Homeostasis Mini-cases Final Exam

Homeostasis Mini-cases Final Exam 74 yo, Neurodegenerative, severe weakness over 3 months, difficulty breathing. Short of breath and breathing rate increased when lying down. Correct Answer: Weakness of hand and arm, ...

Homeostasis Mini-cases Final Exam 74 yo, Neurodegenerative, severe weakness over 3 months, difficulty breathing. Short of breath and breathing rate increased when lying down. Correct Answer: Weakness of hand and arm, suggests impairment of C5 and T1. C5 is innervation of diaphragm so suggests diaphragm is weak. Lying down you lose the effects of gravity helping her moving diaphragm downwards and chest up and out. Internal intercostal and abdominal muscles innervated by thoracic = T1. Describe innervation and muscles used for inspiration and expiration Correct Answer: During quiet inspiration using diaphragm (innervated by C3, C4, C5, moves down) and external intercostals (innervated by thoracic). During max inspiration use pectoralis major, scalene, and sternocleidomastoid. During quiet expiration the diaphragm and the intercostal relax which leads to recoil. During max expiration utilize abdominal muscles (innervated by thoracic and lumbar) and internal intercostals (innervated by thoracic). 74 yo, Neurodegenerative, severe weakness over 3 months, difficulty breathing. Short of breath and breathing rate increased when lying down. Why would she breath faster when lying down? Correct Answer: Ventilation, carbon dioxide elimination. If she wants to maintain the same minute ventilation, harder for her to take a full breath, so she will make many small breaths instead. Aspirating food into airway where is food most likely to go? Correct Answer: Right main bronchus is almost a straight shot down. Will go to most posterior part: If standing upright then food will go into right lower. If someone is lying down then food will go into right upper lobe and superior segment right lower lobe. Middle lobe is anterior so probably won't go in there. A patient has fluid in the pleural space in the right chest. You want to place a needle into the pleural space along the 8th rib. Given you knowledge of anatomy, how would you decide whether it is safest to insert the needle along top margin of the rib or along the lower margin of the rib? Correct Answer: Neurovascular bundle runs right under the rib. So always want to go just above the top of the rib. If go below risk hitting neurovascular bundle and causing significant bleeding. You are trying to determine if the left atrium is enlarged in your patient. You have an x-ray, which shows clearly the right and left mainstem bronchi; how would you determine if the left atrium is enlarged based on the position of the bronchi Correct Answer: If left atrium gets larger it lifts up the left mainstem bronchi which increases angle will be widened left mainstem bronchus will be more horizontal, sign you have left atrial enlargement Tripod Correct Answer: Fix arms, then pectoralis major rather than lifting arms can lift chest up and out 2 mo infant, not growing appropriately, whooshing between heart beat on auscultation, diagnoses defect, or an opening between ventricles, where is blood going and how do you know? Correct Answer: Whooshing is turbulent flow. In this case, suggests left to right blood flow since able to here on anterior side of patient: ventricular septal defect with left to right shunt. Hole is causing blood to go from left ventricle to right ventricle. Since right ventricle is more anterior and hear whooshing on anterior suggests going left to right shunt. In addition if patient is normally saturated (not blue / cyanotic) then may further suggest left to right. Right to left shunt would lead to deoxygenated going through aorta which would lead to lower oxygenation. Failure to thrive because inability augment cardiac output. What heart structures anterior vs. posterior? Correct Answer: Anterior view: see right atrium and right ventricle primarily. Posterior view: see left atrium primarily and left ventricle. Angle of interventricular septum with respect to anterior chest wall? Correct Answer: Interventricular septum lies between the two ventricles. From anterior view, interventricular septum points down in the same plane as right ventricle. Near PMI. Normal structures RBC travels through, normal pressure, average oxygenation Correct Answer: Inferior & superior vena cava -> right atrium -> tricuspid -> right ventricle -> pulmonic valve pulmonary artery -> lungs -> pulmonary veins -> left atrium -> mitral valve -> left ventricle -> aortic valve -> aorta. Pressure is higher on the left than on the right. Higher oxygenation on left than on right. Hole between ventricles, how would that affect path blood travels, pressure, and oxygenation? 2 month old fetus Correct Answer: In utero, right ventricle is quite thick compared to left therefore a fetus with hole between ventricles may have blood going from RV to LV and then to aorta, would see lower oxygenation. But as grow the left ventricle is thicker so blood goes from LV to RV and then to pulmonary artery. On echo will see higher oxygenation than normal in the right ventricle. Tricuspid valve regurgitation will be heard when? Correct Answer: Not closing properly leads to turbulent flow, heard during systole. Diastole is when blood filling in ventricles since heart relaxed, therefore valve is open. Systole is when the heart contracts therefore valve closes. Mitral valve regurgitation, when and where will you hear? Correct Answer: Heard during systole. Hear it at the apex (think about anatomy) Create a hypothesis, based on physiological principles, to explain the low blood pressure when Serena arrived in the emergency department. How might the body have compensated to prevent the fall in blood pressure?: Serena is a 75 year old woman with a history of hypertension and recurrent pneumonia. She has also smoked cigarettes for nearly 50 years and tends to get discomfort in her lower legs when she walks more than a few blocks. She has been feeling poorly for the past 24 hours with increased cough. Today she developed chills and fever to 102 degrees; in the past hour she noted dizziness and called her daughter to take her to the hospital. When she arrived in the hospital her blood pressure was 70/40 mm Hg. The doctors found her to be confused when they asked her questions. Her skin was diffusely warm and flushed and a bruit was noted in the periumbilical region. After giving her fluids, antibiotics, and a medication to constrict her blood