Acute Care
Symptoms to Diagnosis

The Journey

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ED Chief Complaints → Symptoms → Screening → Consults → Diagnosis

Chief Complaint Key Symptoms Screening Tests Consults Likely Diagnosis → Confirmation
Chest Pain Pressure/tightness, radiation, diaphoresis, anxiety Vitals; ECG ≤10 min; troponin; SpO₂; glucose Cardiology, Pulmonology, Gastroenterology ACS → ECG + troponin; PE → CTPA; GERD → endoscopy
Shortness of Breath Dyspnea, wheeze, orthopnea, cough, tachypnea Vitals; SpO₂; ECG; ABG; peak flow Pulmonology, Cardiology Asthma/COPD → spirometry; HF → BNP+echo; PE → CTPA
Abdominal Pain RUQ/LLQ pain, nausea/vomiting, bloating, guarding Vitals; abdominal exam; UA; pregnancy test Surgery, Gastroenterology, Urology Appendicitis → CT/US; Cholecystitis → US/HIDA; Pancreatitis → lipase+imaging
Headache Photophobia, stiff neck, thunderclap onset, nausea Vitals; neuro exam; fundoscopy Neurology, ID, Rheumatology SAH → CT/LP; Meningitis → CSF; GCA → biopsy
Fever Chills, rigors, malaise, tachycardia Vitals; systemic exam Infectious Disease, Internal Medicine Pneumonia → CXR; UTI → urine culture; Sepsis → SOFA + cultures
Dizziness / Syncope Lightheadedness, LOC, palpitations, vertigo Vitals; orthostatics; ECG; glucose; Dix–Hallpike Cardiology, Neurology, ENT Arrhythmia → ECG/Holter; BPPV → Dix–Hallpike; Stroke → MRI
AMS / Encephalopathy Confusion, agitation, disorientation, lethargy Vitals; glucose; neuro exam; collateral history Neurology, Critical Care, Toxicology Hypoglycemia → labs; Stroke → imaging; Hepatic → ammonia; Uremic → renal panel
Back Pain Focal tenderness, weakness, bowel/bladder change, fever Vitals; neuro exam; red-flag screen Orthopedics, Vascular, Oncology Disc herniation → MRI; Fracture → CT; Infection → MRI+labs; AAA → US/CTA
Extremity Injury / Ischemia Pain, swelling, deformity, pallor, paresthesia Vitals; neurovascular exam Orthopedics, Vascular Surgery Fracture → X-ray/CT; Ischemia → CTA/Doppler
Alcohol / Drug Intoxication Slurred speech, agitation, drowsiness, pupil changes Vitals; neuro exam; glucose Toxicology, Psychiatry Alcohol → serum ethanol; Opioid → naloxone response; Stimulant → tox screen
Dehydration Dry mucosa, poor skin turgor, tachycardia, hypotension Vitals; exam Hospital Medicine, Nephrology Hypovolemia → BUN/Cr, electrolytes

Symptom-First ED Decision Guide

Structured flow: Definition → Causes → Screening → Diagnostics → Pathology (Confirmed by) → Age Spectrum → Specialty Consult. Uses Nature-style in-text superscripts and AMA references.1,2

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1) Chest Pain

Cardio-Pulm

Definition: Discomfort from base of neck to upper abdomen spanning cardiac, pulmonary, GI and MSK sources.3–5

Common causes: ACS, PE, pneumothorax, pneumonia, GERD, costochondritis, anxiety.3–5

Screening Vitals; ECG ≤10 min; SpO₂; glucose; troponin; focused exam.3,4

Diagnostics Serial troponins/ECGs; CXR; D-dimer → CTPA; echocardiography.3,5

Pathology (Confirmed by):

  • ACS — plaque rupture → thrombosis → ischemia (ECG + troponin rise/fall).3,4
  • PE — embolus to pulmonary artery (CT pulmonary angiography).5
  • GERD — LES dysfunction → acid reflux (Endoscopy or 24-h pH).

