BIO407   Case Studies Exam 2

You must complete all 3 case studies. They are due the day of our second exam. Please be sure to include any sources of information you used to help you answer each question.

Case Study – Aortic Stenosis

Isaiah was a 54 year-old male who started developing chest pains and trouble breathing when he exercised. He told his physician that he had noticed the angina and dyspnea some time ago. At first they were only when he exercised vigorously, but they had steadily worsened until he sometimes experienced them even at rest. When the patient’s chest was auscultated, several abnormalities were observed. His heart was making a harsh systolic murmur that was heard at the upper right sternum, and there were indications of fluid in his lungs. An ECG showed signs of left ventricular hypertrophy. Blood analysis revealed elevated levels of epinephrine, aldosterone and angiotensin. An oral history revealed that he had suffered from a severe case of strep throat that had developed into rheumatic fever about 15 years ago. He was diagnosed with aortic stenosis secondary to his episode of rheumatic fever. The chronically increased afterload on the left ventricle had eventually led to left heart failure (congestive heart failure). The doctor told him that the treatment for heart failure includes trying to increase contractility, decrease preload and decrease afterload, so he was given prescription for a phosphodiesterase inhibitor, an ACE inhibitor and a diuretic.

1. How does strep throat lead to congestive heart failure?

2.  What is the source of the systolic murmur?

3.  Why was Isaiah experiencing dyspnea and fluid in his lungs?

4. Why is the angina and dyspnea exacerbated by exercise?

5. Why does he have elevated levels of epinephrine, aldosterone and angiotensin?

6.  How do the drugs he was given improve cardiac function?

Case Study –Fibrothorax

Lori was 43 years old when her pulmonary problems started. She got extremely ill and was forced to take a week off of work. During this time her body temperature was 41oC and she experienced severe dyspnea (had to stop for breath after walking for 100 yards). She was coughing and producing large amounts of rust colored sputum. She was diagnosed with lobar pneumonia with pleural empyema. She was treated with antibiotic and the infection was controlled. After she returned to work she was still experiencing moderate dyspnea. To determine the reason for the lingering symptoms she underwent several pulmonary function tests. Blood gas measurements and ventilatory function measurements yielded the following:

                                           PaO2                                                           75 mmHg

                                          PaCO2                                                          50 mmHg

                          Residual Volume (RV)                                          2250 ml

                     Forced Vital Capacity (FVC)                                     2680 ml

                Force Expiratory Volume (FEV1)                                2420 ml

It was determined that the pleural exudates had organized into fibrothorax. Her doctor suggested that a decortication surgery might be indicated. She is consulting with her family to decide if she wants to undergo this procedure.

1.  What is dyspnea? Why is Lori experiencing this symptom?

2.  What is lobar pneumonia? How does it compare to lobular or interstitial pneumonia?

3.  What is pleural empyema? How does it relate to the infection she suffered from?

4.  Do these blood gas results tell you anything about Loris pulmonary function?

5.  Do these ventilatory function measurements tell you anything about her disease? Is she suffering from a restrictive or an obstructive disorder?

6.  Do you think she should have the surgery? Why?

Case Study – Venous Insufficiency

Marvin, a 42 year old factory worker, comes to his physician complaining of an open sore on his left shin that does not seem to be healing. As the doctor unwrapped the bandage the patient had applied, a strong odor was detected. She identified the wound as an infected venous stasis ulcer. She noticed that the lower leg was edematous and the skin of the foot and ankle was somewhat discolored. Portions of the saphenous vein were visibly distended and tortuous. An oral history revealed that the patient stood at a workbench all day on the job. She explained to the patient that his varicose veins were caused by valvular incompetence in his veins. This had progressed to the chronic venous insufficiency he was now suffering from.

       After the infection was controlled with antibiotics, the patient was advised to wear elastic stockings, sit down at work whenever possible and to perform toe raises every 5 minutes if he did have to stand up for extended periods.

1.  What is the likely cause of the patient’s valvular incompetence?

2.  Why does valvular incompetence lead to varicose veins and chronic venous insufficiency?

3.  Why does venous insufficiency result in edema and venous stasis ulcer formation?

4.  What is the likely reason that the ulcer became infected?

5.  What is the rationale for the advice about stockings, seated posture and leg raises?