Hypopituitarism following closed head injury

Perspectives in Pediatric Pathology, Chapter 22. Testicular Involvement in Systemic Diseases

Normal testicular physiology requires appropriate function of endocrine glands and other tissues. Testicular lesions have been described in disorders involving the hypothalamus-hypophysis, thyroid glands, adrenal glands, pancreas, liver, kidney, and gastrointestinal tract. Testicular abnormalities can also associate with chronic anemia, obesity, and neoplasia. Although many of the disorders that affect the above-mentioned glands and tissues are congenital, acquired lesions may result in hypogonadism in children and adolescents.

Impaired Pituitary Axes Following Traumatic Brain Injury

Pituitary dysfunction following traumatic brain injury (TBI) is significant and rarely considered by clinicians. This topic has received much more attention in the last decade. The incidence of post TBI anterior pituitary dysfunction is around 30% acutely, and declines to around 20% by one year. Growth hormone and gonadotrophic hormones are the most common deficiencies seen after traumatic brain injury, but also the most likely to spontaneously recover. The majority of deficiencies present within the first year, but extreme delayed presentation has been reported. Information on posterior pituitary dysfunction is less reliable ranging from 3%-40% incidence but prospective data suggests a rate around 5%. The mechanism, risk factors, natural history, and long-term effect of treatment are poorly defined in the literature and limited by a lack of standardization. Post TBI pituitary dysfunction is an entity to recognize with significant clinical relevance. Secondary hypoadrenalism, hypothyroidism and central diabetes insipidus should be treated acutely while deficiencies in growth and gonadotrophic hormones should be initially observed.

Hypothyroidism after a cancer diagnosis: etiology, diagnosis, complications, and management

Hypothyroidism is a common disease that is easily treated in the majority of cases, when readily diagnosed; however, presentation of an aggregate of its symptoms is often clinically overlooked or attributed to another disease and can potentially be lethal. Already prevalent in older women, its occurrence in younger patients is rising as a result of radiation therapy, radioactive iodine therapy, and newer antineoplastic agents used to manage various malignancies. The presence of nonspecific constitutional symptoms and neuropsychiatric complaints in cancer patients can be attributed to a myriad of other diagnoses and therapies. Thyroid dysfunction can be easily overlooked in cancer patients because of the complexity of cancer's clinical picture, particularly in the pediatric population. Underdiagnosis can have important consequences for the management of both hypothyroidism and the malignancy. At minimum, quality of life is adversely affected. Untreated hypothyroidism can lead to heart failure, psychosis, and coma and can reduce the effectiveness of potentially life-saving cancer therapies, whereas iatrogenic causes can provoke atrial fibrillation and osteoporosis. Consequently, the diagnosis and treatment of hypothyroidism in cancer patients are pertinent. We summarize the history, epidemiology, pathophysiology, clinical diagnosis, and management of hypothyroidism in cancer patients.

Neuroendocrine function following traumatic brain injury and subsequent intensive care treatment: a prospective longitudinal evaluation

Neuroendocrine dysfunction following traumatic brain injury (TBI) has been described extensively. However, few studies are longitudinal and most lack subtle radiological, clinical, and repetitive endocrine assessment in the acute phase. Accordingly, we prospectively assessed neuroendocrine function in 71 patients after TBI. Injury was documented by a computed tomography (CT). During the first week, critical clinical data (Glasgow Coma Score, APACHE score), treatment variables such as duration of analgosedation for mechanical ventilation, were related to basal pituitary function. More than 2 years later, a subgroup of patients was re-evaluated using dynamic testing with ACTH and GHRH-arginine tests. The Pearson's correlation analysis and Mann-Whitney rank sum test for group differences were used for statistical analysis. None of the CT findings predicted neuroendocrine dysfunction following TBI. The adaptive response to critical illness with significantly elevated cortisol levels on admission and decreased levels thereafter in patients ventilated for more than 24 h (p < 0.05) was attenuated following severe TBI (p < 0.05). However, the coincidence of low serum cortisol and increased urinary excretion of glucocorticoid metabolites in about 80% of patients challenges the relevance of basal hormone measurements. In ventilated patients, total T3 and free T4 were decreased (p < 0.05), TSH was low on day 3 (p < 0.05), and a gonadotropic insufficiency was present (p < 0.05). The thyrotropic and gonadotropic system recovered completely within the follow-up period. With regard to the somatotropic system, neither brain injury severity nor mechanical ventilation was associated with an insufficiency during the acute phase post-injury. However, initially low GH levels predicted a persistent deficiency (r = 0.731, p < 0.001). We conclude that both severe TBI and prolonged mechanical ventilation result in hormonal disturbances early after injury, suggesting a pathophysiological response to brain injury and subsequent intensive care treatment rather than morphological damage.

Hypopituitarism: A Sequela of Severe Hypoxic Encephalopathy

BACKGROUND/PURPOSE

Central diabetes insipidus (DI) is an established phenomenon after hypoxic encephalopathy or brain death, but hypopituitarism is seldom described. This study investigated the characteristics of 11 patients with DI and hypopituitarism which developed after severe hypoxic encephalopathy.