Age spectrum: Pediatric: infection/congenital; Young: MSK/anxiety; Middle-aged: ACS/PE; Older: ACS, dissection, PE.

Specialty consult: Cardiology; Pulmonology (PE/pneumothorax/pneumonia); GI (reflux).

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2) Shortness of Breath (Dyspnea)

Resp/Cardiac

Definition: Subjective breathing discomfort from pulmonary, cardiac, metabolic or hematologic causes.6–8

Common causes: Asthma/COPD, pneumonia, PE, heart failure, pneumothorax, anemia.6–8

Screening Vitals, auscultation, SpO₂, ECG, peak flow ± ABG.8

Diagnostics CXR; BNP; CBC; D-dimer → CTPA; echocardiogram.6–9

Pathology (Confirmed by):

  • Asthma/COPD — airway inflammation/obstruction (Spirometry with reversibility).
  • Heart failure — pulmonary congestion (BNP + echocardiography).9
  • PE — V/Q mismatch (CTPA).5

Age spectrum: Pediatric: asthma/bronchiolitis; Young: asthma/pneumothorax; Middle-aged: COPD/pneumonia; Older: HF/ILD.

Specialty consult: Pulmonology; Cardiology; Hematology (anemia).

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3) Abdominal Pain

GI

Definition: Pain between chest and pelvis; broad benign-to-surgical spectrum.10–12

Common causes: Appendicitis, cholecystitis, pancreatitis, SBO, diverticulitis, renal colic.11–13

Screening Vitals, abdominal exam, urinalysis, pregnancy test (if applicable).

Diagnostics CBC, CMP/LFTs, lipase; RUQ ultrasound; CT abdomen/pelvis.11–13

Pathology (Confirmed by):

  • Appendicitis — luminal obstruction/infection (CT or US).12
  • Cholecystitis — cystic duct obstruction (RUQ US; HIDA if equivocal).13
  • Pancreatitis — enzyme activation/autodigestion (Lipase ≥3× + imaging).

Age spectrum: Pediatric: constipation/intussusception; Young: appendicitis; Middle-aged: gallstones; Older: diverticulitis/AAA/malignancy.

Specialty consult: General Surgery; GI; Urology (stones).

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4) Headache

Neuro

Common causes: Migraine, tension/cluster, SAH, meningitis, giant cell arteritis.14,15

Screening Neuro exam, vitals, fundoscopy; red flags (thunderclap, neuro deficit, fever/immunosuppression).14

Diagnostics Non-contrast CT; LP if SAH suspected after negative CT; ESR/CRP if GCA suspected.14,15

Pathology (Confirmed by):

  • SAH — aneurysmal bleed (CT ± LP).14
  • Meningitis — CNS infection (CSF analysis/culture).
  • GCA — large-vessel arteritis (Temporal artery biopsy).15

Age spectrum: Young: migraine/tension; Middle-aged: migraine/cluster; Older: GCA, tumor, stroke.

Specialty consult: Neurology; Infectious Disease; Rheumatology (GCA).

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5) Fever

Infectious

Definition: Core temperature ≥38 °C; infection most common driver.7,8

Common causes: Viral URI, pneumonia, UTI, SSTI, sepsis.7,8

Diagnostics CBC, urinalysis/culture, CXR; blood cultures/targeted imaging as indicated.7,8,16

Pathology (Confirmed by):

  • Community-acquired pneumonia — alveolar infection (CXR).7
  • UTI — bacterial infection (Urinalysis + culture).
  • Sepsis — dysregulated host response (Infection + organ dysfunction per Sepsis-3).8,16

Age spectrum: Pediatric: viral illness/otitis; Adult: pneumonia/UTI; Older: UTI/pneumonia/sepsis (often subtle).

Specialty consult: Infectious Disease; Internal Medicine; Pediatrics (children).

