persistant metabolic acidosis

lactic acidosis, ketoacidosis, and amino or organic acidemia.
consanguinity?
inborn errors of metabolism and physical examination
showed no dysmorphic features.

In proximal RTA
(type 2) the threshold for bicarbonate reabsorption in the
proximal tubule is lower than normal (15-16 mEq/L rather
than 22-23 mEq/L). Because 85% of the filtered bicarbonate
is normally reabsorbed in the proximal tubule, high doses of
oral bicarbonate are needed to normalize the HCO3

serum
level in patients with proximal RTA. In these patients, serum
bicarbonate levels will not reach the normal range, despite
provision of very large amounts of bicarbonate.

urine
anion gap (uAG), calculated as: (Na K)
Cl
. In
normal subjects, in conditions of metabolic acidosis, the increased
excretion of NH4/Cl
results in negative uAG
(excess of Cl
) and a low urine pH.

osmotic versus secretory. Osmotic
diarrhea is characterized by lower pH (5.0), lower sodium
concentration (70 mEq/L), and positive reducing substances

congenital lactase deficiency and glucose-galactose
malabsorption

hydrolyzed
formula (Neocate®) containing glucose polymer, an etiology
of disacchridase deficiency was unlikely. Subsequently, the
infant was fed a carbohydrate-free formula (RCF, Ross Carbohydrate
Free®) with no resolution of the diarrhea


protracted diarrhea of infancy (PDI

normal
villous PDI, congenital ion transport defects cause secretory
diarrhea presenting at birth. The most common congenital
ion transport defect is the chloride-bicarbonate exchanger, in
which HCO3
is not secreted into the gastrointestinal tract
lumen, leading to alkalosis.

fecal chloride concentration, which did not exceed
the fecal sodium level, did not support the diagnosis of
congenital chloride diarrhea. Congenital sodium diarrhea, a
disorder of the intestinal H/Na-exchanger, is characterized
by hyponatremia, alkaline diarrhea, and high concentration of
stool sodium

Protracted diarrhea of infancy with villous atrophy can
be a result of infectious or post-infectious enteropathy, and
autoimmune or allergic enteropathy, the IPEX syndrome
(i.e., Immune dysregulation, Polyendocrinopathy, Enteropathy,
X-linkage).

microvillus inclusion disease (MID)
and tufting enteropathy. MID is a severe enteropathy, the
second most common cause (following infectious) of protracted
diarrhea


CD10 (1A), PAS (1B), and alkaline phosphatase (1C)
stains compatible with MID


ref;
A Newborn Infant with Protracted Diarrhea and Metabolic Acidosis
AMIR BAR, MD, ARIEH RISKIN, MD, THEODORE IANCU, MD, IRENA MANOV, PHD, AYALA ARAD, MD, AND RON SHAOUL, MD