Panic Disorder Clinical Overview
I. The "On-Call" Snapshot
Clinical Significance in Malaysia
This is a high-priority "mimic." Patients with Panic Disorder frequently present to the A&E convinced they are having a heart attack or severe asthma attack. Your job as a House Officer is to safely and efficiently rule out life-threatening organic causes (like ACS or PE) without over-investigating and to initiate appropriate management to break the cycle of repeated A&E visits.
High-Yield Definition
(Based on DSM-5) Panic Disorder is characterised by recurrent, unexpected panic attacks. A panic attack is an abrupt surge of intense fear or discomfort that peaks within minutes, during which four (or more) of the 13 specific physical and cognitive symptoms occur. The disorder is diagnosed when these attacks are followed by $\geq$1 month of persistent concern about more attacks or by a significant maladaptive change in behaviour (e.g., avoidance).
Clinical One-Liner
"The patient keeps coming to A&E for 'heart attacks,' but their ECGs, troponins, and physical exams are always normal."
II. Etiology & Risk Factors
Etiology
Multifactorial. There is no single cause. The main drivers are:
Neurobiological: Imbalance in neurotransmitters (serotonin, norepinephrine) and a hypersensitive "fear circuit" involving the amygdala, hypothalamus, and brainstem.
Genetic: Strong familial component; 40-50% heritability.
Psychosocial: Major life stressors, adverse childhood experiences (e.g., abuse, trauma), or learned fear responses.
Risk Factors
Female sex (2-3x more common)
Family history of panic disorder or other anxiety/mood disorders
Personal history of other psychiatric illness (e.g., MDD, other anxiety disorders)
History of childhood trauma or abuse
Significant psychosocial stressors (e.g., job loss, divorce)
Substance use (e.g., caffeine, stimulants) and smoking
III. Quick Pathophysiology
Think of it as a faulty "fight-or-flight" alarm. The amygdala (the brain's fear centre) inappropriately fires, triggering a massive sympathetic nervous system surge. This causes the physical symptoms (tachycardia, palpitations, tachypnoea, sweating). The patient's prefrontal cortex then catastrophically misinterprets these physical symptoms as a sign of imminent death (e.g., "My heart is racing, I must be having a heart attack!"). This cognitive fear feeds back into the amygdala, creating a vicious positive feedback loop that results in a full-blown panic attack.
IV. Classification
The primary classification is from the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, 5th Ed.).
The key distinction is:
Panic Disorder: Recurrent unexpected attacks plus anticipatory anxiety or avoidance.
Panic Attack Specifier: The panic attack occurs in the context of another mental disorder (e.g., a patient with a specific phobia of spiders has a panic attack when they see a spider).
Clinically, we also classify it as:
Panic Disorder without Agoraphobia
Panic Disorder with Agoraphobia: Fear and avoidance of places or situations from which escape might be difficult or help unavailable if a panic attack occurs (e.g., crowds, public transport, being outside the home alone).
V. Clinical Assessment
🚩 Red Flags & Immediate Actions
Your priority is to rule out organic pathology. If these signs are present, manage them as the emergency they are.
Flag: Chest pain radiating to the jaw/arm, associated with diaphoresis, in a high-risk patient (DM, HPT).
Action: Immediate ECG, cardiac enzymes. Manage as ACS.
Reason: Rules out Myocardial Infarction.
Flag: Sudden, severe SOB with pleuritic chest pain, hypoxia ($SpO_2 <94\%$), and unilateral leg swelling.
Action: D-dimer, Wells' Score, consider CTPA. Manage as potential PE.
Reason: Rules out Pulmonary Embolism.
Flag: Palpitations with associated syncope or a specific ECG abnormality (e.g., broad complex tachycardia, delta waves).
Action: Cardiac monitoring, urgent cardiology consult.
Reason: Rules out life-threatening arrhythmia.
Flag: Focal neurological deficits (e.g., unilateral weakness, slurred speech).
