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Table of Contents
Year : 2014  |  Volume : 18  |  Issue : 2  |  Page : 229-231

Brain death in ICU patients: Clinical significance of endocrine changes

Department of Anaesthesiology and Intensive Care Medicine, Gian Sagar Medical College and Hospital, Banur, Patiala, Punjab, India

Date of Web Publication19-Mar-2014

Correspondence Address:
Sukhminder Jit Singh Bajwa
House No-27-A, Ratan Nagar, Tripuri, Patiala - 140 601, Punjab
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2230-8210.129118

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Numerous studies have been carried out among patients admitted in intensive care unit (ICU) having primary endocrine pathology, endocrine manifestations of systemic diseases or post-endocrine tissue surgery. However, minimal literary evidence is available highlighting the endocrine changes occurring during brain death in critically ill patients. A precise and timely diagnosis of brain death is required to convey the relatives about the prognosis and also to possibly plan for organ retrieval for transplantation purposes. The diagnosis of this condition as of today remains largely a clinical one. Brain death is associated with a multitude of endocrinological alterations which are yet to be completely unraveled and understood. Evaluating these endocrinological modifications lends us an added vista to add to the existing clinical parameters which might help us to confirm the diagnosis of brain death with a higher degree of precision. Moreover, since the efficacy of hormone replacement therapy to benefit in organ retrieval remains yet unproven, newer diagnostic modalities and research studies are definitely called for to strategize the optimal dosage and duration of such therapies.

Keywords: Brain death, blood glucose, catecholamines, thyroid hormones

How to cite this article:
Bajwa SS, Haldar R. Brain death in ICU patients: Clinical significance of endocrine changes. Indian J Endocr Metab 2014;18:229-31

How to cite this URL:
Bajwa SS, Haldar R. Brain death in ICU patients: Clinical significance of endocrine changes. Indian J Endocr Metab [serial online] 2014 [cited 2021 May 12];18:229-31. Available from: https://www.ijem.in/text.asp?2014/18/2/229/129118

   Introduction Top

Brain death is a common unfortunate clinical entity encountered in day to day practice of intensive care. It is defined as "irreversible loss of all functions of brain including brainstem" and is established with the presence of three essential findings of coma, absence of brainstem reflexes and apnoea. This scenario is linked with various clinical and ethical dilemmas which can have significant social impact. [1]

The admission pattern of critical care units is highly variable and many a times number of patients with primary endocrine pathology, endocrine manifestations of systemic diseases, endocrine emergencies or post surgical resection of endocrine tissues get admitted to ICU. [2],[3],[4],[5],[6] Moreover, patients with severe systemic diseases, poisoning and terminal pathology with or without endocrine involvement may get admitted to ICU. [7],[8] The prognosis in such patients is guarded and they invariably have a higher morbidity and mortality. Literary evidence is studded with patho-physiological and endocrine changes in these patients; however, the least studied is the significance of endocrine changes in patients with brain death. Besides these facts, care of such patients throws numerous socio-clinical, legal and administrative challenges to the attending intensivist.

Euthanasia is not legalized in our country and as such intensivists are bound to act within these ethical norms in spite of clinically declaring a critically ill patient as brain dead. The decision is invariably imposed by the relatives, majority of whom do not want to take patients from the ICU or consent to withdraw life support. In a resource-starved nation like ours and with the growing public awareness regarding organ transplantation, necessity of diagnosing brain-dead patients promptly and accurately is the need of the hour.

The diagnosis of brain death is primarily done on clinical grounds which involve conclusively performed clinical examination, two assessments of brainstem reflexes and a single apnea test. [1] However, in the absence of clinical findings or confirmatory tests consistent with brain death, the diagnosis or brain death becomes a predicament. Under such conditions, additional parameters, if available would be invaluable to proceed toward the diagnosis with a degree of certainty. From an endocrine perspective, pathophysiological processes associated with brain death and the hormonal milieu is highly significant. Various endocrinological alterations occur, whose analysis might help us to formulate our diagnosis or in making the existing diagnosis concrete. The present article is an attempt to highlight the various endocrinological changes occurring in brain-dead patients and also to explore the possibility of adding this as an added dimension for consideration in such patients.

