A More Accurate Diagnosis of Cushing’s Syndrome

Cushing’s syndrome is associated with excessive cortisol production and, if left untreated, can result in severe complications, such as heart attacks, strokes, and type 2 diabetes. To diagnose this condition, a dexamethasone suppression test is commonly performed.

Various factors, such as metabolic rate and interactions with other medications, can affect test efficacy. Therefore, it is crucial to measure the concentration of dexamethasone concurrently with cortisol to avoid false-positive results.

To address this issue, a team of researchers at the University of Turin, led by Professor Giulio Mengozzi in the Department of Medical Sciences, has developed a liquid chromatography-tandem mass spectrometry method.

This new method enables the simultaneous quantification of cortisol, cortisone, dexamethasone, and six additional exogenous corticosteroids, leading to a more accurate diagnosis of Cushing’s syndrome.

The symptoms of Cushing’s syndrome

Cushing’s syndrome is a medical condition characterized by an abnormal and prolonged increase in cortisol production, typically affecting females between the ages of 30 and 50.1

While the issue may originate from within the body (endogenous), it is more commonly caused by external factors, such as the use of glucocorticoid medications.

Visible symptoms of Cushing’s syndrome include weight gain, an accumulation of fat around the base of the neck, a fatty hump between the shoulders, the appearance of a “moon face”, and easy bruising. However, not all individuals with the syndrome exhibit these symptoms, rendering diagnosis challenging. Without timely treatment, Cushing’s syndrome can lead to severe complications, including heart attack, stroke, blood clots in the legs and lungs, increased susceptibility to infections, memory loss, and type 2 diabetes.

Dexamethasone testing

A commonly used method for diagnosing Cushing’s syndrome is the dexamethasone suppression test (DST), which measures the adrenal gland’s response to adrenocorticotropic hormone (ACTH).

ACTH regulates cortisol levels in the blood plasma and stimulates the adrenal cortex to produce cortisol. When cortisol levels increase, ACTH secretion is suppressed. Dexamethasone, a synthetic steroid similar to cortisol, is administered during the DST to lower ACTH levels.

DSTs are available in low-dose (LDDST) and high-dose (HDDST). They can be performed overnight or over two days.

LDDSTs are used initially to diagnose Cushing’s syndrome. If the result is positive, HDDSTs help classify the disease as ACTH-dependent or independent. These tests are typically conducted in the following manner.2

A more accurate diagnosis of Cushing’s syndrome

Cortisol is a steroid hormone of the glucocorticoid class made by the adrenal glands.

Image Credit: Shutterstock/Kateryna Kon

LDDST

  • Overnight protocol: 1 mg of dexamethasone is administered at 11:00 pm, and the serum cortisol levels are measured at 8:00 am the following morning.
  • Two-day protocol: serum cortisol levels are measured at 8:00 am and 0.5 mg of dexamethasone is administered every six hours (9:00 am, 3:00 pm, 9:00 pm, 3:00 am) for two days, totalling 4 mg. Serum cortisol levels are then measured at 9:00 am, six hours after the last dose has been delivered.

HDDST

  • Overnight protocol: baseline serum cortisol or 24-hour urinary free cortisol (UFC) is measured in the morning, and 8 mg of dexamethasone is given at 11.00 pm. Cortisol level in blood is then measured at 8.00 am the following morning.
  • Two-day protocol: Baseline serum cortisol or 24-hour UFC is measured at 8:00 am; 2 mg of dexamethasone is administered every six hours (9:00 am, 3:00 pm, 9:00 pm, 3:00 am) for two days, totaling 16 mg, in tandem with the collection of urine for UFC measurements. Serum cortisol levels are measured at 9:00 am, six hours after the last dose.

Patients whose pituitary glands produce excessive amounts of ACTH will exhibit an abnormal response to the low-dose test but a normal reaction to the high-dose test.

During the LDDST, cortisol levels should decrease following the administration of dexamethasone, and a cut-off value of below 18 ng/mL is recommended to distinguish a healthy response from an unhealthy one.

For the HDDST, a decrease in urine-free cortisol (UFC) or serum cortisol greater than 50% indicates the presence of ACTH-dependent Cushing’s syndrome. This rule applies to both the overnight LDDST and the two-day HDDST methods.

Measuring cortisol levels

Chemiluminescence immunoassay (CLIA) is a widely used method for measuring cortisol and other steroids due to its simplicity, automation, and good sensitivity.

However, it has some drawbacks, including cross-reactivity leading to overestimation of target analyte levels, non-standardization of kits, and the inability to measure more than one analyte per analysis. This is particularly problematic since studies indicate that measuring dexamethasone in combination with cortisol can reduce the number of false-positive DST results and improve interpretability. 3,4,5

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has emerged as a popular alternative to CLIA for DSTs due to its ability to measure multiple analytes simultaneously and its superior specificity.

