Ankle swelling and fatigue in a 60yo.

A 60yo male teacher from the local high school presents to you with complaints of swelling in the feet/ankles by the end of the day, frequent urination at night and increasing fatigue/shortness of breath upon light exercise like taking the steps to a different floor. He does not sleep well at night and feels that breathing while in bed seems to be a bit harder than when sitting or standing. Use of added pillows seems to help. He has a history of heart disease in the family and he has previously been diagnosed with mild atrial fibrillation, which is only being monitored.
Upon examination, you find BP 170/110, pulse rate 70-75, normal temperature and mild pitting edema at the ankles bilaterally. Chest exam reveals light crackles (rales) upon respiration and no abnormal heart sounds. There is no dullness upon listening to the heart. Rectal exam reveals normal sized prostate and no bleeding/blood in the stool. Abdominal exam reveals only mildly enlarged liver, normal spleen and no areas of tenderness. The jugular vein appears distended when in a reclined position to 30 degrees, but not when upright. Central venous pressure measured by JVD is 9cm H2O.
1) Considering the Starling forces (not cardiac Frank-Starling law) affecting fluid movement in a capillary, describe two ways to promote an increase in net fluid movement into the interstitium (i.e. increase/decrease in a given force that is part of calculating net fluid movement).
2) Given the Starling forces that can promote movement describe above, list three organs that need to be evaluated because of their ability to promote such edema and why (i.e. how is the Starling forces altered by dysregulation of that organ).
3) Describe why he is having shortness of breath using Starling forces terminology.
4) Describe how interstitial fluid compares to plasma. Is interstitial fluid intracellular or extracellular?
Bloodwork reveals a normal ESR (a non-specific measure of inflammation), normal hemoglobin, hematocrit, white blood cell count/distribution, albumin and blood glucose levels. Chest X ray show some shadowing of lung tissues more prominently in the base, confirming the presence of edema. The ventricles of the heart are enlarged. No other abnormality noted. A 24 hour urine collection revealed no abnormalities.
5) Given the above information, you diagnose him with congestive heart failure. You consider various medications for his treatment, which aim to improve his cardiac function by slowing the rate and increasing contractility. Digoxin is one such drug (though it does appear to have a 20% higher all-cause mortality rate in atrial fibrillation patients, so it is not given without careful consideration). How does digoxin work in terms of altering movement of Na+, K+ and Ca++ and how does that relate to the improvement in cardiac function (increased contractility and slower heart rate)?
A 15yo girl presents with a sore throat and headache x 5 days. She has been treating it with Advil. Examination reveals slightly elevated heart rate, oral temperature of 99.7 degrees, and sore neck on palpation with enlarged lymph nodes. Rapid Strep test is positive.
6) In general, what is the most common cause of sore throat in children 15yo and younger?

7) Why is it important to treat strep throat within the first nine days or so? What is the mechanism for damage beyond the throat area (rare, serious complications) if left untreated?

8) During alkalosis, as can occur from vomiting and or diarrhea, causes what kind of shift in K+ concentrations occur (regarding fluid compartments, i.e. extracellular (plasma and interstitial) vs intracellular) and thus may show up in blood chemistry readings?

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