The reference given when answering the question about the increase in permeability of sodium ions during hypocalcemia is satisfactory but "does hypocalcemia not reduce the release of neurotransmitters at a chemical synapse" Will it not affect the speed and efficiency of conduction of impulse. Therefore how will it cause tetany?"
Increased Permeability of the Sodium Channels When There Is a Deficit of Calcium Ions.
The concentration of calcium ions in the extracellular fluid also has a profound effect on the voltage level at which the sodium channels become activated. When there is a deficit of calcium ions, the sodium channels become activated (opened) by very little increase of the membrane potential from its normal, very negative level. Therefore, the nerve fiber becomes highly excitable, sometimes discharging repetitively without provocation rather than remaining in the resting state. In fact, the calcium ion concentration needs to fall only 50 per cent below normal before spontaneous discharge occurs in some peripheral nerves, often causing muscle “tetany.”This is sometimes lethal because of tetanic contraction of the respiratory muscles. The probable way in which calcium ions affect the sodium channels is as follows:These ions appear to bind to the exterior surfaces of the sodium channel protein molecule. The positive charges of these calcium ions in turn alter the electrical state of the channel protein itself, in this way altering the voltage level required to open the sodium gate.
From: Guyton, Arthur C. Textbook of medical physiology / Arthur C. Guyton, John E. Hall.—11th ed.
In NeuroPsychiatry it might be difficult to locate its territory, and find its niche. This might be an uneasy endeavour as its two parent branches neurology and psychiatry are still viable, also it siblings organic psychiatry, behavioural neurology and biological psychiatry are also present. This blogpost attempts to search for the definition and domains of neuropsychiatry.
Neuropsychiatry can be defined as the 'biologic face' of mental health (Royal Melbourne Hospital, Neuropsychiatry unit). It is the neurological aspects of psychiatry and the psychiatric aspects of neurology (Pacific Neurpsychiatry Institute). It is not a new term. Many physicians used to brand themselves as neuropsychiatrists at the rise of the twentieth century. It has been looked upon with a sense of unease as a hybrid branch. Also, it was subject to pejorative connotations, as the provenance of amateurs in both parent disciplines (Lishman, 1987). The foundational claim is that 'all' mental disorders are disorders of the brain' (Berrios and Marková, 2002). The American NeuroPsychiatric Association (ANPA) defines it as 'the integrated study of psychiatric and neurologic disorders' (ANPA, 2013). The overlap between neuropsychiatry and biological psychiatry was observed (Trimble and George, 2010) as the domain of enquiry of the first and the approach of the second will meet at point. Berrios and Marková seemed to have focused on the degree of conversion among biological psychiatry, organic psychiatry, neuropsychiatry and behavioural neurology. They stated that they share the same foundational claims (FCcs): (1) mental disorder is a disorder of the brain; (2) reasons are not good enough as causes of mental disorder; and (3) biological psychiatry and its congeners have the patrimony of scientific truth. They further elaborated that the difference is primarily due to difference in historic origins. (D'haenen et al., 2002). The American Neuropsychiatric Association (ANPA) defines neuropsychiatry as the integrative study of neurological and psychiatric disorders on a clinical level, on a theoretical level; ANPA defines it as the bridge between neuroscience and clinical practice. The interrelation between both specialities is adopted by The Royal Australia and New Zealand College of Psychiatrists as it defines it as a psychiatric subspeciality. This seems to resonate the concept that 'biologisation' of psychiatry is inevitable (Sachdev and Mohan, 2013). The definition according to Gale Encyclopedia encompasses the interface between the two disciplines (Fundukian and Wilson, 2008). In order to acknowledge the wide use of the term 'neuropsychiatry'; the fourth edition of Lishman's Organic Psychiatry, appeared and it was renamed as 'textbook of neuropsychiatry'. The editor stated that the term is not used in its more restrictive sense (David, 2009).
Ostow backtracked the origin of biological causes for illness to humoral view of temperament.In the nineteenth century, the differentiation between both did not seem to be apparent. The schism seems to have emerged in the twentieth century. The difficulties that arose with such early adoption of neuronal basis to psychiatric disorders are that they were based on on unsubstantiated beliefs and wild logic rather than scientific substance. (Panksepp, 2004). Folstein stated that Freud and Charcot postulated psychological and social roots for abnormal behaviours, thus differentiating neurology from psychiatry. (David, 2009). The separation may have lead to alienation of doctors on both camps and helped in creating an arbitary division in their scope of knowledge and skills. The re-emergence of interest in neurospsychiatry has been described to be due to the growing sense of discomfort in the lack of acknowledgment of brain disorders when considering psychiatric symptoms (Arciniegas and Beresford, 2001).