Analytes are separated via LC, and their concentrations are measured by MS, with triple quadrupole MS configurations commonly used for this purpose. This technique provides the ability to measure multiple analytes simultaneously, along with higher accuracy and sensitivity than CLIA.

Increased ease of use and accuracy

In the Division of Endocrinology, Diabetes, and Metabolism at the University of Turin, a team has developed an LC-MS/MS technique for simultaneous quantifying cortisol, cortisone, dexamethasone, and six other exogenous corticosteroids in serum/plasma samples.6

This method can be readily applied in any clinical laboratory equipped with a mass spectrometer and is effective in DSTs, enabling precise measurements of the target analytes in a single chromatographic run (Figure 1).

Sample preparation (1 Hour)

  1. Dilute 200 μL of the serum/plasma sample with 200 μL of water.
  2. Perform supported liquid extraction, manually transferring 400 μL of sample to a microplate.
  3. Apply positive pressure using Tecan Resolvex® A200 automated positive pressure processor.
  4. Elute with 700 μL of methyl tert-butyl ether.
  5. Evaporate and reconstitute in H2 O/MeOH (1:1, v/v).
  6. Agitate.

LC-MS/MS analysis (10 Minutes)

  • LC column: C18 (100 × 2.1 mm, 1.7 μm)
  • Flow rate: 400 μL/min
  • Temperature: 30 °C
  • Injection volume: 20 μL
  • Mobile phase A: H2O + 0.2 mM ammonium fluoride
  • Mobile phase B: acetonitrile
  • Elution programme: Table 1.

The study demonstrated a strong correlation between the results obtained from the newly developed LC-MS/MS method and those obtained using a commercially available CE IVD-marked Steroid Panel LC-MS* kit (Tecan).

The Tecan kit enables simultaneous dexamethasone, cortisol, and cortisone measurement and includes all the necessary components for easy implementation, such as calibrators and controls. The samples are prepared using solid-phase extraction (SPE), which can be semi-automatically performed on a Resolvex® A200 positive pressure processor (Tecan). The kit can measure 15 other steroids in the core steroid metabolism pathway due to the effectiveness of the SPE process.

Table 1. LC gradient elution programme. Source: Tecan

Time (min) Mobile phase A (%) Mobile phase B (%)
0 90 10
0.5 65 35
4.5 65 35
4.51 35 65
6.0 2 98
8.0 2 98
8.01 90 10
10.0 90 10

* In USA: for research use only. Not for use in diagnostic procedures. Product availability and regulatory status may vary from country to country. Consult with your Tecan associate for further information.

A more accurate diagnosis of Cushing’s syndrome

Figure 1. Example chromatogram of the Steroid Panel LC-MS internal standard – run 1. ESI, electrospray ionization; 1, aldosterone; 2, cortisone; 3, dehydro-epiandrosterone sulfate; 4, cortisol; 5, 21-deoxycortisol; 6, corticosterone; 7, dexamethasone; 8, 11-deoxycortisol; 9, androstenedione; 10, 11-deoxycorticosterone; 11, testosterone; 12, dehydroepiandrosterone; 13, 17-hydroxyprogesterone; 14, dihydrotestosterone; 15, progesterone.

Image Credit: Tecan

Summary

Early diagnosis of Cushing’s syndrome is critical to prevent potentially fatal complications. A reliable method for reducing the number of false positives in DSTs involves the simultaneous measurement of cortisol and dexamethasone levels, which can be accurately achieved using LC-MS/MS.

The LC-MS/MS method described in this article enables the simultaneous measurement of multiple analytes, such as cortisol, cortisone, and dexamethasone, in serum or plasma.

This analytical approach can provide clinical laboratories with a straightforward method for performing DSTs, and the commercially available kit can ensure consistent and dependable results.

