Delayed hypopituitarism following Russell's viper envenomation: a case series and literature review

Unusual and lesser-known rare causes of adult growth hormone deficiency

Growth hormone is among the most common hormones to be deficient in pituitary insult. It can occur either in isolation or combined with other hormone deficiencies. Growth hormone deficiency in adults (AGHD) can be due to causes acquired in adulthood or have a childhood-onset etiology, but the former is about three times more common. Usual causes of AGHD include mass effects due to a pituitary tumour, and/or its treatment (surgery, medical therapy, or radiotherapy), or radiotherapy to the head and neck region for non-pituitary lesions. The unusual or lesser-known causes of AGHD, are usually due to non-tumoral etiology and range from vascular and infective to inflammatory and miscellaneous causes. These not only expand the spectrum of AGHD but may also contribute to increased morbidity, adverse metabolic consequences, and mortality due to the primary condition, if unrecognised. The review features these lesser-known and rare causes of AGHD and highlights their clinical and diagnostic implications.

The concept of Big Four: Road map from snakebite epidemiology to antivenom efficacy

Snake envenomation is a life-threatening disease caused by the injection of venom toxins from the venomous snake bite. Snakebite is often defined as the occupational or domestic hazard mostly affecting the rural population. India experiences a high number of envenoming cases and fatality due to the nation's diversity in inhabiting venomous snakes. The Indian Big Four snakes namely Russell's viper (Daboia russelii), spectacled cobra (Naja naja), common krait (Bungarus caeruleus), and saw-scaled viper (Echis carinatus) are responsible for majority of the snake envenoming cases and death. The demographic characteristics including occupation, stringent snake habitat management, poor healthcare facilities and ignorance of the rural victims are the primary influencers of high mortality. Biogeographic venom variation greatly influences the clinical pathologies of snake envenomation. The current antivenoms against the Big Four snakes are found to be less immunogenic against the venom toxins emphasizing the necessity of alternative approaches for antivenom generation. This review summarizes the burden of snake envenomation in India by the Big Four snakes including the geographic distribution of snake species and biogeographic venom variation. We have provided comprehensive information on snake venom proteomics that has aided the better understanding of venom induced pathological features, summarized the impact of current polyvalent antivenom therapy highlighting the need for potential antivenom treatment for the effective management of snakebites.

Clinical aspects of snakebite envenoming and its treatment in low-resource settings

There is increasing recognition of the public health importance of snakebite envenoming. Worldwide annual incidence is likely to be 5 million bites, with mortality exceeding 150 000 deaths, and the resulting physical and psychological morbidity leads to substantial social and economic repercussions. Prevention through community education by trained health workers is the most effective and economically viable strategy for reducing risk of bites and envenoming. Clinical challenges to effective treatment are most substantial in rural areas of low-resource settings, where snakebites are most common. Classic skills of history taking, physical examination, and use of affordable point-of-care tests should be followed by monitoring of evolving local and systemic envenoming. Despite the profusion of new ideas for interventions, hyperimmune equine or ovine plasma-derived antivenoms remain the only specific treatment for snakebite envenoming. The enormous interspecies and intraspecies complexity and diversity of snake venoms, revealed by modern venomics, demands a radical redesign of many current antivenoms.

Approach to a case with an unusual cause of hypopituitarism

Hypopituitarism refers to insufficiency of one or more hormones of the pituitary and can be due to myriad causes. The clinical and radiological spectrum of the condition is heterogeneous, based on the age, gender, clinical setting and/or other past medical history. Hypopituitarism includes central hypocortisolism, hypothyroidism, hypogonadism and growth hormone deficiency. Both hypo- and hyperprolactinemia can be associated with hypopituitarism, with low prolactin signifying more extensive pituitary damage. Posterior pituitary insufficiency (arginine vasopressin deficiency), occurs either in isolation or with anterior pituitary hormone deficiency. Clinical symptomatology of hypopituitarism is usually non-specific and insidious in onset and progression. Overall, the most common cause of hypopituitarism is a pituitary adenoma and/or its management (surgery, radiotherapy, pharmacotherapy or a combination of these). However, it is this subset of patients which is more likely to be identified and managed timely, possibly alleviating the premature mortality associated with hypopituitarism. What is more challenging is the recognition of hypopituitarism in less common settings, which may be either due to direct involvement of the pituitary (infection, traumatic brain injury, or infiltrative causes) or indirectly as a consequence of the primary process (thalassemia, vasculotoxic snakebite, subarachnoid hemorrhage). These entities are often under-recognised, and increased awareness can help in greater recognition of the problem burden. Further, pituitary insufficiency in most of these settings is dynamic, which may progress, or rarely, show recovery of function. This renders complexity to the problem, but makes it even more imperative to suspect, screen and appropriately manage patients with less common causes of hypopituitarism.

