Subcortical dementias includes those diseases which predominantly affects the basal ganglia along with features of cognitive decline. Diseases such as progressive supranuclear palsy, Huntingtons chorea and Parkinsons disease are different in many features from the other cortical dementias like Alzheimers disease. Yet these patients present clinically with mild forgetfulness and slowed thought process along with abnormal movements and problems with motility. Clinical features
Clinically subcortical dementia usually is seen with features like slowness of mental processing, forgetfulness, impaired cognition, lack of initiative-apathy, depressive symptoms (such as anhedonia, negative thoughts, loss of self-esteem and dysphoria), loss of social skills along with extrapyramidal features like tremors and abnormal movements.In most of the patients with Huntingtons diseases the first clinical feature to appear is the change in personality. The dementia is more severe in patients with early onset of Huntingtons disease. Parkinsons disease is characterised by features of dementia in older age. The adult type "leukodystrophy" also causes subcortical dementia with prominent frontal lobe features. As a general rule the earliest symptoms in "cortical" dementia include difficulty with high-level behaviors such as memory, language, problem-solving and reasoning, mathematics and abstract thoughts – functions associated with the cerebral cortex. Such patients have prominent apraxia and agnosia. However, in "subcortical" dementia these high-level behaviours are less affected. Pathophysiology
In most common types of dementias there is widespread degeneration in the cerebral cortex – such as the plaques and neuro fibrillary tangles which are the hallmark of Alzheimers disease. In subcortical dementia, there is targeted damage to regions lying under the cortex.
Palmar erythema is reddening of the palms at the thenar and hypothenar eminences. : 139

Causes
It is associated with various physiological as well as pathological changes, or may be a normal finding:

Portal hypertension
Chronic liver disease (including chronic hepatitis)
Pregnancy
Polycythemia
Thyrotoxicosis
Rheumatoid arthritis (especially in patients with polycythaemia)
Eczema and psoriasis
Deep telangiectasias
Coxsackievirus A infection (Hand, foot and mouth disease)
Rocky Mountain spotted fever
Secondary syphilis
Kawasaki disease
Adverse drug reaction: palmoplantar erythrodysesthesia (acral erythema)Because circulating levels of estrogen increase in both cirrhosis and pregnancy, estrogen was thought to be the main cause for the increased vascularity. More recently, nitric oxide has also been implicated in the pathogenesis of palmar erythema. Diagnosis
Palmar erythema has no specific treatment. Management is based on the  underlying cause. When its cause is treated then patients get relief. If it is attributable to a particular drug then the drug should be withdrawn. See also
Toxic erythema
List of cutaneous conditions

References


== External links ==