Correspondence

Extreme Hyperkalemia in Munchausen-by-Proxy Syndrome

N Engl J Med 1999; 340:1293-1294April 22, 1999

Article

To the Editor:

A 20-month-old girl was admitted to the hospital because of a reported febrile convulsion. Her medical history included recurrent simple febrile convulsions and unexplained slight gynecomastia. Physical examination revealed a well-nourished and cheerful child, with normal vital signs and physical and psychomotor development, except for the slight gynecomastia. Repeated blood tests from different puncture sites sent in different test tubes to the hospital laboratory revealed extreme hyperkalemia, incompatible with life, and very high serum creatinine concentrations (Table 1Table 1Biochemical Values in a Girl with Munchausen-by-Proxy Syndrome., samples 1 through 3). The electrocardiogram showed no signs of hyperkalemia. Urine output was normal. The discrepancy between the clinical findings and the laboratory results raised the suspicion of factitious hyperkalemia and azotemia. Since it is common practice in our medical center for samples to be delivered to the laboratory by family members, another blood sample from the girl was taken directly to the laboratory by hospital staff. The results were normal (Table 1, sample 4). A blood sample was drawn from a boy with normal kidney function (sample 5). A portion of it was labeled with the girl's name and given to her mother to take to the laboratory (Table 1, sample 6). Once again, severe hyperkalemia and high serum creatinine concentrations were found. Further questioning revealed that all the initial samples from the girl had been delivered to the laboratory by her mother. We concluded that the mother was deliberately contaminating the samples, and therefore Munchausen-by-proxy syndrome was diagnosed.

To explain the method by which the mother could have altered the samples to yield these results, we calculated the expected effect of adding urine, the only readily available solution that could yield this constellation of laboratory findings, to a blood sample. Because the hematocrit of the mixed blood samples decreased by approximately 20 percent, we calculated that the plasma volume was diluted by 30 percent. We then diluted the girl's serum by one third with urine from a normal adult (Table 1, sample 7) and obtained results that were very similar to the original, bizarre values.

The mother was confronted with the suspicion that she was contaminating the blood samples. She denied doing so, as is typically reported in Munchausen-by-proxy syndrome.1 A hospital pediatric social worker and a psychiatrist were unable to elicit reasons for the mother's behavior. The girl was discharged under the supervision of community social services and a local child-welfare agency.

There are reports in the literature of Munchausen-by-proxy syndrome in children in which their urine samples were mixed with menstrual secretions,2 blood,3 feces,4 and other exogenous substances.5 It seems that in the case of Munchausen-by-proxy syndrome, the perpetrator may be more creative than physicians can imagine. This case serves as a reminder that Munchausen-by-proxy syndrome should be suspected whenever there is an unexplained discrepancy between clinical and laboratory findings.

Daniella Magen, M.D.
Karl Skorecki, M.D.
Rambam Medical Center, Haifa 31096, Israel

5 References

1. 1

   Schreier HA, Libow JA. Munchausen by proxy syndrome: a modern pediatric challenge. J Pediatr 1994;125:S110-S115
   CrossRef | Web of Science | Medline

2. 2

   Meadow R. Münchausen syndrome by proxy: the hinterland of child abuse. Lancet 1977;2:343-345
   CrossRef | Web of Science | Medline

3. 3

   Jacobs JC. Factitious hematuria in two teenage boys. Am J Dis Child 1979;133:550-551
   Web of Science | Medline

4. 4

   Reich P, Lazarus JM, Kelly MJ, Rogers MP. Factitious feculent urine in an adolescent boy. JAMA 1977;238:420-421
   CrossRef | Web of Science | Medline

5. 5

   Mitas JA II. Exogenous protein as the cause of nephrotic-range proteinuria. Am J Med 1985;79:115-118
   CrossRef | Web of Science | Medline

Citing Articles (2)

Citing Articles

1. 1

   H??ctor Aran??bar, Mario Cerda. (2005) Hypoglycemic Seizure in Munchausen-by-Proxy Syndrome. Pediatric Emergency Care 21:6, 378-379
   CrossRef

2. 2

   Mary S Sheridan. (2003) The deceit continues: an updated literature review of Munchausen Syndrome by Proxy. Child Abuse & Neglect 27:4, 431-451
   CrossRef