What are concise step‑by‑step clinical algorithms for evaluating and managing common internal‑medicine presentations such as acute chest pain, dyspnea, fever of unknown origin, anemia, and hypertension?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: November 7, 2026 • View editorial policy

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.

Ask Question

Internal Medicine Disease Algorithms

Acute Chest Pain Evaluation

For patients presenting with acute chest pain, obtain a 12-lead ECG within 10 minutes and measure serial high-sensitivity cardiac troponin levels to rapidly stratify risk and guide immediate management 1.

Step-by-Step Algorithm:

Immediate Actions (First 10 minutes):

  • Obtain 12-lead ECG immediately
  • If ST-elevation present → activate STEMI protocol for immediate catheterization 1
  • If ST-depression present → manage as NSTE-ACS 1
  • Obtain chest radiograph to evaluate cardiac, pulmonary, and thoracic causes 1

Serial ECG Strategy:

  • If initial ECG is normal or nondiagnostic, repeat ECGs serially while symptoms persist 1
  • Compare with prior ECGs when available
  • Critical pitfall: Up to 6% of evolving ACS patients have normal initial ECG 1
  • Left circumflex and right coronary occlusions may be "electrically silent" – consider right-sided leads 1
  • Left ventricular hypertrophy, bundle branch blocks, and ventricular pacing can mask ischemia 1

Biomarker Protocol:

  • Use high-sensitivity cardiac troponin I or T as preferred biomarker 1
  • Measure serial levels to identify abnormal values and rising/falling patterns indicating acute myocardial injury 1
  • High-sensitivity troponin enables rapid rule-out pathways in low-risk patients 2

Imaging:

  • Chest radiograph useful for: pneumonia, pneumothorax, rib fractures, pleural effusions, widened mediastinum (aortic dissection), pulmonary artery enlargement 1
  • Should not delay urgent revascularization if indicated 1

Hypertensive Emergencies

Hypertensive emergencies require immediate intravenous BP reduction based on the specific organ damage present, not on an arbitrary BP threshold 3.

Recognition and Classification:

Definition: Substantially elevated BP with acute hypertension-mediated organ damage (HMOD) 3

Key presentations requiring immediate IV therapy:

Clinical Presentation Target BP Timeline
Acute aortic dissection SBP <120 mmHg + HR <60 bpm Immediate
Acute cardiogenic pulmonary edema SBP <140 mmHg Immediate
Acute coronary syndrome SBP <140 mmHg Immediate
Acute hemorrhagic stroke (SBP >180) 130<SBP<180 mmHg Immediate
Eclampsia/severe preeclampsia SBP <160, DBP <105 mmHg Immediate
Hypertensive encephalopathy MAP −20% to −25% Immediate
Malignant hypertension ± TMA MAP −20% to −25% Several hours
Acute ischemic stroke (SBP >220 or DBP >120) MAP −15% 1 hour

3

Diagnostic Workup:

History focus:

  • Preexisting hypertension
  • Medication nonadherence
  • BP-elevating drugs: NSAIDs, steroids, immunosuppressants, sympathomimetics, cocaine, antiangiogenic therapy 3

Physical examination:

  • Cardiovascular and neurologic assessment
  • Fundoscopy (hemorrhages, cotton wool spots, papilledema) 3

Laboratory analysis:

  • Hemoglobin, platelets, creatinine, sodium, potassium
  • LDH, haptoglobin (for thrombotic microangiopathy)
  • Urinalysis for protein and sediment 3

Additional testing based on presentation:

  • Troponins if chest pain
  • Chest X-ray if congestion/fluid overload
  • Echocardiogram for cardiac structure/function
  • CT/MRI brain if neurologic symptoms
  • CT-angiography if acute aortic disease suspected 3

Critical note: Secondary causes found in 20-40% of malignant hypertension cases – appropriate workup indicated 3

Acute Dyspnea Evaluation

Dyspnea carries 9% in-hospital mortality and 16-18% ICU admission rate, requiring rapid triage using structured pathophysiologic assessment across cardiac, pulmonary, and systemic domains 4.

RHELITA Diagnostic Framework:

The structured approach spans seven domains 5:

R - Risk factors:

  • Cardiac: prior MI, heart failure, arrhythmias
  • Pulmonary: COPD, asthma, prior PE
  • Thromboembolic: immobility, malignancy, surgery

H - History:

  • Onset (sudden vs. gradual)
  • Positional changes
  • Associated symptoms (chest pain, fever, cough, hemoptysis)

E - Examination findings:

  • Vital signs including oxygen saturation
  • Cardiac: JVD, S3 gallop, peripheral edema
  • Pulmonary: wheezing, crackles, decreased breath sounds
  • Signs of tamponade: muffled heart sounds, pulsus paradoxus

L - Laboratory:

  • Arterial blood gas analysis
  • Troponin if cardiac etiology suspected
  • BNP/NT-proBNP for heart failure
  • D-dimer based on PE probability

I - Imaging:

  • Chest radiograph (first-line)
  • ECG (arrhythmias, ischemia)
  • Advanced imaging as indicated

T - Treatment response:

  • Response to empirical therapy helps confirm diagnosis

A - Alternate diagnosis exclusion:

  • Systematically rule out life-threatening causes

5

Pulmonary Embolism Assessment:

Use Wells criteria for clinical risk stratification 6:

  • Low risk: D-dimer testing
  • Intermediate risk: D-dimer testing
  • High risk: Proceed directly to imaging (CT pulmonary angiography) 6

Common Pitfalls Across All Algorithms:

  1. Over-reliance on single normal test: Normal ECG doesn't exclude ACS; normal initial troponin doesn't exclude MI 1

  2. Ignoring "electrically silent" territories: Left circumflex occlusions often show normal ECG 1

  3. Treating BP number instead of organ damage: Asymptomatic severe hypertension without HMOD is not an emergency 3

  4. Inadequate serial assessment: Single time-point evaluation misses evolving pathology 1

  5. Missing secondary causes: 20-40% of malignant hypertension has identifiable secondary cause 3

References

Related Questions

What are the guidelines for assessing and ruling out life‑threatening causes of chest pain?
What is the recommended approach to evaluating and managing a patient presenting with chest pain?
What is the appropriate evaluation and management for a 38-year-old patient presenting with mild chest tightness and a blood pressure of 143/90 mm Hg?
Should a 55‑year‑old woman with chest pressure radiating to the neck, diaphoresis, persistent mild chest pain, and tachycardia be sent to the emergency department for urgent cardiac evaluation?
What is the appropriate initial evaluation and management for a 61-year-old male presenting with chest pain and a history of coronary artery disease?
What are the causes of chronic neurogenic muscle pain?
What is the appropriate management of melena (blackish stool) in a patient?
What is the recommended management for Pott's disease of the spine?
Do I need to obtain hepatitis B and hepatitis C screening before starting Olumiant (baricitinib)?
Which antidiabetic agents are safe and recommended for patients with chronic kidney disease?
In a patient with a suppressed TSH of 0.1 µIU/mL, normal free T4 (1.08 ng/dL) and free T3 (2.95 pg/mL), is it appropriate to initiate amiodarone therapy?

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.