To the Editor: In the discussion of the Case Record by Bonkovskyet al. (June 26 issue)1 about a patient with porphyria who becamesymptomatic after gastric bypass surgery, there was no mentionof the patient's nutritional care, which may have played a majorcontributory role. The persistent ketonuria before hospitalizationindicates a daily carbohydrate intake of less than 100 g, whereasthe very low serum creatinine level on admission indicates limitedmeat intake and a marked reduction in skeletal muscle, reflectingsevere protein-calorie malnutrition.2 These findings are consistentwith limited energy and protein intake postoperatively, whichwas at least 18 days before a subsequent hospital admissionthat was more than 5 weeks in duration. If the patient remainedin a semistarved state in terms of protein and energy for thatentire period, this would contribute substantially to the extrememotor weakness that increased with time and perhaps contributedto the continued activity of the porphyria. An additional factoris the possible contribution of deficiencies of thiamine andother micronutrients; these deficiencies have been observedpreviously after gastric bypass and are associated with polyneuropathyand encephalopathy.3,4,5
Bruce R. Bistrian, M.D., Ph.D. Beth Israel Deaconess Medical Center Boston, MA 02215
References
Case Records of the Massachusetts General Hospital (Case 20-2008). N Engl J Med 2008;358:2813-2825. [Free Full Text]
Bistrian BR, Blackburn GL, Sherman M, Scrimshaw NS. Therapeutic index of nutritional depletion in hospitalized patients. Surg Gynecol Obstet 1975;141:512-516. [Web of Science][Medline]
Carrodeguas L, Kaidar-Person O, Szomstein S, Antozzi P, Rosenthal R. Preoperative thiamine deficiency in obese population undergoing laparoscopic bariatric surgery. Surg Obes Relat Dis 2005;1:517-522. [CrossRef][Medline]
Juhasz-Pocsine K, Rudnicki SA, Archer RL, Harik SI. Neurologic complications of gastric bypass surgery for morbid obesity. Neurology 2007;68:1843-1850. [Free Full Text]
Koffman BM, Greenfield LJ, Ali II, Pirzada NA. Neurologic complications after surgery for obesity. Muscle Nerve 2006;33:166-176. [CrossRef][Web of Science][Medline]
To the Editor: Bonkovsky et al. report an interesting case of a 57-year-old woman with abdominal pain and weakness 1 monthafter gastric bypass surgery for morbid obesity. The cause ofthe symptoms could have been a primary disease or a consequenceof the bariatric surgery. Abdominal pain is a frequent symptomafter surgery for obesity and is caused by a variety of postoperativecomplications (shown in Table 2 of the article). Neurologiccomplications (Table 1) are not uncommon after bariatric surgeryand have been reported in 5 to 10% of patients.1 Any part ofthe nervous system may be involved, with a broad variety ofsymptoms. The majority of neurologic complications after bariatricsurgery are caused by nutritional deficiencies, particularlydeficiencies of iron, folate, vitamin B1, and vitamin B12, andthey are mostly recognized as late complications.2 Vitamin B1deficiency is a rare but important cause of early acute polyneuropathyafter bariatric surgery.3 Furthermore, neurologic disordersmay be the result of accelerated fat metabolism. Some authorssuggest that a toxin from the fast metabolism of fat, a lossof carnitine, or lactate acidosis is responsible.1,2
Table 1. Progressive Weakness after Bariatric Surgery.