References and further reading

  1. Cushing’s syndrome [website]. National Institute of Diabetes and Digestive and Kidney Diseases 2018 (https://www.niddk.nih.gov/health-information/endocrine-diseases/cushings-syndrome).
  2. Dogra P, Vijayashankar NP. Dexamethasone suppression test. StatPearls 2022, 8 August (https://www.ncbi.nlm.nih.gov/books/NBK542317 ).
  3. Ceccato F, Artusi C, Barbot M, et al. Dexamethasone measurement during low-dose suppression test for suspected hypercortisolism: threshold development with and validation. J Endocrinol Invest 2020;43(8):1105–1113. doi: 10.1007/s40618-020-01197-6.
  4. Roper SM. Yield of serum dexamethasone measurement for reducing false-positive results of low-dose dexamethasone suppression testing. J Appl Lab Med 2021;6(2):480–485. doi: 10.1093/jalm/jfaa193.
  5. Fleseriu M, Auchus R, Bancos I, et al. Consensus on diagnosis and management of Cushing’s disease: a guideline update. Lancet Diabetes Endocrinol 2021;9(12):847–875. doi: 10.1016/S2213- 8587(21)00235-7.
  6. Ponzetto F, Parasiliti-Caprino M, Settanni F, et al. Simultaneous measurement of cortisol, cortisone, dexamethasone and additional exogenous corticosteroids by rapid and sensitive LC-MS/MS analysis. Molecules 2022;28(1):248. doi: 10.3390/molecules28010248.

From https://www.news-medical.net/whitepaper/20240524/A-more-accurate-diagnosis-of-Cushinge28099s-syndrome.aspx

Day 15, Cushing’s Awareness Challenge

Today’s Cushing’s Awareness Challenge post is about kidney cancer (renal cell carcinoma). You might wonder how in the world this is related to Cushing’s. I think it is, either directly or indirectly.

I alluded to this a couple days ago when I said:

I finally started the Growth Hormone December 7, 2004.
Was the hassle and 3 year wait worth it?
Stay tuned for tomorrow, April 15, 2016 when all will be revealed.

So, as I said, I started Growth Hormone for my panhypopituitarism on December 7, 2004.  I took it for a while but never really felt any better, no more energy, no weight loss.  Sigh.

April 14 2006 I went back to the endo and found out that the arginine test that was done in 2004 was done incorrectly. The directions were written unclearly and the test run incorrectly, not just for me but for everyone who had this test done there for a couple years. My endo discovered this when he was writing up a research paper and went to the lab to check on something.

So, I went off GH again for 2 weeks, then was retested. The “good news” was that the arginine test is only 90 minutes now instead of 3 hours.

Wow, what a nightmare my arginine retest started! I went back for that Thursday, April 27, 2006. Although the test was shorter, I got back to my hotel and just slept and slept. I was so glad that I hadn’t decided to go right home after the test.

Friday I felt fine and drove back home, no problem. I picked up my husband for a biopsy he was having and took him to an outpatient surgical center. While I was there waiting for the biopsy to be completed, I started noticing blood in my urine and major abdominal cramps.

There were signs all over that no cellphones were allowed so I sat in the restroom (I had to be in there a lot, anyway!) and I left messages for several of my doctors on what I should do. It was Friday afternoon and most of them were gone 😦  I finally decided to see my PCP after I got my husband home.

When Tom was done with his testing, his doctor took one look at me and asked if I wanted an ambulance. I said no, that I thought I could make it to the emergency room ok – Tom couldn’t drive because of the anaesthetic they had given him. I barely made it to the ER and left the car with Tom to park. Tom’s doctor followed us to the ER and instantly became my new doctor.

They took me in pretty fast since I was in so much pain, and had the blood in my urine. At first, they thought it was a kidney stone. After a CT scan, my new doctor said that, yes, I had a kidney stone but it wasn’t the worst of my problems, that I had kidney cancer. Wow, what a surprise that was! I was admitted to that hospital, had more CT scans, MRIs, bone scans, they looked everywhere.

My new “instant doctor” felt that he wasn’t up to the challenge of my surgery, so he called in someone else.  My next new “instant doctor” came to see me in the ER in the middle of the night.  He patted my hand, like a loving grandfather might and said “At least you won’t have to do chemotherapy”.  And I felt so reassured.

It wasn’t until later, much after my surgery, that I found out that there was no chemo yet that worked for my cancer.  I was so thankful for the way he told me.  I would have really freaked out if he’d said that nothing they had was strong enough!

My open radical nephrectomy was May 9, 2006 in another hospital from the one where the initial diagnosis was made. My surgeon felt that he needed a specialist from that hospital because he believed preop that my tumor had invaded into the vena cava because of its appearance on the various scans. Luckily, that was not the case.

My entire left kidney and the encapsulated cancer (10 pounds worth!) were removed, along with my left adrenal gland and some lymph nodes. Although the cancer (renal cell carcinoma AKA RCC) was very close to hemorrhaging, the surgeon believed he got it all.

He said I was so lucky. If the surgery had been delayed any longer, the outcome would have been much different. I will be repeating the CT scans every 3 months, just to be sure that there is no cancer hiding anywhere. As it turns out, I can never say I’m cured, just NED (no evidence of disease). This thing can recur at any time, anywhere in my body.

