Topic 8 - diabetes Flashcards
What is type 1 diabetes?
an endocrine disorder of insulin deficiency secondary to pancreatic beta cell destruction (insulin dependent diabetes)
What is the effect of exogenous insulin replacement in T1D?
Exogenous insulin replacement is imperfect and results in variable blood glucose levels with risk of hyperglycemia or hypoglycemia
In T1D, chronic exposure to hyperglycemia is related to …
micro- and macrovascular damage which relate to reduced psychomotor efficiency
What are the core features of cognitive dysfunction in T1D?
reduced psychomotor efficiency and mental inflexibility
What is the effect of mild hypoglycemia on cognition in adults with T1D?
cognitive slowing in mental processing, attention and planning
what is the effect of severe hypoglycemia in adults with T1D?
absence of all neuro-electrical activity for several minutes - necessary to produce cell death
What ar the consequences of insufficient glucose levels in adults with T1D?
insufficient glucose disrupts normal neuronal functioning and is related to reduced cerebral blood flow, particularly to the frontal cortex, followed by 2-4 x increased cerebral hyperperfusion
Recurrent hypo’s in adults with T1D can cause ..
lasting neuroanatomical effects (basal ganglia). It is also associated with reduced gray matter density in brain regions associated with language and limbic memory and in the cerebellum associated with attention and planning
What is the effect of an acute hyper on cognition in adults with T1D?
reduced speed of information processing, verbal fluency and executive functioning
What is the effect of a chronic hyper in adults with T1D?
a lasting detrimental cognitive effect (indexed by glycohemoglobin or microvascular disease complications)
What are the neuroanatomical consequences of hyper’s in adults with T1D?
smaller white matter volume (advanced retinopathy, slower speed of info processing, attention and EF) + reductions in gray matter volume
What is the effect of an acute hypo on cognition in children with T1D?
reduced attention, EF and speed of responding. Similar to adults, however, effects may linger for up to 45 minutes.
What is the effect of recurrent mild hypo’s on cognition in children with T1D?
may have a lasting impact on visuospatial abilities
What is the effect of a nocturnal hypo in children with T1D?
impacts mood the following day but not cognitive status
What is the effect of a hyper on cognition in children with T1D?
slowed mental processing
What is the effect of chronic hyper in children with T1D?
poor metabolic control is related to reduced visuospatial and math performance, disrupted attention, memory and EF
Recurrent hypo’s and chronic hyper’s in children with T1D have an effect on ..
memory and learning, limbic system appears to be vulnerable
Early onset diabetes shows ..
white matter lesions in the hippocampus and lateral ventricle increase + reduced whole brain volume.
-> relates to reduced attention and EF and slowed information processing
What are the vascular consequences of recurrent hypo’s
- disruptions in cerebral blood flow: contribute to the inability of cerebral blood vessels to adequately vasodilate and result in cerebral ischemia
- neuronal damage: lactate + glutamate results in cellular acidosis
- loss of white and gray matter
What is the effect of depression in T1D on cognitive status?
the effect of depression to T1D cognitive status is negligible
What is the effect of hypertension in T1D on cognitive status?
comorbid hypertension is slightly in T1D and it’s not likely to have a major influence on cognition
What is type 2 diabetes?
a metabolic disorder that is characterized by elevated glucose levels that result from insulin resistance and relative insulin insufficiency
What are the cognitive dysfunctions found in T2D?
disrupted psychomotor efficiency and memory and learning impairments
What is the effect of an acute hyper in T2D?
slowed psychomotor speed
What is the effect of chronic hyper in T2D?
lowered HbA1c levels which is related to slowed psychomotor efficiency and processing, memory and abstract reasoning
Which microvascular changes are associated with T2D?
retinopathy, neuropathy and angiopathy
Which cerebrovascular abnormalities are associated with T2D?
deep white matter lesions
(sub)cortical atrophy -> reduced attention and EF
reduced hippocampal volume -> memory impairments
infarcts
What are comorbid macrovascular diseases in T2D?
Hypertension: T2D + hypertension = MCI
Obesity: effects of obesity on cognitive function only in men
Smoking: T2D + smoking -> lower semantic/WM + perceptual speed
What is the prevalence and consequence of depression in T2D?
prevalence doubled in T2D. Depression + T2D leads to poorer self-care and diabetes management
Why have T2D a higher genetic predisposition to AD?
because of the higher incidence of APOE genotype
What are the common symptoms of T2D and AD?
hippocampal atrophy and related memory dysfunction common in both AD and T2D. However, diabetes is associated with damage to the dentate gyrus, while AD is related to damage of the entorhinal cortex
What about the cognitive pattern of T2D and T1D?
the cognitive pattern of T2D is mostly similar to that of T1D after 7 years. Also hemodynamic changes in reduced blood flow and cerebral atrophy occur similar
What kind of damage may relate to chronic hyperglycemia
damage to the dental gyrus of the hippocampus: associated with reduced verbal memory
