Successful organ transplantation after treatment of fatal cyanide poisoning with hydroxocobalamin

BACKGROUND

Cyanide-poisoned patients are potential organ donors provided that organs are not damaged by the poison or by antidotal treatment.

CASE STUDY

A patient with third-degree burns and smoke inhalation-associated cyanide poisoning confirmed by measurements of whole blood cyanide was found in cardiac arrest and administered epinephrine and hydroxocobalamin (5 g + 5 g). Cardiac activity resumed, but the patient was declared brain dead on the third day of hospitalization when coma deteriorated to a shock state with refractory hypoxemia. Kidneys, heart, and liver were removed and transplanted into four patients. Gross pre-transplantation inspection of the donor organs and renal histology showed no evidence that hydroxocobalamin caused organ toxicity. Donor organs functioned normally through follow-up periods of several months.

CONCLUSION

Anoxic cardiac arrest following acute cyanide poisoning treated with hydroxocobalamin (5 g + 5 g) was not a contraindication to organ transplantation after confirmed encephalic death in this patient.

Diagnostic work-up and management of patients with isolated methylmalonic acidurias in European metabolic centres

The long-term outcome of patients with methylmalonic aciduria (MMA) is still uncertain due to a high frequency of complications such as chronic renal failure and metabolic stroke. The understanding of this disease is hampered by a huge variation in the management of these patients. The major aim of this study was to evaluate the current practice in different European metabolic centres. A standardized questionnaire was sent to 20 metabolic centres asking for standard procedures for confirmation of diagnosis, testing cobalamin responsiveness, dietary treatment, pharmacotherapy, and biochemical and clinical monitoring. Sixteen of 20 metabolic centres (80%) returned questionnaires on 183 patients: 89 of the patients were classified as mut(0), 36 as mut(-), 13 as cblA, 7 as cblB, and 38 as cblA/B. (1) Confirmation of diagnosis: All centres investigate enzyme activity by propionate fixation in fibroblasts; six centres also perform mutation analysis. (2) Cobalamin response: Ten centres follow standardized protocols showing large variations. A reliable exclusion of nonspecific effects has not yet been achieved by these protocols. (3) Long-term treatment: In cobalamin-responsive patients, most centres use hydroxocobalamin (1-14 mg/week i.m. or 5-20 mg/week orally), while two centres use cyanocobalamin. All cobalamin-nonresponsive patients and most cobalamin-responsive patients are supplemented with L: -carnitine (50-100 mg/kg per day). Fourteen centres use intestinal decontamination by antibiotic therapy. Most centres follow D-A-CH (n = 6) or Dewey (n = 4) recommendations for protein requirements. Fourteen centres regularly use precursor-free amino acid supplements. Standardized monitoring protocols are available in seven centres, again showing high variability.

Hemolytic uremic syndrome (HUS) secondary to cobalamin C (cblC) disorder

Diarrhea-positive hemolytic uremic syndrome (HUS) is a common cause of acute renal failure in children. Diarrhea-negative (D-), or atypical HUS, is etiologically distinct. A Medline search identified seven previously reported D- cases of HUS secondary to cobalamin C (cblC) disease presenting in infancy. An infantile presentation is reported to be associated with a high mortality rate (6/7 cases). We describe the results of a 5-year longitudinal follow-up in a child diagnosed with D- HUS secondary to cblC disease in infancy. Mutation analysis in this patient identified homozygosity for the 271 dupA mutation (c.271 dupA) in the cblC MMACHC gene. We briefly review the published experience in cblC-associated HUS to highlight the clinical characteristics of this uncommon, but potentially treatable, condition.

[Floppy baby with macrocytic anemia and vegan mother]

We report the case of a 7 month-old girl that presented with acute anemia, generalized muscular hypotonia and failure to thrive. Laboratory evaluation revealed cobalamin deficiency, due to a vegan diet of the mother. The clinical triad of an acquired floppy baby syndrome with megaloblastic anemia and failure to thrive is pathognomic for infantile cobalamin deficiency. Neurological abnormalities are often irreversible and may be associated with delayed myelinization in the MRI. A normal cobalamin level in maternal serum and absence of anemia do not exclude subclinical deficiency. If cobalamin deficiency is suspected, e.g. in pregnant women on vegan diet, urinary methylmalonic acid excretion and plasma homocysteine levels should be determined and cobalamin substitution should be started at an early stage to avoid potentially irreversible damage of the fetus.