I credit the arginine re-test with somehow aggravating my kidneys and revealing this cancer. Before the test, I had no clue that there was any problem. The arginine test showed that my IGF is still low but due to the kidney cancer I couldn’t take my growth hormone for another 5 years – so the test was useless anyway, except to hasten this newest diagnosis.

So… either Growth Hormone helped my cancer grow or testing for it revealed a cancer I might not have learned about until later.

My five years are up now.  When I was 10 years free of this cancer my kidney surgeon *thought* it would be ok to try the growth hormone again.  I was a little leery about this, especially where I didn’t notice that much improvement.

What to do?

BTW, I decided to…

PET/MRI may improve diagnosis of Cushing disease

PET/MRI could become the diagnostic method of choice over MRI alone for identifying small pituitary tumors associated with Cushing disease, according to a study published March 21 in the Journal of Nuclear Medicine.

In patients diagnosed with the disease yet who had inconclusive MRI results, PET/MRI was positive in 100% of cases, noted lead author Ilanah Pruis, a doctoral student at Erasmus University Medical Center in Rotterdam, Netherlands.

“This multimodal imaging technique provides a welcome improvement for diagnosis, planning of surgery, and clinical outcome in patients with Cushing disease,” the authors wrote.

Cushing disease is characterized by small tumors in pituitary glands, which causes them to secrete excess cortisol, the authors explained. While it is a rare disease, over time it can cause severely disabling conditions, such as high blood pressure or type II diabetes.

Currently, guidelines recommend the use of MRI and inferior petrosal sinus sampling (IPSS) to diagnose these tumors. IPSS is an invasive procedure in which cortisol hormone levels are sampled from the veins that drain the pituitary gland.

In up to 40% of patients, however, MRI is inconclusive, as the lesions are smaller than 10 millimeters in diameter. Even advanced MRI techniques, such as dynamic perfusion imaging, can leave small lesions undetected in up to one third of patients, the authors noted.

In preclinical work, PET imaging using a radiotracer named F-18 FET has been shown to bind with high affinity to a molecular target in pituitary tumors, and in this study, the researchers aimed to test this technique combined with MRI in a multimodal approach.

The researchers analyzed results from 22 patients (68% women; mean age 48 years) who underwent F-18 FET PET/MRI at Erasmus MC between February 2021 and December 2022. All patients showed a clear pituitary tumor F-18 FET-PET/MRI, whereas reading of the MRI alone yielded a suspected lesion in only 50%, the authors found.

T1-weighted postgadolinium MR images (A and C) and F-18 FET-PET/MR images (B and D) centered at pituitary before (A and B) and after (C and D) transsphenoidal surgery. This patient with Cushing disease showed clear focal uptake (B) but no clear lesion on previously obtained and accompanying MRI (A). Postoperative tissue analysis did confirm resection of small pituitary adenoma/PitNET, and postoperative F-18 FET-PET showed no residual uptake (D). Image courtesy of the Journal of Nuclear Medicine.T1-weighted postgadolinium MR images (A and C) and F-18 FET-PET/MR images (B and D) centered at pituitary before (A and B) and after (C and D) transsphenoidal surgery. This patient with Cushing disease showed clear focal uptake (B) but no clear lesion on previously obtained and accompanying MRI (A). Postoperative tissue analysis did confirm resection of small pituitary adenoma/PitNET, and postoperative F-18 FET-PET showed no residual uptake (D). Image courtesy of the Journal of Nuclear Medicine.

Importantly, 16 patients underwent treatment based on the results — either surgery, Gamma Knife, or CyberKnife therapy — with 12 of these patients achieving short-term remission, the authors noted.

“[F-18 FET-PET/MRI] is of great clinical value because it allows precision surgery and targeted Gamma Knife or CyberKnife therapy,” the group wrote.

The researchers noted that only one previous study evaluated F-18 FET-PET/MRI in these patients and that their study was limited, given the relatively small number of patients.

“Future studies will be directed at head-to-head comparisons of the performance of F-18 FET- PET and other diagnostic techniques, including advanced MRI sequences… preferably in patients at the time of initial clinical presentation,” the authors concluded.

A link to the full study can be found here.

