Persistent elevation of transaminases as the presenting finding in an adolescent with an unsuspected muscle glycogenosis

Incidental raised transaminases: a clue to muscle disease

Twenty-one patients with incidental hypertransaminasaemia who were eventually diagnosed as muscular dystrophy are described. There were two females and 19 males aged between 2 and 11 years [mean (SD) 6.7 (3.4) y]. Serum alanine and aspartate transaminase levels were between 73 and 595 IU/L (30-35) and 68 and 550 IU/L (30-35), respectively. Muscle disease was suspected when creatine phosphokinase levels were elevated and confirmed in each patient by muscle biopsy. The time interval between incidental hypertransaminasemia and the diagnosis of muscle disease was between 3 and 12 months. Eleven patients were diagnosed as Becker's muscle dystrophy, eight as Duchenne muscle dystrophy and two had sarcoglycanopathy. Long-term elevation of transaminase levels might be a sign of occult muscle disease. Invasive tests such as liver biopsy should not be performed in patients with unexplained hypertransaminasaemia without first determining creatinine phosphokinase levels.

Aminotransferases and muscular diseases: a disregarded lesson. Case reports and review of the literature

The aim of this study was to call the attention to the often disregarded message that hypertransaminasemia may be a marker of both liver and muscle diseases by presenting personal case reports and a systematic literature review. Three male children (mean age 5.7 years) were inappropriately addressed, during the last 12 months, to our paediatric liver unit for diagnostic work-up of a chronic hypertransaminasemia of unknown origin. In one of them, a liver biopsy had already been performed. On admission, physical examination, evaluation of serum levels of creatine kinase, and dystrophin genetic testing finally led to a diagnosis of muscular dystrophy. One hundred fourteen similar cases, 21 with unnecessary liver biopsy, were found by Medline search. Expensive and invasive tests planned to investigate liver diseases should be postponed until alternative sources of increased serum aminotransferases, primarily myopathic injury, have been excluded.

Serum transaminase levels in boys with Duchenne and Becker muscular dystrophy

OBJECTIVE

Serum alanine transaminase (ALT) and aspartate transaminase (AST) levels are commonly used as biochemical indicators of hepatocellular injury but can also detect occult muscle disease. High concomitant serum creatine phosphokinase (CPK) levels can point to muscle as the source of high transaminase levels. Nevertheless, clinicians may be reluctant to attribute high transaminase levels to muscle.

METHODS

Study patients were boys with a genetic or biopsy-confirmed dystrophinopathy whose concomitant serum CPK, ALT, and AST levels were measured.

RESULTS

We report 82 enzyme data sets from 46 patients with Duchenne muscular dystrophy (DMD) and 9 with Becker muscular dystrophy. Our results show a linear relationship between serum CPK and serum ALT and AST and a logarithmic relationship between serum enzyme levels and age for boys with DMD. We developed a mathematical model to predict serum ALT and AST levels when the serum CPK level and age are known. For 6 boys, initial failure to consider muscle as a cause of high transaminase levels led to delay of diagnosis and extensive testing for hepatic dysfunction. A second group of 4 boys with known DMD were investigated for liver disease after high transaminase levels were detected. Serum transaminase levels were highest in ambulant boys with DMD, whose levels reached 1220 U/L (ALT) (22.6 times higher than upper-limit normal levels) and 801 U/L (AST) (12.3 times higher than upper-limit normal levels).

CONCLUSIONS

By recognizing muscle as a potential source of serum transaminase levels, clinicians can avoid unnecessary and invasive procedures, expedite clinical diagnosis, and avoid unnecessary cessation of concomitant drug therapy.

"Liver function tests" are not always tests of liver function

A child with Wilm's tumor and a child with immune thrombocytopenic purpura (ITP) were each noted to have persistent elevations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH). Both children underwent thorough evaluation for liver disease and, as a result, experienced delays in treatment of the Wilm's tumor and ITP. Eventually both children were found to have extremely elevated serum creatine kinase (CK). Muscle biopsy confirmed diagnoses of Duchenne's muscular dystrophy in one child, and Becker's muscular dystrophy in the second. Hematologists/oncologists should consider obtaining a serum CK to rule out muscle disease in patients with unexplained elevations of AST, ALT, and LDH.

Assessing liver function and hyperbilirubinemia in the newborn

In clinical practice, “liver function” is assessed by either measuring the concentration of substances produced by the hepatocyte, measuring the serum content of substances that are changed by hepatocyte damage, evaluating the serum concentrations of substances released from the cells as a result of injury, assessing the ability of the liver to perform a metabolic task such as conjugation or detoxification, or by measuring enzyme activity and substrate content of the cell and its organelles. After birth, with cessation of placental function, the neonatal liver must assume many different tasks. Distinct developmental sequences rapidly progress for numerous hepatic functions as the newborn adapts to its environment. This manuscript is an attempt to provide guidelines for the evaluation and management of the newborn infant when assessing liver function and hyperbilirubinemia. These guidelines, like all sets of guidelines, are only recommendations and do not substitute for good clinical judgment based upon the individual circumstances of each patient.

Diagnosis of occult muscular dystrophy: importance of the "chance" finding of elevated serum aminotransferase activities

We report our experience with four children, including one girl, in whom the eventual diagnosis of muscular dystrophy was made because of persistent, unexplained elevated serum aminotransferase values. Measurement of serum creatine kinase activity and careful physical examination are the most useful and cost-effective means of correctly identifying these patients.