Enhancing public health preparedness for a terrorist attack involving cyanide

The US government considers cyanide to be among the most likely agents of chemical terrorism. Cyanide differs from many other biological or chemical agents for which little or no defense is available because its individual and public health effects are largely remediable through appropriate preparedness and response. Because the toxicity of the cyanide antidote currently available in the United States renders it ill-suited for use in terrorist incidents and other situations requiring rapid out-of-hospital treatment, hydroxocobalamin--an effective and safe cyanide antidote being used in other countries--has been introduced in the United States. Unlike the other available cyanide antidote, hydroxocobalamin can be administered at the scene of a cyanide disaster, and it need not be reserved for cases of confirmed cyanide poisoning but can be administered in cases of suspected poisoning. Both of these attributes facilitate the rapid intervention necessary for saving lives. To realize the potential benefits of hydroxocobalamin, progress also needs to be realized in other aspects of readiness, including but not limited to developing plans for ensuring local and regional availability of antidote, educating emergency responders and health care professionals in the recognition and management of cyanide poisoning, and raising public awareness of the potential for a chemical weapons attack and of how to respond.

Hydroxocobalamin for severe acute cyanide poisoning by ingestion or inhalation

This chart review was undertaken to assess efficacy and safety of hydroxocobalamin for acute cyanide poisoning. Hospital records of the Fernand Widal and Lariboisière Hospitals were reviewed for intensive care unit admissions with cyanide poisoning for which hydroxocobalamin was used as first-line treatment from 1988 to 2003. Smoke inhalation cases were excluded. Hydroxocobalamin (5-20 g) was administered to 14 consecutive patients beginning a median 2.1 hours after cyanide ingestion or inhalation. Ten patients (71%) survived and were discharged. Of the 11 patients with blood cyanide exceeding the typically lethal threshold of 100 micromol/L, 7 survived. The most common hydroxocobalamin-attributed adverse events were chromaturia and pink skin discoloration. Severe cyanide poisoning of the nature observed in most patients in this study is frequently fatal. That 71% of patients survived after treatment with hydroxocobalamin suggests that hydroxocobalamin as first-line antidotal therapy is effective and safe in acute cyanide poisoning.

Sodium Thiosulfate or Hydroxocobalamin for the Empiric Treatment of Cyanide Poisoning?

Cyanide poisoning must be seriously considered in victims of smoke inhalation from enclosed space fires; it is also a credible terrorism threat agent. The treatment of cyanide poisoning is empiric because laboratory confirmation can take hours or days. Empiric treatment requires a safe and effective antidote that can be rapidly administered by either out-of-hospital or emergency department personnel. Among several cyanide antidotes available, sodium thiosulfate and hydroxocobalamin have been proposed for use in these circumstances. The evidence available to assess either sodium thiosulfate or hydroxocobalamin is incomplete. According to recent safety and efficacy studies in animals and human safety and uncontrolled efficacy studies, hydroxocobalamin seems to be an appropriate antidote for empiric treatment of smoke inhalation and other suspected cyanide poisoning victims in the out-of-hospital setting. Sodium thiosulfate can also be administered in the out-of-hospital setting. The efficacy of sodium thiosulfate is based on individual case studies, and there are contradictory conclusions about efficacy in animal models. The onset of antidotal action of sodium thiosulfate may be too slow for it to be the only cyanide antidote for emergency use. Hydroxocobalamin is being developed for potential introduction in the United States and may represent a new option for emergency personnel in cases of suspected or confirmed cyanide poisoning in the out-of-hospital setting.

Prospective Study of Hydroxocobalamin for Acute Cyanide Poisoning in Smoke Inhalation

STUDY OBJECTIVE

To assess outcomes in patients treated with hydroxocobalamin at the fire scene or in the ICU for suspected smoke inhalation-associated cyanide poisoning.

