Tuesday, November 23, 2010

Male Reproductive System: Hormone Pathways

A lecture on the hormones that play a role in the male reproductive system, with emphasis on the hormonal pathways.

Labels: ,

Pocket Anesthesia (Pocket Notebook Series)

Designed for easy transport and quick reference, this new addition to the Pocket Notebook Series presents essential information that residents, anesthesiologists, CRNAs, and medical students need on the wards and in the operating room. Edited by anesthesia faculty at Harvard Medical School, Pocket Anesthesia is ideally suited for today’s fast-paced anesthesia environment—it is concise, easy to read, and evidence-based. Essential information is presented in a well-organized schematic outline format with many tables, algorithms, and diagrams. The book is filled with must-know facts about drugs, frequent intraoperative problems, differential diagnosis, common disease states, patient evaluation, and anesthetic considerations for each subspecialty.

Labels: ,

Ultrasound of Amoebic Liver Abscess

Amoebic liver abscess is usually single but can be multiple. Typically located in the right lobe of liver subcapsular close to the diaphragm and posterolateral, though it can be situated in any location. It`s size may vary from few centimeters to a large size occupying almost entire right lobe of liver.

Very early stage :
In the initial stage, cell death occurs but entire dissolution and liquefaction is not complete as the contents are not liquid. This may be termed as solid abscess. On ultrasound these lesions are usually small and probably are the most challenging as compared to the other stages of the liver abscesses. The margins of the abscess may be ill defined, the abscess is hypoechoic as compared to the surrounding liver. However, there is no true liquefaction at this stage and therefore there is poor or no posterior acoustic enhancement. The demarcation between the abscess and the surrounding liver is also poor.

At this stage, the differential diagnosis of fat spared area in a fatty liver or an early neoplastic lesion have to be considered.

Recently formed amoebic abscesses :
An abscess of recent onset has a distinct central liquified area. This is seen on ultrasound as a sonolucent or an hypoechoic area usually with fine internal echoes. Because of the liquefaction, there is associated posterior acoustic enhancement. The cavity may be round, oval or branching. The walls of the abscess at this stage are usually not very thick and sometimes the demarcation between the wall and the surrounding tissue can be poor. Sometimes the walls may be thicker and these may be seen as shaggy, ill-defined echogenic areas along the walls (see Picture). It is at this stage of the abscess that aspiration may be required. Small amount of air in the abscess because of secondary infection or following an aspiration is seen as highly reflective dots.

It is at this stage of the abscess that differential diagnosis of a cyst in the liver, a cyst with haemorrhage, cystic metastatic deposit or sometimes a hydatid cyst and haematoma are to be considered.

Abscesses of some duration :
The basic difference between an acute abscess and an abscess of some duration is that; in the latter the body has had time to wall up the lesion by producing a layer of fibrous tissue around it. On sonography an abscess shows thick walls which may vary from a few mm to 1.5 cm in thickness. The echogenicity of the abscess also varies, abscesses generally become more sonolucent at this stage, some abscesses become more echogenic because of organisation of fluid.

Healing Stage :
The abscess heals, the liquid contents dry up, which has been described as putty appearance. On ultrasound it is seen again as a lesion with thick walls fairly echogenic as compared to surrounding organs. This shadow can be seen on ultrasound for a long time, even years. It is usually at this stage that the differential diagnosis of a neoplasm, haemangioma or granuloma in liver come into picture.


Good video explains Action Potentials

This video explains the process by which a nerve cell receives, conducts, and transmits signals.

This video is from:
Essential Cell Biology, 3rd Edition


Agents for Spinal anesthesia

"Little Boys Prefer Toys":
  • Lidocaine
  • Bupivicaine
  • Procaine
  • Tetracaine

1-Lidocaine provides a short duration of anesthesia and is primarily useful for surgical and obstetrical procedures lasting less than one hour.

2-Tetracaine Vs Bupivacaine:Tetracaine and bupivacaine are used for procedures lasting 2 to 5 hours. Tetracaine appears to provide a somewhat longer duration of anesthesia and a more profound degree of motor block than does bupivacaine. On the other hand, compared with tetracaine, bupivacaine has been demonstrated to be associated with a decreased incidence of hypotension.
In addition, bupivacaine may be better than tetracaine for use in orthopedic surgical procedures since it appears to be associated with a lower incidence of tourniquet pain.

3-Vasoconstrictors can prolong the duration of spinal anesthesia of all three agents. However, the greatest duration is seen when vasoconstrictors are added to tetracaine solutions.

Labels: , ,

Guidelines for color of bruises

1. Red to blue: about 1 to 2 days old
2. Blue to purple: about 3 to 5 days old
3. Green: about 6 to 7 days old
4. Yellow to brown: about 8 to 10 days old
5. Resolved: at least 13 to 28 days old
6. It is likely safest to describe bruises as either: "new" (red, purple, or blue) or
"old" (green, yellow, or brown)

Note: The presence of bruises that have various ages may signify multiple episodes of injury caused by ongoing physical abuse.

Labels: ,

Ultrasound-Guided Femoral Nerve Block