METHODS

The medical records of patients with DI and hypopituitarism after severe hypoxic encephalopathy from 1997 to 2002 were retrospectively reviewed. Eleven patients with DI and hypopituitarism after severe hypoxic episodes were included. Demographic data, primary diagnosis, the time of onset of DI, the time of diagnosis of hypopituitarism, the presence of symptoms of hypopituitarism, and outcome of these patients were analyzed.

RESULTS

Eleven patients comprising nine females and two males aged 47.4 +/- 19.3 years (range, 24-74 years) were included. The mean interval from the precipitating event to the onset of DI was 60 +/- 46 hours (range, 11-131 hours). The mean interval from the precipitating event to the diagnosis of hypopituitarism was 423 +/- 182 hours (range, 132-672 hours). The average duration of hospitalization was 63 +/- 35 days (range, 9-113 days). The overall mortality rate during hospitalization was 45%. Four patients died of sepsis and one died of heart failure due to acute myocardial infarction.

CONCLUSION

The development of DI after severe hypoxic encephalopathy is a sign of severe brain damage. It usually ensues immediately or days after loss of brain stem reflexes. Hypopituitarism developed several weeks later than DI in these patients. Recognition and treatment of these deficiencies may prevent organ dysfunction.

Endocrine dysfunction following traumatic brain injury: mechanisms, pathophysiology and clinical correlations

Despite growing recognition among those who provide care for traumatic brain injury patients, endocrine dysfunction following brain injury is an often under-recognized phenomenon. From historical reports one would conclude that endocrine dysfunctions hardly ever occurs following trauma to the head. However, recent studies suggest that a significant proportion of patients suffer some degree of hypopituitarism. To date, there are no clear predicting factors identifying patients at risk for developing hormonal disturbances and thus no parameters exist for screening. Several retrospective analyses and literature reviews, and more recently, a few longitudinal studies of brain injured patients have been performed.

Prevalence of hypopituitarism and growth hormone deficiency in adults long-term after severe traumatic brain injury

OBJECTIVE

Traumatic brain injury (TBI) has been associated with hypopituitarism and GH deficiency. However, TBI-mediated hypopituitarism may be more frequent than previously thought. The present work, performed in patients with severe TBI at least 1 year before, had three aims: (i) to evaluate the prevalence of hypopituitarism, (ii) in particular to evaluate the prevalence of GH deficiency, and (iii) to compare three different tests of GH reserve in this cohort.

DESIGN AND PATIENTS

From a nonselected group of 249 patients admitted to our Clinical Centre for severe TBI over the last 5 years, 200 of them answered a custom made questionnaire of symptoms of hypopituitarism enclosed in the invitation letter to participate in the study. A total of 170 (99 men and 14 women), accepted to participate in the study (study cohort); 57 had normal questionnaires and were not further studied, 14 discontinued the study, and 99 attended the hospital for dynamic tests of pituitary hormone deficiencies. From these, 44 subjects with IGF-I in the lower range were tested with GHRH+GHRP-6; ITT; and glucagon tests of GH reserve, on three different occasions.

MEASUREMENTS

Pituitary hormones plus IGF-I and target gland hormones were analysed.

RESULTS

With regard to the initial cohort of 170 subjects (100%), three (1.7%) showed diabetes insipidus; 10 (5.8%) TSH deficiency, 11 (6.4%) ACTH deficiency and 29 (17%) gonadotrophin deficiency. In 10 subjects (5.8%), GH deficiency was diagnosed by strict criteria. Finally, 15 (8.8%) showed combined deficit of several hormones.

CONCLUSION

After severe head trauma, gonadotrophin deficiency was the most common pituitary deficit. GH deficiency showed a prevalence similar to ACTH and TSH deficits, i.e. near 6% of the cohort. Taken together, 24.7% of the subjects studied showed any type of pituitary hormone deficiency.

Secondary hypothyroidism following head trauma in a cat

An 18-month-old female neutered domestic short hair cat was examined because of marked polydipsia and stunted growth following head trauma when it was 8 weeks old. Diagnostic evaluation revealed hyposthenuric urine, low concentrations of thyroid hormone and undetectable thyroid stimulating hormone concentrations which did not rise following thyroid releasing hormone administration. Lateral radiographs of the left and right tibiae revealed incomplete mineralisation of the greater tubercle and open physis. An almost empty sella turcica and a greatly reduced pituitary were visible on magnetic resonance images of the brain. A presumptive diagnosis of secondary hypothyroidism and central diabetes insipidus following head trauma was made.

Hypopituitarism and growth hormone deficiency in adult subjects after traumatic brain injury: who and when to test

Traumatic brain injury (TBI) was traditionally considered an infrequent cause of hypopituitarism. However recent reports strongly suggest that TBI-mediated pituitary hormones deficiency may well be more frequent than previously thought. As the prevalence of hypopituitarism is not dependent on the severity of the trauma and considering the high number of TBI events in all industrialized countries a screening procedure for detecting hormone deficiencies in all TBI patients is not possible. In the present work a suggestion for screening a subgroup of TBI patients is discussed in order to increase the effectiveness of the whole procedure.