Sammy A. Baierlein, M.D. Anja Wistop, M.D. Thomas Peters,M.D. St. Claraspital Basel 4016 Basel, Switzerland sammybaierlein{at}web.de
References
Berger JR. The neurological complications of bariatric surgery. Arch Neurol 2004;61:1185-1189. [Free Full Text]
Paulson GW, Martin EW, Mojzisik C, Carey LC. Neurologic complications of gastric partitioning. Arch Neurol 1985;42:675-677. [Free Full Text]
Halverson JD. Metabolic risk of obesity surgery and long-term follow-up. Am J Clin Nutr 1992;55:Suppl:602S-605S. [Medline]
To the Editor: The reduction in food intake, frequent vomiting,and the loss of absorptive surface puts patients at risk ofvitamin deficiency after bariatric surgery. In the case described,the patient's anorexia and severe peripheral neuropathy, whichdeveloped a few weeks after surgery, are consistent with thiaminedeficiency. One of the most serious consequences of this deficiencyis Wernicke's encephalopathy. The well-known triad of confusion,ophthalmoplegia, and ataxia plus typical laboratory or radiologicfindings is not always present.1,2 The diagnosis of Wernicke'sencephalopathy is usually missed clinically.3 Intravenous administrationof dextrose or carbohydrate loading may worsen the course ofthis deficiency syndrome.1 Parenteral thiamine prevents or treatsthiamine deficiency in poorly nourished patients.1,2
Perhaps thiamine deficiency played some part in the confusingand serious clinical course of this patient. It would be interestingto know whether she received parenteral vitamins at any pointin her complicated course after bariatric surgery.
Frances R. Frankenburg, M.D. Edith Nourse Rogers Memorial Veterans Hospital Bedford, MA 01730 frances.frankenburg{at}med.va.gov
References
Reuler JB, Girard DE, Cooney TG. Wernicke's encephalopathy. N Engl J Med 1985;312:1035-1039. [Web of Science][Medline]
Singh S, Kumar A. Wernicke encephalopathy after obesity surgery: a systematic review. Neurology 2007;68:807-811. [Free Full Text]
Harper C. The incidence of Wernicke's encephalopathy in Australia -- a neuropathological study of 131 cases. J Neurol Neurosurg Psychiatry 1983;46:593-598. [Free Full Text]
To the Editor: Genetic testing may have established the diagnosisof variegate porphyria in this patient, but the apparent factthat there was no history of skin lesions before she receivedparenteral iron-containing hematin suggests newly unmasked porphyriacutanea tarda superimposed on variegate porphyria. (The occurrenceof variegate and cutanea tarda porphyria in the same familyhas been described in persons with mixed Dutch and Bantu ancestry.1)Further genetic testing for mutations in the HFE hemochromatosisgene would help corroborate that porphyria cutanea tarda alsowas present in this patient.
In addition, there are two errors in Table 4 of the article.The deficient enzyme for protoporphyria (ferrochelatase) ismissing from the table. "Hepatocarboxylporphyrin" should beheptacarboxylporphyrin (shown correctly in Table 5).
James Kalivas, M.D. University of Arizona College of Medicine Tucson, AZ 85724
References
Dean G. The porphyrias. Philadelphia: J.B. Lippincott, 1963.
The discussant and a colleague reply: Bistrian, Baierlein etal., and Frankenburg point out the most common causes of neurologicdisorders after gastric bypass surgery. Thiamine deficiencyis an important consideration, especially in patients with recurrentvomiting; however, vomiting was not a feature of this patient'spresentation. During the first 6 weeks after surgery, she wasconsuming the recommended liquid nutritional drinks, eatingsoft food without difficulty, and taking multivitamins regularly.
When weakness suddenly developed, thiamine was administeredintravenously and vitamin B12 was administered intramuscularly.The serum thiamine level obtained before thiamine administrationwas 72 nmol per liter (normal range, 87 to 286); the levelsof vitamins A, B2, B6, B12, and folate were normal. Within 24hours after intubation, a nasojejeunal tube was placed; 10 dayslater, laparoscopic exploration was performed that showed normalanatomy after gastric bypass, and a gastrostomy tube was placedin the bypassed gastric remnant. Thus, we believed her nutritionwas adequate.
In response to the comment of Kalivas: subsequent testing formutations in the gene for familial hemochromatosis (HFE) showedno mutations. However, the serum ferritin levels were persistentlyhigh after discontinuation of hematin infusions, and regularphlebotomy was recently begun for a presumptive diagnosis ofacquired porphyria cutanea tarda. Kalivas also correctly pointsout in Table 4 the omission of ferrochelatase (the gene andenzyme that are defective in erythropoietic protoporphyria)and the misspelling of heptacarboxylporphyrin.
Janey S.A. Pratt, M.D. Massachusetts General Hospital Weight Center Boston, MA 02114
Herbert L. Bonkovsky, M.D. Carolinas Medical Center Charlotte, NC 28232
Correction
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