Copeptin Rules Out Diabetes Insipidus Post Pituitary Surgery

Posted on March 21, 2022 by MaryO

The study covered in this summary was published on Research Square as a preprint and has not yet been peer reviewed.

Key Takeaways

  • A study of 78 patients who underwent elective transsphenoidal adenomectomy to remove a pituitary tumor or other lesions within the pituitary fossa at a single center in the UK suggests that postoperative plasma levels of copeptin — a surrogate marker for levels of arginine vasopressin (antidiuretic hormone) — can rule out development of central (neurogenic) diabetes insipidus caused by a deficiency of arginine vasopressin following pituitary surgery.
  • The researchers suggest using as a cutoff a copeptin level of >3.4 pmol/L at postoperative day 1 to rule out diabetes insipidus. Such a cutoff yields the following:
    • A high sensitivity of 91% for ruling out diabetes insipidus.
    • A negative predictive value of 97%. Only 1 of 38 patients with a copeptin value >3.4 pmol/L at day 1 postoperatively developed diabetes insipidus.
    • A low specificity of 55%, meaning that copeptin level is not useful for diagnosing diabetes insipidus

Why This Matters

  • An estimated 1% to 67% of patients who undergo pituitary gland surgery develop diabetes insipidus, often soon after surgery, although it is often transient.
  • Diagnosing diabetes insipidus in such patients requires a combination of clinical assessment, the monitoring of fluid balance, and determining plasma and urine sodium and osmolality.
  • Currently, clinical laboratories in the UK do not have assays for arginine vasopressin, which has a short half-life in vivo and is unstable ex vivo, even when frozen, and is affected by delayed or incomplete separation from platelets.
  • Copeptin, an arginine vasopressin precursor, is much more stable and measurable by commercial immunoassays.
  • The findings suggest that patients who have just undergone pituitary gland surgery and are otherwise healthy and meet the copeptin cutoff for ruling out diabetes insipidus could be discharged 24 hours after surgery and that there is no need for additional clinical and biochemical monitoring. This change would ease demands on the healthcare system.

Study Design

  • The study reviewed 78 patients who underwent elective transsphenoidal adenomectomy to remove a pituitary tumor from November 2017 to June 2020 at the John Radcliffe Hospital in Oxford, United Kingdom.
  • Patients remained in hospital for a minimum of 48 hours after their surgery.
  • Clinicians collected blood and urine specimens preoperatively and at day 1, day 2, day 8, and week 6 post surgery.
  • The patients were restricted to 2 L of fluid a day postoperatively to prevent masking of biochemical abnormalities through compensatory drinking.
  • Diabetes insipidus was suspected when patients’ urine output was >200 mL/h for 3 consecutive hours or >3 L/d plus high plasma sodium (>145 mmol/L) and plasma osmolality (> 295 mosmol/kg) plus inappropriately low urine osmolality. Definitive diagnosis of diabetes insipidus was based on clinical assessment, urine and plasma biochemistry, and need for treatment with desmopressin (1-deamino-8-D-arginine vasopressin).

Key Results

  • The median age of the patients was 55, and 53% were men; 92% of the lesions were macroadenomas; the most common histologic type was gonadotroph tumor (47%).
  • Among the 78 patients, 11 (14%) were diagnosed with diabetes insipidus postoperatively and required treatment with desmopressin; of these, seven patients (9%) continued taking desmopressin after 6 weeks (permanent diabetes insipidus), but the other four did not need to take desmopressin for more than a week.
  • Patients who developed diabetes insipidus were younger than other patients (mean age, 46 vs 56), and 8 of the 11 patients who developed diabetes insipidus (73%) were women.
  • Preoperative copeptin levels were similar in the two groups. At day 1, day 8, and 6 weeks postoperatively, copeptin levels were significantly lower in the diabetes insipidus group; there were no significant differences at day 2, largely because of an outlier result.
  • An area under the receiver operating characteristic curve (AUC; C-statistic) analysis showed that on day 1 after surgery, copeptin levels could account for 74.22% of the incident cases of diabetes insipidus (AUC, 0.7422). On postop day 8, the AUC for copeptin was 0.8015, and after 6 weeks, the AUC associated with copeptin was 0.7321.