From https://www.auntminnie.com/clinical-news/molecular-imaging/article/15667496/petmri-may-improve-diagnosis-of-cushing-disease

Delayed Diagnosis of Ectopic Cushing Syndrome

Abstract

Here, we present the case of a 40-year-old man in whom the diagnosis of ectopic adrenocorticotropin (ACTH) syndrome went unrecognized despite evaluation by multiple providers until it was ultimately suspected by a nephrologist evaluating the patient for edema and weight gain. On urgent referral to endocrinology, screening for hypercortisolism was positive by both low-dose overnight dexamethasone suppression testing and 24-hour urinary free cortisol measurement. Plasma ACTH values confirmed ACTH-dependent Cushing syndrome. High-dose dexamethasone suppression testing was suggestive of ectopic ACTH syndrome. Inferior petrosal sinus sampling demonstrated no central-to-peripheral gradient, and 68Ga-DOTATATE scanning revealed an avid 1.2-cm left lung lesion. The suspected source of ectopic ACTH was resected and confirmed by histopathology, resulting in surgical cure. While many patients with Cushing syndrome have a delayed diagnosis, this case highlights the critical need to increase awareness of the signs and symptoms of hypercortisolism and to improve the understanding of appropriate screening tests among nonendocrine providers.

Introduction

Even in the face of overt clinical signs and symptoms of hypercortisolism, diagnosing Cushing syndrome requires a high index of suspicion, and people with hypercortisolism experience a long road to diagnosis. In a recent meta-analysis including more than 5000 patients with Cushing syndrome, the mean time to diagnosis in all Cushing syndrome, including Cushing disease and ectopic adrenocorticotropin (ACTH) syndrome, was 34 months (1). Reasons for delayed diagnosis are multifactorial, including the nonspecific nature of subjective symptoms and objective clinical signs, as well as notorious challenges in the interpretation of diagnostic testing. Furthermore, the health care system’s increasingly organ-specific referral patterns obfuscate multisystem disorders. Improving the recognition of and decreasing time to diagnosis in Cushing syndrome are critical factors in reducing morbidity and mortality.

Here, we present the case of a patient who, despite classic signs of Cushing syndrome as well as progressive physical and mental decline, remained undiagnosed for more than 3 years while undergoing repeated evaluation by primary care and subspecialty providers. The case (1) highlights the lack of awareness of Cushing syndrome as a potential unifying diagnosis for multiorgan system problems; (2) underscores the necessity of continued education on the signs and symptoms of hypercortisolism, appropriate screening for hypercortisolism, and early referral to endocrinology; and (3) provides an opportunity for systemic change in clinical laboratory practice that could help improve recognition of pathologic hypercortisolism.

Case Presentation

In August 2018, a previously healthy 40-year-old man with ongoing tobacco use established care with a primary care provider complaining that he had been ill since the birth of his son 13 months prior. He described insomnia, headaches, submandibular swelling, soreness in his axillary and inguinal regions, and right-sided chest discomfort (Fig. 1). Previously, he had been diagnosed with sinusitis, tonsillitis, and allergies, which had been treated with a combination of antibiotics, antihistamines, and intranasal glucocorticoids. He was referred to otolaryngology where, in the absence of cervical lymphadenopathy, he was diagnosed with sternocleidomastoid pain with recommendations to manage conservatively with stretching and massage. A chest x-ray demonstrated a left apical lung nodule. Symptoms continued unabated throughout 2019, now with a cough. Repeat chest x-ray demonstrated opacities lateral to the left hilum that were attributed to vascular structures.

 

Figure 1.

Timeline of development of subjective symptoms and objective clinical findings preceding diagnosis and surgical cure of ectopic Cushing syndrome.

In May 2020, increasingly frustrated with escalating symptoms, the patient transitioned care to a second primary care provider and was diagnosed with hypertension. He complained of chronic daily headaches that prompted brain imaging with magnetic resonance imaging (MRI), which noted findings consistent with left maxillary silent sinus syndrome. He was sent back to otolaryngology, which elected to proceed with sinus surgery. During this time, he suffered a fibular fracture for which he was evaluated by orthopedic surgery. In the second half of 2020, he was seen by neurology to evaluate his chronic headaches and paresthesias with electromyography demonstrating a left ulnar mononeuropathy consistent with cubital tunnel syndrome. His primary care provider diagnosed him with fibromyalgia for which he started physical therapy, and he was referred to a pain clinic for cognitive behavioral therapy. Unfortunately his wife, dealing with her husband’s increasing cognitive and personality changes including irritability and aggression, filed for divorce.

At the end of 2020, the patient developed bilateral lower extremity edema and was prescribed hydrochlorothiazide, subsequently developing hypokalemia attributed to diuretic use. With worsening bilateral lower extremity edema and new dyspnea on exertion, he was evaluated for heart failure with an echocardiogram, which was unremarkable. Over the next several months, he gained approximately 35 pounds (∼16 kg). It was in the setting of weight gain that he was first evaluated for hypercortisolism with random serum cortisol of 22.8 mcg/dL (629 nmol/L) and 45.6 mcg/dL (1258 nmol/L) in the late morning and mid-day, respectively. No reference range was provided for the times of day at which these laboratory values were drawn. Although these serum cortisol values were above provided reference ranges for other times of day, they were not flagged as abnormal by in-house laboratory convention, and they were overlooked. The search for other etiologies of his symptoms continued.

