Shortness of Breath OSCE - Anxiety Hyperventilation

Diagnosis: Anxiety Hyperventilation

Case Overview

  • Age/Sex: 23-year-old female
  • Occupation: University student (under exam stress)
  • Setting: Student health clinic / urgent care during exam period
  • Chief complaint: "Shortness of breath"

Patient Script

Who I Am

I'm a 23-year-old university student, currently in the middle of exams and feeling very stressed.

What Brings Me In

"I'm really short of breath and dizzy — it started out of nowhere while I was studying and now I can't catch my breath."

My Story

I woke up fine this morning and went to the library. About an hour ago while revising for an exam, I suddenly felt very short of breath and began breathing faster. It came on quickly over a couple of minutes. I felt my heart racing and got lightheaded and tingly around my mouth and in my fingers. It felt like I couldn't get enough air even though I kept breathing faster. The episodes have been intermittent since it started—each bout lasts a few minutes but I'm still feeling breathless and anxious now. I've had a couple of milder episodes like this before around exam time, but never this intense.

I also had a lot of coffee and an energy drink this morning because I'm tired from late-night studying. I sometimes vape socially at parties (maybe once or twice a month). My aunt has asthma, and I once used an inhaler as a teenager for a bad cough, but I was never told I had asthma. I had a mild cold about 3 weeks ago that settled on its own.

My Medical Background

  • Past medical history: no diagnosed chronic illnesses; occasional panic-type episodes in past during exams (milder)
  • Medications: combined oral contraceptive pill
  • Allergies: none known
  • Social: drinks several cups of coffee / energy drinks during exam weeks; occasional vaping at parties; no regular smoking; lives in student accommodation
  • Family history: mother well, aunt with asthma

What I Think & Worry About

  • "I'm worried this could be something serious like my heart or lungs — what if it's a blood clot or something wrong with my heart?"
  • "I think I'm having a panic attack because I'm so stressed about exams — but what if I'm wrong and it's something dangerous?"
  • "I want something that will stop this quickly so I can get back to studying."

If You Ask Me About Other Symptoms...

  • Chest pain: "I have a mild tightness in my chest but no crushing pain — more like pressure when I breathe fast."
  • Cough/fever: "No cough, no fever."
  • Sputum: "No phlegm."
  • Leg pain/swelling: "No, my legs are fine."
  • Fainting/syncope: "I felt lightheaded but didn’t faint."
  • Recent travel/immobility: "No recent travel, I've been at university all week."
  • Medication/substance use: "Only the contraceptive pill; I had an energy drink and two coffees today; I sometimes vape at parties but not today."
  • Pregnancy: "I’m not pregnant as far as I know."

Clinical Summary

Examination

  • General: anxious, hyperventilating, appears distressed
  • Vital signs: T 36.8°C, HR 110 bpm (sinus tachycardia), RR 26 breaths/min, BP 118/72 mmHg, SpO2 99% on room air
  • Respiratory: chest expansion equal, good air entry bilaterally, no wheeze, no crackles
  • Cardiovascular: tachycardic, normal S1/S2, no murmurs, no peripheral oedema
  • Abdomen: soft, non-tender
  • Neurological: alert and oriented, no focal deficits; perioral and distal finger paresthesia reported on exam

Investigations

  • Pulse oximetry: SpO2 99% on room air (reassuring)
  • Arterial blood gas (room air): pH 7.55 (alkalosis), PaCO2 19 mmHg (low), PaO2 100 mmHg (normal), HCO3- 17 mEq/L (slightly low) (consistent with acute respiratory alkalosis)
  • ECG: sinus tachycardia at 110 bpm, no ischemic changes or arrhythmia
  • Chest X-ray: clear, no consolidation, no pneumothorax
  • Peak expiratory flow: 470 L/min (within expected range for age/height) (argues against acute bronchospasm)
  • FBC: Hb 13.0 g/dL (no anaemia)
  • Electrolytes: Na/K/Cl normal; ionized calcium borderline low (e.g., 1.10 mmol/L) consistent with symptoms of paresthesia

Diagnosis

  • Primary: Anxiety-related hyperventilation / panic-associated hyperventilation resulting in acute respiratory alkalosis

    • Evidence: acute onset during exam stress, rapid shallow/deep breathing, perioral and distal paresthesia, normal oxygen saturation, normal chest examination and CXR, normal peak flow, ABG showing respiratory alkalosis (low PaCO2, high pH).

  • Differentials:

    • Asthma exacerbation — less likely: no wheeze, normal peak flow, no cough or history of regular asthma
    • Pulmonary embolism — less likely: sudden dyspnoea and tachycardia can occur, but low pre-test probability (young, ambulatory, no DVT signs), normal SpO2 and no risk factors; would consider if clinical suspicion higher
    • Cardiac arrhythmia or ischaemia — less likely: ECG shows sinus tachycardia without ischemic changes and she is young with no cardiac history
    • Anaemia — less likely: Hb normal

Management

  • Immediate:

    • Reassure the patient calmly and address the anxiety directly
    • Coach controlled breathing: slow diaphragmatic breathing (inhale for 4, exhale for 6) or guided paper/closed-circuit rebreathing only if oxygenation is normal and no suspicion of hypoxia (prefer controlled breathing over paper bag technique in many settings)
    • Sit patient upright and loosen tight clothing
    • Observe vital signs; repeat SpO2 and monitor
    • Consider a short dose of a benzodiazepine (e.g., lorazepam) if severe distress and non-pharmacologic measures fail — use lowest effective dose and consider consent/contraindications

  • Investigations/avoidance of harm:

    • No routine oxygen therapy unless hypoxic
    • Avoid unnecessary bronchodilators unless objective evidence of bronchospasm
    • If clinical suspicion for PE or other organic disease increases, escalate with D-dimer/CTPA as indicated

  • Follow-up and long-term:

    • Explain diagnosis: link symptoms to hyperventilation and anxiety
    • Provide brief education on paced breathing and grounding techniques
    • Advise reduction of caffeine/energy drinks during exam periods
    • Arrange prompt follow-up with primary care and referral to student counselling/mental health services for cognitive behavioural therapy (CBT) and review of recurrent panic symptoms
    • Consider pharmacotherapy (SSRI) if recurrent/persistent panic disorder after specialist review

Key Learning Points

  • Hyperventilation from anxiety typically produces acute respiratory alkalosis (low PaCO2, high pH) with preserved oxygen saturation and normal chest examination—distinguish from primary cardiopulmonary causes.

  • Management focuses first on reassurance and controlled breathing techniques; treat physiologic disturbance and address acute anxiety, and reserve invasive or disease-specific treatments for when objective evidence supports them.

  • Always consider and exclude red flags (hypoxia, focal neurological signs, risk factors for pulmonary embolism, significant chest pain or arrhythmia) before attributing symptoms to anxiety.

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