Neuroendocrinology

Neuroendocrinology examines the complex bidirectional relationship between the nervous system and the endocrine system. Dr. Funk diagnoses neuroendocrine disorders by integrating advanced neurological examination, endocrine and metabolic laboratory testing, neuroimaging, autonomic physiology, medication effects, sleep and circadian regulation, neuroimmune mechanisms, and the patient's broader neurological condition.

Dr. Funk evaluates and diagnoses a broad range of hypothalamic-pituitary and neuroendocrine disorders, including traumatic brain injury (TBI)-related neuroendocrine dysfunction, post-traumatic hypopituitarism, hypothalamic dysfunction; pituitary adenomas, pituitary cysts, Rathke cleft cysts and other sellar or suprasellar abnormalities; hyperprolactinemia and other prolactin disorders; growth hormone deficiency and excess; ACTH deficiency and central adrenal insufficiency; central hypothyroidism; and syndrome of inappropriate antidiuretic hormone secretion (SIADH).

Brain injury is particularly important in neuroendocrinology because traumatic brain injury can disrupt the hypothalamus, pituitary gland, pituitary stalk, vascular supply, and regulatory pathways connecting the brain with the endocrine system. Resulting dysfunction may affect growth hormone, ACTH/cortisol, thyroid, gonadal, prolactin, and vasopressin regulation and can contribute to fatigue, cognitive dysfunction, sleep disturbance, altered body composition, sexual dysfunction, mood and behavioral changes, autonomic symptoms, and impaired neurological recovery. Dr. Funk specifically investigates these potentially overlooked neuroendocrine consequences when evaluating patients with persistent neurological symptoms following TBI and concussion.

Dr. Funk also evaluates neurological disorders that can produce or coexist with important neuroendocrine abnormalities. Spontaneous intracranial hypotension (SIH) can produce pituitary enlargement and hyperemia as part of the intracranial hypotension syndrome and may be associated with hypothalamic-pituitary dysfunction or mimic primary pituitary disease on neuroimaging. Idiopathic intracranial hypertension (IIH) is frequently associated with partial or complete empty sella, reflecting remodeling of the sellar region in the setting of chronically elevated intracranial pressure. Flattening of the pituitary gland within an empty sella can also be accompanied by abnormalities of pituitary function in some patients. Dr. Funk integrates these findings with the patient's neuroimaging, neuro-ophthalmological findings, intracranial-pressure physiology, and neuroendocrine evaluation rather than interpreting the pituitary abnormality in isolation.

Localization is essential because the same endocrine abnormality can originate at very different levels of a regulatory system. Dr. Funk determines whether dysfunction is arising from the hypothalamus, pituitary gland, pituitary stalk, peripheral endocrine organ, hormonal feedback system, neurotransmitter regulation, medication effect, structural lesion, brain injury, or another neurological process. He then integrates these findings across the hypothalamic-pituitary-adrenal (HPA), hypothalamic-pituitary-thyroid (HPT), hypothalamic-pituitary-gonadal (HPG), growth hormone/IGF-1, prolactin/dopamine, and vasopressin systems to establish a coherent neuroendocrine diagnosis.

A polysubspecialty approach becomes especially important when neuroendocrine dysfunction intersects with Brain Injury Medicine, Neuroimaging, Neuro-Ophthalmology, Dysautonomia/POTS, Neuroimmunology, Vascular Neurology, Cognitive and Memory Disorders, Neurodegenerative Disorders, Headache and Migraine, and other neurological disease. Dr. Funk determines how the neuroendocrine abnormality fits within the patient's larger neurological condition rather than separating interconnected findings into unrelated diagnoses.

Treatment follows the diagnosis, localization, and underlying mechanism. Dr. Funk identifies modifiable neurological, endocrine, metabolic, inflammatory, autonomic, nutritional, sleep, circadian, and physiological factors contributing to the disorder and develops an individualized treatment strategy that may incorporate neurological rehabilitation, neuromodulation, nutraceutical and over-the-counter interventions, and other targeted strategies. When prescription hormone therapy, specialized endocrine testing, endocrine procedures, or ongoing medical management is indicated, Dr. Funk refers to and collaborates with endocrinologists and other appropriate specialists for co-management.

The objective is not simply to identify an abnormal hormone level. Dr. Funk determines where within the brain-endocrine system dysfunction is occurring, identifies the neurological, structural, and physiological mechanisms producing it, determines how those abnormalities interact with the patient's larger neurological condition, and targets the mechanisms that can be treated or rehabilitated.