METHODS

Adult smoke inhalation victims with suspected cyanide poisoning as determined by soot in the face, mouth, or nose or expectorations and neurologic impairment received an intravenous infusion of hydroxocobalamin 5 g (maximum 15 g) at the fire scene or in the ICU in this observational case series conducted from 1987 to 1994. Blood cyanide specimens were collected before administration of hydroxocobalamin. The threshold for cyanide toxicity was predefined as greater than or equal to 39 micromol/L.

RESULTS

The sample included 69 patients (mean age 49.6 years; 33 men), of whom 39 were comatose. Out-of-hospital deaths were excluded. Fifty of the 69 patients (72%) admitted to the ICU survived after administration of hydroxocobalamin. In the group in which cyanide poisoning was confirmed a posteriori (n=42), 67% (28/42) survived after administration of hydroxocobalamin. The most common adverse events were chromaturia (n=6), pink or red skin discoloration (n=4), hypertension (n=3), erythema (n=2), and increased blood pressure (n=2). No serious adverse events were attributed to hydroxocobalamin. Laboratory tests revealed transient alterations in renal and hepatic function consistent with the critical condition of the patients and mild anemia consistent with progressive hemodilution.

CONCLUSION

Empiric administration of hydroxocobalamin was associated with survival among 67% of patients confirmed a posteriori to have had cyanide poisoning. Hydroxocobalamin was well tolerated irrespective of the presence of cyanide poisoning. Hydroxocobalamin appears to be safe for the out-of-hospital treatment of presumptive cyanide poisoning from smoke inhalation.

[Sodium azide--clinical course of the poisoning and treatment]

Sodium azide poisonings occur very rarely. The mechanism of sodium azide toxic effect has not yet been fully explained. Despite the lack of an explicit procedure for the cases of sodium azide poisonings, in vitro tests and rare case reports suggest that treatment with antidotes for cyanide poisoning victims can be effective. This study describes two cases of suicidal sodium azide ingestion. Case 1. 30-year-old male ingested ca. 180 mg of sodium azide. On admission to hospital, within 4 hours from poisoning, the man complained of dizziness and anxiety. Physical examination revealed horizontal nystagmus, flapping tremor, HR 135/min. In laboratory tests, higher blood concentration of lactates (3 mmol/l) was detected, as well as lower potassium concentration (3.4 mmol/L) and increased transaminase activity (ALT 74 U/l, AST 90 U/l). Electrocardiographic tests showed a negative T wave in limb lead III. Other results were within normal. As the patient ingested a toxic dose of sodium azide, he was treated according to the therapy prescription for cyanide poisoning (amyl nitrite inhalation followed by intravenous administration of sodium nitrite and sodium thiosulphate). ECG record of the last day of hospitalization (7th day of treatment) showed negative T waves in lead III, V4-V6. He was discharged from hospital in good condition. Case 2.23-year-old male ingested 10 g of sodium azide 1.5 hours prior to admission to hospital. At the beginning, the patient's condition was good, but it changed to critical state within the first hours of hospitalization. He developed a deep coma, respiratory and circulatory insufficiency, metabolic acidosis, cardiac dysrrhythmias and anuria. Cardiac activity monitoring showed alternating tachycardia (140 beats per minute) and bradycardia (48 beats per minute), numerous additional supraventricular and ventricular extrasystoles and sinus dysrrhythmia. Cardiac arrest (asystolia) occurred twice, the second incident with fatal outcome. The patient received supportive therapy, he was also treated according to the therapy prescription for cyanide poisoning. Circulatory disturbances observed in both cases have been described in literature as symptoms of sodium azide poisoning. However, available literature data are scarce and lack systematization, most of them coming from several decades ago. The lack of patient's consent for detailed examination of circulatory system and liver made it impossible to gather further knowledge on the subject. The efficacy of treatment with antidotes for cyanide poisoning has not been unequivocally determined for this kind of intoxication.

Prehospital administration of hydroxocobalamin for smoke inhalation-associated cyanide poisoning: 8 years of experience in the Paris Fire Brigade

INTRODUCTION

This article reports the results of a retrospective study of 8 years of experience of the Paris Fire Brigade with the prehospital use of hydroxocobalamin.