In early 2021, diuretic therapy and potassium supplementation were escalated for anasarca. He developed lower extremity cellulitis and received multiple courses of antibiotics. Skin biopsy performed by dermatology demonstrated disseminated Mycobacterium and later Serratia (2), prompting referral to infectious disease for management. Additional subspecialty referrals included rheumatology (polyarthralgia) and gastroenterology (mildly elevated alanine transaminase with planned liver biopsy). In July 2021, he was evaluated for edema by nephrology, where the constellation of subjective symptoms and objective data including hypertension, central weight gain, abdominal striae, fracture, edema, easy bruising, medication-induced hypokalemia, atypical infections, and high afternoon serum cortisol were noted, and the diagnosis of Cushing syndrome was strongly suspected. Emergent referral to endocrinology was placed.

Diagnostic Assessment

At his first clinic visit with endocrinology in June 2021, the patient’s blood pressure was well-controlled on benazepril. Following weight gain of 61 pounds (∼28 kg) in the preceding 2 years, body mass index was 33. Physical examination demonstrated an ill-appearing gentleman with dramatic changes when compared to prior pictures (Fig. 2), including moon facies, dorsocervical fat pad, violaceous abdominal striae, weeping lower extremity skin infections, an inability to stand without assistance from upper extremities, and depressed mood with tangential thought processes.

 

Figure 2.

Photographic representation of physical changes during the years leading up to diagnosis of ectopic Cushing syndrome in June 2021 and after surgical resection of culprit lesion.

Diagnostic workup for hypercortisolism included a morning cortisol of 33.4 mcg/dL (922 nmol/L) (normal reference range, 4.5-22.7 mcg/dL) and ACTH of 156 pg/mL (34 pmol/L) (normal reference range, 7.2-63 pg/mL) following bedtime administration of 1-mg dexamethasone, and 24-hour urine free cortisol of 267 mcg/24 hours (737 nmol/24 hours) (normal reference range, 3.5-45 mcg/24 hours). Morning serum cortisol and plasma ACTH following bedtime administration of 8-mg dexamethasone were 27.9 mcg/dL (770 nmol/L) and 98 pg/mL (22 pmol/L), respectively. Given concern for potential decompensation, he was hospitalized for expedited work-up. Brain MRI did not demonstrate a pituitary lesion (Fig. 3), and inferior petrosal sinus sampling under desmopressin stimulation showed no central-to-peripheral gradient (Table 1). He underwent a positron emission tomography–computed tomography 68Ga-DOTATATE scan that demonstrated a 1.2-cm left pulmonary nodule with radiotracer uptake (Fig. 4).

 

Figure 3.

A, Precontrast and B, postcontrast T1-weighted sagittal magnetic resonance imaging of the sella. Images were affected by significant motion degradation, precluding clear visualization of the pituitary gland on coronal imaging.

 

Figure 4.

68Ga-DOTATATE imaging. A, Coronal and B, axial views of the chest after administration of radiopharmaceutical. Arrow in both panels indicates DOTATATE-avid 1.2-cm left lung lesion.

 

Table 1.

Bilateral petrosal sinus and peripheral adrenocorticotropin levels preintravenous and postintravenous injection of desmopressin acetate 10 mcg

Time post DDAVP, min Left petrosal ACTH Left petrosal:peripheral ACTH Right petrosal ACTH Right petrosal:peripheral ACTH Peripheral ACTH Left:right petrosal ACTH
0 172 pg/mL
(37.9 pmol/L)
1.1 173 pg/mL
(38.1 pmol/L)
1.2 150 pg/mL
(33.0 pmol/L)
1.0
3 288 pg/mL
(63.4 pmol/L)
1.8 292 pg/mL
(64.3 pmol/L)
1.8 162 pg/mL
(35.7 pmol/L)
1.0
5 348 pg/mL
(76.6 pmol/L)
1.8 341 pg/mL
(75.1 pmol/L)
1.8 191 pg/mL
(42.1 pmol/L)
1.0
10 367 pg/mL
(80.8 pmol/L)
1.3 375 pg/mL
(82.6 pmol/L)
1.3 278 pg/mL
(61.2 pmol/L)
1.0

Abbreviations: ACTH, adrenocorticotropin; DDAVP, desmopressin acetate.

