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MedTutor is an online tutoring site for medical students and young doctors in Internal Medicine. Write to MedTutor at: <moc.liamg|todikiwrotutdem#moc.liamg|todikiwrotutdem>.

For discussion with final year medical students (March to July 2015)

A. Student initiated discussions Weeks 1 and 2
B. Student initiated discussions Weeks 3 and 4

Other topics for discussion:

1. Looking at this ABG report: pH 7.26; PaO2 94mm Hg; PaCO2 28mm Hg; Serum HCO3 16mmol/L,
a. A student said that it shows respiratory acidosis. Why is that wrong? b. Some students said that it shows metabolic acidosis with respiratory compensation while a few others said that it shows metabolic acidosis with respiratory alkalosis. Who is correct?


2. When asked for the treatment of hyperkalemia, a student answered "Insulin" and another student answered "Insulin and Glucose". Who is in error?


3. A patient has acute renal failure with oliguria. A student wanted to give her normal saline to promote diuresis. What is the error here?


4. Why is prescribing ACE inhibitors or ARB for patients with end stage renal failure and hyperkalemia a bad idea?


5. A patient with rheumatic heart disease and atrial fibrillation is on warfarin. He presents with mild bleeding from gums and nose. There is also hematuria. His INR is very high.
a. A student wanted the warfarin to be stopped and low molecular weight heparin to be given instead. Is that right? b A student wanted to evaluate this patient for bladder cancer and urinary infection in view of the hematuria. Is this appropriate?
c. A student wanted to give an intramuscular injection of Vitamin K for this patient. Is there a problem here?


6. A 12 year old girl is on Inj. Mixtard insulin 10 units in the morning before breakfast and 16 units in the night before dinner. Her fasting plasma glucose is 6.8mmol/L but her glycosylated hemoglobin is always above 8 percent. What will you do to achieve target HbA1c values?


7. A 28 year old man presented with a short history of left sided chest pain that is increased on inspiration and relieved by leaning forward. Auscultation revealed a friction rub audible during both inspiration and expiration over the left sternal edge. His ECG showed ST elevation in most of the chest leads. A small pericardial effusion was detected on echocardiogram. His serum Troponin I was elevated. What is your diagnosis that explains all the clinical information given here?


8. While discussing precipitating causes of heart failure, arrhythmia was mentioned as one of those things that can precipitate heart failure. When asked to name some specific kinds of arrhythmia that can precipitate heart failure, a student mentioned atrial fibrillation and ventricular fibrillation. What is odd about this answer?


9. A patient with sick sinus syndrome presented with syncope. Explain the link between syncope and sick sinus syndrome.


10. A patient has end stage renal failure and she presented with shortness of breath. On examination, crepitations were detected in the lungs. The diagnosis by a student was: Fluid overload secondary to end stage renal failure. How should the diagnosis be written?


11. A 60 year old woman has IHD, HPT and impaired fasting glucose. She is being treated with Atorvastatin, Aspirin, Metformin, Perindopril, GTN, Bisoprolol and Hydrochlorothiazide. Her blood reports are: Urea 4.4mmol/L; Sodium 137mmol/L; Potassium 3.1mmol/L; Creatinine 51umol/L; Total cholesterol 5.2mmol/L; Triglycerides 1.8mmol/L; HDL Cholesterol 1.5mmol/L; LDL cholesterol 2.9mmol/L and Fasting plasma glucose 4.0mmol/L. What change, if any, will you make to her medications?


12. A 64 year old woman has HPT and suffered a stroke with R hemiplegia 10 years ago. She has atrial fibrillation and is on Warfarin. Her ECHO was done only recently. It showed the presence of mitral stenosis, tricuspid regurgitation and aortic regurgitation. Based on this information, can you say what type of heart disease she has?


13. A 72 year old man presented with difficulty in breathing for 1 day. He takes treatment for diabetes and hypertension.

Question: What is the first thing you will consider as a reason for this man’s difficulty in breathing?

