Brenda, a 74-year-old woman with a history of rheumatic feverwhile in her twenties, presented to her physician with complaintsof increasing shortness of breath (\"dyspnea\") upon exertion. Shealso noted that the typical swelling she's had in her ankles foryears has started to get worse over the past two months, making itespecially difficult to get her shoes on toward the end of the day.In the past week, she's had a decreased appetite, some nausea andvomiting, and tenderness in the right upper quadrant of theabdomen.On physical examination, Brenda's jugular veins werenoticeably distended. Auscultation of the heart revealed alow-pitched, rumbling systolic murmur, heard best over the leftupper sternal border. In addition, she had an extra, \"S3\" heartsound. A chest X-ray reveals a normal cardiac silhouette that isnormal in diameter, but her physical examination revealshepatomegaly and ascites, as well as pitting edema in her ankles.She is advised to wear support stockings and given a prescriptionfor digoxin. Two weeks later she returns to the office for afollow-up visit; upon physical examination, she still hassignificant hepatomegaly and pitting edema, and is significantlyhypertensive (i.e. she has high blood pressure). Her physicianprescribes a diuretic called furosemide (or \"Lasix\").
1. What is the general diagnosis for Brenda’s condition? Whatwould the diagnosis be if there were pulmonary edema instead ofsystemic edema?
2. Why is Brenda started on digoxin? How does it work? Stateyour answers in terms of chronotropism and inotropism, the Na+/K+ATPase, cytoplasmic Ca++ concentrations, and the proteins in acardiomyocyte’s sarcomere.
3. What happened to Brenda in the two weeks before her follow-upvisit? In other words, how did her body begin to compensate fordecreased stroke volume? Utilize cardiac output, sympatheticnervous system, vasoconstriction to “less vital†organs (includingthe kidney) the renin-angiotensin-aldosterone (R-A-A) axis,Angiotensin II, ADH, pre-load and after-load, the Frank-Starlinglaw, and the actions of digoxin.
4. Why was she given Lasix medication, and how does it work?