METHODS

The head physician at the Paris Fire Brigade extracted and summarized data from standardized forms completed at the fire scene and, when available, hospital reports to assess survival status and clinical parameters associated with the use of hydroxocobalamin for each patient who received it for smoke inhalation-associated cyanide poisoning from 1995 to 2003.

RESULTS

Of the 101 patients administered hydroxocobalamin, 30 survived, 42 died (17 at the fire scene and 25 at the intensive-care unit), and survival status was not known in the remaining 29 patients. Among the 72 patients for whom survival status was known, survival rate was 41.7% after the administration of hydroxocobalamin. Of the 38 patients found in cardiac arrest, 21 had a return of spontaneous circulation during prehospital care. Of the 12 patients who were initially hemodynamically unstable (systolic blood pressure 0 to < or =90 mmHg), 9 recovered systolic blood pressure an average of 30.6 minutes after the start of hydroxocobalamin infusion. Among nonsedated patients in the sample as a whole (n = 52), mean (SD) Glasgow coma scale score improved from 7.9 (5.4) initially to 8.5 (5.7) after administration of hydroxocobalamin. Among nonsedated patients who were initially neurologically impaired (n = 18), Glasgow coma scale score improved in 9 patients, did not change in 8 patients, and worsened in 1 patient. Two adverse events--red or pink coloration of urine or skin (n = 5) and cutaneous rash (n = 1)--were assessed as being possibly related to hydroxocobalamin.

CONCLUSION

Hydroxocobalamin has a risk:benefit ratio rendering it suitable for prehospital use in the management of acute cyanide poisoning caused by smoke inhalation.

Efficacy of hydroxocobalamin for the treatment of acute cyanide poisoning in adult beagle dogs

INTRODUCTION

The efficacy of hydroxocobalamin for acute cyanide poisoning was compared with that of saline vehicle in dogs.

METHODS

Anesthetized adult beagle dogs were administered potassium cyanide (0.4 mg/kg/min, IV) until 3 min after the onset of apnea. Hydroxocobalamin (75 mg/kg [n = 19] or 150 mg/kg [n = 18], IV) or saline vehicle [n = 17] was then infused over 7.5 min while animals were ventilated with 100% oxygen, which was stopped after 15 min.

RESULTS

In vehicle-treated animals cyanide produced deterioration that culminated in a moribund state requiring euthanasia within 4 h in 10 of 17 animals and in neurological deficits necessitating euthanasia within 2-4 d in an additional 4 animals (mortality rate 82%). Survival through 14 d was observed in 15 of 19 animals administered hydroxocobalamin 75 mg/kg (mortality rate 21%), and 18 of 18 administered hydroxocobalamin 150 mg/kg (mortality rate 0%).

CONCLUSION

Hydroxocobalamin reversed cyanide toxicity and reduced mortality in a canine model.

Subacute combined degeneration of the spinal cord in cblC disorder despite treatment with B12

Subacute combined degeneration (SCD) of the spinal cord is a characteristic complication of vitamin B12 deficiency, but it has never been neuropathologically demonstrated in a B12-inborn error of metabolism. In this report SCD is documented in a 15-year-old boy with early-onset cobalamin C (cblC) disorder. The neuropathologic findings included multifocal demyelination and vacuolation with predilection for the dorsal and lateral columns at the mid-thoracic level of the spinal cord, confirming the similarity of SCD in cblC disorder to the classic adult SCD due to vitamin B12 deficiency. SCD developed in this boy despite treatment for cblC disorder that began at 3 months of age. There is clinical and experimental evidence to suggest that a deficiency in remethylation with concomitant reduction in brain methionine may be the cause of SCD. In this patient plasma methionine levels were low without betaine and/or l-methionine supplementation and in the normal range for only a 2-year period during compliance with therapy. In cblC disorder, a consistent increase in blood methionine to high normal or above normal levels by the use of betaine and l-methionine supplementation may be helpful in preventing SCD. This is especially important now that the presymptomatic detection of cblC disorder is possible through the expansion of newborn screening.

cblE type of homocystinuria due to methionine synthase reductase deficiency: functional correction by minigene expression