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6) Dizziness / Syncope

Neuro/Cardiac

Definition: Dizziness = imbalance/lightheadedness; Syncope = transient LOC from cerebral hypoperfusion.17,28,30

Common causes: Vasovagal, orthostatic hypotension, arrhythmia/structural heart disease; BPPV, vestibular neuritis, Ménière’s; posterior circulation stroke.17,28–30

Screening Orthostatic vitals; ECG & glucose for all syncope; focused neuro exam; Dix-Hallpike for positional vertigo.17,29

Diagnostics Echo/Holter/tilt-table as indicated; MRI/vascular imaging if central signs.17,30

Pathology (Confirmed by):

  • Arrhythmia — conduction disorder (ECG/Holter).18
  • BPPV — otolith displacement (Positive Dix-Hallpike).29
  • Posterior stroke — central ischemia (MRI brain).30

Age spectrum: Young: vasovagal/BPPV; Middle-aged: orthostasis/Ménière’s/arrhythmia; Older: arrhythmia/structural disease/stroke.

Specialty consult: Cardiology; Neurology; ENT (vestibular).

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7) Altered Mental Status / Encephalopathy

Neuro/Metabolic

Definition: Acute change in cognition, attention, or consciousness, including toxic-metabolic and hepatic/uremic encephalopathy.20,21

Common causes: Hypoglycemia, stroke, sepsis, intoxication, hepatic/uremic encephalopathy.20,21

Screening Vitals, glucose, SpO₂, focused neuro exam; collateral history.

Diagnostics CBC/CMP, ABG, ammonia, tox screen; CT head; EEG if seizure suspected.20,21

Pathology (Confirmed by):

  • Stroke — focal ischemia/infarct (CT/MRI).21
  • Sepsis-associated encephalopathy — systemic inflammation (Infection + organ dysfunction).8
  • Hepatic encephalopathy — ammonia-mediated dysfunction (↑Ammonia + clinical course).
  • Uremic encephalopathy — renal failure toxins (↑BUN/Cr).
  • Toxic-metabolic encephalopathy — deranged milieu (Corrective response + labs).

Age spectrum: Young: intoxication/trauma/infection; Middle-aged: stroke/metabolic; Older: infection/metabolic/stroke.

Specialty consult: Neurology; Critical Care; Toxicology.

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8) Back Pain

MSK/Neuro

Common causes: Strain, herniated disc, fracture, spinal infection, malignancy, aneurysm.22–24

Diagnostics Neuro exam; MRI for radiculopathy/red flags; X-ray/CT for fracture; ESR/CRP for infection.22,23

Pathology (Confirmed by):

  • Herniated disc — nerve compression (MRI).23,24
  • Vertebral fracture — cortical disruption (X-ray/CT).22,24
  • Spinal infection — discitis/osteomyelitis (MRI + cultures).22

Age spectrum: Young: strain/herniation; Middle-aged: herniation/fracture; Older: fracture/cancer/infection/AAA.

Specialty consult: Orthopedics; Neurosurgery; Vascular Surgery (AAA); Oncology.

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9) Extremity Injury / Limb Ischemia

Trauma/Vascular

Definition: Acute limb trauma or arterial occlusion compromising perfusion (pain, pallor, pulselessness, paresthesia, paralysis, poikilothermia).27

Common causes: Fracture/dislocation, crush injury, arterial embolism/thrombosis, iatrogenic vascular injury.

Screening Distal pulses, capillary refill, motor/sensory exam; compartment checks when indicated.

Diagnostics X-ray; CT for complex fractures; Doppler US; CT angiography for ischemia; compartment pressure if suspected.25–27

Pathology (Confirmed by):

  • Fracture — cortical disruption (X-ray/CT).25,26
  • Compartment syndrome — ischemia from elevated compartment pressure (Compartment pressure measurement).27
  • Acute limb ischemia — arterial occlusion (CTA/Doppler).

Age spectrum: Pediatric: sports/falls; Young: work/sport trauma; Middle-aged: occupational trauma; Older: fragility fractures, PAD/embolism.

Specialty consult: Orthopedics; Vascular Surgery.

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10) Alcohol & Drug Intoxication

Tox/Psych

Definition: Acute impairment from ethanol, opioids, sedatives, stimulants, or polysubstance use.35–37

Common causes: Alcohol intoxication/withdrawal; opioid toxicity; cocaine/amphetamine toxicity; benzodiazepine/sedative overdose.