Action: CT Brain, manage as stroke.
Reason: Rules out CVA/TIA.
History
Key Diagnostic Clues (Pathognomonic/Classic Presentations)
Abrupt & Peaking: Symptoms develop abruptly and peak within 5-10 minutes.
Recurrent & Unexpected: Attacks happen "out of the blue," not always tied to a specific trigger.
Anticipatory Anxiety: The patient develops a "fear of the fear itself," spending much of their time worrying about when the next attack will strike.
Catastrophic Cognitions: During the attack, the patient genuinely believes they are dying, "going crazy," or losing control.
Symptom Breakdown (DSM-5 Criteria - Need 4+)
Common (>50%): Palpitations/pounding heart, sweating, trembling/shaking, shortness of breath, feelings of choking, chest pain, nausea, dizziness/lightheadedness, fear of dying, fear of losing control.
Less Common (10-50%): Chills or heat sensations, paresthesias (numbness/tingling), derealization (feelings of unreality), depersonalization (being detached from oneself).
Pertinent Negatives
No fever (rules out sepsis, infection).
No exertional component to chest pain (argues against stable angina).
No true syncope (lightheadedness is common, loss of consciousness is rare).
No preceding aura (argues against temporal lobe epilepsy).
Symptoms are not better explained by substance use (e.g., cocaine) or a medical condition (e.g., hyperthyroidism).
Physical Examination (OSCE Approach)
The physical exam is often completely normal between attacks. During an attack, you may find signs of sympathetic overdrive.
General Inspection: Patient appears highly anxious, distressed, may be pacing or tearful.
Vitals: Tachycardia (usually sinus), tachypnoea, transiently elevated BP. Absence of fever or hypoxia.
Disease-Specific Examination (System-based):
Cardiovascular: Tachycardic, regular rhythm. Pertinent Negatives: No murmurs, no rubs, no JVP elevation, no peripheral oedema.
Respiratory: Tachypnoeic, but air entry is clear and equal bilaterally. Pertinent Negatives: No wheeze, no crackles.
Neurological: GCS 15/15. Patient is alert and oriented. May have peripheral tingling from hyperventilation (respiratory alkalosis). Pertinent Negatives: No focal deficits, power 5/5 all limbs, normal cranial nerves.
Other: Check thyroid for goitre, eyes for exophthalmos (to rule out thyrotoxicosis).
Differentiating Disease Stage
This is less about "staging" and more about severity and chronicity.
Early / Mild Disease: Infrequent attacks, minimal anticipatory anxiety, no avoidance behaviour.
Intermediate / Moderate Disease: More frequent attacks, clear anticipatory anxiety, starting to avoid specific situations (e.g., driving on the highway).
Late / Severe Disease: Frequent (daily/weekly) attacks, severe anticipatory anxiety, significant agoraphobia (e.g., unable to leave the home).
Clinical Pearl
A patient having a panic attack often says, "Doctor, I feel like I'm dying!" A patient with a true MI is often quiet, pale, and just says, "Doctor, chest pain." The distress level is not always proportional to the organic pathology.
VI. Diagnostic Workflow
Differential Diagnosis
This is a diagnosis of exclusion. Your main job is to rule these out.
Acute Coronary Syndrome (ACS)
Points For: Chest pain, SOB, palpitations, diaphoresis, sense of doom.
Points Against: Normal ECG, negative troponins, pain is often sharp/atypical (not crushing/exertional), patient is often young with no risk factors.
How to Differentiate: Serial ECGs and cardiac enzymes.
Pulmonary Embolism (PE)
Points For: Sudden onset SOB, tachycardia, sense of doom, pleuritic chest pain.
Points Against: No hypoxia, no VTE risk factors (e.g., immobility, OCP, malignancy), negative D-dimer (in low-risk patient).
How to Differentiate: Wells' Score, D-dimer, CT Pulmonary Angiogram (if indicated).
