Today’s PBL muse is on what students remember about their teachers. Amazingly it’s not their ties although I have seen some I won't forget in my lifetime. Click here.
Maynard
Sunday, May 31, 2009
Clinical Skills Muse #24: Transfusions Part 1
Patients with acute blood loss or symptomatic anemia frequently require blood replacement therapy. SO TODAY'S QUESTIONS ARE 1) CAN YOU DESCRIBE THE PATHOPHYSIOLOGY OF 5 DIFFERENT TRANSFUSION REACTIONS 2) WHICH IS THE MOST COMMON?
As a clerk, one of the things you will be called to assess (or were called to assess!) are adverse blood transfusions reactions . . . if you suspect a reaction, the first treatment is to stop the transfusion. So what are some of the adverse effects of a blood transfusion?
1) Hemolytic transfusion reactions are the result of antibodies in the recipient's plasma directed against antigens on the donor's erythrocytes. This results in rapid intravascular hemolysis of the donor red blood cells. ABO incompatibility due to clerical error is the most frequent cause. This results in hemoglobinemia, hemoglobinuria, disseminated intravascular coagulation (DIC), renal failure, and complement-mediated cardiovascular collapse.
2) Nonhemolytic febrile reactions are thought to stem from the formation of cytokines during the storage of the blood. These reactions seldom proceed to hypotension or respiratory distress.
3) Infectious diseases also may be transmitted through transfusion. (Hep B and Hep C, bacteria, viruses etc)
4) Transfusion-related acute lung injury may be caused by transfusing any plasma-containing blood product. It is caused by the interaction between the recipient's leukocytes and preexisting donor antileukocyte antibodies. This results in complement activation and increased pulmonary vascular permeability. In addition, mediators of inflammation that form while the blood is in storage are also felt to be contributory.
5) Massive transfusion is defined as the replacement of more than one-half of the blood volume within a 24-hour period or the replacement of 10 units of blood over the course of a few hours. Complications of massive transfusion include the following: -Coagulopathy is caused by a dilutional effect on the host's clotting factors and platelets, as well as the lack of platelets and clotting factors in packed red blood cells.
-Volume overload
-Hypothermia
-Hyperkalemia may be caused by lysis of stored red cells and is increased in irradiated red blood cells.
-Metabolic alkalosis and hypokalemia may be caused by the transfusion of a large amount of citrated cells.
-Hypocalcemia due to citrate toxicity may occur in those with hepatic failure, congestive heart failure (CHF), or other low-output states.
Frequency
1) Hemolytic transfusion reactions occur in 1 per 40,000 transfused units of packed RBCs.
2) (MOST COMMON) Nonhemolytic febrile reactions and minor allergic reactions are the most common transfusion reactions, each occurring in 3-4% of all transfusions.
3) Nonhemolytic febrile reactions and extravascular hemolysis are observed more commonly in patients who have developed antibodies from prior transfusions.
4) Anaphylactic reactions occur in 1 per 20,000 transfused units.
5) Due to improved preventative measures, the incidence of GVH disease is less than 0.15%.
6) Transfusion-related acute lung injury complicates 0.1-0.2% of all transfusions.
7) Risk of transfusion-related hepatitis B is 1 per 50,000 units transfused. Risk for hepatitis C is 1 per 3000-4000 units transfused. Risk of transfusion-related HIV infection is 1 per 150,000 units transfused.
Posted on behalf of M. Luterman
As a clerk, one of the things you will be called to assess (or were called to assess!) are adverse blood transfusions reactions . . . if you suspect a reaction, the first treatment is to stop the transfusion. So what are some of the adverse effects of a blood transfusion?
1) Hemolytic transfusion reactions are the result of antibodies in the recipient's plasma directed against antigens on the donor's erythrocytes. This results in rapid intravascular hemolysis of the donor red blood cells. ABO incompatibility due to clerical error is the most frequent cause. This results in hemoglobinemia, hemoglobinuria, disseminated intravascular coagulation (DIC), renal failure, and complement-mediated cardiovascular collapse.