Screening Vitals, mental status, glucose, SpO₂; targeted exam for trauma/aspiration.

Diagnostics Serum ethanol; urine/blood tox screen; CMP; ABG if hypoventilation; ECG for stimulants.35–37

Pathology (Confirmed by):

  • Opioid toxicity — μ-agonism → respiratory depression (Clinical + tox screen; response to naloxone).35
  • Alcohol intoxication — CNS depression (Serum ethanol).
  • Sympathomimetic toxicity — catecholamine surge (Clinical + tox screen/ECG).

Age spectrum: Young: recreational use; Middle-aged: polysubstance/dependence; Older: meds interactions/overdose.

Specialty consult: Medical Toxicology; Psychiatry; Internal Medicine/Critical Care.

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11) Dehydration

Fluid/Electrolyte

Definition: Total body water deficit impairing perfusion; hypovolemic and hypernatremic states carry distinct risks.36,38

Common causes: GI losses (vomiting/diarrhea), heat illness, poor intake (infants/older adults), diuretics, osmotic diuresis.

Screening Orthostatic vitals, mucous membranes, skin turgor, capillary refill, urine output.

Diagnostics BMP (electrolytes, BUN/Cr ratio), serum osmolality, urinalysis; lactate if shock.36,38

Pathology (Confirmed by):

  • Hypovolemia — reduced preload/CO (↑BUN/Cr ratio, hemoconcentration, clinical response to fluids).
  • Hypernatremic dehydration — cellular dehydration (↑Serum Na / osmolality).

Age spectrum: Pediatric: GI illness/high turnover; Adult: exercise/heat; Older: impaired thirst/renal changes/meds.

Specialty consult: Internal Medicine; Nephrology (electrolyte/renal involvement).

References (AMA-style)