Arrhythmia (e.g., SVT, AF)
Points For: Sudden onset palpitations, dizziness, tachycardia.
Points Against: ECG shows Sinus Tachycardia, not a primary arrhythmia. Vagal manoeuvres have no effect.
How to Differentiate: ECG during an episode, Holter monitor.
Hyperthyroidism (Thyrotoxicosis)
Points For: Anxiety, tachycardia, sweating, tremors.
Points Against: Symptoms are episodic (not constant), absence of goitre, exophthalmos, or weight loss.
How to Differentiate: Thyroid Function Tests (TFTs).
Hypoglycemia
Points For: Anxiety, sweating, tremor, tachycardia.
Points Against: Patient is not diabetic, symptoms resolve with reassurance (not food), RBS is normal.
How to Differentiate: Bedside glucometer (RBS).
Investigations Plan
Bedside / Initial (First 15 Mins):
Vitals: ($BP, HR, RR, SpO_2, Temp$). Look for tachycardia, tachypnoea.
ECG (12-lead): CRITICAL. Rule out STEMI, arrhythmia. (Will show sinus tachycardia in panic).
RBS: Rule out hypoglycemia.
First-Line Labs & Imaging: (Tailor to history)
Cardiac Enzymes: (Troponin I/T). Essential if patient has chest pain.
FBC: Rule out severe anaemia causing tachycardia.
TFTs: Rule out hyperthyroidism.
D-dimer: If clinical suspicion for PE is present (use Wells' score).
CXR: If respiratory symptoms are prominent (rule out pneumothorax, pneumonia).
Confirmatory / Gold Standard:
There is no lab test for Panic Disorder.
The diagnosis is clinical, based on DSM-5 criteria, after all relevant organic causes have been excluded.
VII. Staging & Severity Assessment
Panic Disorder Severity Scale (PDSS): This is a 7-item clinician-rated or self-reported scale.
It assesses frequency of attacks, distress during attacks, anticipatory anxiety, avoidance, and functional impairment.
Impact: A high score ($\geq 14$) suggests severe disorder and indicates the need for more intensive treatment (e.g., definite pharmacotherapy + CBT) vs. psychoeducation alone for mild cases.
VIII. Management Plan
A. Principle of Management
Acute: Provide safety, reassurance, and break the acute attack.
Long-Term: Prevent future attacks, reduce anticipatory anxiety, and treat co-morbidities.
The most effective long-term strategy is a combination of pharmacotherapy and psychotherapy.
B. Immediate Stabilisation (The A&E Plan)
(This applies to a patient in A&E with a severe panic attack after red flags are ruled out).
A (Airway): Secure.
B (Breathing): Patient is tachypnoeic but $SpO_2$ is normal.
Action: Provide reassurance. Encourage slow, deep breaths (or "box breathing"). Do not give paper bag (risk of hypoxia if cause is organic). High-flow oxygen can be given for its placebo/reassurance effect.
C (Circulation): Vitals stable, BP normal/high, sinus tachycardia.
Action: IV access (if not already sited for workup).
D (Disability): GCS 15/15, anxious.
Action: Place patient in a quiet, non-stimulating room. Use a calm, reassuring voice.
Medication (Judicious use): If reassurance fails and patient is highly agitated, a short-acting benzodiazepine can be used.
PO Diazepam 2-5mg (slower onset, longer-acting)
IM/IV Midazolam 1-2mg (fast-acting, use with caution, monitor vitals)
Crucial: This is not a long-term solution. This is for acute agitation in A&E.
E (Exposure): N/A.
C. Definitive Treatment (The Ward Round / Clinic Plan)
(Based on Malaysian CPG on Management of Depression/Anxiety and UpToDate)
First-Line: SSRI + CBT
Psychotherapy: Cognitive Behavioural Therapy (CBT) is first-line. Refer to Psychiatry / Clinical Psychologist. This is the curative-intent treatment.