2) Nonhemolytic febrile reactions are thought to stem from the formation of cytokines during the storage of the blood. These reactions seldom proceed to hypotension or respiratory distress.
3) Infectious diseases also may be transmitted through transfusion. (Hep B and Hep C, bacteria, viruses etc)
4) Transfusion-related acute lung injury may be caused by transfusing any plasma-containing blood product. It is caused by the interaction between the recipient's leukocytes and preexisting donor antileukocyte antibodies. This results in complement activation and increased pulmonary vascular permeability. In addition, mediators of inflammation that form while the blood is in storage are also felt to be contributory.
5) Massive transfusion is defined as the replacement of more than one-half of the blood volume within a 24-hour period or the replacement of 10 units of blood over the course of a few hours. Complications of massive transfusion include the following: -Coagulopathy is caused by a dilutional effect on the host's clotting factors and platelets, as well as the lack of platelets and clotting factors in packed red blood cells.
-Volume overload
-Hypothermia
-Hyperkalemia may be caused by lysis of stored red cells and is increased in irradiated red blood cells.
-Metabolic alkalosis and hypokalemia may be caused by the transfusion of a large amount of citrated cells.
-Hypocalcemia due to citrate toxicity may occur in those with hepatic failure, congestive heart failure (CHF), or other low-output states.
Frequency
1) Hemolytic transfusion reactions occur in 1 per 40,000 transfused units of packed RBCs.
2) (MOST COMMON) Nonhemolytic febrile reactions and minor allergic reactions are the most common transfusion reactions, each occurring in 3-4% of all transfusions.
3) Nonhemolytic febrile reactions and extravascular hemolysis are observed more commonly in patients who have developed antibodies from prior transfusions.
4) Anaphylactic reactions occur in 1 per 20,000 transfused units.
5) Due to improved preventative measures, the incidence of GVH disease is less than 0.15%.
6) Transfusion-related acute lung injury complicates 0.1-0.2% of all transfusions.
7) Risk of transfusion-related hepatitis B is 1 per 50,000 units transfused. Risk for hepatitis C is 1 per 3000-4000 units transfused. Risk of transfusion-related HIV infection is 1 per 150,000 units transfused.
Posted on behalf of M. Luterman
Monday, May 25, 2009
Clinical Muse #23: UTI's and Cranberries
Cranberries for preventing urinary tract infections.......something patients in your office always ask about......and now you can buy cranberry tablets.....I sometimes where a cranberry colored thong if my prostrate is bothering me (only kidding)....anyways I came across this article and like everything you will hear, without good evidence it’s at best anecdotal and so someone looked at cranberries and UTI's.....Maynard
Here is the link to the review.
Here is the link to the review.
PBL Muse #23: Disciplinary Action by Medical Boards and Prior Behavior in Medical School
Here is a summary of a paper form the NEJM on professional behavior and why it is so important we identify and correct any aberrations early on. Maynard.
Clinical Muse #22: Dialysis
Working in the Welland ER, I see a lot of renal patients.....thought this data was interesting on dialysis...
DIALYSIS SURVIVAL
Summary:
• The survival of all dialysis patients starting dialysis in 1993 to 2002 was 90%, 73%, 60% and 39% at one year, 3 years, 5 years and 10 years respectively.
• CAPD patients had a 74% higher risk of death compared to haemodialysis patients.
• Survival of dialysis patients in recent vintage was lower than in earlier vintage. Compared to the 1997-1998 cohort the mortality risk of 1999-2000 and 2001-2002 cohorts were increased by 21% and 27% respectively.
• Diabetics on dialysis had 2.1 times higher risk of death compared to non-diabetics.
• Low serum albumin concentration, low body mass index and low serum cholesterol level were independent risk factors for mortality.
• There was a U-shaped relationship between diastolic blood pressure and risk of mortality.
• The haemoglobin level associated with the lowest risk of mortality was 110-120.