Endocrine and Metabolic Manifestations of Snakebite Envenoming

Snakebite envenoming is a neglected, public health problem in tropical and subtropical regions. Local tissue necrosis, neurotoxic, and hemo-vasculotoxic effects are well-recognized features, whereas the endocrine and metabolic derangements are not as well known. In addition to contributing to morbidity, some of these manifestations can be potentially life-threatening if not recognized early. The most prominent endocrine manifestation is hypopituitarism (HP), which can manifest acutely or remain asymptomatic and present years later. Unexplained recurrent hypoglycemia and refractory hypotension are early clinical clues to suspect corticotroph axis involvement in acute settings. Chronic pituitary failure may present, like Sheehan's syndrome, several years after the bite. The occurrence of acute kidney injury, capillary leak syndrome, and disseminated intravascular coagulation are predictors of HP. Adrenal hemorrhages are documented in autopsy series; however, primary adrenal insufficiency is very rare and confounded by the presence of HP. Hyponatremia, hypokalemia or hyperkalemia, and dysglycemia can occur, but the mechanisms involved are only partially understood. Awareness, a high index of suspicion, correct interpretation of hormonal parameters, and timely treatment of these abnormalities can be lifesaving.

ACQUIRED ECTOPIC POSTERIOR PITUITARY BRIGHT SPOT DUE TO VASCULOTOXIC SNAKEBITE

OBJECTIVE

Vasculotoxic envenomation is an uncommon cause of hypopituitarism. Most described cases have varying extent of anterior pituitary dysfunction, but posterior pituitary involvement is extremely rare.

METHODS

Clinical, biochemical, and radiologic evaluation of a young female who presented with secondary amenorrhea was performed. A brief literature review of envenomation-induced hypopituitarism is included.

RESULTS

A 26-year-old female presented with secondary amenorrhea since the age of 20 years. She had normal stature. Her past medical history was significant for a vasculotoxic snakebite 12 years back requiring hemodialysis, but no hormonal testing was done at that time. Current evaluation showed anterior hypopituitarism. An insulin-induced hypoglycemia test confirmed deficiencies of cortisol and growth hormone axes (peak values 348 nmol/L and 0.03 ng/mL). There was no diabetes insipidus. Magnetic resonance imaging revealed a hypoplastic anterior pituitary with an ectopic posterior pituitary. In view of normal stature and secondary amenorrhea, a diagnosis of envenomation-induced hypopituitarism with ectopic posterior pituitary (EPP) was made. A brief literature review of envenomation-induced hypopituitarism showed both acute and delayed presentation, male predominance, and variable lag period (weeks to years). Nearly half of all patients were asymptomatic. The most common axis involved in acute presentation was the cortisol axis, whereas the thyroid and gonadotroph axes were commonly involved in delayed hypopituitarism.

CONCLUSION

Vasculotoxic envenomation is a rare cause of acquired hypopituitarism. EPP in the index case was probably due to the "axonal dieback" phenomenon and subsequent regeneration of the axons at a more caudal site. This case, being the first instance of acquired EPP following envenomation, expands the spectrum of envenomation-induced hypopituitarism.

A case of acute hypogonadism following taipan (Oxyuranus scutellatus) envenomation

A previously well man developed acute, marked tender bilateral gynaecomastia two months after confirmed taipan (Oxyuranus scutellatus) envenomation. He had had laboratory evidence of thrombotic microangiopathy (TMA) including microangiopathic haemolytic anaemia, thrombocytopenia and acute kidney injury. Scrotal ultrasound revealed bilateral testicular atrophy, his serum testosterone was repeatedly low, while his luteinising and follicle stimulating hormone were elevated. It is hypothesised that TMA-related testicular ischaemia was responsible for his primary gonadal failure and dramatic clinical presentation.

