CHPS Whole CHPS revision in 10min Easy way of understanding CHPS Mechanism of abnormalities in CHPS Metabolic alkalosis in CHPS paradoxical aciduria in CHPS How kidney worsen the existing metabolic alkalosis in CHPS Treatment of CHPS Why pottasium supplements given only after adequate urine output in CHPS Onset of symptoms in CHPS Why can't symptoms develops at birth Why dehydration happens in CHPS Fluid management in CHPS Why hypocalcemia occurs more common in CHPS Knowing normal physiology in comparison with CHPS pathology Movie style teaching Simple film pic comparing to know the mechanism of CHPS

1. Congential Hypertrophic
pyloric stenosis
PRESENTED BY : DR M.KARTHIK EMMANUEL
MODERATOR: DR P.VENKATESHWARA REDDY

2. Anatomy of stomach

3. Introduction
• Male predominance
• Male : female = 5:1
• First born
• Onset of symptoms = 3 – 6 wks after birth
WHY CAN’T SYMPTOMS DEVELOPE AT THE TIME OF BIRTH ????

4. • Because initially at the time of birth the muscle is looking normal BUT
with time it tends to become hypertrophy and causes obstruction
which leads to symptoms
ASSOCIATED SYNDROMES
• Any congenital or neonatal condition is associated with multiple
syndromes
therefore if we have one anatomical abnormality we should look for
another anatomical abnormality
1. Trisomy 21 & 18
2. Cornelia de lange
3. Apert syndrome ( acrocephalosyndactyly)
4. Paramyotonia congenita

5. Maternal risk factors
Smoker Obesity

6. • History of erythromycin intake during pregnancy
• Younger mother ( age <25yrs )
FETAL RISK FACTORS
1. Very preterm
2. First born child

7. Before knowing the symptoms – lets have a look
on normal physiology of GIT – ESOPHAGUS
• Esophagus = shorter , lower third – peristalsis less efficient
• Regurgitation is common in neonates
HOW TO DIFFERENTIATE WHETHER THE
REGURGITATION IS BECAUSE OF NORMAL PHYSIOLOGY
OR BECAUSE OF CHPS
• Crying increases IAP & makesthe esophagus shorter and incompetent
• Hence this is the reason for regurgitation during crying

8. SYMPTOMS
• Initially when mother reports they say that the child was regurgitating
• Slowly it turn to vomiting and in turn it becomes projectile
1. Non- bilious projectile vomiting
WHY NON- BILIOUS ????
WHY PROJECTILE ?????
2. Slow weight gain ( weight gain is not good as we expected )
3. After feeding = Characteristic peristaltic wave moving across the
epigastrium noted

11. EXAMINATION
1. An enlarged pylorus described as olive – palpated in the RUQ or
epigastrium of abdomen in 60 – 80 %
2. Visible persistasis i.e, LUQ to epigastrium = better seen after the
feed
3. Jaundice ( 2% )
WHY JAUNDICE IS SEEN ???
WHY UGT ENZYME IS DOWNREGULATED ??

12. • We notice decreased hepatic glucuronyl transferase ( liver enzyme )
• Normal function of heptic glucuronyl transferase is – it is the sole
enzyme that can metabolize bilirubin
• Food restriction i.e, starvation appears to selectively downregulate
hepatic UDP-Glucuronyl transferase
HOW TO DIAGNOSE AND CONFIRM ????
1. For diagnosis 3 P’s
• Projectile vomiting
• Peristalsis
• Palpable olive

13. • Confirmed by USG Abdomen = dignostic if pyloric muscle thickness is
>4mm thickness and muscle length >14mm in term baby
TIMMING OF SURGERY
• It is a MEDICL EMERGENCY ; NOT A SURGICAL EMERGENCY
• Surgery for CHPS is urgent but is not an emergency
• Medical emergency = Dehydration, electrolytes and acid-base
imbalance have to be corrected

