A 50-year-old morbidly obese woman presents to a primary care clinic for the first time. She states that her father recently died due to kidney failure and wants to make sure she is healthy. She works as an accountant, is not married or sexually active, and drinks alcohol occasionally. She currently does not take any medications. She does not know if she snores at night but frequently feels fatigued. She denies any headaches but reports occasional visual difficulties driving at night. She further denies any blood in her urine or increased urinary frequency. She does not engage in any fitness program. She has her period every 2 months with heavy flows. Her initial vital signs reveal that her blood pressure is 180/100 mmHg and heart rate is 70/min. Her body weight is 150 kg (330 lb). On physical exam, the patient has droopy eyelids, a thick neck with a large tongue, no murmurs or clicks on cardiac auscultation, clear lungs, a soft nontender, albeit large abdomen, and palpable pulses in her distal extremities. She can walk without difficulty. A repeat measurement of her blood pressure shows 155/105 mmHg. Which among the following is part of the most appropriate next step in management?

Renal artery doppler ultrasonography

A 50-year-old man with a history of stage 4 kidney disease was admitted to the hospital for an elective hemicolectomy. His past medical history is significant for severe diverticulitis. After the procedure he becomes septic and was placed on broad spectrum antibiotics. On morning rounds, he appear weak and complains of fatigue and nausea. His words are soft and he has difficulty answering questions. His temperature is 38.9°C (102.1°F), heart rate is 110/min, respiratory rate is 15/min, blood pressure 90/65 mm Hg, and saturation is 89% on room air. On physical exam, his mental status appears altered. He has a bruise on his left arm that spontaneously appeared overnight. His cardiac exam is positive for a weak friction rub. Blood specimens are collected and sent for evaluation. An ECG is performed (see image). What therapy will this patient most likely receive next?

Send the patient for hemodialysis

Perform a STAT pericardiocentesis

Prepare the patient for renal transplant

Treat the patient with cyclophosphamide and prednisone

A 62-year-old man comes to the physician in May for a routine health maintenance examination. He feels well. He underwent a right inguinal hernia repair 6 months ago. He has hypertension and type 2 diabetes mellitus. There is no family history of serious illness. Current medications include metformin, sitagliptin, enalapril, and metoprolol. He received the zoster vaccine 1 year ago. He received the PPSV23 vaccine 4 years ago. His last colonoscopy was 7 years ago and was normal. He smoked a pack of cigarettes a day for 20 years but quit 17 years ago. He drinks two to three alcoholic beverages on weekends. He is allergic to amoxicillin. He is scheduled to visit Australia and New Zealand in 2 weeks to celebrate his 25th wedding anniversary. He appears healthy. Vital signs are within normal limits. An S4 is heard at the apex. The remainder of the examination shows no abnormalities. Which of the following is the most appropriate recommendation at this time?

Pneumococcal conjugate vaccine 13

A primary care physician who focuses on treating elderly patients is researching recommendations for secondary prevention. She is particularly interested in recommendations regarding aspirin, as she has several patients who ask her if they should take it. Of the following, which patient should be started on lifelong aspirin as monotherapy for secondary prevention of atherosclerotic cardiovascular disease?

A 63-year-old male with a history of a transient ischemic attack

An 83-year-old female with a history of a hemorrhagic stroke 1 year ago without residual deficits

A 75-year-old male who had a drug-eluting coronary stent placed 3 days ago

A 67-year-old female who has diabetes mellitus and atrial fibrillation

A 45-year-old female with no health problems

A 71-year-old man develops worsening chest pressure while shoveling snow in the morning. He tells his wife that he has a squeezing pain that is radiating to his jaw and left arm. His wife calls for an ambulance. On the way, he received chewable aspirin and 3 doses of sublingual nitroglycerin with little relief of pain. He has borderline diabetes and essential hypertension. He has smoked 15–20 cigarettes daily for the past 37 years. His blood pressure is 172/91 mm Hg, the heart rate is 111/min and the temperature is 36.7°C (98.0°F). On physical examination in the emergency department, he looks pale, very anxious and diaphoretic. His ECG is shown in the image. Troponin levels are elevated. Which of the following is the best next step in the management of this patient condition?

Clopidogrel, atenolol, anticoagulation and monitoring

CT scan of the chest with contrast

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

"Can you tell me more about the symptoms you have been experiencing?"

"Does the diarrhea typically precede the constipation, or vice-versa?"

"Is the diarrhea foul-smelling?"

"Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"

"Are the symptoms worse in the morning or at night?"