There is considerable blurring regarding defining the territory and the boundaries of neuropsychiatry. The Royal College of Psychiatrists founded section of Neuropsychiatry in 2008. The major working groups include epilepsy, sleep disorders, brain injury and complex neurodisability. In 1987 the British NeuroPsychiatry Association was established, to address the professional need for distinction, without adopting the concept of formal affiliation with parent disciplinary bodies as the Royal College of Psychiatrists. The ANPA was founded in 1988. It issued training guide for residents. The guide included neurological and psychiatric assessments, interpretation of EEG and brain imaging techniques. With regards to the territory, it included delirium, dementia, psychosis, mood and anxiety disorders due to general medical condition. Neurpsychiatric aspects of psychopharmacologic treatments, epilepsy, neuropsychiatric aspects of traumatic brain injury and stroke. The diagnosis of movement disorders, neurobehavioural disorders, demyelinating disease, intellectual and developmental disorders, as well as sleep disorders was also included. The World Federation of Societies of Biological Psychiatry (WFSBP) was established in Buenos Aires in 1974 to address the rising significance of biological psychiatry and to join local national societies together. The National Institute of Mental Health (NIMH), is currently working on a biologically-based diagnosis, that incorporates neural circuits, cells, molecules to behavioural changes. The diagnostic system - named 'Research Domain Criteria (RDoC) - is agnostic to current classification systems DSM-5 & ICD-10. Especially that the current diagnostic classficiations are mostly based on descriptive rather than neurobiological aetiological basis. (Insel et al., 2010). For example, the ICD-10 F-Code designates the first block to Organic illness, however, it seems to stop short of localisation of the cause of illness apart from the common prefix organic. It also addresses adverse drug events as tardive dyskinesia but stops short of describing it neural correlates. Also, psychosocial roots of mental illness seem to be apparent in aetiologically-based diagnoses as Post-Traumatic Stress Disorder, acute stress reaction, and adjustment disorders, the diagnostic cluster emphasise the necessity of having 'stress'. Other diagnoses seem to draw from the psychodynamic literature, e.g. conversion[dissociative] disorder.
The need for neuropsychiatry, has been increasing as the advances in diagnostic imaging and laboratory investigations became more clinically relevant. Nowadays, there are tests as DaT-Scan that can tell the difference between neurocognitive disorder with Lewy Bodies and Parkinson's Disease. Vascular neurocognitive disorders warrant imaging as the rule rather than the exception, vascular depression has been addressed is a separate entity. Frontal Lobe Syndromes have been subdivided into orbitofrontal and dorsolateral (Moore,2008) Much training is needed to address this subspeciality.
The early cases that may have stirred up the neurological roots of psychiatric disorders can be backdated to the case of Phineas Gage, and later, the case H.M. The eearlier fruits of adopting a neuropsychiatric perspective can be shown in the writings of Eliot Slater, as he attempted to search for the scientific underpinnings of psychiatry, and helped via seminal articles to highlight the organic aspect of psychiatry. Articles like 'The diagnosis of "Hysteria", where Slater, challenged the common wisdom of concepts like hysteria and conversion, rejecting the social roots of mental illness, and presenting a very strong case for the possibility of organicity, and actual cases of for which 'hysteria' was a plain misdiagnosis was way ahead of its time prior to CT Brain. Slater even challenged the mere existence of the concept of 'hysteria. (Slater, 1965) Within the same decade Alwyn Lishman published his textbook 'Organic Psychiatry' addressing the organic aspects of psychiatric disorders. Around the same time, the pioneers of social/psychological roots of mental illness became under attack. Hans Eysenck, published his book 'Decline and Fall of the Freudian Empire'. Eysenck stated clearly that the case of Anna O. seems to have been mispresented and that she never had 'hysteria' and recovered she actually had 'tuberculous meningitis' and she died of its complications (Eysenck, 1986).
To summarise, it seems difficult and may be futile to sharply delineate neurpsychiatry, biological psychiatry, organic psychiatry and behavioural neurology. However, it seems important to learn about the biological psychiatry as an approach and practice neuropsychiatry as a subspeciality. The territory is yet unclear from gross organic lesions as stroke to the potential of encompassing entire psychiatry as the arbitary distinction between 'functional' and 'organic' fades away. Perhaps practice will help to shape the domain of the speciality, and imaging will guide it. To date, the number of post-graduate studies are still low in comparison to the need for such speciality, much more board certification may be needed as well as the currently emerging masters and doctoral degrees.
This post is previously posted on bmj doc2doc blogs
Eysenck, H.J., Decline and Fall of the Freudian Empire, Pelican Series, 1986
German E Berrios, I.S.M., The concept of neuropsychiatry: A historical overview, Journal of Psychosomatic Research, 2002, Vol. 53, pp. 629-638
Kieran O’Driscoll, J.P.L., “No longer Gage”: an iron bar through the head, British Medical Journal, 1998, Vol. 317, pp. 1637-1638
Perminder S. Sachdev, A.M., Neuropsychiatry: Where Are We And Where Do We Go From Here?, Mens Sana Monographs, 2013, Vol. 11(1), pp. 4-15
Slater, E., The Diagnosis of "Hysteria", British Medical Journal, 1965, Vol. 5447(1), pp. 1395–1399
Thomas Insel, Bruce Cuthbert, R.H.M.G.K.Q.C.S.P.W., Research Domain Criteria (RDoC): Toward a New Classification Framework for Research on Mental Disorders, American Journal of Psychiatry, 2010, Vol. 167:7, pp. 748-751
Organic Psychiatry, Anthony S. David, Simon Fleminger, M. D. K. S. L. J. D. M. (ed.), Wiley-Blackwell, 2009
Neuropsychiatry an introductory approach, Arciniegas & Beresford (ed.), Cambridge University Press, 2001
Biological Psychiatry, Hugo D’haenen, J.A. den Boer, P. W. (ed.), John Wiley and Sons, 2010
Gale Encyclopedia of Mental Health, Laurie J. Fundukian, J. W. (ed.), Thomson Gale, 2008
Biological Psychiatry, M. Trimble, M. G. (ed.), Wiley-Blackwell, 2010
Textbook of Neuropsychiatry, Moore, D. P. (ed.), Hodder Arnold, 2008
Textbook of Biological Psychiatry, Panksepp, J. (ed.), John Wiley and Sons, 2004
The American Neuropsychiatric Association Website www.anpaonline.org
The Royal Melbourne Neuropsychiatry Unit Website http://www.neuropsychiatry.org.au/
The British Neuropsychiatry Association website www.bnpa.org.uk
The Royal College of Psychiatrists website www.rcpsych.ac.uk
The World Federation of Societies of Biological Psychiatry website www.wfsbp.org
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