In the bloodstream, the bacteria can infect both phagocytes and non-phagocytes. B. pseudomallei use their flagella to move near host cells, then attach to the cells using various adhesion proteins, including the type IV pilus protein PilA as well as adhesion proteins BoaA and BoaB. Additionally, adhesion of the bacteria partially depends on the presence of the host protein Protease-activated receptor-1 which is present on the surface of endothelial cells, platelets, and monocytes. Once bound, the bacteria enter host cells through endocytosis, ending up inside an endocytic vesicle. As the vesicle acidifies, B. pseudomallei uses its Type 3 secretion system (T3SS) to inject effector proteins into the host cell, disrupting the vesicle and allowing the bacteria to escape into the host cytoplasm. Within the host cytoplasm, the bacteria evade being killed by the host autophagy using various T3SS effector proteins. The bacteria replicate in the host cytoplasm.Inside the host cell, the bacteria move by inducing the polymerization of the host actin behind them, propelling the bacteria forward. This actin-mediated motility is accomplished with the autotransporter BimA which interacts with actin at the tail-end of the bacterium. The bacteria that has BimABm allele has higher possibility of causing neurological melioidosis, thus higher chance of death and residual disability to the host when compared to the bacteria that has BimABp variant. Propelled by actin, the bacteria push against the host membrane, creating protrusions that extend into neighbouring cells. These protrusions cause neighboring cells to fuse, leading to the formation of multinucleated giant cells (MNGCs).
Alcoholism may cause physiological thirst since ethanol inhibits vasopressin, the hormone primarily responsible for water retention in osmoregulation. The following conditions should also be excluded: DI, cerebral salt wasting, pseudohyponatraemia caused by hyperlipidemia or hyperparaproteinemia, SIADH, mineralcorticoid deficiency, salt-wasting nephropathy, nephrotic syndrome, chronic heart failure and cirrhosis.Tobacco smoking is an often overlooked factor linked to hyponatremia, due to the ADH-releasing effect of nicotine, although this is usually limited to heavy smokers. One study suggested that around 70% of patients with self-induced polydipsia were tobacco smokers. Diagnostic tests for primary polydipsia usually involves the fluid deprivation test to exclude ADH problems. The desmopressin test is also used, in which the synthetic hormone is used as a diagnostic workup to test for inappropriate secretion of vasopressin, as seen in DI and SIADH. Patient profiles
Psychogenic polydipsia is found in patients with mental illnesses, most commonly schizophrenia, but also anxiety disorders and rarely affective disorders, anorexia nervosa and personality disorders. PPD occurs in between 6% and 20% of psychiatric inpatients. It may also be found in people with developmental disorders, such as those with autism. While psychogenic polydipsia is usually not seen outside the population of those with serious mental disorders, it may occasionally be found among others in the absence of psychosis, although there is no existent research to document this other than anecdotal observations. Such persons typically prefer to possess bottled water that is ice-cold, consume water and other fluids at excessive levels. However, a preference for ice-cold water is also seen in diabetes insipidus.