Differentials
Bipolar disorder
SIGNS / SYMPTOMS
Clinical examination using the DSM-5-TR criteria establishes differentiating symptoms and signs.
Elevated mood, decreased need for sleep, inflated self-esteem or grandiosity, increased goal-directed activities, racing thoughts, pressured speech, and reckless pleasurable behaviour are all characteristics of hypomanic or manic episodes of a bipolar illness. A child, particularly an adolescent, who presents with a history or concurrent manic or hypomanic symptoms needs to be assessed carefully to exclude the possibility of a bipolar illness.
It is important to have a low index of suspicion for bipolar disorder even if the symptoms are subthreshold, given that bipolar disorder often presents in the depressed polarity.
INVESTIGATIONS
No differentiating test.
Anxiety disorder
SIGNS / SYMPTOMS
Clinical examination using the DSM-5-TR criteria establishes differentiating symptoms and signs. Dysphoria associated with anxiety will dissipate in the absence of an anxiogenic situation.
Anxiety disorders that meet diagnostic criteria will usually precede depressive symptoms. Anxiety disorders do not occur exclusively during a mood disorder; rather, symptoms of anxiety are present even in the absence of mood symptoms.
However, anxiety disorders are highly comorbid with depressive disorders, and assessment and management of both disorders will improve outcome.
INVESTIGATIONS
No differentiating test.
ADHD
SIGNS / SYMPTOMS
Clinical examination using the DSM-5-TR criteria establishes differentiating symptoms and signs. Mood changes due to ADHD can be either due to a side effect of stimulants, or demoralisation as a result of difficulties in school, with family, or with peers.
ADHD is diagnosed when full diagnostic criteria are met prior to age 12 years. In patients with ADHD only, poor concentration is a chronic symptom that precedes depressive symptoms. ADHD, however, is highly comorbid with depressive disorders, and assessment and management of both disorders will improve outcome.
INVESTIGATIONS
No differentiating test.
Substance use disorder
SIGNS / SYMPTOMS
Clinical examination using the DSM-5-TR criteria helps to establish differentiating symptoms and signs.
A substance use disorder may precede depressive symptoms or occur as a consequence of depression.
INVESTIGATIONS
Urine drug screen confirms concomitant use of substance.
Adjustment disorder with depressed mood
SIGNS / SYMPTOMS
A stressor always precedes the depressive symptoms.
In addition, the depressive symptoms should not meet full DSM-5-TR criteria for major depressive disorder.
INVESTIGATIONS
No differentiating test.
Bereavement
SIGNS / SYMPTOMS
A recent loss of a loved one always precedes the depressive symptoms.
INVESTIGATIONS
No differentiating test.
Acute stress disorder
SIGNS / SYMPTOMS
A recent exposure to a traumatic event, by experiencing, witnessing, or confronting, which causes intense fear, helplessness, or horror.
In addition, a child has dissociative symptoms, re-experiencing of the trauma, avoidance behaviour, and increased anxiety or arousal.
INVESTIGATIONS
No differentiating test.
Post-traumatic stress disorder
SIGNS / SYMPTOMS
Exposure to a traumatic event, by experiencing, witnessing, or confronting, which causes intense fear, helplessness, or horror for at least 1 month after the event.
In addition, the child has dissociative symptoms, re-experiencing of the trauma, avoidance behaviour, and increased anxiety or arousal.
INVESTIGATIONS
No differentiating test.
Oppositional defiant disorder
SIGNS / SYMPTOMS
Clinical examination using the DSM-5-TR criteria helps to establish differentiating symptoms and signs.
Irritability and defiance without other symptoms of depression, although epidemiological studies show that oppositional defiant disorder is a risk factor for eventual development of depression.
Behavioural problems are more chronic and present without concurrent mood symptoms.
INVESTIGATIONS
No differentiating test.
Anorexia nervosa
SIGNS / SYMPTOMS
Clinical examination using the DSM-5-TR criteria helps to establish differentiating symptoms and signs. Difficult to assess depressive status until nutritional and weight deficiencies are restored.
Additional symptoms, such as body image distortions and fear of gaining weight, occur without mood symptoms.
However, eating disorders and depression can be comorbid.
INVESTIGATIONS
No differentiating test.
Bulimia nervosa
SIGNS / SYMPTOMS
Clinical examination using the DSM-5-TR criteria helps to establish differentiating symptoms and signs.
Additional symptoms, such as body image distortions and over-eating, occur without mood symptoms.
However, eating disorders and depression can be comorbid.
INVESTIGATIONS
No differentiating test.
Thyroid dysfunction
SIGNS / SYMPTOMS
Hypothyroidism may be associated with weight gain and constipation. On examination there may be dry, coarse skin, goitre, bradycardia, facial puffiness, slow return of deep tendon reflexes, or tongue thickening.
Hyperthyroidism may be associated with weight loss, increased appetite, sweating, and nervousness. On examination there may be goitre, rapid return of deep tendon reflexes, or tremor.
INVESTIGATIONS
In primary hypothyroidism, thyroid-stimulating hormone (TSH) is elevated and free thyroxine (T4) is low.
In central hypothyroidism, TSH is inappropriately low or normal for the free T4 level, and free T4 is low.
In hyperthyroidism, TSH is suppressed and serum free T4 and/or triiodothyronine (T3) are elevated.
Anaemia
SIGNS / SYMPTOMS
May be associated with a history of poor nutrition, pallor, and prominent fatigue.
INVESTIGATIONS
Full blood count reveals low haemoglobin.
Infectious mononucleosis
SIGNS / SYMPTOMS
History of initial symptoms of fever, fatigue, malaise, pharyngitis, and cervical or generalised lymphadenopathy.
INVESTIGATIONS
Positive agglutination test (e.g., monospot) showing heterophile antibodies.
Serological test demonstrating Epstein-Barr virus-specific antibodies.
Full blood count with differential may demonstrate lymphocytosis, atypical lymphocytosis, anaemia, and reticulocytosis.
Vitamin deficiency
SIGNS / SYMPTOMS
May be associated with a history of poor nutrition, pallor, and prominent fatigue.
INVESTIGATIONS
Full blood count may reveal anaemia.
Blood levels of vitamins may be low. However, tests would only usually be performed if vitamin deficiency were considered a likely cause of symptoms.
Further specific tests of vitamin deficiency may be used to confirm deficiency.
Temporal lobe epilepsy
SIGNS / SYMPTOMS
History of recurrent and chronic focal seizures.
INVESTIGATIONS
Electroencephalogram reveals spikes or sharp waves in the temporal lobe area. This would only usually be performed if temporal lobe epilepsy were considered a likely cause of symptoms.
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