virilization (e.g., clitoromegaly). ​They usually have a blind-ending vagina and often prepubertal breast development because DHT is important for male genital dev...

  5-alpha reductase inhibitors (finasteride and dutasteride) inhibit the conversion of testosterone to dihydrotestosterone (DHT), thereby reducing DHT levels and lowering serum PSA levels by approximately 50% after 6-12 months of therapy. 5-alpha reductase converts testosterone \rightarrow dihydrotestosterone (DHT) , the more potent androgen responsible for prostatic growth. Inhibition of this enzyme: Decreases intraprostatic DHT levels Shrinks prostate volume Improves urinary flow Reduces the risk of acute urinary retention and need for surgery in BPH Testosterone levels are usually unchanged or may show a slight compensatory increase; they are not significantly reduced. PSA levels typically decrease by about 50% after prolonged therapy. Therefore, in patients taking 5-alpha reductase inhibitors, the measured PSA should generally be doubled when screening for prostate cancer. Common indications: Benign prostatic hyperplasia (BPH) Androgenetic alopecia (finaste...