Let's Talk About Medicine [Lecture Series]

[Lorenzo]

Dear friends and colleagues,

This thread will be established for medical lectures on issues that are pertinent to today's society and health issues. All are welcome to ask questions and share input.


Best,
Lorenzo

[Lorenzo]

Cardiovascular System Lesson: The Heart's Blood Supply

The heart is the organ that supplies blood and oxygen to all parts of the body. It is about the size of a clenched fist, weighs about 10.5 ounces and is shaped like a cone. The heart is located in the chest cavity just posterior to the breastbone, between the lungs and superior to the diaphragm. The heart is surrounded by a fluid filled sac called the pericardium. Blood is pumped away from the heart through arteries and returns to the heart through veins. The major artery of the body is the aorta and the major veins of the body are the vena cavae.

The heart is composed of 4 chambers: 2 atria (right and left atrium) and 2 ventricles (right and left ventricle). The heart also has 4 valves: Tricuspid valve (separates right atrium from right ventricle), Mitral Valve (separates left atrium from left ventricle), Pulmonic Valve (separates right ventricle from pulmonary artery), Aortic Valve (separates left ventricle from Aorta).



Presented by: Lorenzo L.

Heart Arterial Supply

[Lorenzo]

On Ophthalmpathology: Open-Angle Glaucoma VS Closed-Angle Glaucoma


Ope angle glaucoma is a chronic condition with increased intraocular pressure due to decreased reabsorptio of aqueus humor, which leads to progressive (pailess) visual loss and, if left untreated, blindness. Management of OAG is via beta blockers and muscarinic activators. The beta blockeres are used to decrease formation of fluid by ciliary epithelial cells. The muscarinic activators improve drainage of the chanal of Schlemm, thereby reducing symptoms.

Closed-angel glaucoma is a condition with increased intraocoular pressure (IOP) due to blockade of the canal of schlemm. Management of this condition is via cholinomimetics, carbonic anhydrase ihibitors and or mannitol.


Presented by: Lorenzo L.

Pharmacology: Treating Glaucoma

[Lorenzo]

The Cardiovascular Circulation : Pulmonary Circulation VS Systemic Circulation

Presented by: Lorenzo L.

Cardiovascular circulation

[Lorenzo]

Treating Hyperlipidemic States (High Cholesterol)

It is important to regulate and control cholesterol levels:
-Uncontrolled high cholesterol has an increased risk of atherosclerosis
-Increased risk of cardiovascular (heart) and cerebrovascular (brain) diseases

Medical Strategy:
-Reduce LDL (low density lipoprotein) and atheroma plaque formation


High Cholesterol: Treat with = Cholestyramine, Colestipol, Ezetimibe
High Triglycerides: Treat with = Gemzofibril, Phenofibrates
High Cholesterol and High Triglycerides: Treat with = Statins, Niacin, Ezetimibe

[Lorenzo]

H I V  [ Human Immunodeficiency Virus ] Prophylaxis


Treatment:

a)   ZDV + 3TC for 1 month

b) {in case of high risk}, ZDV + 3TC + Indinavir

c) {in case pregnant mother is HIV-positive}, ZDV full dose, trimester 2 and 3, plus 6 weeks to neonate
    = This reduces vertical transmission by 80%-- possible recombination if high maternal viral RNA



ZDV = Zidovudine
3TC = Lamivudine
Indinavir = Indinavir

Note: All are effective anti-virals

[Lorenzo]

Maternal Age, Risk of Down Syndrome and Prenatal Diagnosis




Surveys of babies with trisomy 21 show that approximately 90% to 95% of the time, the extra copy of the chromosome is contributed by the mother. The increased risk of Down syndrome with maternal age is well documented. The risk of bearing a child with down syndrome is less than 1/1000 for women younger than 30. The risk increases to about 1/400 at age 35, 1/100 at age 40 and 3-4% or more after age 45.

This increase reflects and elevated rate of nondisjunction in older ova (egg).

Down syndrome can be screened by assaying the following maternal serum levels of:

1) alpha-fetoprotein

2) chorionic gonadotropin

3) unconjugated estriol


This is called 'Triple screen' and can detect approximately 70% of fetuses with Down syndrome.

[Lorenzo]

Tetanus refers to tetanic paralysis , a result of the blockage of glycine from the Renshaw cells in the spinal cord. As a result, there is spastic paralysis, trismus (lockjaw), and risus sardonicus. Tetanus is caused by a gram-positive, spore forming , obligate anaerobic bacteria called Clostridium tetani.

Classic presentation of patient suffering from tetanospasmin:

[Lorenzo]

Presented by: Lorenzo

http://www.youtube.com/watch?v=YANZd8lRjG8

[Lorenzo]

Presented by: Lorenzo

http://www.youtube.com/watch?v=zouErWgLpFE

[Lorenzo]

Lecture presentation by: Lorenzo L, M.D-Ph.D-c

http://www.youtube.com/watch?v=HfatPaUlbGY

[Lorenzo]

Presented by: Lorenzo L, M.D-Ph.D-c

http://www.youtube.com/watch?v=8W0UzjmSPWc

[Lorenzo]

Why is group B Streptococcus (Streptococcus agalactiae) so common in neonates?

Answer: This is common in neonates because Group B Strep is a normal vaginal flora in 25% of women.
Complication: Group B Strep causes meningitis, sepsis and pneumonia in neonates and thus should be treated accordingly in a strategic manner.

How to treat: Obstetrician should take vaginal swab during 35-36th week of pregnancy and culture for presence of Group B Strep. If present, patient should be given prophylactic Penicillin or Ampicillin during labor to minimize the probability of neonatal infection.

[Lorenzo]

(an actual USMLE Step 2 CK Board Question)


You are on call and receive a call from a nurse asking if she can give some sleep medicine or diphenhydramine to an elderly patient with mild dementia who is currently hospitalized in the ICU for MI. What do you give the patient?


Answer: Immediately tell the nurse NOT to give benadryl. Benadryl (Diphenhydramine) has anti-cholinesterase  side effects and can cause delirium to this patient.

Preferred Action: Order the nursing staff to give antidepressant TRAZODONE (a tetracyclic) or give Haloperidol because it has lower anti-cholinesterase activity.

MEDICAL OBJECTIVE: Never give anti-cholinesterase drugs to MI patients.

[Lorenzo]

Coronary Artery Diseases: Atherosclerosis and Arteriosclerosis

Lecture by: Lorenzo

http://www.youtube.com/watch?v=Gnh75zQR1I0