BOF: 21
A 33-year-old female who has had multiple resections of
the small bowel has been left with 90 cms of jejunum anastamosed to the colon.
She is maintained on a diet high in polysaccharides and manages well on this
diet. She is admitted to the ward
with ataxia, blurred vision, ophthalmoplegia and nystagmus.
The likely cause of this complication is
a)
Thiamine deficiency
b)
Vitamin B 12 deficiency
c)
Magnesium deficiency
d)
L (+) lactic acidosis
e)
D (-) Lactic acidosis
Answer:
e)
In patients with a short small bowel and an intact colon,
energy is absorbed from the colon by bacterial fermentation of polysaccharides
to short chain fatty acid, which can be absorbed by the colonocytes.
In rare instances mono and oligosaccharides may be metabolised to D (-)
lactic acid by abnormal bacteria. The normal lactic acid produced by man is L
(+) lactic acid. Absorption of D (-) lactic acid results in ataxia, blurred
vision, ophthalmoplegia and nystagmus. Treatment
is with broad-spectrum antibiotics such as neomycin or vancomycin, thiamine
and a change in diet to one high in polysaccharides and low in mono and
oligosaccharides.