Treatment

The patient was started on ketoconazole 200 mg daily for medical management of ectopic ACTH-induced hypercortisolism while awaiting definitive surgical treatment. Within a month of initial endocrinology evaluation, he underwent thoracoscopic left upper lobe wedge resection with intraoperative frozen histopathology section consistent with a well-differentiated neuroendocrine tumor and final pathology consistent with a well-differentiated neuroendocrine tumor. Staining for ACTH was positive (Fig. 5). Postoperative day 1 morning cortisol was 1.4 mcg/dL (39 nmol/L) (normal reference range, 4.5-22.7 mcg/dL). He was started on glucocorticoid replacement with hydrocortisone and was discharged from his surgical admission on hydrocortisone 40 mg in the morning and 20 mg in the afternoon.

 

Figure 5.

Lung tumor histopathology. A, The tumor was epicentered around a large airway (asterisk) and showed usual architecture for carcinoid tumor. B, The tumor cells had monomorphic nuclei with a neuroendocrine chromatin pattern, variably granulated cytoplasm, and a delicate background vascular network. By immunohistochemistry, the tumor cells were strongly positive for C, synaptophysin; D, CAM5.2; and E, adrenocorticotropin. F, Ki-67 proliferative index was extremely low (<1%).

Outcome and Follow-up

Approximately 12 days after discharge, the patient was briefly readmitted from the skilled nursing facility where he was receiving rehabilitation due to a syncopal event attributed to hypovolemia. This was felt to be secondary to poor oral intake in the setting of both antihypertensive and diuretic medications as well as an episode of emesis earlier in the morning precluding absorption of his morning hydrocortisone dose. Shortly after this overnight admission, he was discharged from his skilled nursing facility to home. In the first month after surgery, he lost approximately 30 pounds (∼14 kg) and had improvements in sleep and mood.

Eight months after surgery, hydrocortisone was weaned to 10 mg daily. Cosyntropin stimulation testing holding the morning dose showed 1 hour cortisol 21.5 mcg/dL (593 nmol/L). Hydrocortisone was subsequently discontinued. In June 2022, 1 year following surgery, 3 sequential midnight salivary cortisol tests were undetectable. At his last visit with endocrinology in June 2023, he felt well apart from ongoing neuropathic pain in his feet and continued but improved mood disturbance. Though his health has improved dramatically, he continues to attribute his divorce and substantial life disruption to his undiagnosed hypercortisolism.

Discussion

Endogenous neoplastic hypercortisolism encompasses a clinical spectrum from subclinical disease, as is common in benign adrenal cortical adenomas, to overt Cushing syndrome of adrenal, pituitary, and ectopic origin presenting with dramatic clinical manifestations (3) and long-term implications for morbidity and mortality (4). Even in severe cases, a substantial delay in diagnosis is common. In this case, despite marked hypercortisolism secondary to ectopic ACTH syndrome, the patient’s time from first symptoms to diagnosis was more than 3 years, far in excess of the typical time to diagnosis in this subtype, noted to be 14 months in 1 study (1).

He initially described a constellation of somatic symptoms including subjective neck swelling, axillary and inguinal soreness, chest discomfort, and paresthesias, and during the year preceding diagnosis, he developed hypertension, fibular fracture, mood changes, weight gain, peripheral edema, hypokalemia, unusual infections, and abdominal striae. Each of these symptoms in isolation is a common presentation in the primary care setting, therefore the challenge arises in distinguishing common, singular causes from rare, unifying etiologies, especially given the present epidemics of diabetes, obesity, and associated cardiometabolic abnormalities. By Endocrine Society guidelines, the best discriminatory features of Cushing syndrome in the adult population are facial plethora, proximal muscle weakness, abdominal striae, and easy bruising (5). Furthermore, Endocrine Society guidelines suggest evaluating for Cushing disease when consistent clinical features are present at a younger-than-expected age or when these features accumulate and progress, as was the case with our patient (5).

However, even when the diagnosis is considered, the complexities of the hypothalamic-pituitary-adrenal axis make selection and interpretation of screening tests challenging outside the endocrinology clinic. We suspect that in most such situations, a random serum cortisol measurement is far more likely to be ordered than a validated screening test, such as dexamethasone suppression testing, urine free cortisol, and late-night salivary cortisol per Endocrine Society guidelines (5). Although random serum cortisol values are not considered a screening test for Cushing syndrome, elevated values can provide a clue to the diagnosis in the right clinical setting. In this case, 2 mid-day serum cortisols were, by in-house laboratory convention, not flagged as abnormal despite the fact that they were above the upper limit of provided reference ranges. We suspect that the lack of electronic medical record flagging of serum cortisol values contributed to these values being incorrectly interpreted as ruling out the diagnosis.

