Factitious Cushing's syndrome masquerading as Cushing's disease.

CONTEXT: Factitious Cushing's syndrome is extremely rare. The diagnosis is challenging as cross-reactivity of synthetic corticosteroids or their metabolites in immunoassay measurements of plasma or urinary cortisol can make distinguishing between true and factitious Cushing's syndrome difficult. Adrenocorticotropin (ACTH) is usually suppressed in factitious Cushing's syndrome. PATIENT: A 54-year-old woman presented with clinical and biochemical features of Cushing's syndrome and an unsuppressed ACTH concentration. She denied recent exogenous corticosteroid use. INVESTIGATIONS AND RESULTS: Initial investigations revealed a markedly elevated urinary free cortisol, mildly elevated midnight salivary cortisol and normal morning cortisol concentration. Plasma ACTH was not suppressed at 13 ng/l (RR 10-60 ng/l). A pituitary MRI was normal, but inferior petrosal sinus sampling (IPSS) revealed a post corticotrophin releasing hormone ACTH ratio >20:1 in the left petrosal sinus. Ketoconazole therapy amplified discordance between the urinary free and morning plasma cortisol concentrations. Further investigation of this discordance using high-pressure liquid chromatography tandem mass spectrometry (HPLC-MS/MS) revealed a urinary free cortisol excretion of only 20 nmol/24 h, but prednisolone excretion of 16,200 nmol/24 h. CONCLUSIONS: Factitious Cushing's syndrome can mimic endogenous ACTH-dependent hypercortisolism during initial investigations and IPSS. This case highlights the importance of (i) recognizing the significance of discordant results; (ii) using an ACTH assay capable of reliably differentiating ACTH-dependent from ACTH-independent Cushing's syndrome; and (iii) appreciating that IPSS is only useful to localize the source of ACTH in confirmed ACTH-dependent Cushing's syndrome. In this case, measurement of corticosteroids by HPLC-MS/MS was essential in reaching the correct diagnosis.

'Watered down' renal colic: using tap water mixed with blood to simulate macroscopic haematuria.

Renal colic is a frequent presentation to the emergency department. Although most cases are genuine, up to 0.6% of cases are factitious, representing attempts to procure parenteral narcotic medication or rarely, to attain unnecessary investigation or invasive treatment. Urethral catherization has been recommended to procure an untampered urine sample, but is viewed as invasive. Calculi analysis has no relevance to acute management. We report a case of factitious renal colic which was definitively proven to be so using sample biochemistry to confirm a tap water sample contaminated with blood. This is diagnostically useful if tap water or normal saline is used to produce an alleged urine sample.

[Elevated hormone levels without endocrinopathy: hypercortisoluria and hypoglycemia as facticious disorders]. / Hormonale overmaat zonder endocrinopathie: hypercortisolurie en hypoglykemie als nagebootste stoornissen.

A 29-year-old female patient with weight gain and intermittent hypertension was suspected of having Cushing's syndrome due to conspicuous hypercortisoluria. Specific laboratory tests demonstrated that the urine samples contained prednisolone, which had resulted in a false positive elevation of urine-free cortisol measurements. The patient admitted to having taken prednisolone tablets and also to having added them to several urine collections. In a 21-year-old male patient with unexplained hypoglycaemia, hypoglycaemia was recorded during a 72-hour fast together with an elevated level of plasma insulin and a low level of plasma C-peptide. The presence of insulin autoantibodies could be excluded, making a diagnosis of factitious hypoglycaemia highly likely. Both patients were confronted with the factitious disorder and received psychiatric counselling, after which no further problems arose. Where excessive hormone levels occur, the possibility of a factitious disorder needs to be considered. In such cases, specific supplementary laboratory tests may prove helpful.

Factitious proteinuria: diagnosis and protein identification by use of isoelectric focusing.

Factitious proteinuria is an unusual finding. We present a case in which clinical suspicion was aroused by the disparity between the clinical history and findings and the 24-h excretion of protein in urine. Electrophoresis of the patient's serum and urine confirmed the presence of an unusual protein. By isoelectric focusing we identified it as egg-white, a finding confirmed by immunofixation with antiserum to egg-albumen. In the past, confirmation of the identity of such a protein has required specific antiserum for immunofixation or immunodiffusion. Such antiserum may not always be available. However, isoelectric focusing gives sufficient resolution for positive identification of exogenous proteins, even in the presence of true proteinuria.

Spurious stones.

One hundred and sixteen (3.5%) of 3,300 specimens submitted by 72 patients as urinary stones were artifacts, i.e. not formed of accepted constituents of urinary calculi. The laboratory diagnostic methods included infrared and wet chemical analysis, and X-ray diffraction. Twenty-eight were of organic origin and some of these were undoubtedly submitted by accident as calculi. Eighty-eight were of mineral origin, mainly quartz and feldspar, and it is believed that the great majority were submitted for secondary gain or for psychiatric reasons. Ten patients each submitted from 2 to 10 artifacts. Five cases studies are presented which illustrate some confounding clinical and laboratory findings. Spurious stones can lead to difficult clinical and laboratory problems.