  1. Rui P, Kang K. National Hospital Ambulatory Medical Care Survey: 2017 Emergency Department Summary Tables. National Center for Health Statistics; 2017.
  2. Stang AS, Wingert AS, Hartling L, Plint AC. Adverse events related to emergency department care: a systematic review. Pediatrics. 2013;132(2):314-322.
  3. Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC Guideline for the Evaluation and Diagnosis of Chest Pain. Circulation. 2021;144(22):e368-e454.
  4. Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC guideline for the management of patients with non–ST-elevation acute coronary syndromes. Circulation. 2014;130(25):e344-e426.
  5. Konstantinides SV, Meyer G, Becattini C, et al. 2019 ESC Guidelines for the diagnosis and management of acute pulmonary embolism. Eur Heart J. 2020;41(4):543-603.
  6. Mueller C, Scholer A, Laule-Kilian K, et al. Use of B-type natriuretic peptide in the evaluation and management of acute dyspnea. N Engl J Med. 2004;350(7):647-654.
  7. Metlay JP, Waterer GW, Long AC, et al. Diagnosis and treatment of adults with community-acquired pneumonia. Am J Respir Crit Care Med. 2019;200(7):e45-e67.
  8. Singer M, Deutschman CS, Seymour CW, et al. The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3). JAMA. 2016;315(8):801-810.
  9. Yancy CW, Jessup B, Bozkurt B, et al. 2013 ACCF/AHA Guideline for the Management of Heart Failure. Circulation. 2013;128(16):e240-e327.
  10. Cartwright SL, Knudson MP. Evaluation of acute abdominal pain in adults. Am Fam Physician. 2008;77(7):971-978.
  11. American College of Radiology (ACR). ACR Appropriateness Criteria® Acute Abdominal Pain. ACR; 2021.
  12. Smith MP, Katz DS, Lalani T, et al. ACR Appropriateness Criteria® Right Lower Quadrant Pain—Suspected Appendicitis. J Am Coll Radiol. 2018;15(11S):S373-S387.
  13. Yokoe M, Hata J, Takada T, et al. Tokyo Guidelines 2018: diagnostic criteria and severity grading of acute cholecystitis. J Hepatobiliary Pancreat Sci. 2018;25(1):41-54.
  14. Edlow JA, Panagos PD, Godwin SA, Thomas TL, Decker WW; ACEP. Clinical policy: adult patients with acute headache. Ann Emerg Med. 2008;52(4):407-436.
  15. Mack WJ, Greenberg SM. Evaluation and management of giant cell arteritis. JAMA. 2015;314(12):1272-1281.
  16. Bone RC, Balk RA, Cerra FB, et al. Definitions for sepsis and organ failure. Chest. 1992;101(6):1644-1655.
  17. Shen WK, Sheldon RS, Benditt DG, et al. 2017 ACC/AHA/HRS Guideline for patients with syncope. J Am Coll Cardiol. 2017;70(5):e39-e110.
  18. Krahn AD, Klein GJ, Yee R, et al. Use of ambulatory monitoring in syncope and presyncope. Ann Intern Med. 1999;130(10):847-853.
  19. Kapoor WN. Evaluation and outcome of patients with syncope. Medicine (Baltimore). 2000;79(3):160-175.
  20. Wijdicks EFM, Sheth KN, Carter BS, Greer DM, Kasner SE, Kimberly WT. ENLS: approach to coma. Neurocrit Care. 2017;27(Suppl 1):25-36.
  21. Adams HP Jr, del Zoppo G, Alberts MJ, et al. Early management of adults with ischemic stroke. Stroke. 2007;38(5):1655-1711.
  22. Chou R, Qaseem A, Snow V, et al. Diagnosis and treatment of low back pain. Ann Intern Med. 2007;147(7):478-491.
  23. Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Ann Intern Med. 2002;137(7):586-597.
  24. Deyo RA, Weinstein JN. Low back pain. N Engl J Med. 2001;344(5):363-370.
  25. Stiell IG, Greenberg GH, McKnight RD, et al. Decision rules for radiography in acute ankle injuries. JAMA. 1993;269(9):1127-1132.
  26. Bachmann LM, Kolb E, Koller MT, ter Riele J, et al. Accuracy of Ottawa ankle rules to exclude fractures. BMJ. 2003;326(7393):417.
  27. Hunt D, Lau L, Meijer DL, et al. Compartment syndrome: diagnosis and emergency management. J Trauma. 2017;83(2):341-349.
  28. Kerber KA, Newman-Toker DE. Misdiagnosing dizzy patients: pitfalls in practice. Neurol Clin. 2015;33(3):565-575.
  29. Tusa RJ. Benign positional vertigo. N Engl J Med. 2019;380(12):1119-1127.
  30. Newman-Toker DE, Edlow JA. Avoiding misdiagnosis in dizziness/vertigo. Emerg Med Clin North Am. 2015;33(3):465-481.
  31. Kearon C, Akl EA, Ornelas J, et al. Antithrombotic therapy for VTE disease (CHEST). Chest. 2016;149(2):315-352.
  32. Wells PS, Anderson DR, Bormanis J, et al. Value of pretest probability (DVT). Lancet. 1997;350(9094):1795-1798.
  33. Righini M, Le Gal G, Roy PM, et al. D-dimer in suspected DVT. J Thromb Haemost. 2006;4(6):1243-1248.
  34. Bernardi E, Camporese G, Büller HR, et al. Serial limited vs whole-leg US for DVT. Ann Intern Med. 2008;149(4):276-285.
  35. Boyer EW. Management of opioid analgesic overdose. N Engl J Med. 2012;367(2):146-155.
  36. Volkow ND, McLellan AT. Opioid abuse in chronic pain—misconceptions and mitigation strategies. N Engl J Med. 2016;374(13):1253-1263.
  37. Hoffman RS, Howland MA, Lewin NA, Nelson LS, Goldfrank LR. Goldfrank’s Toxicologic Emergencies. 11th ed. McGraw-Hill; 2019.
  38. McGee S, Abernethy WB, Simel DL. The rational clinical examination. Is this patient hypovolemic? JAMA. 1999;281(11):1022-1029.