vessels, the blood pressure was 100/70 mm Hg. Serena's confusion had resolved but over the course of 10 hours, she made minimal urine. Over the course of the next 12 hours, blood pressure rose to 130/90 mm Hg and the urine output increased. Correct Answer: Bacterial infection -> systemic infection -> cytokines release -> vasodilation and increased permability. Vasodilation -> increased radius -> decreased blood pressure. Increase permeability -> decreased intravascular volume-> decreased blood pressure. Decrease intravascular volume -> decreased urination. Create a hypothesis, based on physiological principles, to explain the bruit heard on the abdominal exam. Include in your answer an explanation for why Serena's confusion improved with blood pressure 100/70 mm Hg but the urine output remained low until the blood pressure rose to 130/90 mm Hg: Serena is a 75 year old woman with a history of hypertension and recurrent pneumonia. She has also smoked cigarettes for nearly 50 years and tends to get discomfort in her lower legs when she walks more than a few blocks. She has been feeling poorly for the past 24 hours with increased cough. Today she developed chills and fever to 102 degrees; in the past hour she noted dizziness and called her daughter to take her to the hospital. When she arrived in the hospital her blood pressure was 70/40 mm Hg. The doctors found her to be confused when they asked her questions. Her skin was diffusely warm and flushed and a bruit was noted in the periumbilical region. After giving her fluids, antibiotics, and a medication to constrict her blood vessels, the blood pressure was 100/70 mm Hg. Serena's confusion had resolved but over the course of 10 hours, she made minimal urine. Over the course of the next 12 hours, blood pressure rose to 130/90 mm Hg and the urine output increased. Correct Answer: Stenosis in aorta is causing turbulent flow = bruits. Which is why her legs hurt when she walks (claudication). Prioritize the blood flow to the brain to preserve brain function since most important. Also, kidneys are not getting enough perfusion because downstream of a blockage therefore need a higher pressure. Takes more work to overcome higher resistance where blockage is. Create a hypothesis to explain the wheezing when Juan listened to Mike's chest. In your answer explain why the wheeze varied with the phase of breathing. Create a hypothesis to explain the sensation that Mike had that he had to work harder to breathe. Explain your reasoning based on changes in physiology: Swallowing peanuts (one goes wrong way), then working harder to breathe, wheezing and diminished breath sounds on right chest posteriorly, wheeze prominent on exhalation than inhalation Correct Answer: Obstruction right lower lobe -> decrease radius -> increase resistance -> increase velocity to maintain flow -> increase reynold's number -> increase turbulence -> vibrations in airways -> focal wheezing. Exhalation (less volume, more resistance) is when lung volume is smallest which leads to smaller airways radius which leads to wheezing heard on exhalation. Work harder to breathe: increasing resistance, flow stays same, increase change in pressure which increases work required to take a breath based on Ohm's Law. (V = IR -> change in pressure = flow x resistance) 85 yo with memory loss, visual loss, chronic hypertension; prescribed beta 1 blocker, took 3 by accident -> dizziness, stumbling. Create physiological hypotheses to explain: a) why did she feel dizzy when standing? b) Why did she feel better when lying down? Correct Answer: Beta 1 receptor normally is activated by epinephrine leads to higher contractility (does not affect veins since controlled by beta 2 receptor). Giving beta 1 blocker would decreases contractility which would decrease systemic blood pressure. Less blood going to brain makes dizzy. Cellular level: epinephrine -> beta receptor -> Gs -> adenylate cyclase -> cAMP -> PKA -> phosphorylate ryanodine receptors and phospholambin -> calcium in cytosol -> tropomyosin doesn't block actin binding. Blocking beta receptor leads to lower calcium less actin myosin interaction leads to less contractility. When standing up heart needs to work harder to pump blood to the brain because larger pressure differential due to gravity. Lying down increase venous return increase preload. Normally when blood pressure drops activate sympathetic nervous system to increase heart rate, contractility, and systemic vascular resistance. Beta blocker prevents increase heart rate and contractility. Why did the norepinephrine have relatively little impact on the Mr. Robinson's blood pressure? Draw a normal Starling curve and show where Mr. Robinson would be on that curve before he was given fluids or medicines. How would this curve change with the administration of norepinephrine?: 30 year-old, taking indomethacin four times a day, at work today, he felt nauseated and a bit light-headed, vomited liter of bright red blood -> started intravenous fluids, blood pressure was measured at 60/40 mm Hg -> norepinephrine and the patient's heart rate rose from 130 to 150 beats/min but only small increase in blood pressure -> increased fluids and transfusing blood while reducing the norepinephrine dose. Mr. Robinson's blood pressure rose over the next hour to 100/70 mm Hg and his heart rate fell to 100 beats/min. Correct Answer: Indomethacin (NSAID) -> erode stomach mucosa -> stomach ulcers -> ulcerate down to artery -> GI bleeding -> High blood loss -> decreased volume -> decreased preload (move to left on Starling curve since decreased EDV)-> decrease blood pressure. Giving norepinephrine increases contractility, heart rate, increase SVR. Leads to upward shift on Frank Starling curve. Even though increase stroke volume, such low volume doesn't matter how much beating heart won't lead to increased blood pressure. Also body was already increasing heart rate (130). When give blood and fluids then able to move along Frank Starling curve. Blood is colloid, and stays in blood stream much better than IV fluids increases volume more. Why did the administration of fluids and blood achieve a better result than the norepinephrine? Where would the patient be on his Starling curve after the administration of fluid and blood?: 30 year-old, taking indomethacin four times a day, at work today, he felt nauseated and a bit light-headed, vomited liter of bright red blood -> started intravenous fluids, blood pressure was measured at 60/40 mm Hg -> norepinephrine and the patient's heart rate rose from 130 to 1