DHA Clinical Practice & Guidelines 2 — Questions and Answers
Question 1: A 58-year-old male presents with crushing chest pain radiating to the left arm for 30 minutes. ECG shows ST elevation in leads II, III, and aVF. Which coronary artery is most likely occluded?
- Left anterior descending artery
- Right coronary artery (Correct answer)
- Left circumflex artery
- Obtuse marginal artery
Correct answer: Right coronary artery
ST elevation in leads II, III, and aVF indicates an inferior myocardial infarction, which is most commonly caused by occlusion of the right coronary artery (RCA), which supplies the inferior wall of the left ventricle in most patients.
Inferior STEMI (ST elevation in II, III, aVF) is caused by RCA occlusion in ~80% of cases. The RCA supplies the SA node, AV node, right ventricle, and inferior wall of the LV. DHA exam tip: always check for right-sided leads (V4R) in inferior STEMI to rule out RV involvement, which changes management (avoid nitrates).
Question 2: According to DHA clinical guidelines, what is the recommended first-line treatment for newly diagnosed type 2 diabetes mellitus in an otherwise healthy adult?
- Insulin glargine
- Metformin (Correct answer)
- Sulfonylurea
- GLP-1 receptor agonist
Correct answer: Metformin
Metformin remains the first-line pharmacological treatment for type 2 diabetes mellitus per international guidelines endorsed by DHA. It is cost-effective, weight-neutral, and has a proven cardiovascular safety profile.
DHA and international diabetes guidelines (IDF, ADA) recommend metformin as initial pharmacotherapy for T2DM unless contraindicated (eGFR <30, hepatic impairment). It works by reducing hepatic glucose output and improving insulin sensitivity. It is generally well-tolerated, inexpensive, and does not cause hypoglycemia as monotherapy.
Question 3: A patient is prescribed warfarin for atrial fibrillation. The therapeutic INR range for this indication is:
- 1.0–1.5
- 1.5–2.0
- 2.0–3.0 (Correct answer)
- 3.0–4.5
Correct answer: 2.0–3.0
The therapeutic INR range for atrial fibrillation anticoagulation with warfarin is 2.0–3.0. This range balances stroke prevention with acceptable bleeding risk.
For non-valvular AF, DVT prophylaxis, and PE treatment, the target INR is 2.0–3.0. For mechanical heart valves (especially mitral), a higher range of 2.5–3.5 is recommended. DHA exam frequently tests warfarin management — know that INR >3 increases bleeding risk and INR <2 increases thromboembolic risk.
Question 4: Which of the following is the most sensitive early indicator of acute kidney injury (AKI)?
- Serum creatinine
- Blood urea nitrogen (BUN)
- Urine output less than 0.5 mL/kg/hr for 6 hours (Correct answer)
- Serum cystatin C
Correct answer: Urine output less than 0.5 mL/kg/hr for 6 hours
Urine output decrease (<0.5 mL/kg/hr for ≥6 hours) is an early sensitive indicator of AKI per KDIGO criteria. Serum creatinine rises later as it only increases when GFR falls by approximately 50%.
KDIGO defines AKI as: serum creatinine rise ≥0.3 mg/dL within 48 hours, OR rise ≥1.5× baseline within 7 days, OR urine output <0.5 mL/kg/hr for ≥6 hours. Oliguria is often the earliest sign before creatinine rises. Cystatin C is more sensitive than creatinine but not routinely used in clinical practice.
Question 5: A 35-year-old pregnant woman at 32 weeks gestation presents with blood pressure 160/110 mmHg, proteinuria 3+, and headache. What is the most appropriate immediate management?
- Oral labetalol and outpatient monitoring
- Intravenous magnesium sulfate and antihypertensive therapy (Correct answer)
- Immediate cesarean section
- Bed rest and dietary sodium restriction
Correct answer: Intravenous magnesium sulfate and antihypertensive therapy
This presentation is consistent with severe preeclampsia. IV magnesium sulfate is given for seizure prophylaxis (eclampsia prevention) and IV antihypertensives (labetalol or hydralazine) are used for BP control. Delivery is planned but not always immediate.
Severe preeclampsia (BP ≥160/110 with symptoms) requires magnesium sulfate 4–6g IV loading dose for eclampsia prophylaxis, followed by 1–2 g/hr maintenance. Antihypertensives (IV labetalol, hydralazine, or oral nifedipine) target SBP <160 and DBP <110. Delivery is the definitive treatment, timing depends on gestational age and maternal/fetal status.
Question 6: In the management of community-acquired pneumonia (CAP) in a previously healthy adult not requiring ICU admission, which antibiotic regimen is most appropriate per current guidelines?
- IV vancomycin
- Oral amoxicillin-clavulanate alone
- Oral amoxicillin or macrolide monotherapy (Correct answer)
- IV piperacillin-tazobactam
Correct answer: Oral amoxicillin or macrolide monotherapy
For outpatient CAP in a healthy adult with no comorbidities and no recent antibiotic use, monotherapy with amoxicillin or a macrolide (azithromycin) is recommended. Combination therapy or broad-spectrum agents are not needed for low-risk patients.
IDSA/ATS guidelines recommend for outpatient CAP: amoxicillin 1g TID or macrolide (azithromycin/clarithromycin) for patients without comorbidities in low-resistance areas. Doxycycline is an alternative. Respiratory fluoroquinolones are reserved for patients with comorbidities or recent antibiotic use. IV antibiotics are not indicated for outpatient management.
DHA Clinical Practice & Guidelines 2
A 58-year-old male presents with crushing chest pain radiating to the left arm for 30 minutes.
ECG shows ST elevation in leads II, III, and aVF.
Which coronary artery is most likely occluded?