Bipolar Type 2 Disorder Clinical Overview

I. The "On-Call" Snapshot

• Clinical Significance in Malaysia: This is a common, underdiagnosed mood disorder that you will encounter frequently. Patients often present with recurrent depressive episodes and are mismanaged with antidepressants alone, which can worsen the condition. Your job is to pick up the subtle signs of hypomania.

• High-Yield Definition: Bipolar II Disorder is defined by a clinical course of at least one hypomanic episode and at least one major depressive episode. Crucially, there has never been a full manic episode. (DSM-5 Criteria).

• Clinical One-Liner: Basically, it's a pattern of significant lows (major depression) with distinct periods of subtle, energetic highs (hypomania) that don't escalate into full-blown mania.

II. Etiology & Risk Factors

• Etiology: It's a complex interplay of genetic, neurobiological, and environmental factors. There's a strong genetic component.

• Risk Factors:

  • Non-modifiable:

    • Family history: Having a first-degree relative with bipolar disorder is the single strongest risk factor.

  • Modifiable:

    • Substance misuse (e.g., cannabis, stimulants).

    • Significant psychosocial stressors or trauma.

    • Disrupted circadian rhythms (e.g., shift work).

III. Quick Pathophysiology

Think of it as a dysregulation of brain circuits controlling mood, energy, and sleep. During a depressive episode, there's a deficit of neurotransmitters like serotonin and norepinephrine in key areas. In hypomania, there's an excess. This isn't just a chemical imbalance; it's a circuit problem. This is why simply giving an SSRI can push a susceptible patient from depression into a hypomanic state.

IV. Clinical Assessment

Red Flags & Immediate Actions:

• Suicidal or self-harm ideation: → Alert senior immediately, ensure patient safety (1:1 nursing if needed), and do not let the patient leave.

• Significant functional impairment (e.g., unable to work, relationship breakdown): → This suggests the current episode is severe. Alert your senior for a comprehensive management plan.

• Impulsive, reckless behaviour (e.g., spending sprees, sudden trips): → A key clue for hypomania. Take a detailed collateral history.

History:

• Always screen for hypomania in ANY patient presenting with depression. Use the "DIGFAST" mnemonic:

  • Distractibility

  • Indiscretion (excessive involvement in pleasurable activities)

  • Grandiosity

  • Flight of ideas

  • Activity increase (goal-directed)

  • Sleep (decreased need for)

  • Talkativeness (more than usual)

• Ask specifically: "Have you ever had a period of a few days where you felt unusually energetic, needed less sleep, and your thoughts were racing?" Patients often don't view these as problems.

• Pertinent Negatives: Ask about psychotic symptoms (hallucinations, delusions) to rule out Bipolar I Disorder or a psychotic disorder.

Physical Examination:

• The primary goal is to rule out organic causes.

• Perform a full neurological examination to exclude CNS pathology.

• Look for signs of thyroid disease (a common mimic) or substance misuse.

Clinical Pearl:

Collateral history is not optional; it's mandatory. The patient often lacks insight into their hypomanic episodes. A family member or close friend will be the one to tell you about the sudden "great moods," the impulsive projects, or the uncharacteristic irritability.

V. Diagnostic Workflow

Differential Diagnosis:

• Major Depressive Disorder (MDD):

  • Points For: The presenting complaint is almost always depression.

  • Points Against: A history of distinct periods of elevated mood and energy.

  • How to Differentiate: A thorough history specifically probing for hypomania.

• Borderline Personality Disorder (BPD):

  • Points For: Mood instability and impulsivity are common to both.

  • Points Against: Mood shifts in BPD are rapid (hours) and often triggered by interpersonal events. Bipolar II episodes are sustained (days to weeks).

  • How to Differentiate: Focus on the duration and triggers of mood swings.

• Attention Deficit Hyperactivity Disorder (ADHD):

  • Points For: Distractibility, talkativeness, and increased activity.

  • Points Against: Symptoms in ADHD are chronic and trait-like, not episodic like in Bipolar II.

  • How to Differentiate: Establish the timeline; Bipolar II has clear episodes with periods of normal mood in between.

Investigations Plan:

• Bedside / Initial:

  • Urine toxicology screen: To rule out substance-induced mood changes.

• First-Line Labs & Imaging:

  • Thyroid Function Test (TFT): Hypo- and hyperthyroidism can mimic depression and hypomania, respectively.