Cushing syndrome remains among the most evasive and difficult diagnoses in medicine due to the doubly difficult task of considering the disorder in the face of often protean signs and symptoms and subsequently conducting and interpreting screening tests. The challenges this presents for the nonendocrinologist have recently been recognized by a group in the United Kingdom after a similarly overlooked case (6). We believe that our case serves as a vivid illustration of the diagnostic hurdles the clinician faces and as a cautionary tale with regard to the potential downstream effects of a delay in diagnosis. Standardization of clinical laboratory practices in flagging abnormal cortisol values is one such intervention that may aid the busy clinician in more efficiently recognizing laboratory results suggestive of this diagnosis. While false-positive case detection is a significant downside to this approach, given the potential harm in delayed or missed diagnosis, the potential benefits may outweigh the risks.

Learning Points

  • People with Cushing syndrome frequently experience a prolonged time to diagnosis, in part due to lack of recognition in the primary care and nonendocrine subspecialty settings of the constellation of clinical findings consistent with hypercortisolism.
  • Endocrine Society guidelines recommend against random serum cortisol as initial testing for Cushing syndrome in favor of dexamethasone suppression testing, urine free cortisol, and late-night salivary cortisol.
  • Increased awareness of Cushing syndrome by primary care providers and specialists in other fields could be an important and impactful mechanism to shorten the duration of symptom duration in the absence of diagnosis and hasten cure where cure is achievable.
  • We suggest clinical laboratories consider standardizing flagging abnormal cortisol values to draw attention to ordering providers and perhaps lower the threshold for endocrinology referral if there is any uncertainty in interpretation, especially in the context of patients with persistent symptoms and elusive diagnoses.

Acknowledgments

We are grateful to the patient for allowing us to present his difficult case to the community with the hopes of improving time to diagnosis for patients with hypercortisolism.

Contributors

All authors made individual contributions to authorship. J.M.E., E.M.Z., and K.R.K. were involved in the diagnosis and management of this patient. B.C.M., J.M.E., E.M.Z., and K.R.K. were involved in manuscript submission. S.M.J. performed and analyzed histopathology and prepared the figure for submission. All authors reviewed and approved the final draft.

Funding

No public or commercial funding.

Disclosures

J.M.E. was on the editorial board of JCEM Case Reports at the time of initial submission.

Informed Patient Consent for Publication

Signed informed consent obtained directly from the patient.

Data Availability Statement

Data sharing is not applicable to this article as no data sets were generated or analyzed during the current study.

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Abbreviations

 

  • ACTH

    adrenocorticotropin

  • MRI

    magnetic resonance imaging

© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.
This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

Epicardial and Pericoronary Adipose Tissue and Coronary Plaque Burden in Patients with Cushing’s Syndrome

Abstract

Purpose

To assess coronary inflammation by measuring the volume and density of the epicardial adipose tissue (EAT), perivascular fat attenuation index (FAI) and coronary plaque burden in patients with Cushing’s syndrome (CS) based on coronary computed tomography angiography (CCTA).

Methods

This study included 29 patients with CS and 58 matched patients without CS who underwent CCTA. The EAT volume, EAT density, FAI and coronary plaque burden were measured. The high-risk plaque (HRP) was also evaluated. CS duration from diagnosis, 24-h urinary free cortisol (UFC), and abdominal visceral adipose tissue volume (VAT) of CS patients were recorded.

Results

The CS group had higher EAT volume (146.9 [115.4, 184.2] vs. 119.6 [69.0, 147.1] mL, P = 0.006), lower EAT density (− 78.79 ± 5.89 vs. − 75.98 ± 6.03 HU, P = 0.042), lower FAI (− 84.0 ± 8.92 vs. − 79.40 ± 10.04 HU, P = 0.038), higher total plaque volume (88.81 [36.26, 522.5] vs. 44.45 [0, 198.16] mL, P = 0.010) and more HRP plaques (7.3% vs. 1.8%, P = 0.026) than the controls. The multivariate analysis suggested that CS itself (β [95% CI], 29.233 [10.436, 48.03], P = 0.014), CS duration (β [95% CI], 0.176 [0.185, 4.242], P = 0.033), and UFC (β [95% CI], 0.197 [1.803, 19.719], P = 0.019) were strongly associated with EAT volume but not EAT density, and EAT volume (β [95% CI] − 0.037[− 0.058, − 0.016], P = 0.001) not CS was strongly associated with EAT density. EAT volume, FAI and plaque burden increased (all P < 0.05) in 6 CS patients with follow-up CCTA. The EAT volume had a moderate correlation with abdominal VAT volume (r = 0.526, P = 0.008) in CS patients.

Conclusions

Patients with CS have higher EAT volume and coronary plaque burden but less inflammation as detected by EAT density and FAI. The EAT density is associated with EAT volume but not CS itself.

From https://link.springer.com/article/10.1007/s40618-023-02295-x

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