Profile of mothers at risk: An analysis of injury and pregnancy loss in 1,195 trauma patients

BACKGROUND

Trauma is the number one cause of maternal death during pregnancy, but incidence of fetal loss exceeds maternal loss by more than 3 to 1. We hypothesized that we could identify women at risk for injury during pregnancy and focus our prevention efforts.

STUDY DESIGN

Women of childbearing age in the American College of Surgeon's National Trauma Data Bank served as the study population. Pregnant patients were compared with nonpregnant patients with respect to age, race, mechanism of injury, injury patterns and severity, risk-taking behaviors, and outcomes. Multivariate logistic regression analysis was used to identify risk factors for loss of pregnancy in mothers who survived their trauma.

RESULTS

Pregnant trauma patients (n = 1,195) were younger, less severely injured, and more likely to be African American or Hispanic as compared with the nonpregnant cohort (n = 76,126). Twenty percent of injured pregnant patients tested positive for drugs or alcohol, and approximately one-third of those involved in motor vehicle crashes were not using seatbelts. Independent risk factors for fetal loss after trauma included Injury Severity Score > 15; Adjusted Injury Score > or = 3 in the head, abdomen, thorax, or lower extremities; and Glasgow Coma Score < or = 8.

CONCLUSIONS

Young, African-American, and Hispanic pregnant women are at higher risk for trauma in pregnancy and are most likely to benefit from primary trauma prevention efforts. Those with severe head, abdominal, thoracic, or lower extremity injuries are at high risk for pregnancy loss. Reduction of secondary insults and early recognition of fetal distress may improve outcomes for both the mother and fetus in this high-risk group.

Endocrine abnormalities in critical care patients with moderate-to-severe head trauma: incidence, pattern and predisposing factors

OBJECTIVE

To investigate the incidence and type of endocrine abnormalities in critical care patients with traumatic brain injury (TBI) and to examine their relationships to possible predisposing factors.

DESIGN

Prospective study.

SETTING

General intensive care unit in a university hospital.

PATIENTS AND PARTICIPANTS

Thirty-four TBI patients (27 men, 7 women), having a mean age of 37+/-16 years, were studied after weaning from mechanical ventilation.

INTERVENTIONS

Baseline endocrine assessment was carried out by measuring cortisol, corticotropin, dehydroepiandrosterone sulfate, free thyroxine, thyrotropin (TSH), testosterone, oestradiol, follicle stimulating hormone (FSH), luteinizing hormone, prolactin, growth hormone and insulin-like growth factor I. Dynamic evaluation was performed by human corticotropin releasing hormone and growth hormone releasing hormone in all patients. Male patients underwent additional investigation with gonadotropin-releasing hormone. Severity of neurological derangement was graded according to Glasgow Coma Scale (GCS), Marshall Computerized Tomographic Classification and intracranial pressure (ICP) levels.

MEASUREMENTS AND RESULTS

Eighteen of the 34 patients (53%) had an abnormal result in at least one hormonal axis tested, with cortisol hyporesponsiveness and gonadal dysfunction being equally common, affecting 24% of patients. Endocrine abnormalities were associated with a higher brain CT-scan classification score ( p=0.02). The GCS on admission correlated positively with baseline FSH (r=0.37, p=0.03), peak FSH (r=0.41, p=0.03), testosterone (r=0.44, p=0.02) and TSH (r=0.39, p=0.03). There were no relations between ICP(max) and any baseline or dynamic hormone measurements.

CONCLUSIONS

Patients with TBI receiving critical care show changes in their neuroendocrine responses, which depend upon clinical and radiological measures of head injury severity. Most common abnormalities include cortisol hyporesponsiveness and hypogonadism.

Hypothyroidism

Hypothyroidism is common, potentially serious, often clinically overlooked, readily diagnosed by laboratory testing, and eminently treatable. The condition is particularly prevalent in older women, in whom autoimmune thyroiditis is common. Other important causes include congenital thyroid disorders, previous thyroid surgery and irradiation, drugs such as lithium carbonate and amiodarone, and pituitary and hypothalamic disorders. Worldwide, dietary iodine deficiency remains an important cause. Hypothyroidism can present with nonspecific constitutional and neuropsychiatric complaints, or with hypercholesterolaemia, hyponatraemia, hyperprolactinaemia, or hyperhomocysteinaemia. Severe untreated hypothyroidism can lead to heart failure, psychosis, and coma. Although these manifestations are neither specific nor sensitive, the diagnosis is confirmed or excluded by measurements of serum thyrotropin and free thyroxine. Thyroxine replacement therapy is highly effective and safe, but suboptimal dosing is common in clinical practice. Patient noncompliance, drug interactions, and pregnancy can lead to inadequate treatment. Iatrogenic thyrotoxicosis can cause symptoms, and, even when mild, provoke atrial fibrillation and osteoporosis. We summarise present understanding of the history, epidemiology, pathophysiology, and clinical diagnosis and management of hypothyroidism.