The cblE type of homocystinuria is a rare autosomal recessive disorder caused by impaired reductive activation of methionine synthase. Although earlier biochemical studies proposed that the methionine synthase enzyme might be activated by two different reducing systems, mutations were reported in only the methionine synthase reductase gene (MTRR) in cblE patients. The pathogenicity of MTRR mutations, however, has not yet been tested functionally. We report on nine patients of European origin affected by the cblE type of homocystinuria. They presented between 2 weeks and 3 years of age (median age 4 weeks) with anemia, which was macrocytic in only three patients, and with neurological involvement in all but two cases. Bone marrow examination performed in seven patients showed megaloblastic changes in all but one of them. All patients exhibited moderate to severe hyperhomocysteinemia (median plasma total homocysteine [Hcy] 92 mumol/L, range 44-169), while clearly reduced methionine was observed only in four cases. Pathogenic mutations were identified in both parental alleles of the MTRR gene in all patients. Five known (c.903+469T>C, c.1361C>T, c.1459G>A, c.1557-4_1557+3del7, and c.1622_1623dupTA) and three novel mutations (c.7A>T, c.1573C>T, and c.1953-6_1953-2del5) were detected. Importantly, transfection of fibroblasts of cblE patients with a wild-type MTRR minigene expression construct resulted in a significant approximately four-fold increase of methionine synthesis, indicating correction of the enzyme defect. Our study shows a link between a milder predominantly hematological presentation and homozygosity for the c.1361C>T mutation, but no other obvious genotype-phenotype correlation. The identification of mutations in the MTRR gene, together with restoration of methionine synthesis following MTRR minigene expression in cblE cells confirms that this disease is caused by defects in the MTRR gene.

Cellular folate vitamer distribution during and after correction of vitamin B12 deficiency: a case for the methylfolate trap

Haematological sequellae of vitamin B12 deficiency are attributed to disturbed DNA synthesis, but vitamin B12 itself plays no role in DNA biosynthesis. A proposed explanation for this is the methylfolate trap hypothesis. This hypothesis states that B12 deficiency impairs overall folate metabolism because 5-methyltetrahydrofolate (5MTHF) becomes metabolically trapped. This trap results from the fact that 5MTHF can neither be metabolised via the methionine synthase pathway, nor can it be reconverted to its precursor, methylenetetrahydrofolate. Other manifestations of the methylfolate trap include cellular folate loss because of shorter 5MTHF polyglutamate chains and global hypomethylation. The methylfolate trap has never been demonstrated in humans. We describe a patient with B12 deficiency who was homozygous for the common methylenetetrahydrofolate reductase (MTHFR) C677T mutation. We analysed red blood cell (RBC) folate vitamers and global DNA methylation by liquid chromatography (LC) in combination with tandem mass spectrometry, and 5MTHF polyglutamate length by LC-electrochemical detection. Compared to post-B12 supplementation values, homocysteine was higher (52.9 micromol/l vs. 16.8 micromol/l), RBC folate was lower (268.92 nmol/l vs. 501.2 nmol/l), the 5MTHF fraction of RBC folate was much higher (94.5% vs. 67.4%), polyglutamate chain length was shorter (more tetra- and pentaglutamates), and global DNA methylation was 22% lower. This is the first time that virtually all features of the methylfolate trap hypothesis have been demonstrated in a human with vitamin B12 deficiency.

Two newborns with nutritional vitamin B12 deficiency: challenges in newborn screening for vitamin B12 deficiency

Vitamin B12 deficiency causes decreased Methionine Synthase and L-Methylmalonyl-CoA Mutase activity and results in accumulation of Homocysteine, Methylmalonic acid and Propionylcarnitine. Propionylcarnitine is included in tandem mass spectrometry-based newborn screening programs for detection of certain inborn errors of metabolism. We report two asymptomatic newborns with Vitamin B12 deficiency due to maternal deficiencies. One was detected incidentally at 3 weeks of age; the second on supplemental newborn screening based on elevated Propionylcarnitine at 2 days of age. This illustrates the potential for false negative results for Vitamin B12 deficiency screening by acylcarnitine profiling in newborn screening. Homocysteine and Methylmalonic acid may be better markers of Vitamin B12 deficiency. In conclusion, we suggest measuring Methylmalonic acid, Propionylcarnitine and Homocysteine levels in blood spots in expanded newborn screening in order to detect asymptomatic newborns with Vitamin B12 deficiency. Further studies are needed to establish the sensitivity of these three markers in screening for Vitamin B12 deficiency.