14. Composition of GI secretion
• Stomach has
1. Volume = 1500 ml/24hrs
2. Sodium = 60 mmol/lit ( < plasma level )
3. Pottassium = 10 mmol/lit ( twice the plasma level )
4. Chloride = 130 mmol/lit (> plasma levels )
5. Bicarbonate = zero
• Therefore stomach have much higher concentration of pottassium
and chloride when compared to plasma

15. Metabolic disturbances
1. Hypovolemia
• Reason: Obstruction – Vomiting of HCL and stomach fluid = first thing we see is
hypovolemia
2 . Metabolic alkalosis
• Reason:1. Obstruction – Vomiting of HCL – Deficiency of H+ & CL- =alkalosis
2. Loss of HCL – less gastric juice entering the duodenum – less pancreatic
HCO3-ion secretion = Hco3 ion retain in the body i.e, persistant metbolic alkalosis
3. Hypo = kalemia,calcemia,natremia
• Reason: As these are the composition of stomach secretions
4. Hypocalcemia ( Reason: Any severe Metabolic alkalosis likely to cause
hypocalcemia )

16. 5. Initially mild cases = Hypo K+,CL- and metabolic alkalosis
severe cases = Progress to metabolic acidosis because of significant
dehydration
NOTE
• Metabolic disturbances varies with depending on the severity of
obstruction
OVERVIEW OF METABOLIC ALKALOSIS + PARADOXICAL ACIDURIA
WHY IT IS CALLED PARADOXICAL ????
WHY ACIDURIA HAPPENING EVEN THOUGH ALKALOSIS EXISTS ??

17. Arundhati version of CHPS

18. Body before
Metabolic alkalosis
Metabolicalkalosis

19. Kidney (RAS) Aldosterone

20. Kidney coming with Aldosterone
to correct the metabolic
abnormality
With Aldosterone kidney further
worsens the situation i.e,
Met alk + paradoxical aciduria

21. Body after metabolic abnormality

22. Kidney inner feeling after worsening the
metabolic abnormality

23. Actual Rx = I.V fluids Finally I.V fluids ending the
abnormality

24. • Obstruction – Vomiting of HCL - Deficiency of H+ & CL- = Alkalosis
• Now Renal compensation occurs – Initially Kidney ecretes more
HCO3-ion
• HCO3- ion loss along with NA+ = So urine is rich in HCO3-ion & NA+
• ULTIMA lands in hyponatremia
• Because of which RAS activated – Aldosterone released – acts on
collecting ducts = NA+ and H2O reabsorption and K+,H+ions
excretion
NOTE
1. Inspite of body having metabolic alkalosis – body tends to cause
aciduria which is a paradox ( normally body should excrete HCO3-
ion as a compensatory mechanism )

25. NORMAL PHYSIOLOGY

26. • In adults – ICF is much higher than ECF volume
• In neonates – ECF is higher than ICF
• These implies – DEHYDRATION can occurs quickly and they also have
higher body water turn over. So they tends to loose around 30 – 40%
of body fluid through urine,feces sweating & respiration

27. Response to metabolic alkalosis
• Respiratory response – Hypoventilation which causes Respiratory acidosis
SIGNS OF DEHYDRATION
1. Sunken eyes
2. Sunken anterior fontanella ( Normally closes @ 12-18 months )
3. Prolonged CRT i.e, > 2sec ( Normally < 2sec )
4. Decreased skin turgor
5. Weight change
6. Normally diapers are wet every 3 – 4hrs but in these we see dry diapers

28. CLINICAL SIGNIFICANCE OF HYPOCALCEMIA
• Neonates tends to have calcium dependant myocardial contractility
• Therefore hypocalcemia- Decreases cardiac contractility which further
decreases cardiac output
NORMAL PHYSIOLOGY OF CARDIAC OUTPUT
1. CARDIAC OUTPUT
• Because of higher metabolism in children,they tends to have
higher cardiac output (Neonates = 300 – 400ml/kg/min ;
Adult = 100ml/kg/min )