• Hyperphosphataemia, hypercalcaemia and low calcium phosphate product were associated with increased risk of death.
• Hepatitis B or Hepatitis C status did not affect patient survival.
Maynard Luterman
PBL Muse #22: Medical Student Professionalism
Today’s muse asks the question: is there a relationship between medical student professionalism and lapses in professionalism when they become physicians?
Professional behavior is considered essential to the practice of medicine, and is increasingly emphasized in medical school curricula. However, several obstacles limit the effectiveness of professionalism education in medical training. Medical educators struggle to define and measure professionalism, which, in fact, is usually identified in terms of its absence-when unprofessional behavior is observed in trainees. Instruments to assess professionalism reflect this struggle for consistency and credibility. There is also skepticism as to whether professionalism is a learnable skill or an inborn character trait. Student peers and teachers are often reluctant to report negative behaviors, either because they do not directly observe such behaviors, or feel personally uncomfortable with (or fear) the confrontation that arises in making such reports. Finally, faculty typically encounter such behaviors as isolated events, and may be hesitant to generalize about what are seen as solitary behaviors in individual students.
Professional behavior is considered essential to the practice of medicine, and is increasingly emphasized in medical school curricula. However, several obstacles limit the effectiveness of professionalism education in medical training. Medical educators struggle to define and measure professionalism, which, in fact, is usually identified in terms of its absence-when unprofessional behavior is observed in trainees. Instruments to assess professionalism reflect this struggle for consistency and credibility. There is also skepticism as to whether professionalism is a learnable skill or an inborn character trait. Student peers and teachers are often reluctant to report negative behaviors, either because they do not directly observe such behaviors, or feel personally uncomfortable with (or fear) the confrontation that arises in making such reports. Finally, faculty typically encounter such behaviors as isolated events, and may be hesitant to generalize about what are seen as solitary behaviors in individual students.
Monday, May 11, 2009
Clinical Skills Muse #21 - Microscopic Hematuria
This week is about microscopic hematuria.....and these answers are based on the Canadian Urological Association Guidelines.....so here are the questions....
1) What is microscopic hematuria? 2) Who do you workup? 3) What do you do with the negative workups?
Click here for the answers.
Maynard Luterman
PBL Muse # 21 - Death and Dying
This study is interesting, and important for our students, many of whom will encounter death and dying for the first time during med school.
How does McMaster handle the issue? This is part of the Professional Competencies (Procomp) curriculum, which runs every Tuesday morning. Our students are divided into 2 groups which stay together for their entire preclerkship. Each group has 2 "Longitudinal Facilitators" - one is a physician and one a non-physician; in our case this year the non-docs are a nurse and a psychologist. The Procomp curriculum is quite comprehensive and covers all the non-scientific elements of being a doctor: professionalism, ethics, legal issues, communication, and more. End of-life is part of the Procomp curriculum. There's quite an intense focus on this, I've seen students quite shaken after some sessions.
There's focus on both appropriate professional behavior as well as the students' own feelings and how to deal with them. Students' intense feelings during these particular Procomp sessions sometimes affect them later - they might be 'out of sorts' during tutorial or clinical skill sessions on those days.
Maybe not clearly a PBL topic but as the PBL Tutors see and hear from our students in a short period more than anyone else on our faculty I thought I would talk about death and dying. Students by this point are doing horizontal electives and are seeing real events in real time. I came across this study and after reading it I thought it’s a good intro to the topic. One of the things I have had trouble remembering about my medical school experience was how I felt. Truth is at McGill in the 1980's I don't think anybody ever asked. I found the conclusions of this study most interesting.
********************
Background: Medical schools require time for end-of-life topic. However, there is very little medical literature that directly addresses how medical students and residents are to behave, manage emotion, and confront their own grieving process when patients die.
Objective: The purpose of this study was to understand how preclinical medical students describe feelings toward the death of a hypothetical patient in order to affect curricular change at our institution.
Design: Qualitative methods using narrative analysis of student papers to identify patterns, core constructs, and themes related to student's projected feelings on patient death.