Late-onset thrombocytic microangiopathy caused by cblC disease: association with a factor H mutation

BACKGROUND

cblC disease is a cause of hemolytic uremic syndrome (HUS), which has been primarily described in neonates and infants with severe renal and neurological lesions.

PATIENTS

Two sisters aged 6 and 8.5 years presented with a latent hemolytic process characterized by undetectable or low plasma haptoglobin, respectively, associated with renal failure and gross proteinuria. Renal biopsies performed in both patients found typical findings of thrombotic microangiopathy suggesting the diagnosis of HUS. Both patients were free of neurologic signs.

RESULTS

Biochemical investigations found a cobalamin processing deficiency of the cblC type. Search for additional factors susceptible to worsen endothelial damage revealed homozygosity 677C--> T mutation in the methylenetetrahydrofolate reductase gene as well as heterozygosity for a 3254T--> C mutation in factor H in the patient with the most severe clinical presentation. Long-term subcutaneous administration of hydroxocobalamin in combination with oral betaine and folic acid resulted in clinical and biological improvement in both patients.

CONCLUSION

cblC disease may be a cause of chronic HUS with delayed onset in childhood. Superimposed mutation of factor H gene might influence clinical severity.

Prenatal and postnatal treatment in cobalamin C defect

OBJECTIVE

To evaluate prenatal treatment with hydroxycobalamin (OH-Cbl) in a pregnancy at risk for a severe form of the cobalamin C defect and postnatal treatment of the affected child.

STUDY DESIGN

Observational study with non-randomized intervention.

RESULTS

In contrast to reported pregnancies with affected fetuses in which maternal methylmalonic aciduria was found in the last trimester of pregnancy, there was no maternal methylmalonic aciduria in our case, given prenatal treatment with intramuscular OH-Cbl. We did not find that the concentration of odd long-chain fatty acids in cord blood erythrocytes reflects fetal methylmalonic academia. After birth, the infant was treated with intramuscular OH-Cbl and oral carnitine. Oral folate and betaine were added as adjunct therapy to decrease plasma total homocysteine. Because of inadequate metabolic control, a diet reduced in natural protein was introduced. The child had normal developmental milestones but had nystagmus, hyperpigmented retinopathy, and discrete truncal muscular hypotonia.

CONCLUSIONS

Despite prenatal and postnatal treatment, adequate metabolic control, absence of metabolic crises, and normal developmental milestones, this patient with the cobalamin C defect had characteristic symptoms of the disease.

Life-Threatening Interaction Between Complementary Medicines: Cyanide Toxicity Following Ingestion of Amygdalin and Vitamin C

OBJECTIVE:

To describe a case of severe accidental cyanide poisoning following a single ingestion of amygdalin with therapeutic intent.

CASE SUMMARY:

A 68-year-old patient with cancer presented to the emergency department shortly after her first dose (3 g) of amygdalin with a reduced Glasgow Coma Score, seizures, and severe lactic acidosis requiring intubation and ventilation. The patient also ingested 4800 mg of vitamin C per day. She responded rapidly to hydroxocobalamin treatment. The adverse drug reaction was rated probable on the Naranjo probability scale.

DISCUSSION:

Amygdalin and laetrile (a synthetic form of amygdalin) are commonly used as complementary or alternative medicine (CAM) for the treatment of cancer. Vitamin C is known to increase the in vitro conversion of amygdalin to cyanide and reduce body stores of cysteine, which is used to detoxify cyanide. Amygdalin has been used for decades by patients with cancer who are seeking alternative therapies, and severe reactions have not been reported with this dose. An interaction with vitamin C is a plausible explanation for this life-threatening response.

CONCLUSIONS:

This case highlights the fact that CAMs can produce life-threatening toxicity. This case also adds a further note of caution, namely, the potential for serious interactions between CAMs, particularly where there is no tradition of concomitant use.