00:00 Let's move on to some questions. 00:03 A 63 year old hemophiliac had contracted hepatitis B from contaminated blood products in the 1980's. 00:11 He stopped his medications against medical advice three months ago. 00:15 And presents now with fulminant transaminitis and jaundice. 00:19 The following are true statements about Hepatitis B in medications. 00:25 A. Interferon alpha acts through tyrosine kinase receptors. 00:29 B. Interferon alpha is quickly absorbed at the injection site. 00:34 C. Interferon alpha inhibits ribonuclease that degrades viral messengerRNA. 00:40 And D. Interferon alpha promotes the formation of natural killer cells. 00:46 So find the true statement. 00:51 Fantastic, you picked D. 00:53 Interferon alpha promotes the formation of natural killer cells. 00:59 Let's move on to the next question. 01:01 A 45 year old male has contracted influenza B. 01:05 The following statements are true: A. Zamanivir is an intranasal spray that may be beneficial for this patient if taken within 24 hours of the onset of symptoms. 01:16 B. Amantadine may be used as a prophylaxis for this patient. 01:20 C. Rimantadine may be beneficial for this patient if taken within 24 hours of the onset of symptoms. 01:28 D. Amantadine is an inhibitor of neuraminidase. 01:32 or E. Zamanivir which acts through blockage of a proton port in the cell wall that prevents acidification of the interior of the virus. 01:45 The answer is A. 01:46 Zamanivir is an intranasal spray that may be beneficial for this patient if taken within 24 hours of the onset of symptoms. 01:53 D is incorrect because amantadine is a blocker of a proton pump in the vesicle wall, that would have allowed transcription with an acidic environment. 02:02 E is incorrect because zamanivir is a neuraminidase inhibitor. 02:07 It does not act on a proton port. 02:09 Therefore, the correct answer is A. 02:14 Let's go on to another question. 02:17 A 34 year old male represents with a painful left eye. 02:21 He has a loss of vision in the left visual field. 02:24 The funduscopic image is displayed on the following slide. 02:28 So there you have the funuscopic image. 02:31 Now let's take a look at our choices here. 02:35 The appropriate treatment for this patient would be A. Valganciclovir 900 mg orally twice a day for 21 days and then once a day. 02:47 B. An intravitreal injection of ganciclovir or foscarnet over 7 to 10 days, then valganciclovir 900 mg twice a day for 21 days or resolution. 03:00 C. Ganciclovir 5mg per kilogram intravenous every 12 hours for 21 days. 03:09 Or D. Oral valganciclovir 900 mg twice a daily for 7 days. 03:16 Which is the right choice? You chose B. 03:22 The intravitreal injection of ganciclovir or foscarnet over 7 to 10 days, then oral valganciclovir 900 mg twice daily for 21 days or until resolution. 03:35 So for some reason and I'm not sure why, examination boards love CMV retinitis. 03:43 When I was writing my exams, it was my undergraduate exam, it was on my board, it was on my internal medicine board exam and it was on recertification exams. 03:52 I'm not sure why it keep showing up but examiners love it. 03:55 It's a good disease to know. 03:57 This patient is having retinitis that is threatening the optic nerve. 04:02 This patient has a loss of vision. 04:03 Systemic therapy is not good enough in these situations. 04:08 So intravitreal injection of a strong antiviral like say valganciclovir would be advised. 04:15 Usually it's given every second day for 7 days followed by systemic therapy. 04:19 Sorry, that should be ganciciclovir or foscarnet and then oral valganciclovir for 21 days. 04:27 Or you can give ganciclovir IV for 21 days too. 04:32 Now treatment would obviously be under the care of an eye specialist who is experienced in this disease. 04:37 Ganciclovir intraocular implants are also sometimes used. 04:41 These are teeny-tiny little pluggets that are actually inserted inside the vitreal cavity. 04:47 And they slowly release ganciclovir overtime. 04:50 So those are also being used as well. 04:54 Now for some reason this type of question always shown up on boards. 05:00 I've seen it when I was doing my undergraduate exams, it showed up again for my licensing exams. 05:05 It showed up again for my internal medicine boards. 05:08 And it showed up once again for my recertification exams. 05:11 So we see it over and over and over again in multiple exam formats. 05:16 So exam boards love CMV retinitis. 05:19 It's a very good disease to know. 05:22 Now remember that this patient is having a retinitis that is threatening his optic nerve. 05:26 He has loss of vision. 05:28 So it's very important that to know that systemic therapy is just not enough in this situation. 05:33 So we want to give an intravitreal injection of a strong antiviral like ganiciclovir. 05:39 And we give it usually every second day for 7 to 10 days. 05:44 It's followed then by systemic therapy. 05:46 So that's where oral valganciclovir can be used for 21 days or alternatively we can use intravenous ganciclovir for 21 days too. 05:55 Now treatment is obviously under an eye specialist. 05:59 This is not something that we manage in a general practitioners clinic. 06:03 Now we also have something called ganciclovir intraocular implants. 06:08 These are teeny-tiny little pluggets that are very hard to see with the naked. 06:12 And they are inserted the vitreal cavity or beside the vitreal cavity. 06:16 And those are obviously put in by an eye surgeon as well. 06:20 Those are very, very effective too for CMV retinitis. 06:24 That's it for our questions. 06:28 I'm sure that you're going to do really well. 06:30 Show them what you know.
The lecture Case Study – Antiviral Drugs by Pravin Shukle, MD is from the course Antimicrobial Pharmacology.
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