Limitations

  • Blood samples for copeptin tests from patients who underwent pituitary surgery were collected at specified times and were frozen for later analysis; performing the test in real time might alter patient management.
  • The study may have missed peak copeptin levels by not determining copeptin levels sooner after pituitary gland surgery, inasmuch as other researchers have reported better predictive values for diagnosing diabetes insipidus from samples taken 1 hour after extubation or <12 hours after surgery.

Disclosures

  • The study did not receive commercial funding.
  • The authors report no relevant financial relationships.

This is a summary of a preprint research study, “Post-Operative Copeptin Analysis Predicts Which Patients Do Not Develop Diabetes Insipidus After Pituitary Surgery,” by researchers from John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, in the United Kingdom. Preprints from Research Square are provided to you by Medscape. This study has not yet been peer reviewed. The full text of the study can be found on researchsquare.com.

Read the article here: https://www.medscape.com/viewarticle/970357#vp_1

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Cortisol Levels Predict Remission in Cushing’s Patients Undergoing Transsphenoidal Surgery

Posted on September 25, 2019 by MaryO

In patients with Cushing’s disease, removing the pituitary tumor via an endoscopic transsphenoidal surgery (TSS) leads to better remission rates than microscopic TSS, according to new research.

But regardless of surgical approach, plasma cortisol levels one day after surgery are predictive of remission, researchers found.

The study, “Management of Cushing’s disease: Changing trend from microscopic to endoscopic surgery,” was published in the journal World Neurosurgery.

Because it improves visualization and accessibility, endoscopic TSS has been gaining popularity over microscopic TSS to remove pituitary tumors in Cushing’s disease patients. Yet, although this surgery has been associated with high remission rates, whether it outperforms microscopic surgery and determining the factors affecting long-term outcomes may further ease disease recurrence after TSS.

A team with the All India Institute of Medical Sciences addressed this topic in 104 patients who underwent surgery from January 2009 to June 2017. Among these patients, 47 underwent microscopic surgery and 55 endoscopic surgery. At presentation, their ages ranged from 9 to 55 (mean age of 28). Also, patients had been experiencing Cushing’s symptoms over a mean duration of 24 months.

Eighty-seven patients showed weight gain. Hypertension (high blood pressure) and diabetes mellitus were among the most common co-morbidities, found in 76 and 33 patients, respectively. Nineteen patients had osteoporosis and 12 osteopenia, which refers to lower-than-normal bone mineral density.

As assessed with magnetic resonance imaging, 68 patients had a microadenoma (a tumor diameter smaller than one centimeter) and 27 had a macroadenoma (a tumor one centimeter or larger). Only two patients had an invasive pituitary adenoma.

Two patients with larger tumors were operated on transcranially (through the skull). The surgery resulted in total tumor removal in 90 cases (86.5%). A blood loss greater than 100 milliliter was more common with endoscopic than with microscopic TSS.

Ten patients developed transient diabetes inspidus, two experienced seizures after surgery, and six of nine patients with macroadenoma and visual deterioration experienced vision improvements after TSS.

The incidence of intraoperative leak of cerebrospinal fluid — the liquid surrounding the brain and spinal cord — was 23.2%, while that of post-operative leak was 7.7% and was more common in microadenoma than macroadenoma surgery (9.8% vs. 5.0%).

Seventeen patients were lost to follow-up and two died due to metabolic complications and infections. The average follow-up was shorter for endoscopic than with microscopic surgery (18 months vs. 35 months).

Among the remaining 85 cases, 65 (76.5%) experienced remission, as defined by a morning cortisol level under 5.0 μg/dL, restored circadian rhythm (the body’s internal clock, typically impaired in Cushing’s patients), and suppression of serum cortisol to below 2 μg/dl after overnight dexamethasone suppression test.

The remission rate was 54.5% in pediatric patients and was higher with endoscopic than with microscopic TSS (88.2% vs. 56.6%). Also, patients with microadenoma showed a trend toward more frequent remission than those with macroadenoma (73.2% vs. 64.3%).

Ten of the remaining 20 patients experienced disease recurrence up to 28 months after surgery. Sixteen cases revealed signs of hypopituitarism, or pituitary insufficiency, which were managed with replacement therapy.

