9. Treatment of Amatoxin Poisoning-20 year retrospective analysis

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improves clinical outcome if it is used more than 1 hour
after ingestion. [247] Toxicokinetic studies in the dog
suggested amatoxin absorption or reabsorption from the
intestine. [248] Given the enterohepatic circulation of
amatoxins, administration of activated charcoal as
multiple doses could reduce amatoxin absorption if in
contact with toxin present in the gastrointestinal tract.
Serial charcoal dosing either as a continuous nasogastric
drip or pulse dosing with 20–40 g every 3–4 hours (for
24 hours or more) has been advocated by most authors as
a relatively noninvasive enterohepatic and enteric
dialysis technique. [42,74,233,249 – 251] However, clinical
data are insufficient to support or exclude this oral
detoxication method. [247]
Gastroduodenal aspiration (GA) from the upper
portion of the small intestine through a nasogastric tube
has been recommended as a sole technique or combined
with activated charcoal to remove bile fluids and
interrupt enterohepatic circulation [252] but the actual
benefit of these procedures is not documented.
Amatoxins are present in the gastroduodenal fluids
until 60 hour after mushroom ingestion. [253] Long term
intubation may lead to side effects of bleeding and
pancreatitis and is not always recommended. [14]
Urinary Detoxication
Toxicokinetic reports of human mushroom poisoning
have shown that diuresis substantially enhances the
amatoxin elimination rate. Large amounts of amatoxins
(60–80%) are filtered through the glomeruli. [254] Urinary
elimination of amatoxins has been detected within the
first 8 hours and for 3–4 days after mushroom
ingestion. [167] Amatoxin concentrations in the urine are
from 100 to 150 times higher than those of serum and can
be quantified even when no serum circulating amatoxins
are detectable. [50,51,255 – 257] Maintenance of early and
adequate urine output is theoretically important even
though there is no re-absorption in the proximal tubules
or tubular secretion; “forced diuresis (FD)” with fluids
plus a loop diuretic cannot increase amatoxin elimination.
[14,248] According to Jaeger et al., [257] there is no
proof that FD decreases the amount of amatoxins bound
to the hepatocytes or is more efficient than the
maintenance of an adequate diuresis (from 100 to
200 mL/h). Furthermore, FD is difficult to maintain in a
patient with a severe dehydration.
Extra-corporeal Purification Procedures
Amatoxins are detected in the serum from 24 to
48 hours after mushroom ingestion but at very low
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©2002 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
Enjalbert et al.
[253,256 – 258]
concentrations when compared to the urine.
Extra-corporeal elimination includes hemodialysis (HD),
hemoperfusion (HP), plasmapheresis (PL), and related
methods. HP and HD are theoretically helpful since the
amatoxins are easily dialyzable due to their free
circulation in the serum and their small molecular
weight (about 900 Da); amatoxins also possess a high
affinity for charcoal and polymers used for HP cartridges
and dialyzer membranes. [249] HD initiated as sole
treatment has been reported to be ineffective in the
management of amatoxin syndrome [82,97] but should be
instituted if renal failure occurs. [231] Given the low serum
amatoxin concentration, the utility of toxin removal by
extra-corporeal purification procedures is questionable.
Extra-corporeal purification procedures such as HD, HP,
and PL, and related methods such as continuous
venovenous hemofiltration and exsanguino-transfusion,
are often used in a combined mode; it is difficult to assess
the efficacy of any single treatment.
HP has been applied to amatoxin-intoxicated patients
since 1978 with a possibly favorable effect. [259 – 261] It
has been carried out within the first 36 or 48 hours after
ingestion [246,260,262] but is proposed as most effective if
applied prior to 24 hours. [231] The survival rate of
poisoned patients is claimed to depend on the time of
beginning HP. [14,140,180] Polish and Turkish retrospective
studies have reported increased survival for amatoxinpoisoned
patients treated with HP. [107,173]
Thrombocytopenia, a major side effect of HP that
increases the risk of bleeding, [123,149] diminishes when a
platelet protective agent such as prostacyclin is
administered. [123] Other complications of HP such as
hypotension due to volume loss, hypoglycemia, and
hypocalcemia must be monitored and corrected. [262]
Controversy centers on whether the blood level of
amatoxins is high enough to justify this procedure.
[249,258] HP performed within 12–14 hours after
ingestion of amatoxin-containing mushrooms eliminated
less than 4% of the ingested toxin dose. [225] Although the
benefit of HP to remove amatoxins in the early stages of
intoxication was debatable, [263] it may help support the
patient during hepatic failure. [155] HP eliminates
neurotropic and neurotoxic amino acids and mercaptans;
it has been reported to ameliorate the hepatic
encephalopathy in 75% of amatoxin poisoned
patients. [264,265]
The HP sorbent most frequently used is activated
charcoal. In the United States, the only available HP
sorbent is activated charcoal-coated polymer membranes.
[262] The efficacy of ion-exchange resin (Amberlite
XAD-4) has been experimentally demonstrated. [266]