29. HEART RATE DEPENDENT CARDIAC OUTPUT - REASON
??????
• Cannot increase the myocardial contractility to an extent that they can
increase the CO. So any increase in CO depends on HR
• Childrens already have higher baseline HR, even this capacity to increase
the CO is limited in smaller children & neonate
WHY DO THEY HAVE DECREASED MYOCARDIAL
CONTRACTILITY ???????
• Disorganised myofibrils, immature sarcoplasmic reticulum & immature T-
tubules
• Actual myocardium contains fibers – amount of muscle in fibers is less,they
have more collagen content = bcz of which the tension developed in the
cardiac muscle at EDV is much less it means the SV also compromised

30. Calcium sensitive myocardial contractility
• Normally calcium levels influence cardiac contractility
• Anything which decreases serum calcium levels i.e, rapid blood
transfusions, calcium channel blockers, severe metabolic alkalosis
decreases myocardial contractility
NOTE
• In metabolic alkalosis, bound hydrogen ions dissociate from albumin
which increases the fraction of albumin available for ionized calcium
binding
• Therefoere metabolic alkalosis leads to hypocalcemia

31. Before going to treatment part – lets have a
look on normal physiology
RENAL
• Neonates have lower RBF, lower GFR, lower tubular
function
• These manifested as
1. Drugs excretion can be delayed
2. Fluids,electrolytes and acid base homeostasis may
be impaired in infants ( as kidney is responsible for
fluids, electrolytes, acid base homeostasis)

32. NOTE
• They are more prone for fluid overload or dehydration if we don’t
manage them adequately
GLUCOSE HOMEOSTASIS – LIVER
Why HYPOGLYCEMIA is more common in preterm
&neonates???
• Childrens tends to have low or No glycogen reserve in the liver
• Therefore need dextrose 10% infusion = 3 – 5ml/kg/hr
intraoperatively
• Symptoms of hypoglycemia =jitteriness, convulsions and apnea

33. HYPERGLYCEMIA
• Because the kidneys cannot necessarily reabsorb the excess glucose,if
we give too much glucose to the small child it causes
1. Osmotic diuresis
2. Osmotically induced cerebral fluid shifts may leads to cerebral
haemorrhage
3. Glycosuria
4. Increased extent of neurologic damage during a cerebral hypoxic
ischemic event

34. TREATMENT WITH INTRAVENOUS FLUIDS
1. NPO ( As already vomiting symptom present )
2. Sodium , Dextrose , Pottassium ( Re-establish the volume status
along with electrolytes status )
3. Start Pottassium supplementation ONLY after the neonate start
producing urine –
WHY WE HAVE TO START K+ ONLY AFTER PRODUCING URINE ??????

35. • Once we correct hypovolemia with 0.9%NS boluses – make sure that
the child is passing urine then only start K+ with maintenance fluids
because pottassium has to be excreted in urine
FLUID MANAGEMENT
1. Correct hypovolemia
• 0.9% NS in boluses of 10ml/kg
2. Replace NG losses
• 1ml of gastric losses must be replaced with 1ml of 0.9% NS + 10mmol
of KCL per 500ml bag
3. Maintenance
• HCO3 if >25mmol/lit = DNS + 10mmol KCL per 500ml bag @
150ml/kg/day

36. • HCO3 if <25mmol/lit = DNS + 10mmol KCL per 500ml bag @
100ml/kg/day
• Infants < 44 post conceptual weeks = has poor glycogen stores in
liver,therefore supplement 10% dextrose if they are NPO
WHY SMALL CHILD CAN’T TOLERATE TOO MUCH
FLUIDS NOR TOO MUCH SYSTEMIC VASCULAR
RESISTANCE ????
• Myocardial contractile reserve is low ( Preload and
after load tolerance is poor ). All these compromises
the CO which decreases the SV

37. AIM OF OPTIMIZATION FOR TAKING UP FOR SURGERY
1. Chloride > 100meq/lit
2. HCO3 < 30meq/lit ( To avoid to much of alkalosis )
3. Urine output > 1 – 2ml/kg/hr
4. Pottassium > 3meq/lit
5. Sodium > 130meq/lit

