150 PART II: PRIMARY CARE DISORDERS
3. Determinewhatiscausingtheexcesscortisol,which
usually requires consultation of an endocrinology
specialist:
a. Brainmagneticresonanceimaging(MRI)
b. DST(highdose)
c. SerumACTHlevels
d. Testofcorticotrophin-releasinghormone(CRH),
which acts on the pituitary gland to cause the
releaseofACTH(CRHtest)
e. Test that measures ACTH levels in the veins
that drain the pituitary gland (petrosal sinus
sampling)
20,32
TheEndocrineSociety’sClinicalGuidelinesforCush-
ing’ssyndromesuggestthatthesyndromeshouldnotbe
diagnosedunlesstwoofthetestsfordocumentingexces-
sive cortisol (item2 inthe previouslist)areabnormal.
2
The evidence-based guidelines also recommend against
usingthefollowingtests:randomserumcortisolorplasma
ACTH levels, urinary 17-ketosteroids, insulin tolerance
test, loperamide test, and other tests designed to deter-
minethecauseofCushing’ssyndrome,suchaspituitary
andadrenalimagingandhighdose(8mg)DST.
30,33
Management
Treatmentdependsonwhethertheproblemcausingexces-
sivecortisolisintheadrenalglands,thepituitarygland,or
elsewhere.Itmayincludesurgery,radiation,chemotherapy,
ortheuseofcortisol-inhibitingdrugs.
PituitaryCushing’sdiseaseisbesttreatedviatranssphe-
noidalresection,whichisthesurgicalremovalofthepitu-
itarytumor.Inrarecases,theremovaloftheentirepituitary
glandisrequired,whichresultsinapermanentdeciency
of ACTH and the other pituitary hormones. If surgical
removalofthepituitaryisnotpossible,radiationtherapy
canbeutilized,buttherecoveryfromtheCushing’ssymp-
tomsismuchslower.
31
Lifestyle Changes: Practical Tips for Your
Patients
Mencanexperienceimpotenceandtransientinfertil-
ity,andwomencanexperiencemenstrualirregulari-
tiesandhirsutism.Thiscanplayamajorrolefora
couple who are trying to conceive. Female hirsut-
ism can in itself cause many problems with self-
imageandcondence.
Addison’s Disease and Corticoadrenal
Insufciency
General Characteristics
Theadrenalglandsaresituatedadjacenttothekidneysand
are comprised of two types of hormone-secreting tissue
(Figure11–1).Thecoreistermedthemedulla.Theouter
layeristhecortex,whichisresponsibleforsecretingthree
classes of steroid hormones: androgens, mineralocorti-
coids,andglucocorticoids.Theglucocorticoidhormones
are the most common class in which either excesses or
deciencies are encountered. The disorder of excess is
termedCushing’s disease, and the disorder of deciency
istermedAddison’sdisease.
34,35
Addison’sdiseasehasalso
beenreferredtoasadrenocorticalhypofunction,chronicadre-
nocorticalinsufciency,orprimaryadrenalinsufciency.
Diseasesoftheadrenalglands,eitherexcessivenessor
insufciency,aresuspectedbasedonpatientsymptomsand
physicalmanifestations.Rarelyadrenal masses arefound
incidentallyonabdominalimagingstudiesperformedfor
unrelatedpurposes.
Addison’sdiseasecanstartatanyageandaffectsmales
andfemalesequally.Addison’sdiseaseisrelativelyuncom-
mon,andinapproximately70percentofcasesitiscaused
byanautoimmuneprocessthatresultsinthedestruction
oftheadrenalglands.Aldosteroneisthemajormineralo-
corticoid secreted by the adrenal glands and serves to
promotesodiumreabsorptionandpotassiumexcretionin
the renal tubule. Aldosterone secretion is stimulated by
hypovolemia regulated by the renin-angiotensin system.
Cortisolisthemajor glucocorticoid also secretedbythe
adrenal gland. Its purpose is to maintain vascular tone,
counteracttheeffectsofinsulin,andassistintheinhibi-
tion of protein synthesis in muscles. In the other 30
percentofAddison’sdiseasecases,theadrenalglandsare
destroyedbycancer,aninfectionsuchastuberculosis,or
another identiable disease. In infants and children,
Addison’sdiseasemaybetheresultofageneticabnormal-
ityoftheadrenalglands.
Otherlesscommoncausesofadrenalinsufciencyinclude
secondaryadrenalinsufciencycausedbypituitaryorhypo-
thalamichypofunction.Acuteadrenalinsufciencyisocca-
sionallytheresultofsuddenwithdrawalofchronicexogenous
steroidtherapyorfromphysicalstressonthebody.Addison’s
diseasecanoccurwithhyperthyroidism,hypothyroidism,or
otherendocrinopathies.
Signs, Symptoms, and Diagnosis
SoonafterdevelopingAddison’sdisease,symptomsofweak-
ness,fatigue,andlightheadednessuponstandingaftersit-
tingorlyingmaybeexhibited.Theseproblemsmaydevelop
graduallyandinsidiously.AnotherfeatureofAddison’sdis-
easeispatchesof darkskinthatmayseemliketanning,
butitoccursonareasnotevenexposedtothesun.Black
frecklesmay develop over the forehead, face, and shoul-
ders,andabluishblackdiscolorationmaydeveloparound
thenipples,lips,mouth,rectum,scrotum,orvagina.Most
patients will notice weight loss, dehydration, and poor
appetite,andtheywilldevelopmuscleaches,nausea,vom-
iting,anddiarrhea.Manybecomeunabletotoleratecold.
Unless the disease is severe, symptoms tend to become
apparentonlyduringtimesofstress.Periodsofhypoglyce-
mia,withnervousnessandextremehungerforsaltyfoods,
canoccur,particularlyinchildren.IfAddisonsdiseaseis
nottreated, severeabdominalpains,profound weakness,
extremely low blood pressure, kidney failure, and shock
mayoccur(adrenalcrisis).Anadrenalcrisisoftenoccurs
ifthebodyissubjectedtostress,suchasanaccident,injury,
surgery,orsevereinfection.Deathmayquicklyfollow.
35

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