A subsequent analysis found that morning cortisol level on day one after surgery was the only significant predictor of remission. Specifically, a one-unit increase in cortisol lowered the likelihood of remission by 7%. A cortisol level lower than 10.7 μgm/dl was calculated as predicting remission.

Overall, the study showed that “postoperative plasma cortisol level is a strong independent predictor of remission,” the researchers wrote, and that “remission provided by endoscopy is significantly better than microscopic approach.”

From https://cushingsdiseasenews.com/2019/09/24/cortisol-levels-predict-remission-cushings-patients-undergoing-transsphenoidal-surgery/

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Transsphenoidal Surgery Leads to Remission in Children with Cushing’s Disease

Posted on January 19, 2019 by MaryO

Transsphenoidal surgery — a minimally invasive surgery for removing pituitary tumors in Cushing’s disease patients — is also effective in children and adolescents with the condition, leading to remission with a low rate of complications, a study reports.

The research, “Neurosurgical treatment of Cushing disease in pediatric patients: case series and review of literature,” was published in the journal Child’s Nervous System.

Transsphenoidal (through the nose) pituitary surgery is the main treatment option for children with Cushing’s disease. It allows the removal of pituitary adenomas without requiring long-term replacement therapy, but negative effects on growth and puberty have been reported.

In the study, a team from Turkey shared its findings on 10 children and adolescents (7 females) with the condition, who underwent microsurgery (TSMS) or endoscopic surgery (ETSS, which is less invasive) — the two types of transsphenoidal surgery.

At the time of surgery, the patients’ mean age was 14.8 years, and they had been experiencing symptoms for a mean average of 24.2 months. All but one had gained weight, with a mean body mass index of 29.97.

Their symptoms included excessive body hair, high blood pressure, stretch marks, headaches, acne, “moon face,” and the absence of menstruation.

The patients were diagnosed with Cushing’s after their plasma cortisol levels were measured, and there was a lack of cortical level suppression after they took a low-dose suppression treatment. Measurements of their adrenocorticotropic (ACTH) hormone levels then revealed the cause of their disease was likely pituitary tumors.

Magnetic resonance imaging (MRI) scans, however, only enabled tumor localization in seven patients: three with a microadenoma (a tumor smaller than 10 millimeters), and four showed a macroadenoma.

CD diagnosis was confirmed by surgery and the presence of characteristic pituitary changes. The three patients with no sign of adenoma on their MRIs showed evidence of ACTH-containing adenomas on tissue evaluation.

Eight patients underwent TSMS, and 2 patients had ETSS, with no surgical complications. The patients were considered in remission if they showed clinical adrenal insufficiency and serum cortisol levels under 2.5 μg/dl 48 hours after surgery, or a cortisol level lower than 1.8 μg/dl with a low-dose dexamethasone suppression test at three months post-surgery. Restoration of normal plasma cortisol variation, eased symptoms, and no sign of adenoma in MRI were also requirements for remission.

Eight patients (80%) achieved remission, 4 of them after TSMS. Two patients underwent additional TSMS for remission. Also, 1 patient had ETSS twice after TSMS to gain remission, while another met the criteria after the first endoscopic surgery.

The data further showed that clinical recovery and normalized biochemical parameters were achieved after the initial operation in 5 patients (50%). Three patients (30%) were considered cured after additional operations.

The mean cortisol level decreased to 8.71 μg/dl post-surgery from 23.435 μg/dl pre-surgery. All patients were regularly evaluated in an outpatient clinic, with a mean follow-up period of 11 years.

Two patients showed pituitary insufficiency. Also, 2 had persistent hypocortisolism — too little cortisol — one of whom also had diabetes insipidus, a disorder that causes an imbalance of water in the body. Radiotherapy was not considered in any case.

“Transsphenoidal surgery remains the mainstay therapy for CD [Cushing’s disease] in pediatric patients as well as adults,” the scientists wrote. “It is an effective treatment option with low rate of complications.”

 

From https://cushingsdiseasenews.com/2019/01/15/transsphenoidal-surgery-enables-cushings-disease-remission-pediatric-patients-study/

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