This connection may or may not have a central cavity; if it does, then food within the esophagus may pass into the trachea (and on to the lungs) or alternatively, air in the trachea may cross into the esophagus.TEF can also occur due to pressure necrosis by a tracheostomy tube in apposition to a nasogastric tube (NGT). Diagnosis
TEF should be suspected once the baby fails to swallow after their first feeding during the first day of life. Esophageal atresia can be diagnosed by Ryle nasogastric tube; if the Ryle fails to pass into the stomach, then this indicates esophageal atresia and loss of communication between stomach and esophagus. TEF may be diagnosed by MRI which clarifies the atretic esophagus (if presents) and TEF, as well as its location and anatomy. Gastrograffin contrast swallow should not be used if TEF is suspected, due to its high risk of allergy and severe intractable chest infection. Classification
Fistulae between the trachea and esophagus in the newborn can be of diverse morphology and anatomical location. However, various pediatric surgical publications have attempted a classification system based on the below specified types.Not all types include both esophageal agenesis and tracheoesophageal fistula, but the most common types do. The letter codes are usually associated with the system used by Gross, while number codes are usually associated with Vogt.An additional type, "blind upper segment only" has been described, but this type is not usually included in most classifications.
ICD-11
According to the ICD-11, a BP-II patient will have experienced episodic experiences of one or more hypomaniac episodes and one or more major depressive episodes, and no history of a manic episode or mixed episode. These symptoms cannot be explained by other diagnoses such as

Cyclothymia
ADHD
Oppositional Defiant Disorder
Schizophrenia and other primary psychotic disorders
Substance-Use Disorder
Personality Disorders
Other Mental illness
Physical issues such as a brain tumorThe specifiers are the same as the DSM-5 with the exception of catatonic features and if symptoms have occurred with or without psychosis about 6 weeks after childbirth

Differential diagnoses
The signs and symptoms of BP-II may overlap significantly with those of other conditions. Thus, a comprehensive history, medication review, and laboratory work are key to diagnosing BP-II and differentiating it from other conditions. The differential diagnosis of BP-II is as follows: unipolar major depression, borderline personality disorder, posttraumatic stress disorder, substance use disorders, and attention deficit hyperactivity disorder. : 1653–7  In clinical practice, the difficulty of diagnosing BP-II depends on the accurate detection of hypomania, which is frequently dismissed by patients. Patients can present with increased productivity and energy with the absence of signs of instability or disturbance. As such, there is a risk that BP-II is misdiagnosed as generalized anxiety disorder or unipolar major depression. An accurate evaluation of differential diagnoses are crucial, as they guide treatment and prognostic implications.Major differences between BP-I and BP-II have been identified in their clinical features, comorbidity rates and family histories.