Mr. Jones, a 58 years old sales executive has arrived in Washington DC for a con

Question

Mr. Jones, a 58 years old sales executive has arrived in Washington DC for a convention. He decides to go out with his colleagues and has a heavy dinner. He wakes up in the middle of the night with a dull ache in the center of his chest. He initially thinks, it is indigestion from the heavy meal that he had, but the chest pain gets worse and now starts radiating to the left shoulder, left jaw and left arm. He remembers seeing on TV, that what he is experiencing could be symptoms of a Myocardial infraction (heart attack, . He immediately calls 911.Once. the ambulance arrives, the EMT notice that Mr. Jones is sweating profusely and he is pale. The EMT immediately gives Mr. Jones. Aspirin, puts a oxygen mask and starts IV normal saline. If needed, other drugs can be given via the IV access. As soon as Mr. Jones is brought to the Hospital, the ER nurse takes the vital signs and a brief history. An EKG is done and shows abnormalities. suggesting a MI, Blood is drawn to look for cardiac enzymes. Blood results are back and show elevated Troponin and Creatine Kinase, confirming that Mr. Jones is having a MI. His past medical history is significant for poorly controlled essential hypertension, poorly controlled Diabetes mellitus. Poorly controlled Hypercholesterolemia. His family history is unremarkable. He is a current smoker, has smoked 2 packs of cigarettes for the last 25 years and drinks beer on the weekends. Mr. Jones is immediately taken to the operating room to do an Angiogram (procedure to visualize his coronary blood vessels). The doctors find a block in one of the major blood vessels and decide to do a angioplasty (minor surgery done to open blocked arteries). After the Angioplasty, the, EKG comes back to normal and his cardiac enzymes are tending down. So, the physician decides to observe him in the hospital for 2 days. He is discharged on 3rd day, with advice to make life style changes and start medications: Aspirin, Metoprolol (Beta blocker), Simvastatin for his cholesterol), and follow up with his physician in his home town. Mr. Jones was not compliant with his medications made no changes to his life style. 3 months later, he visits his physician and complains of easy fatiguability, headaches, shortness of breath, unable to lie flat on the bed at night. He says that he has to sit up propped up against 4 pillows in order to sleep On Ausucultation of the chest, there are bilateral crackles heard. The physician concludes that Mr Jones is in heart failure. He now prescribes Diuretics for Mr. Jones. from the history of the patient, explain along with mechanism, why Mr. Jones has abnormal hemogolobin and hematocrit?

Explanation / Answer

1. From the vital signs provided it appears that Mr Jones has Polycythemia.

Polycythemia is a condition characterized by increased red blood cell mass which results in increased blood viscosity and decreased perfusion of tissues.

In Polycythemia Vera, due to poor blood circulation patient(Mr. Jones) complains of headaches, shortness of breath, easy fatiguability or lethargy.

To ensure proper oxygenation to the tissues, adequate haemoglobin level must be maintained. The normal Hb level for males is 14 to 18 g/dl and for females is 12 to 16 g/dl.

Hematocrit measures the red blood cells volume in comparison to total blood volume. The normal hematocrit level for men is 40 to 54% and for women is 36 to 48%.

Here Mr. Jones has Hb = 19 g/dl and Hematocrit = 60%. Both values are above the normal range.

Polycythemia vera patients have significant thrombotic complications. Erythrocytosis and quantitative platelet abnormalities result in thrombosis.

2. Hypertension in other words is high blood pressure and Essential hypertension is the term used when the cause of high blood pressure is not known.

Blood pressure is the measure of the force against the walls of the arteries as the heart pumps blood through the body.

In essential hypertension, there is chronic increase in blood pressure due to an increased arterial wall thickness and media-to-lumen ratio. This means there is decrease in radius of blood vessel.

The mean arterial pressure (MAP) is a term the measure of average blood pressure in an individual in other words it is the average arterial pressure during single cardiac cycle. It can be calculated by given formula;

MAP can be given by the formula analogous to Ohm’s Law for electrical current and sometimes termed as Darcy’s Law.

P = Q * R

where P = pressure difference, Q = bulk flow, R = resistance

This equation can be restated in terms of MAP, peripheral resistance and cardiac output;

MAP = CO * PVR

where MAP = mean arterial pressure, CO = cardiac output which is given by stroke volume × heart rate and PVR = total peripheral vascular resistance

Afterload: During systole the resistance which the ventricle overcomes in order to eject blood is called afterload.

Afterload increases with age and hypertension. With age the arteries become stiff therefore there is less contraction of the ventricle resulting in less ejection of blood.

In hypertension there is increased pressure on left ventricle and over time it grows due to hypertrophy. The enlarged ventricle cannot contract well and thus the cardiac output is reduced.

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