  • Full Blood Count (FBC), Renal Profile (RP), Liver Function Test (LFT): To establish a baseline before starting medications like mood stabilizers.

  • CT Brain (if indicated): Only if there are focal neurological signs or a very atypical presentation to rule out an organic cause.

VI. Staging & Severity Assessment

• Severity is determined by the current mood episode (depressive or hypomanic).

• For a Major Depressive Episode, assess severity based on the number of symptoms, degree of functional impairment, and presence of suicidal ideation.

• For a Hypomanic Episode, the key is the change in functioning. While not causing marked impairment like mania, it must be an observable change from the person's baseline.

• Impact on Management: The choice of initial treatment depends on the polarity and severity of the current episode. A severely depressed and suicidal patient needs more aggressive management and possible admission.

VII. Management Plan

(Based on the Malaysian CPG for Management of Bipolar Disorder, 2nd Edition)

Immediate Stabilisation (The ABCDE Plan):

• This applies mainly to severe depressive episodes with suicidality.

• A & B: Ensure airway and breathing are secure.

• C: Secure IV access if necessary.

• D: Assess GCS and suicidality.

• E: Create a safe environment. Remove any potential means of self-harm.

Definitive Treatment (The Ward Round Plan):

• The goal is long-term mood stabilization.

• First-Line (for Depressive Episode):

  • Quetiapine: Start at 50mg ON, titrate up to a target of 300mg ON. It treats the depression while protecting against a switch to hypomania.

  • Lurasidone: Can also be considered.

  • AVOID ANTIDEPRESSANT MONOTHERAPY. This is a critical point. An SSRI without a mood stabiliser can precipitate hypomania or rapid cycling.

• First-Line (for maintenance):

  • Lamotrigine: Excellent for preventing future depressive episodes, but must be titrated very slowly due to the risk of Stevens-Johnson Syndrome. Start 25mg OD for 2 weeks, then increase.

  • Lithium: Still a gold standard for maintenance, but requires close monitoring of therapeutic levels and renal/thyroid function.

• Psychosocial Interventions:

  • Psychoeducation is vital from the start. Help the patient and family understand the illness.

  • Refer for Cognitive Behavioral Therapy (CBT) or family-focused therapy once the acute episode stabilizes.

Long-Term & Discharge Plan:

• Emphasize lifelong treatment and medication adherence.

• Regular follow-ups to monitor for mood changes and medication side effects.

• Teach sleep hygiene and routine management (Social Rhythm Therapy principles).

VIII. Complications

• Immediate: Suicide (highest during depressive or mixed states).

• Short-Term: Relationship breakdown, job loss due to mood instability and impulsivity.

• Long-Term:

  • Substance Use Disorders: High rate of co-morbidity.

  • Anxiety Disorders: Very common.

  • Metabolic Syndrome: Side effect of some second-generation antipsychotics (e.g., Olanzapine, Quetiapine).

IX. Prognosis

• Bipolar II Disorder is a lifelong, recurrent illness.

• With effective long-term treatment, many individuals can achieve good functional recovery.

• Poor prognostic factors include early age of onset, comorbid substance use, and poor treatment adherence.

X. How to Present to Your Senior

"Dr, for review please. This is Puan Siti in Bed 10, a 35-year-old lady who presented with low mood and suicidal thoughts. Her main diagnosis is Major Depressive Disorder, but on further questioning, she describes several episodes in the past year of feeling very energetic, needing only 3 hours of sleep, and being extremely productive, each lasting about a week. My main differential is now Bipolar II Disorder, current episode severe depression. I have ensured patient safety and sent off baseline bloods including a TFT. I would like to ask about starting Quetiapine instead of an SSRI."

XI. Summary & Further Reading

• Top 3 Takeaways:

  1. Always screen for hypomania in every patient presenting with depression.

  2. Avoid antidepressant monotherapy. It can make things worse.

  3. Collateral history from family is essential for diagnosis.

• Key Resources:

  • Malaysian CPG: Management of Bipolar Disorder (Second Edition), Ministry of Health Malaysia, 2024.

  • UpToDate: "Bipolar II disorder: Clinical features, diagnosis, and course" and "Bipolar II disorder in adults: Pharmacotherapy".

  • Amboss: Bipolar and Related Disorders.