A 60 year old white man was admitted from the emergency department after an unwitnessed collapse and generalised weakness and malaise. He had no medical history of note and was taking no drugs. On clinical assessment he had hypertension, which had not previously been documented, with a blood pressure of 187/91 mm Hg. Blood tests showed severe hypokalaemia (2.1 mmol/L (reference range 3.6-5.0), having been normal (4.7) nine months earlier) and metabolic alkalosis (bicarbonate 38 mmol/L, 22-30). Random blood glucose was 6.0 mmol/L (3.5-7.8).
almost 6 years ago
16 year old male, a secondary school student, arrives in the clinic and you find his blood pressure is 180/80. The history is unremarkable, no systemic symptoms or signs elicited (no headache, visual disturbance,chest pain, dizziness, collapse, urinary symptoms). The examination is normal. No significant previous medical history or family history of hypertension. He is not on any medications. He denies smoking or having taken illicit drugs. BMI is 25. What investigations are you going to order?
about 7 years ago
This month’s case is by Barbara J. Mroz, M.D. and Robin R. Preston, Ph.D., author of Lippincott’s Illustrated Reviews: .Physiology (ISBN: 9781451175677). For more information, or to purchase your copy, visit: http://tiny.cc/PrestonLIR, with 15% off using the discount code: MEDUCATION. The case below is followed by a choice of diagnostic tests. Select the one lettered selection that would be most helpful in diagnosing the patient’s condition. The Case A 54-year-old male 2 pack-per-day smoker presents to your office complaining of cough and shortness of breath (SOB). He reports chronic mild dyspnea on exertion with a daily cough productive of clear mucus. During the past week, his cough has increased in frequency and is now productive of frothy pink-tinged sputum; his dyspnea is worse and he is now short of breath sometimes even at rest. He has had difficulty breathing when lying flat in bed and has spent the past two nights sleeping upright in a recliner. On physical examination, he is a moderately obese male with a blood pressure of 180/80 mm Hg, pulse of 98, and respiratory rate of 22. His temperature is 98.6°F. He becomes winded from climbing onto the exam table. Auscultation of the lungs reveals bilateral wheezing and crackles in the lower posterior lung fields. There is pitting edema in the lower extremities extending up to the knees. Question Which if the following tests would be most helpful in confirming the correct diagnosis? A. Spirometry B. Arterial blood gas C. Complete blood count D. B-type natriuretic peptide blood test E. Electrocardiogram Answer? The correct answer is B-type natriuretic peptide blood test. Uncomfortable breathing, or feeling short of breath, is a common medical complaint with multiple causes. When approaching a patient with dyspnea, it is helpful to remember that normal breathing requires both a respiratory system that facilitates gas exchange between blood and the atmosphere, and a cardiovascular system that transports O2 and CO¬2 between the lungs and tissues. Dysfunction in either system may cause dyspnea, and wheezing (or bronchospasm) may be present in both cardiac and pulmonary disease. In this patient, the presence of lower extremity edema and orthopnea (discomfort when lying flat) are both suggestive of congestive heart failure (CHF). Elevated blood pressure (systolic of 180) and a cough productive of frothy pink sputum may also be associated symptoms. While wheezing could also be caused by COPD (chronic obstructive pulmonary disease) in the setting of chronic tobacco use, the additional exam findings of lung crackles and edema plus systolic hypertension are all more consistent with CHF. What does the B-type natriuretic peptide blood test tell us? When the left ventricle (LV) fails to maintain cardiac output (CO) at levels required for adequate tissue perfusion, pathways are activated to increase renal fluid retention. A rising plasma volume increases LV preload and sustains CO via the Frank-Starling mechanism. Volume loading also stimulates cardiomyocytes to release atrial- (ANP) and B-type (BNP) natriuretic peptides. BNP has a longer half-life than ANP and provides a convenient marker for volume loading. Plasma BNP levels are measured using immunoassay; levels >100 pg/mL are suggestive of overload resulting in heart failure. How does heart failure cause dyspnea? Increasing venous pressure increases mean capillary hydrostatic pressure and promotes fluid filtration from the vasculature. Excess filtration from pulmonary capillaries causes fluid accumulation within the alveoli (pulmonary edema) and interferes with normal gas exchange, resulting in SOB. Physical signs and symptoms caused by high volume loading include: (1) Lung crackles, caused by fluid within alveoli (2) Orthopnea. Reclining increases pulmonary capillary hydrostatic pressure through gravitational effects, worsening dyspnea when lying flat. (3) Pitting dependent edema caused by filtration from systemic capillaries, an effect also influenced by position (causing edema in the lower legs as in our ambulatory patient or in dependent areas like the sacrum in a bedridden patient). What would an electrocardiogram show? Heart failure can result in LV hypertrophy and manifest as a left axis deviation on an electrocardiogram (ECG), but some patients in failure show a normal ECG. An ECG is not a useful diagnostic tool for dyspnea or CHF per se. Wouldn’t spirometry be more suitable for diagnosing the cause of dyspnea in a smoker? Simple spirometry will readily identify the presence of airflow limitation (obstruction) as a cause of dyspnea. It's a valuable test to perform in any smoker and can establish a diagnosis of chronic obstructive pulmonary disease (COPD) if abnormal. While this wheezing patient is an active smoker who could have airflow obstruction, the additional exam findings above point more to a diagnosis of CHF. What would an arterial blood gas show? An arterial blood gas measures arterial pH, PaCO¬2, and PaO2. While both CHF and COPD could cause derangements in the values measured, these abnormalities would not necessarily be diagnostic (e.g., a low PaO2 could be seen in both conditions, as could an elevated PaCO¬2). Would a complete blood count provide useful information? A complete blood count could prove useful if anemia is a suspected cause of dyspnea. Test result BNP was elevated (842 pg/mL), consistent with CHF. Diuretic treatment was initiated to help reduce volume overload and an afterload reducing agent was started to lower blood pressure and improve systolic function.