Pharmacotherapy (SSRI):
Escitalopram: Start 5mg OD, titrate to 10-20mg OD.
Sertraline: Start 25mg OD, titrate to 50-200mg OD.
Key Counselling: Warn patient that anxiety may worsen for the first 1-2 weeks. This is normal. Do not stop.
Bridging Therapy
Because SSRIs take 2-4 weeks to work, you can "bridge" with a benzodiazepine for the first 2-4 weeks, then taper it off.
Example: PO Clonazepam 0.25-0.5mg BD prn.
Warning: High addiction potential. Use short-term only.
Second-Line
Switch to another SSRI.
Switch to an SNRI (e.g., Venlafaxine XR, start 37.5mg OD).
Refer to Psychiatry.
D. Long-Term & Discharge Plan
From A&E: Discharge once stable with a clear diagnosis (e.g., "Non-cardiac chest pain, likely panic attack").
Follow-up: Refer to primary care (Klinik Kesihatan) for initiation of SSRI and monitoring. Refer to Psychiatry clinic if severe, co-morbid, or agoraphobic.
Lifestyle:
Reduce/Stop: Caffeine, smoking, alcohol, and other stimulants.
Start: Regular physical exercise (excellent anxiolytic).
Sleep hygiene.
Medication Duration: Continue SSRI for at least 6-12 months after remission to prevent relapse.
IX. Complications
Immediate/Short-Term:
Agoraphobia: Develops in 30-50% of patients.
Functional Impairment: Inability to work, attend school, or maintain social relationships.
Iatrogenic: Benzodiazepine dependence from improper management.
Long-Term:
Co-morbid MDD: High rate of developing Major Depressive Disorder.
Substance Use Disorder: Self-medicating with alcohol or illicit drugs.
Suicide Risk: Increased risk, especially with co-morbid depression.
X. Prognosis
With treatment (CBT + SSRI), the prognosis is good. Most patients (70-80%) achieve significant improvement or remission.
Without treatment, it is a chronic, relapsing-remitting condition.
Poor Prognostic Factors: Baseline severity, longer duration of illness, presence of agoraphobia, co-morbid psychiatric illness (especially MDD or personality disorder), poor treatment adherence.
XI. How to Present to Your Senior
Use the SBAR format.
"Dr. [Senior's Name], for your review, patient [Name], [Age/Sex] in [Yellow Zone].
S (Situation): Patient presented with an acute episode of chest pain, palpitations, and feeling 'like I am dying.' This is their third A&E visit this month.
B (Background): Vitals are stable. ECG shows sinus tachycardia. Serial troponins and D-dimer are negative. CXR is clear. TFTs and FBC are normal.
A (Assessment): All life-threatening organic causes have been ruled out. The clinical picture, with recurrent, abrupt-onset attacks and catastrophic cognitions, is consistent with Panic Disorder.
R (Recommendation): I have provided reassurance, and the patient's symptoms are resolving. I plan to discharge with a referral to the KK clinic for follow-up and initiation of an SSRI, and a referral to the Psychiatry clinic for CBT. I have also advised on caffeine cessation. Is this plan acceptable?"
XII. Summary & Further Reading
Top 3 Takeaways
Rule out the killers first: Your priority is to exclude ACS, PE, and arrhythmia.
Diagnosis is clinical (DSM-5) after a negative workup. Do not attribute symptoms to panic until organic causes are ruled out.
First-line treatment is SSRI + CBT. Benzodiazepines are a short-term "bridge" or A&E tool, not a long-term solution.
Key Resources
UpToDate: "Panic disorder in adults: Epidemiology, pathogenesis, clinical manifestations, course, assessment, and diagnosis" and "Pharmacotherapy for panic disorder with or without agoraphobia in adults".
Amboss: "Panic disorder"
Local CPG: Malaysian Clinical Practice Guidelines (CPG) on Management of Major Depressive Disorder (2020) - Useful for principles of SSRI use, though anxiety-specific CPGs should be sought.