Disruption of blood supply of hypothalamus and pituitary gland along with the stress response of critical illness cause steady alterations in hormonal production and regulation. Among catecholamines, dopamine, noradrenaline, and adrenaline levels shoot up initially for 15 minutes after brain death. [9] After the initial "catecholamine storm" subsides, circulating levels of catecholamines (noradrenaline and adrenaline) levels start declining but dopamine levels remain elevated for up to 90 minutes. Once vasoparesis sets in, addition of dopamine, noradrenaline and adrenaline infusions can be considered to maintain perfusion pressure and cardiac output which might be beneficial in liver and renal transplant patients. [10]

Diabetes is a frequent accompaniment of multisystem disorders in patients admitted to ICU either due to some medical disease or post-operatively. [11] However, 80% of brain-dead patients experience another diabetes entity, diabetes insipidus, following these pathophysiological changes due to exhaustion of antidiuretic hormone (ADH) which is associated with hypovolemia, hyperosmolarity, and hypernatremia. [12] As such vasopressin infusion is often initiated in such situations to maintain vasopressor support, to reduce the diuresis and also to withdraw potentially detrimental catecholamine support. [13]

The effect of brain death on the hypothalamic pituitary adrenal (HPA) axis is not uniformly elucidated with conflicting outcomes in different researches. Levels of cortisol have been reported to be normal, low or high. [14],[15] This leaves the method of cortisol level measurement prone to inaccuracies and hence other tests like serum cortisol, free cortisol index and free cortisol performed by equilibrium dialysis, stimulation tests utilizing ACTH are employed to measure the functioning of HPA axis even though they have their own advantages and disadvantages. [16],[17]

The levels of circulating thyroid hormones demonstrate a variable response before and after brain death. Free T3 (fT3) levels fall, fT4 levels and TSH remain normal while reverse T3 levels are erratic. [18] T3 levels decline to 50% of their values 24 hours after death and stabilize at 40% of the original over next 7 days. [19] T4 levels, however, remain normal.

Thirty-nine percent of the brain-dead patients experienced a blood glucose level of more than 250 mg/dl. [18] Thus, a sizeable proportion of this population is prone to hyperglycemia. Hence, aggressive management of hyperglycemia (120-180 mg/dl) is kept as one of the primary targets of United Network for Organ Sharing (UNOS). [20]

Thus, it can be seen that a number of well documented endocrinological changes are associated with brain death. However, whether hormonal replacement to increase the quality of donated organ is beneficial in this subset of patients or not remains a matter of debate as available evidence in this regard remains limited. Nonetheless, this dimension of endocrinological evaluation of suspected brain-death patients to confirm the diagnosis for withdrawal of life support or preparation for organ donation still remains an unexplored frontier. As the precision of our investigative modalities increase and knowledge and understanding of the hormonal alterations become advanced, the option of using endocrinological changes as a marker of predicting brain death opens up. The field of hormone replacement therapy in brain-dead patients to improve the quality of donated organ also deserves analysis as the precise variety and amount of supplementation required still remains to be elucidated. Among the existing hormones, thyroid hormones' have a clear-cut salutary effect on cardiovascular system, corticosteroids have attenuating effect on pulmonary injury and tight glucose control is desirable but in spite of their postulated benefits, further evaluation to ascertain their dosage and treatment strategies is needed.