Lippincott Williams & Wilkins
almost 8 years ago
Easy tutorial for a basic physics concept, simply explained. Electrical engineering overlaps with neuroscience and cardiophysiology. Learn why fat increases blood pressure and antagonists decrease signal transmission! Please SUBSCRIBE for new videos: More cool stuff coming as we get more Hippo Helpers! http://www.helphippo.com - for more video tutorials organized by topic/year.
about 7 years ago
If I understand correctly: RAAS is partly activated by a decrease in blood pressure. Sodium intake increases blood pressure. I would therefore think that an increase in sodium (such as from eating a bag of crisps) would not activate RAAS. However, I'm getting conflicting information in my pathophysiology notes. Anyone got any definitive thoughts?
over 8 years ago
In hospital today, while I was taking a patient's blood pressure, another student asked if she could take her pressure on the other arm to practice. The patient didn't mind, but I thought it might be dangerous. Is this dangerous? What would happen if we pumped the cuff on both arms at the same time? Also, would this give an incorrect reading?
over 8 years ago
Concept to my understanding means an idea which is essential or core to understanding the topic or subject. For example Blood Pressure, optmal, low or high means what? To understand blood pressure and how volume, pressure and flow dynamics affects it; I need to know the role of vessel diameter, volume and density of blood plus distance for the blood to travel. Would someone be able to comment that I understand and apply the word concept correctly? or be able to better explain what concept means?
about 8 years ago
A professor asked "What are the 12 factors that influence blood pressure?". The number of factors that I can think of is 4 at most. Does anyone has any idea to what these 12 factors are?
almost 8 years ago
My Professor asked on the first day of my semester "What are the influencing factors of blood pressure?" I only know a few and there are more. Correct me if I am wrong but I believe: Stress Smoking Alcohol Obesity Haemorrhage Heart disease High body temperature Can someone help me please?
over 7 years ago
Metaphors and analogies have long been used to turn complex medical concepts into everyday ones, albeit with fancy terminology. Having been involved with many 3D animations on the topics of Blood Pressure, arteriosclerosis, cholesterol and the like, we find that often a metaphor goes a long way to building understanding, credibility and even compliance with patients. One of my favorite analogies is what we call the arterial highway. Much like their tarmacked counterparts, arteries act as conduits for all the parts that make your body go. A city typically uses highways, gas lines, water pipes, railways and other infrastructure to distribute important materials to its people. Your body is much the same, except that it does it all in one system, the cardiovascular system. This is used to deliver nutrients, extract waste, transport and deliver oxygen and even to maintain the temperature! The arteries can do all these things because of their smart three-layered structure. Our arteries consist of a muscular tube lined by smooth tissue. They have three layers named – the Adventitia, Media and Intima. Each is designed with a specific function and through the magic of evolution has developed to perform its function perfectly. The first is the Tunica Adventitia, or just adventitia. It is a strong outer covering over the arteries and veins. It has special tissues that are fibrous. The fibers let the arteries flex, expanding and contracting to accommodate changes in blood pressure as the blood flows past it. Unlike a steel pipe, arteries pulsate and so must be at once be flexible, and strong. Tunica Media - the middle layer of the walls of arteries and veins is made up of a smooth muscle with some elasticity built in. This layer expands and contracts in a rhythmic fashion, much like a Wave at a baseball game, as blood moves along it. The media layer is thicker in arteries than in veins, and importantly so, as arteries carry blood at a higher pressure than veins. The innermost layer of arteries and veins is the Tunica Intima. In arteries, this layer is composed of an elastic lining and smooth endothelium - a thin sheet of cells that form a type of skin over the surface. The elastic tissue present in the artery can stretch and return, allowing the arteries to adapt to changes in flow and blood pressure. The intima is also a very smoothe, slick layer so that blood can easily flow past it. Every layer of the artery has developed evolutionary traits that help your arterial system to maintain flexibility, strength and promote blood flow. Diseases and conditions like high cholesterol or high blood pressure, diabetes and others prevent the arteries from doing their function well by creating blockages or increasing the stress on one or more of the layers. For example, high blood pressure causes rips in the smooth lining of the Intima. Anybody who has experienced a pipe burst in a house knows that the damage can be extreme and can never fully be restored. Understanding the delicate functions of the arterial structure gives good incentive to treat them better. Conditions like high blood pressure, high cholesterol and lifestyle diseases such as diabetes create tears, holes, blockages, and can disrupt the functions of one or more layers. Getting patients to visualize the effect of bad eating habits on their anatomy helps to increase patient compliance. In modern society, the concept of highways goes hand in hand with the concept of traffic jams. Patients understand that the arterial highway is one that can never be jammed.
Mr. Rohit Singh
over 7 years ago