Transient Tachypnea of New born (TTN)

Transient tachypnea of the newborn

• The clinical case given above indicates the likely

diagnosis of transient tachynea of the newborn, which is otherwise called Respiratory distress syndrome type II.

• It is characterized by the early onset of dyspnea with chest retractions, expiratory grunting and cyanosis. Neonates usually recover within 3 days.

• The syndrome is believed to be secondary to slow absorption of fetal lung fluid resulting in decreased pulmonary compliance and tidal volume.

• The distinctive feature of transient tachypnea of the newborn from hyaline membrane disease is sudden recovery of the infants  and the absence of a radiographic reticulogranular pattern on CXR.

Transient tachypnea of newborn is a benign self limiting disease occurring in term neonates. Symptomatic management is adequate and ventilatory support is never needed.

Ans. is a i.e. Transient tachypnea of the new born

Friends don’t get shocked by the answer, even I was perplexed when I went through the texts given in all the standard reference books.

Let’s see what they have said.

Respiratory distress syndrome (RDS) or hyaline membrane disease (HMD)

• RDS almost always occurs in nreterm babies often less than 34 weeks of gestation.
• It is the commonest cause of respiratory distress in a preterm neonate.

According to Ghai — RDS is seen in preterm babies and not the term babies (as is given in our question).

Now let’s see what Ghai says about transient tachypnea of newborn :

Transient tachypnea of newborn (TTN)

• Transient tachypnea of the newborn is a benign self-limiting disease occurring usually in term neonates and is due to delayed clearance of lung fluid.
• These babies have tachypnea with minimal or no respiratory distress.
• Chest X-ray may show prominent vascular marking and prominent interlobar fissure.
• Oxygen treatment is often adequate and ventilatory support is necessary and prognosis is good.

But Ghai didn’t mention any correlation between TTN and Diabetes. So, I had to search other books for more information.

Neonatal complications : RDS and transient tachypnea are more common in infants of women with poorly controlled diabetics.

Respiratory distress :

“Conventional obstetrical teaching through the late 1980s generally held that fetal lung maturation was delayed in diabetic pregnancies. Thus, these infants were at increased risk for respiratory distress (Gluck and Kulovich, 1973). Subsequent observations have challenged this concept, and gestational age rather than overt diabetes is likely the most significant factor associated with neonatal respiratory distress (Berkowitz and colleagues, 1996; Kjos and colleagues. 1990b)”.

So, it is the gestational age and not diabetes which is the main factor causing neonatal respiratory distress. In our question the baby is delivered at 40 weeks gestation (Full term) so, the answer can not be Hyaline membrane disease rather it is transient tachypnea of newborn (i.e. option ‘a is correct).

Ans is ‘c’ i.e., Elective caesarean section

o In text books, both elective caesarian section and normal preterm or term vaginal delivery have been mentioned as risk factors for transient tachypnea of newborn.

o But the best answer is caesarian section –

“Delivery by caesarian section and gestational age are the risk factors for TTN”. —Articles Obs & Gynae

Transient tachypnea of Newborn (TTN)

o Transient tachypnea of the newborn is a benign self-limiting disease occuring usually in term neonates and is due to delayed clearance of lung fluid.

o It is also called respiratory distress syndrome type II

o TTN follows –

i)        Uneventful normal preterm or term vaginal delivery

ii)     Cesarean delivery

o TTN is believed to be secondary to slow absorption of fetal lung fluid resulting in decreased pulmonary compliance and tidal volume and increased dead space therefore also known as wet lung.

o Clinical manifestations

             Early onset of tachypnea

             Sometimes retraction or expiratory grunting

             Occasionally cyanosis

             Patients usually recover rapidly within 3 days.

             Hypoxemia, hypercapnia and acidosis are uncommon.

Ans. is ‘b’ i.e., Air bronchogram, ‘c’ i.e., Reticular shadows

o Distinguishig this disease from hyaline membrane disease is difficult. The distinctive feature of transient tachyapnea are

             Mild symptomology

             Sudden recovery of the infant

             Absence of roentgenographic reticulogranular pattern or air bronchogram.

Ans. is ‘c’ i.e., Onset of respiratory distress is immediately after birth and it rarely lasts beyond 48 hrs

Ans. is ‘a’ i.e., Transient tachypnea of newborn

o Respiratory distress, which resolves within 24 hours without any respiratory support and fluid in interlobar fissure on chest X-ray suggest the diagnosis of TTN.

Ans. is ‘c’ i.e., 60

Tachypnea

o < 2 months       -->               60 or more RR/min

o 2-12 months    —>               50 or more RR/min

o 12-60 months   –—>             40 or more RR/min