Setting/subjects: Federal medical school with volunteer medical students from the class of 2005.
Results: Two thirds of the students (108/162) volunteered to participate. Five significant themes emerged including: (1) affective responses (guilt, fear, blame, and impotence) (2) personal experience with death, (3) survivorship and professionalism, (4) the meaning of death, and (5) the affects of religion and spirituality. Many feared facing families and responding to grief. An active belief in an afterlife was mentioned as a coping strategy by 40% of the students.
Conclusions: End-of-life curriculum is more than teaching about the clinical care of the patient and support of family. These medical students overwhelmingly identified the need for coping strategies when confronting the dying patient. Teaching students these coping strategies should be an integral part of an end-of-life curriculum.
Writing exercises cannot only help students recognize and reflect upon their emotions and feelings, but also allow educators a window into curricular elements that need to be added to death and dying education.
To cite this paper:
Cynthia M. Williams, Cindy C. Wilson, Cara H. Olsen. Journal of Palliative Medicine. April 1, 2005, 8(2): 372-381.
Maynard Luterman
Monday, May 4, 2009
Clinical Skill Muse #20: Chvostek Sign and Trousseau Sign
Unfortunately there will never be a Luterman sign....so here's the question: what are these signs, when were they discovered and who were the docs who discovered them? Bonus question..which is more sensitive? And how reliable are they?
The Chvostek sign (also Weiss sign) is one of the signs of tetany seen in hypocalcemia. It refers to an abnormal reaction to the stimulation of the facial nerve. When the facial nerve is tapped at the angle of the jaw, the facial muscles on the same side of the face will contract momentarily (typically a twitch of the nose or lips) because of hypocalcaemia (ie from hypoparathyroidism, pseudohypoparathyroidism, hypovitaminosis D) with resultant hyperexcitability of nerves.
Frantisek Chvostek (1835–1884) was an Austrian surgeon who was born in Moravia, Czech Republic. Chvostek investigated the pathology and treatment of neurologic illnesses, including the use of electrotherapy, and described the sign that was to bear his name in 1876.
Trousseau sign of latent tetany is a medical sign observed in patients with low calcium. This sign may become positive before other gross manifestations of hypocalcemia such as hyperreflexia and tetany, but is generally believed to be more sensitive than the Chvostek sign for hypocalcemia.
To elicit the sign, a blood pressure cuff is placed around the arm and inflated to a pressure greater than the systolic blood pressure and held in place for 3 minutes. This will occlude the brachial artery. In the absence of blood flow, the patient's hypocalcemia and subsequent neuromuscular irritability will induce spasm of the muscles of the hand and forearm. The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, and the fingers adduct. The sign is also known as main d'accoucheur (French for "hand of the obstetrician") because it supposedly resembles the position of an obstetrician's hand in delivering a baby.
Armand Trousseau (October 14, 1801 — June 27, 1867) was a French internist. His contributions to medicine include Trousseau sign of malignancy, Trousseau sign of latent tetany, Trousseau-Lallemand bodies (an archaic synonym for Bence Jones cylinders), and the truism, "use new drugs quickly, while they still work." Trousseau was instrumental in creating new modes of treatment of croup, emphysema, pleurisy, goiter, and malaria. He received the prize of the French Academy of Medicine for his classic essay on laryngology which originally appeared in 1837. He was the first in France to perform a tracheotomy, and he wrote a monograph on this as well as intubation in 1851. His textbooks on clinical medicine and therapeutics were both extremely popular and translated into English. Trousseau coined the terms aphasia and forme fruste and popularized eponyms in disease description such as Addison's
disease and Hodgkin's lymphoma.
Trousseau was considered an outstanding teacher. Numerous students of his achieved fame in their own right, including Puerto Rican pro-independence leader, surgeon and Légion d'honneur laureate, Ramón Emeterio Betances. Trousseau’s grandson was the distinguished ophthalmologist Armand Trousseau (1856-1910).
