Cushing's syndrome and NAFLD
The majority of cases of NAFLD are due to the metabolic syndrome with
insulin resistance thought to be a key feature of the pathogenesis. The
authors rightly point out that there are other endocrine causes but they
do not mention Cushing's syndrome.
Cushing's syndrome mirrors many of the features of the metabolic
syndrome (central obesity, hypertension, insulin resistance and
dyslipidaemia) and is associated with a 20% prevalence of NAFLD (1).
Glucocorticoids have a direct effect on hepatic lipid accumulation by
promoting lipogenesis and inhibiting fatty acid beta-oxidation (2).
Although it is a rare condition it can easily be overlooked in NAFLD
patients and it is therefore worth looking out for clinical features (moon
face, striae, dorsocervical fat pad, proximal muscle weakness) and also
considering the diagnosis in those with resistant hypertension.
Hypercortisolism suppresses thyroid function and is also associated
with autoimmune thyroid disease (3). Thus the search for an underlying
endocrine cause may not always end with the identification of
hypothyroidism in association with NAFLD.
1) Rockall AG, Sohaib SA, Evans D, Kaltsas G, Isidori AM, Monson JP
et al. Hepatic steatosis in Cushing's syndrome: a radiological assessment
using computed tomography. Eur J Endocrinol. 2003 149:543-548
2) Letteron P, Brahimi-Bourouina N, Robin MA, Moreau A, Feldmann G,
Pessayre D. Glucocorticoids inhibit mitochondrial matrix acyl-CoA
dehydrogenases and fatty acid beta-oxidation. Am J Physiol. 1997 272:G1141
3) Niepomniszcze H, Pitoia F, Katz SB, Chervin R, Bruno OD. Primary
thyroid disorders in endogenous Cushing's syndrome. Eur J Endocrinol. 2002
Competing interests: No competing interests