Clinicians Think Rare Disease But Clinical Clues Lead to Something More Disturbing

Clinician's Role
Clinician's Role

A new case report published in the journal Pediatrics discusses one of the most challenging situations for clinicians, recognizing "fabricated or induced illness" in a child, also known as Munchausen syndrome by proxy. This case is a model of how induced illness can resemble a real medical condition and how inconsistent diagnostic tests may provide the first clue of fabricated illness.

During hospitalization for gastroenteritis, the patient, a boy of 4 years and 11 months, presented with multiple hypoglycemic episodes (<50mg/dL); this was his third admission after multiple hospitalizations in other centers over preceding years for persistent diarrhea without infection. Past medical history showed neurodevelopmental delay consequent to neonatal ischemia and poorly controlled generalized epilepsy; clinical examination showed hirsuitism. His mother, a nurse, was his only caregiver.

Several consecutive plasma glucose tests confirmed the hypoglycemic episodes and prompted the clinicians to employ a continuous glucose monitoring system (CGMS).  The CGMS pattern, showing marked hypoglycemic episodes alternating with hyperglycemia, was similar to that obtained in a Rabson-Mendenhall syndrome (RMS) case with biallelic insulin receptor (INSR) mutations (E238K/E1074Q), a rare disorder of insulin resistance. During severe hypoglycemic episodes, plasma insulin levels were always very high but simultaneous c-peptide tests were inconsistent with insulin hypersecretion.

To maintain plasma glucose >2.8mmol/L and avoid hypoglycemia, the patient was given an infusion of 3–5mg/kg/min of glucose daily. Despite potassium supplementation and normal serum magnesium, multiple blood gas analysis showed metabolic alkalosis; nephrocalcinosis was detected with abdominal ultrasound. The patient also developed sepsis twice with high fever although the source of infection was not identified.

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