Two days after undergoing an uncomplicated total thyroidectomy, a 63-year-old woman has acute, progressive chest pain. The pain is sharp and burning. She feels nauseated and short of breath. The patient has a history of hypertension, type 1 diabetes mellitus, medullary thyroid cancer, multiple endocrine neoplasia type 2A, anxiety, coronary artery disease, and gastroesophageal reflux disease. She smoked half a pack of cigarettes daily for 24 years but quit 18 years ago. Current medications include lisinopril, insulin glargine, insulin aspart, sertraline, aspirin, ranitidine, and levothyroxine. She appears anxious and diaphoretic. Her temperature is 37.4°C (99.3°F), pulse is 64/min, respirations are 17/min, and blood pressure is 148/77 mm Hg. The lungs are clear to auscultation. Examination shows a 3-cm linear incision over the anterior neck with 1 mm of surrounding erythema and mild serous discharge. The chest wall and abdomen are nontender. There is 5/5 strength in all extremities and decreased sensation to soft touch on the feet bilaterally. The remainder of the examination shows no abnormalities. Which of the following is the most appropriate next step in management?

Obtain an ECG and troponin T levels

Administer IV pantoprazole and schedule endoscopy

Discontinue levothyroxine and obtain fT4 levels

Administer IV levofloxacin and obtain chest radiograph

Obtain urine and plasma metanephrine levels

A 25-year-old man comes to the emergency department because of a 1-week-history of progressively worsening dyspnea and intermittent chest pain that increases on inspiration. He had an upper respiratory tract infection 2 weeks ago. His pulse is 115/min and blood pressure is 100/65 mm Hg. Examination shows inspiratory crackles bilaterally. His serum troponin I is 0.21 ng/mL (N < 0.1). An x-ray of the chest shows an enlarged cardiac silhouette and prominent vascular markings in both lung fields; costophrenic angles are blunted. A rhythm strip shows inverted T waves. Which of the following additional findings is most likely in this patient's condition?

Elevated brain natriuretic peptide

Opening snap with low-pitched diastolic rumble

Special populations (elderly, renal dysfunction) for USMLE Step 3: High-Yield Internal Medicine Lessons

Atypical ACS - Not The Classic Crush

Elderly (>75y) & Renal Dysfunction (CKD): Classic anginal chest pain is often absent. A high index of suspicion is key.
Common Atypical Symptoms:
- Dyspnea (most common)
- Syncope, weakness, fatigue
- Delirium/acute confusion
- Epigastric pain, nausea/vomiting
Diagnostic Challenges:
- ECG: Often non-specific. Pre-existing LBBB, LVH, or pacing can obscure STEMI findings.
- Troponins:
  - Chronically elevated in CKD due to ↓ clearance.
  - Diagnosis requires a dynamic change: a rise/fall of >20% from baseline is significant.

⭐ In patients with advanced CKD, a baseline troponin should be established. A subsequent rise of >20% within hours strongly suggests acute MI, even if the absolute value is high at baseline.

Diagnostic Quirks - Reading The Signals

Elderly Patients (>75y): Atypical is Typical
- Symptoms: Dyspnea on exertion is the most common anginal equivalent. Also watch for syncope, weakness, confusion, or epigastric pain. Classic chest pain is often absent.
- ECG: Frequently confounded by pre-existing LBBB, LVH, or pacemaker rhythms, reducing ST-segment specificity.
Chronic Kidney Disease (CKD) Patients:
- Biomarkers: Baseline troponin (cTnT & cTnI) is often chronically elevated due to decreased renal clearance.
- Diagnosis hinges on dynamic change: a significant rise and/or fall in serial troponin levels is required.

⭐ In CKD, a >20% change in serial high-sensitivity troponin (hs-cTn) within hours is a key indicator for acute MI, valued over a single absolute number.

ECG showing LBBB with discordant ST elevation

Treatment Tweaks - Handle With Care

Elderly (>75y): Atypical presentation (e.g., syncope, delirium) is common. Reduced metabolic clearance increases bleeding risk.
- Lower threshold to reduce or withhold P2Y12 inhibitors or anticoagulants.
- Fibrinolysis: Dose reduction for tenecteplase; increased intracranial hemorrhage risk.
Renal Dysfunction (CKD): Drug accumulation is a major concern. Always calculate CrCl.
- Anticoagulants: Dose adjustments are critical. Avoid certain agents.
- Contrast: Risk of contrast-induced nephropathy (CIN). Hydrate well; use low-osmolar contrast.

⭐ High-Yield: In patients >75 years receiving fibrinolytics for STEMI, the risk of intracranial hemorrhage significantly increases. Half-dose tenecteplase may be considered.

Anticoagulants in Special Populations: Benefits and Harms

Elderly patients often present with atypical symptoms like syncope, weakness, or delirium, delaying ACS diagnosis.

Silent MIs are significantly more common in the elderly and in patients with diabetes.

Baseline ECG abnormalities (e.g., LBBB, LVH) can obscure STEMI diagnosis in older adults.

Renal dysfunction is a major bleeding risk factor; requires careful dose adjustment of anticoagulants (e.g., LMWH, bivalirudin).

Contrast-induced nephropathy (CIN) is a key risk during angiography in patients with CKD; pre-procedure hydration is critical.

Avoid NSAIDs in all ACS patients, but especially those with renal issues, due to ↑ thrombotic risk.

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