As previously mentioned, Chvostek’s sign is a classic signification of hypocalcemia. However, some studies have demonstrated that hypocalcemia is not the only condition in which a positive Chvostek’s sign may be seen. Other conditions that have produced Chvostek’s sign include rickets, diphtheria, measles, scarlet fever, whooping cough, and myxedema. The sign has also been positive in persons without any known disease. One study demonstrated a positive Chvostek’s sign in nearly 25% of healthy individuals. Another study showed that 29% of patients with laboratory- confirmed hypocalcemia had a negative Chvostek’s sign. In turn, the medical community considers Chvostek’s sign as only a crude indicator of neuromuscular irritability and an unreliable indicator of hypocalcemia.
Click here and here for references.
Maynard
The Chvostek sign (also Weiss sign) is one of the signs of tetany seen in hypocalcemia. It refers to an abnormal reaction to the stimulation of the facial nerve. When the facial nerve is tapped at the angle of the jaw, the facial muscles on the same side of the face will contract momentarily (typically a twitch of the nose or lips) because of hypocalcaemia (ie from hypoparathyroidism, pseudohypoparathyroidism, hypovitaminosis D) with resultant hyperexcitability of nerves.
Frantisek Chvostek (1835–1884) was an Austrian surgeon who was born in Moravia, Czech Republic. Chvostek investigated the pathology and treatment of neurologic illnesses, including the use of electrotherapy, and described the sign that was to bear his name in 1876.
Trousseau sign of latent tetany is a medical sign observed in patients with low calcium. This sign may become positive before other gross manifestations of hypocalcemia such as hyperreflexia and tetany, but is generally believed to be more sensitive than the Chvostek sign for hypocalcemia.
To elicit the sign, a blood pressure cuff is placed around the arm and inflated to a pressure greater than the systolic blood pressure and held in place for 3 minutes. This will occlude the brachial artery. In the absence of blood flow, the patient's hypocalcemia and subsequent neuromuscular irritability will induce spasm of the muscles of the hand and forearm. The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, and the fingers adduct. The sign is also known as main d'accoucheur (French for "hand of the obstetrician") because it supposedly resembles the position of an obstetrician's hand in delivering a baby.
Armand Trousseau (October 14, 1801 — June 27, 1867) was a French internist. His contributions to medicine include Trousseau sign of malignancy, Trousseau sign of latent tetany, Trousseau-Lallemand bodies (an archaic synonym for Bence Jones cylinders), and the truism, "use new drugs quickly, while they still work." Trousseau was instrumental in creating new modes of treatment of croup, emphysema, pleurisy, goiter, and malaria. He received the prize of the French Academy of Medicine for his classic essay on laryngology which originally appeared in 1837. He was the first in France to perform a tracheotomy, and he wrote a monograph on this as well as intubation in 1851. His textbooks on clinical medicine and therapeutics were both extremely popular and translated into English. Trousseau coined the terms aphasia and forme fruste and popularized eponyms in disease description such as Addison's
disease and Hodgkin's lymphoma.
Trousseau was considered an outstanding teacher. Numerous students of his achieved fame in their own right, including Puerto Rican pro-independence leader, surgeon and Légion d'honneur laureate, Ramón Emeterio Betances. Trousseau’s grandson was the distinguished ophthalmologist Armand Trousseau (1856-1910).
As previously mentioned, Chvostek’s sign is a classic signification of hypocalcemia. However, some studies have demonstrated that hypocalcemia is not the only condition in which a positive Chvostek’s sign may be seen. Other conditions that have produced Chvostek’s sign include rickets, diphtheria, measles, scarlet fever, whooping cough, and myxedema. The sign has also been positive in persons without any known disease. One study demonstrated a positive Chvostek’s sign in nearly 25% of healthy individuals. Another study showed that 29% of patients with laboratory- confirmed hypocalcemia had a negative Chvostek’s sign. In turn, the medical community considers Chvostek’s sign as only a crude indicator of neuromuscular irritability and an unreliable indicator of hypocalcemia.