Physical findings:
Pulse rate: 102 beats per minute, and regular in rhythm.
Blood pressure: 115/60 mmHg; Respiratory rate: 22 breaths per minute; Temperature: Normal; Sp02 was 98% under room air.
Jugular venous pressure was 4.5cm of H2O above the angle of Louis.
The cardiac apex beat was palpable at the left 6th intercostal space, at the midaxillary line and was thrusting in nature. There were no palpable thrills felt or parasternal heaving. On auscultation S1 and S2 were heard with an added S3 heart sound. He also had a pan systolic murmur at the mitral region which radiated to the axilla. It was best heard on expiration.
Auscultation of the lungs revealed bibasal fine crepitations.
Abdominal examination was normal.
Neurological examination did not detect any major abnormality.

Question: What is the cause of the man’s breathing difficulty? Give supporting evidence for your answer.
Question: What information does the cardiac apex beat give you?
Question: What would you like to say about the murmur in his heart? Tell what you think it is due to and suggest an etiology for it.

Investigations:
ECG – this showed sinus rhythm with broad QRS complexes. These QRS complexes were predominantly positive in Lead V6 and predominantly negative in Lead V1.
X-ray chest – this showed cardiomegaly and perihilar haziness
Cardiac enzymes – these were normal
Arterial blood gases – the pH was slightly low, the PaCO2 was low, the PaO2 was normal and the serum HCO3 was low.
Fasting plasma glucose – 4.5mmol/L

Question: How do you interpret the ECG?
Question: What is the significance of the perihilar haziness on chest x-ray?
Question: Suggest reasons for the abnormalities detected in the arterial blood gases
Question: How do you interpret the fasting plasma glucose value?


14. A 50 year old man with DM, HPT and CRF had a serum creatinine of 266umol/L in November 2014 and 309umol/L in March 2015. At present his fasting plasma glucose is 8.9mmol/L, HbA1c is 10.8%. His blood pressure is 154/88mm Hg. His current medications are: Inj Mixtard insulin 34 units sc BD, Tab Metoprolol 25mg BD, Tab Amlodipine 10mg OD and Tab Atorvastatin 40mg ON. What changes do you wish to make to his treatment?


15. A 53 year old woman with DM and HPT was first admitted in October 2014 for cough, breathlessness and sweating. At that time her BP was 149/89mm Hg and her lungs were clear on auscultation. The cardiac examination was normal. The initial ECG showed sinus rhythm with inverted T waves in leads V1 to V4. A repeat ECG a few hours later showed incomplete RBBB. The x-ray chest showed cardiomegaly. Non specific cardiac enzymes (total CK, AST and LDH) were all significantly raised. Renal function was normal. There was no record of her plasma glucose value. She was diagnosed and treated as acute NSTEMI, HPT and Urinary tract infection. During the initial review 3 months after discharge, she was diagnosed to have congestive cardiac failure. During the second review, a month later, she was noted to be still in congestive cardiac failure. She was readmitted in February 2015 when a Contrast Enhanced CT thorax was done. This showed evidence of pulmonary embolism and she was started on anticoagulants along with other medications. In March 2015, her ECG showed sinus tachycardia with T wave inversion in V1 to V4. There was no conduction defect and the cardiac axis was normal. Do you think that there was evidence to suspect pulmonary embolism during her first admission in October 2014?


16. A coronary angiogram was done for a 55 year old man with DM and HPT who was asymptomatic (that is, he did not have any cardiac-related symptoms). The angiogram showed: 1. Left main stem normal; 2. Left anterior descending artery having mild to moderate disease; 3. Left circumflex artery having moderately severe disease (the artery was small and non-dominant); 4. Right coronary artery having mild to moderate disease (the artery was dominant). How do you think this patient should be managed - medical therapy or revascularisation therapy?


Dr Vela Menon, MD
Clinical Associate Professor of Medicine
International Medical University, Malaysia

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