Case #2

1. "The patient is a 54 year-old male with a history of coronary artery disease who was admitted to the hospital for increasing lower extremity edema, abdominal swelling and shortness of breath." What does this suggest? 

Congestive heart failure

2. "The patient had noted an ~30 pound weight gain over the past month ". What is the reason for his weight gain and explain why that occurs with your diagnosis?

Kidney perceives decreased cardiac output and intravascular volume and tries to correct it by conserving sodium and water. Total body fluids increase and primarily settles in extravascular space. Body weight increase is due to water retention. Following weight, is a good index of control of congestive heart failure and drug regimens are adjusted based on serial follow up of weights.

3. "during the past week has had three pillow orthopnea.". What is orthopnea.? Why is he orthopneic?

When shortness of breath is ameliorated in upright position we call it orthopnea. Patients with congestive heart failure usually sleep with elevation of head with 2-3 pillows. Orthopnea can be encountered in multiple clinical situations

• Congestive heart failure

• Diaphragmatic paralysis

• Obstructive pulmonary disease 

• Superior vena caval obstruction

Understanding the mechanism of orthopnea in each instance is important. In heart failure following mechanisms are in play

• 10% more venous return in supine position

• Smaller lungs in supine position

• Enlarged engorged liver pushing the diaphragm up in supine position

• Ability to use accessory muscle s of respiration

4. Explain the significance of his cardiac findings. "Cardiac exam had an S1, S2 and S3 without S4 or murmur". 

S3 implies volume work

5. Pulmonary exam was remarkable for bilateral rales 2/3rd up both lung fields.  What does this suggest to you?

Congested lungs from heart failure. You have to distinguish it from diffuse interstitial fibrosis which can also give similar findings.

With accumulation of fluid the integrity of surfactant is affected and the alveoli collapse. The crackle is generated as the air enters the alveoli and pops them open. The crackles occur at the end of inspiration. They are gravity dependant, hence in bases of lungs. You can move the crackles to dependant lung in a lateral decubitus position.

Crackles of diffuse interstitial fibrosis are coarse, persistent and not gravity dependant.

6. "Abdomen was enlarged with a positive fluid wave. " What does this imply? Demonstrate fluid wave.

Abdominal enlargement is due to enlarged engorged liver and ascites.

Fluid wave is demonstrable

7. "Lower extremities were remarkable for 3+ pitting edema." Demonstrate how you will assess pitting edema. Where would you look for edema in a bed ridden patient with CHF?

Keep your thumb gently but firmly pressed over shin of tibia for few seconds. a depression is indicative of pitting.

In a bedridden patient the edema tends to accumulate in sacral area which is the dependant portion.

8. "Renal ultrasound- Right kidney 10 x 5.5, Left kidney 10.5 x 6.0." What is the significance of this report? 

The Kidney is 

9. Is the cause of this patient’s renal failure acute or chronic? What is your reasoning?

The recent onset and rapid rise in bun and creatinine are consistent with acute renal failure.

10. Calculate the fractional excretion of sodium. 

(10 mmol/l/134 mmol/l) x 100= .075/37 x 100=.20% 
(130 mg/dl)/(3.5 mg/dl)

11. Is this patient’s renal failure consistent with a prerenal cause or acute tubular necrosis? What is the rationale for your conclusion?

Prerenal: Creatinine is near normal with elevated BUN

Renal: Proportionate elevation of creatinine and BUN

12. What is the patient’s volume status?

This patient is clinically volume overloaded because of congestive heart failure. 

The kidney perceives itself as being in a low volume state due to the decreased effective circulating arterial volume.

• Total body fluids: Increased

• Extravascular fluid: Increased

• Intravascular fluid: Decreased

13  What would you recommend to improve renal perfusion in this case?

The options are

• Intravenous sodium chloride

  • This would worsen the congestive heart failure.

• Intravenous pressure support

  • This patient is already hypertensive.

• Inotropic support with after load reduction (i.e. Dobutamine)

  • This would improve cardiac output and renal perfusion.

14. When is it appropriate to order urine lytes to determine the fractional excretion of sodium in a patient with renal failure? 

• When the renal function is deteriorating. 
• If function is improving one would expect to see an elevated fractional excretion of sodium as the excess salt and water is removed by the kidney.

15. Calculate the fractional excretion of sodium on July 4th. 

(50 mmol/l35 mmol/l) x 100=0.37/8.5 x 100= 4.3% 
(40 mg/dl/4.7 mg/dl)

16.  Is this patient’s renal failure consistent with a prerenal cause or acute tubular necrosis? 

ATN

17. What is the most likely etiology of renal failure in this patient on July 4th? 

This is probably due to the hypotensive episode associated with the myocardial infarction.

18. What is acute tubular necrosis?