   References Top

1.Goila AK, Pawar M. The diagnosis of brain death. Indian J Crit Care Med 2009;13:7-11.  Back to cited text no. 1
[PUBMED]  Medknow Journal  
2.Bajwa SS, Jindal R. Endocrine emergencies in critically ill patients: Challenges in diagnosis and management. Indian J Endocrinol Metab 2012;16:722-7.  Back to cited text no. 2
3.Bajwa SS. Intensive care management of critically sick diabetic patients. Indian J Endocrinol Metab 2011;15:349-50.  Back to cited text no. 3
4.Bajwa S, Bajwa SK. Anesthesia and Intensive care implications for pituitary surgery: Recent trends and advancements. Indian J Endocrinol Metab 2011;15:224-32.  Back to cited text no. 4
5.Bajwa SS, Bajwa SK. Implications and considerations during pheochromocytoma resection: A challenge to the anesthesiologist. Indian J Endocrinol Metab 2011;15:337-44.  Back to cited text no. 5
6.Bajwa SJ, Bajwa SK, Bindra GS. The anesthetic, critical care and surgical challenges in the management of craniopharyngioma. Indian J Endocrinol Metab 2011;15:123-6.  Back to cited text no. 6
7.Bajwa SS, Bajwa SK, Kaur J. Care of terminally Ill cancer patients: An intensivist's dilemma. Indian J Palliat Care 2010;16:83-9.  Back to cited text no. 7
[PUBMED]  Medknow Journal  
8.Bajwa SJ, Bajwa Kaur SK, Kaur J, Singh K, Panda A. Management of celphos poisoning with a novel intervention: A ray of hope in the darkest of clouds. Anesth Essays Res 2010;4:20-4.  Back to cited text no. 8
  Medknow Journal  
9.Chen EP, Bittner HB, Kendall SW, Van Trigt P. Hormonal and hemodynamic changes in a validated animal model of brain death. Crit Care Med 1996;24:1352-9.  Back to cited text no. 9
10.Schnuelle P, Berger S, de Boer J, Persijn G, van der Woude FJ. Effects of catecholamine application to brain-dead donors on graft survival in solid organ transplantation. Transplantation 2001;72:455-63.  Back to cited text no. 10
11.Bajwa SS, Kalra S. Diabeto-anaesthesia: A subspecialty needing endocrine introspection. Indian J Anaesth 2012;56:513-7.  Back to cited text no. 11
[PUBMED]  Medknow Journal  
12.Smith M. Physiologic changes during brain stem death-lessons for management of the organ donor. J Heart Lung Transplant 2004;23:S217-22.  Back to cited text no. 12
13.Chen JM, Cullinane S, Spanier TB, Artrip JH, John R, Edwards NM, et al. Vasopressin deficiency and pressor hypersensitivity in hemodynamically unstable organ donors. Circulation 1999;100:244-6.  Back to cited text no. 13
14.Dimopoulou I, Tsagarakis S, Anthi A, Milou E, Ilias I, Stavrakaki K, et al. High prevalence of decreased cortisol reserve in brain-dead potential organ donors. Crit Care Med 2003;31:1113-7.  Back to cited text no. 14
15.Lopau K, Mark J, Schramm L, Heidbreder E, Wanner C. Hormonal changes in brain death and immune activation in the donor. Transpl Int 2000;13:S282-5.  Back to cited text no. 15
16.Arafah BM. Hypothalamic pituitary adrenal function during critical illness: Limitations of current assessment methods. J Clin Endocrinol Metab 2006;91:3725-45.  Back to cited text no. 16
17.Cooper MS, Stewart PM. Adrenal insufficiency in critical illness. J Intensive Care Med 2007;22:348-62.  Back to cited text no. 17
18.Powner DJ, Hendrich A, Lagler RG, Ng RH, Madden RL. Hormonal changes in brain dead patients. Crit Care Med 1990;18:702-8.  Back to cited text no. 18
19.Taniguchi S, Kitamura S, Kawachi K, Doi Y, Aoyama N. Effects of hormonal supplements on the maintenance of cardiac function in potential donor patients after cerebral death. Eur J Cardiothorac Surg 1992;6:96-101.  Back to cited text no. 19
20.UNOS. United Network for Organ Sharing (UNOS) critical pathway for the organ donor: Cardiothoracic donor management. Available from: http://www.unos.org/[Last accessed on 2013 Sep 02].  Back to cited text no. 20

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