Dengue: Foreshadowing from Ancient Foe

Dengue is a painful, debilitating mosquito-borne disease(female mosquitoes of the Aedes genus, principally Aedes aegypti)caused by any one of four closely related dengue viruses. It is endemic in tropical and subtropical continent. World health organization (WHO) currently estimates there may be 50 -100 million dengue infections worldwide every year with over 2.5 billion people at risk of dengue. Symptomatic dengue virus infection may manifest as undifferentiated fever, classical dengue fever (with or without unusual hemorrhages), and dengue hemorrhagic fever (with or without shock). Expanded dengue syndrome(EDS) was coined by WHO in the year 2012 to describe cases, which do not fall into either dengue shock syndrome or dengue hemorrhagic fever. The atypical manifestations noted in expanded dengue are multisystem and multifaceted with organ involvement, such as liver, brain, heart, kidney, central/peripheral nervous system, gastrointestinal tract, lympho reticular system.

The interrelation of neurophysiological, psychological, and biochemical indicators in patients with occupational chronic mercury intoxication suffering from insomnia

Introduction. Despite the apparent connection of the existing neurological disorders and changes in the psycho-emotional sphere with sleep disorders in patients with chronic mercury intoxication (CRI), these relationships remain the least studied in the clinic neurointoxications. The study aimed to establish a connection between neurophysiological, biochemical, and psychopathological indicators in patients with occupational chronic mercury intoxication and insomnia. Materials and methods. Thirty-six patients took part in the examination in the remote period of CRI. The average age of patients in this group was 50.7±1.05 years, with an average work experience of 14.7±1.05. The authors carried out a psychological examination to determine the levels of depression, anxiety, asthenic state, computed electroencephalography (EEG), cognitive evoked potentials (CEP), polysomnography, the level of neurotransmitters. Results. The study showed that asthenization, when exposed to mercury, occurs due to a decrease in the limbic-hypothalamo-reticular complex activity (the presence of equivalent dipole sources of pathological activity in the area of diencephalic formations (thalamus, hypothalamus) in 56.2±5.6% of cases. The study showed a decrease in activity cerebral cortex, confirmed by weakening the coherent connections of the α-range in the occipital, central and frontal leads according to the data of coherent EEG analysis and changes on the part of the CEP. There was a direct correlation between the level of total sleep time and the serotonin level (rs=0.45), an inverse relationship between the level of depression and histamine level (rs=-0.56). Conclusion. The studies carried out to make it possible to establish the mechanisms of insomnia disorders in chronic mercury intoxication, which cause a weakening of the tone of the cerebral cortex and changes in neurotransmitter metabolism, as well as disorders of the reticular system with limbic structures. The study showed a close direct relationship between neurophysiological, psychological, and biochemical parameters in implementing insomnia in patients with chronic mercury intoxication.

Coma

Coma is a pathological state of unconsciousness from which a patient cannot be roused to wakefulness by stimuli, and reflects dysfunction of the brainstem reticular system and its thalamic projections (the neuronal basis of wakefulness), or diffuse injury of both cerebral hemispheres. A unilateral lesion of a cerebral hemisphere (e.g. haemorrhagic stroke) will not cause coma unless there is secondary compression of the contralateral hemisphere or brainstem. Coma is a medical emergency, because a comatose patient is at high risk of permanent brain injury or death, caused either by the underlying disorder or the secondary effects of coma. Stabilization of the airway, breathing, and circulation, and exclusion of hypoglycaemia are the first priorities, before diagnosis is explored further. Clinical assessment together with neuroimaging will usually identify the likely cause or causes. The clinical approach to diagnosis and management of the comatose patient is described in this chapter.

Consciousness without a cortex, but what kind of consciousness is this?

Merker suggests that the thalamocortical system is not an essential system for consciousness, but, instead, that the midbrain reticular system is responsible for consciousness. Indeed, the latter is a crucial system for consciousness, when consciousness is regarded as the waking state. However, when consciousness is regarded as phenomenal consciousness, for which experience and perception are essential elements, the thalamocortical system seems to be indispensable.