Effect of Traditional Chinese Medicine on Long-Term Outcomes of Snakebite in Taiwan

Herein, we review the characteristics of the six predominant venomous snakes in Taiwan and the effects of traditional Chinese medicine on the long-term outcomes of snakebite venom. We electronically searched databases, including PubMed, ClinicalKey, China National Knowledge Infrastructure, National Digital Library of Theses and Dissertations in Taiwan, and Airiti Library, from their inception to November 2019 by using the following Medical Subject Headings' keywords: snakebite, long-term, chronic, Chinese medicine, CAM, herb, and Taiwan. The most common long-term effects of snakebite envenomation include "migraine-like syndrome", brain injuries caused by hypoxia or intracranial hemorrhage, and chronic kidney disease. In addition, hypopituitarism is also worth mentioning. Traditional Chinese medicine can potentially be used in a complementary or alternative treatment for these effects, but additional studies are needed.

Predictors of hypopituitarism due to vasculotoxic snake bite with acute kidney injury

PURPOSE

Hypopituitarism frequently develops following vasculotoxic snake bite complicated by acute kidney injury (AKI). Well defined prospective studies of prevalence of hypopituitarism and its predictors in vasculotoxic snake bites complicated by AKI are unavailable.

METHODS

Fifty-one consecutive patients of AKI following vasculotoxic snake bite were evaluated for various clinical/biochemical parameters (including Free T4, TSH, Cortisol, ACTH, total testosterone, FSH, LH, prolactin, and IGF-1). Diabetes insipidus was evaluated in relevant cases. Twenty minutes whole blood clotting time (WBCT) at presentation was measured in all. MRI of hypothalamo-pituitary region was done at 3 months in subjects with hypopituitarism to rule out structural lesion.

RESULTS

21.6% (11/51) patients developed hypopituitarism at baseline (within 7 days), 39.3% (13 /33) at 3 months developed hypopituitarism. Cortisol deficiency was the commonest abnormality. Subjects who developed hypopituitarism at baseline were younger compared to those without hypopituitarism (35.67 years vs. 46.59 years, p = 0.032) and required more sessions of hemodialysis (8 vs. 3, p = 0.041). Binary logistic regression confirmed that development of hypopituitarism could be predicted by increased number of sessions of hemodialysis (OR 1.51, p = 0.008) and 20 min WBCT (OR 1.2, p = 0.038).

CONCLUSION

Hypopituitarism is common following vasculotoxic snake bite in subjects who develop AKI requiring hemodialysis. Hypopituitarism can develop as early as 7 days following snake bite and should be evaluated for particularly in younger subjects, especially those requiring increasing number of sessions of hemodialysis and in subjects with abnormal 20 min WBCT at presentation.

Long-term Effects of Snake Envenoming

Long-term effects of envenoming compromise the quality of life of the survivors of snakebite. We searched MEDLINE (from 1946) and EMBASE (from 1947) until October 2018 for clinical literature on the long-term effects of snake envenoming using different combinations of search terms. We classified conditions that last or appear more than six weeks following envenoming as long term or delayed effects of envenoming. Of 257 records identified, 51 articles describe the long-term effects of snake envenoming and were reviewed. Disability due to amputations, deformities, contracture formation, and chronic ulceration, rarely with malignant change, have resulted from local necrosis due to bites mainly from African and Asian cobras, and Central and South American Pit-vipers. Progression of acute kidney injury into chronic renal failure in Russell's viper bites has been reported in several studies from India and Sri Lanka. Neuromuscular toxicity does not appear to result in long-term effects. Endocrine anomalies such as delayed manifestation of hypopituitarism following Russell's viper bites have been reported. Delayed psychological effects such as depressive symptoms, post-traumatic stress disorder and somatisation have been reported. Blindness due to primary and secondary effects of venom is a serious, debilitating effect. In general, the available studies have linked a clinical effect to a snakebite in retrospect, hence lacked accurate snake authentication, details of acute management and baseline data and are unable to provide a detailed picture of clinical epidemiology of the long-term effects of envenoming. In the future, it will be important to follow cohorts of snakebite patients for a longer period of time to understand the true prevalence, severity, clinical progression and risk factors of long-term effects of snake envenoming.