Click here and here for references.
Maynard
PBL Muse #20: Students in academic difficulty
One of the biggest myths in the medical school process is that once you get into medical school, it is relatively easy to STAY in medical school. Each year, approximately 5% of those who enter fail one or more courses or fail out of medical school entirely. (These numbers are an average and are lower at McMaster) Why does this happen after being subjected to a selection process that is very stringent?
The biggest reason for students failing a course or failing out of medical school is an inability to put in the study time that a very competitive medical school curriculum demands. A sizable proportion of first year medical students may have been able to get through their undergraduate studies by the “last minute knowledge cram” method, only to find that they are in deep trouble fast.
Most of these students will adjust their time management skills and do well enough to pass their coursework but some are not able to make the transition from undergraduate to medical school. These folks find themselves behind their class very quickly and fail to catch up enough to learn the core knowledge required.
Another small proportion of students will have too many personal demands to keep up with their studies. They may be parents or spouses or they may have personal illness that actually prevents them from the mastery of their work. In these cases, a wise Dean of Students will offer a Leave of Absence before the student finds himself/herself in academic difficulty. It pays to alert Karl, Maynard or Kathy Swayze at the first sign of personal trouble. Often the Dean can alleviate the problem and get the student back on track. Again, sometimes the problem is so pervasive, that only a Leave of Absence will allow the student to take care of personal matters and return to academics without penalty.
Few medical students are intellectually unable to master the curriculum. While the amount of information to be mastered is massive, the difficulty of the material is fairly average. This means that the key to keeping yourself academically sound is disciplined study habits that enable you to digest this large body of information in a short period of time. Most students study daily and keep a rigorous study schedule even on weekends.
Many students will become caught in the “no one else is struggling so I must be stupid” trap. Every medical student from time to time will struggle with something. Most students figure out what they need, ask for help and get the task accomplished. Some students will become depressed and procrastinate. Procrastination is the enemy of good scholarship and leads to more depression. Again, chatting with a few classmates or the Dean of Students can often put your problems into perspective and give you new ideas that get you on your way.
Key message is if you see someone struggling please tell Karl, Kathy or myself as soon as possible.
Maynard
The biggest reason for students failing a course or failing out of medical school is an inability to put in the study time that a very competitive medical school curriculum demands. A sizable proportion of first year medical students may have been able to get through their undergraduate studies by the “last minute knowledge cram” method, only to find that they are in deep trouble fast.
Most of these students will adjust their time management skills and do well enough to pass their coursework but some are not able to make the transition from undergraduate to medical school. These folks find themselves behind their class very quickly and fail to catch up enough to learn the core knowledge required.
Another small proportion of students will have too many personal demands to keep up with their studies. They may be parents or spouses or they may have personal illness that actually prevents them from the mastery of their work. In these cases, a wise Dean of Students will offer a Leave of Absence before the student finds himself/herself in academic difficulty. It pays to alert Karl, Maynard or Kathy Swayze at the first sign of personal trouble. Often the Dean can alleviate the problem and get the student back on track. Again, sometimes the problem is so pervasive, that only a Leave of Absence will allow the student to take care of personal matters and return to academics without penalty.
Few medical students are intellectually unable to master the curriculum. While the amount of information to be mastered is massive, the difficulty of the material is fairly average. This means that the key to keeping yourself academically sound is disciplined study habits that enable you to digest this large body of information in a short period of time. Most students study daily and keep a rigorous study schedule even on weekends.
Many students will become caught in the “no one else is struggling so I must be stupid” trap. Every medical student from time to time will struggle with something. Most students figure out what they need, ask for help and get the task accomplished. Some students will become depressed and procrastinate. Procrastination is the enemy of good scholarship and leads to more depression. Again, chatting with a few classmates or the Dean of Students can often put your problems into perspective and give you new ideas that get you on your way.
Key message is if you see someone struggling please tell Karl, Kathy or myself as soon as possible.
Maynard
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