Case 29

16 day old male born via planned C-section due to placenta previa presents due to vomiting. Mother says pt was vomiting in hospital and vomits after every feed. Notably, formula changed at DOL 7 due to inadequate weight gain, born 6 lb 15oz now 8lb. Currently taking 2-3 oz/feed and vomiting about 1 oz after every feed. Had 4 episodes projectile vomiting day of presentation.  Still with normal wet diapers and bowel movements. Mother’s brother had history of pyloric stenosis.

ROS
Constitutional: no fever.
Respiratory: no cough or respiratory distress.
GI: see HPI
Neuro: normal activity level

EXAM
VITALS: T 98.0F, P 175, RR 39, 100% on RA
HEAD : anterior fontanelle not sunken or distended
EYE : No conjunctival injection
ENT: No oropharyngeal erythema or exudate, vesicles, or ulcers. Mucous membranes are somewhat dry. RESP:  Chest is clear to auscultation b/l. Respiratory effort is unlabored, and there are no subcostal or intercostal retractions.
ABD:  Soft/non-distended. No obvious scrotal asymmetry, erythema, or palpable inguinal masses.
EXT: The patient moves all extremities spontaneously. 

QUESTIONS

  1. What is your differential diagnosis for a vomiting neonate?
  2. What likely diagnosis is represented by IMAGE 1 below?
  3. What ultrasound diagnostic criteria are used?
  4. What is the next step in management...eg lab work, consultants?
IMAGE 1

IMAGE 1

ANSWERS

  1. Pyloric stenosis, obstruction, GERD, metabolic disorders, necrotizing enterocolitis, feeding intolerance, milk protein allergy, UTI, toxic ingestion
  2. Pyloric Stenosis!!! 
  3. Pyloric stenosis is diagnosed if the pylorus muscle thickness (single wall) >3-4mm and/or the pyloric channel length is >14-15mm.  (To remember: think of the numerical value of pi - 3.1415)  See IMAGE 2 below. 

    To find the pylorus:
    a.  Linear probe, start in transverse position and identify gallbladder. Pylorus is medial and posterior to GB (image 2 below).  The muscular layer is usually a hypoechogenic thin layer less than 2 mm in thickness. It is important to be aware that tangential views and contractions can produce pseudo-thickening. Visualize the passage of the gastric content through the pylorus, distending the antropyloric region.
    b.  Oblique positioning and performing ultrasound immediately after feeding can alleviate problems of gas-filled stomach, and a stomach filled with water can act as an acoustic window for pylorus evaluation.
  4. Hydration, correction of electrolyte abnormalities, surgical consult for pyloromyotomy or alternative more conservative treatments such as placement of an NGT though the pylorus.
Measurements 1 and 2 are the muscle wall thickness Measurement 3 is the pyloric channel length

Measurements 1 and 2 are the muscle wall thickness

Measurement 3 is the pyloric channel length