38. WHY ALKALOSIS CORRECTION IS SO
IMPORTANT ??????

39. • Normally H+ions will go and stimulate respiratory center
• Therefore persistent alkalosis can depress the respiratory drive, thus
risk for post operative apnea
WHAT ARE THE THINGS TO BE DONE PRIOR TO INDUCTION ??
• Good intravenous access , volume status
• Suction – to make sure that the stomach is empty
• Some times they rotate the child until minimum to no gastric
contents return
INDUCTION
1. Classic RSI – Predetermined dose of induction agent + muscle
relaxant (sch) – wait for 60sec & then intubate

40. • But in paediatric age group especially neonates – Apnea tolerance is
limited which means they can’t tolerate the 60sec apnea time
WHY APNEA TOLERANCE IS LIMITED OR WHY THEY ARE
VULNERABLE TO HYPOXIA ??????
1. Low FRC
• FRC indicates oxygen reserve we have during the apneic
period
• It is the balance between the compliance of chest wall &
lung
• In children chest wall compliance is 3 – 6 times more
compliant than the lung compliance

41. • Therefore FRC is on lower end. So, during normal respiration
significant percent of the alveoli will be closed in children. So they are
more susceptible to hypoxia when they have apneic episodes
COMPENSATION FOR LOW FRC
• Laryngeal braking- partial adduction of vocal cords during
expiration which is seen clinically as grunting ( Normally
GRUNTING indicate respiratory pathology but in children it is
a normal phenomenon to compensate for low FRC )
• Increased RR – decreases the duration of inspiration &
expiration – tends to create Intrinsic PEEP which increases
FRC
• Narrow nasal passage offers resistance to expiratory flow

42. 2. High oxygen consumption
• Childrens tends to have faster metabolism
• Higher work of breathing ( accounts for 15% of O2 consumption)
3. Higher airway resistance
4. Compliant chest wall
2.Because of all the above things we go for MODIFIED RSI
• Induction + sch = once after giving sch,do gentle mask ventilation for
30 – 40sec then intubate. This minimizes the possibility of
desaturation & give time to intubation as well
3. Awake intubation is avoid bcz of risk of intraventricular
haemorrhage

43. SURGERY
• Ramstedt pyloromyotomy
• Duration of surgery = 30mins
• Can be open or laproscopic
Disadvantage of laproscopy
1. Increased incidence of inadequate pyloromyotomy
2. Increased risk of mucosal perforation in the pyloric canal & of tear
of duodenal cap – bcz they tend to elevate the duodenum & do
splitting
Advantage of laproscopy – feeding can be started even more earlier
when compare to open

44. • Incisions – Right hypochondrium incision or periumbilical incision
Steps of surgery
1. After incision – pulling of pylorus out
2. Split the pylorus open
3. Once if we see the lining of pylorus bulging out of incision it indicates
that the surgery is successful i.e, we have split the hypertrophic muscle
completely
NOTE
• After opening the pylorus muscle some surgeons may ask for air inje tion of
50 – 100ml into NG tube to verify the integrity of duodenal mucosa
• If there is no bubbling air through mucosa indicates no leak
• Make sure that after checking – aspirate the air back again

45. ANALGESIA
• Generally postoperative pain in this surgery is minimally noted
• PCM
• Wound infiltration
• Opioids – best avoided – reason ????
1. Because of immature hepatic system opioid metabolism is slow
2. Because of potential for alkalosis- increased Sn to opioids noted
which results in decreased respiratory drive
POSTOPERATIVE COMPLCATIONS
1. Presence of metabolic alkalosis increases the risk of apnea
2. Perforation of stomach – leakage – sepsis
3. Persistent vomiting – Inadequate division of hypertrophic muscle

46. • Feeding – start few hours after surgery
SUMMARY
1. It is a medical emergency
2. Correction of acid-base, electrolyte & volume repletion
3. Target preoperative = Hco3 < 30meq/lit
4. Surgery - short duration, less painful & good recovery