Pick's Disease

PICK'S DISEASE (Pick), described by the author under the name "limited senile atrophy of the brain", is characterized mainly by focal symptoms, developing gradually in the absence of strokes and referring b. ch. to the syndrome of the left temporal lobe. Amnestic aphasia, echolalia, and Wernicke's transcortical sensory aphasia are especially characteristic. In the extreme paucity of spontaneous speech, patients repeat well the words spoken by others. In other cases, alexia, paragraphia, apractic and asymbolic disorders are observed, which already refers to the inferior temporal syndrome. Finally, in some cases, Pick's peculiar disorders of vision in the form of so-called "apperceptive blindness" are described, in which there are no gross lesions of vision, but the patient at times does not perceive visual sensations and behaves as if blind, while at other moments vision is restored, and visual functions are as if activated under the influence of the simultaneous action of other irritants (e.g. olfactory). On the psychic side, progressive dementia, mood changes, often sharp apathy (elements of the frontal syndrome), and sometimes short states of confusion are noted. The tendency of patients to aimless wandering (in the beginning of the disease) is quite characteristic. The course of the disease is slow. Death occurs in a state of marasmus. The etiology of the disease is unclear; there are no indications of the influence of any exogenous factors; the significance of heredity also requires further proof. People of advanced age suffer from the disease, women three times more often than men. The differential diagnosis is especially difficult when distinguishing from cerebral arteriosclerosis, which can also give focal symptoms analogous to those observed in Pick's disease, dementia, and marasmus. However, in arteriosclerosis, focal phenomena are established b. ch. after strokes and in any case not so slowly and gradually. Alzheimer's disease differs from Pick's form by a more rapid breakdown, a predominance of severe motor disorders (contractures, cranial nerve pareses, epileptiform attacks, etc.). Cerebral syphilis can be distinguished from Pick's disease by the presence of serological reactions and the occurrence of focal symptoms in connection with strokes. Anatomically verified cases described to date exceed 40. In the patho-anatomical examination of Pick's disease, local limited atrophy of the cortex and white matter of the large brain is noted, which is already noticeable macroscopically. Mainly, the prefrontal and temporal areas are affected, then sometimes the inferior temporal and in some cases the occipital lobes. From other areas of the brain, involvement of the caudate body and the optic thalamus is most often noted. The mentioned foci of local atrophy correspond to clinical symptoms (temporal, frontal, inferior temporal syndromes), which makes it possible to localize precisely the disorders observed in this disease. Microscopic data indicate the presence in the atrophic foci of a parenchymatous degenerative process and a predominant lesion of the II and III layers of the cortex. In nerve cells, swelling, death of fibrils and chromatin substance, argyrophilic granules and balls (very characteristic for this disease) are noted. At the same time, gliosis occurs, the multiplication of cells not being in the foreground, but the proliferation of glial fibers. Nerve fibers are also sharply affected: changes in axial cylinders and disintegration of myelin are observed. Furthermore, a large amount of decomposition products and pigment is established in the affected foci. Druses characteristic of senile dementia and Alzheimer's fibrillar changes are usually not found in Pick's disease (with the exception mainly of cases with atypical localization in the occipital lobes). Changes in mesodermal tissue, in particular blood vessels, are not observed in any marked degree. The above anatomical data and especially the absence of changes specific for senile dementia give most authors at present the basis to consider Pick's form a separate disease, and not atypical senile dementia, as Pick himself thought. On the other hand, however, it is possible that not all cases described under this name are homogeneous. Some of them (with the presence of druses, etc.) apparently still relate to atypical senile dementia. A combination of Pick's disease with arteriosclerosis is also possible. In general, many authors tend to consider vascular changes, which disturb (less roughly than in ordinary arteriosclerosis) the nutrition of brain tissue, a very important factor in the development of Pick's disease, which determines the focal nature of the disease. Other authors (and including Pick) explain the selective focal nature of lesions by a functional moment, conditioning the wear and tear of certain areas of the cortex. It is characteristic that in Pick's disease mainly associative systems and phylogenetically new areas of the cortex, which are the predominant property of the human brain, are affected.

M. Gurievich. PICNOSIS (from Greek picnoo - to make dense), condensation with shrinkage, observed during necrobiosis (see) in the protoplasm and nuclei of cells. Nuclear picnosis precedes in some cases its disintegration (see Kariorexis). Gradual condensation is associated with a decrease in the cell and its transformation into a compact mass. The protoplasm becomes at the same time darker, homogeneous or with very densely arranged granularity, showing a strong tendency to stain with nuclear staining dyes. In many cases, a picnotic cell is stained so diffusely and intensely that its nucleus is no longer distinguishable. In this stage, the cells take an irregular shape, their contours become toothed, and cracks appear inside. Nuclear picnosis, accompanying picnosis of the protoplasm, is more complex and in general reduces to the fact that the nucleus becomes smaller due to the absorption of liquid components and the gluing of chromatin; the nucleus often loses its round shape and acquires an especially intense and diffuse staining. In deeper disorders of cell nutrition, the staining content of the nucleus (chromatin and nucleolar substance) collects on the nuclear envelope (marginal hyperchromatism of the nucleus). Further, karyorexis passes into nucleus splitting. Sometimes during picnosis the nucleus becomes incorrectly rounded, angular, lobed, with notches. In some nuclei that have still preserved their form, light bubble-shaped vacuoles of various sizes are encountered. Next, during picnosis, forms of nuclei in the form of mulberry berries are observed, and finally in picnotic cells nuclei are encountered, the chromatin of which takes the form of rings, elongated, oval or irregularly shaped formations. A good object for observing picnotic changes of the cell and nucleus can be the desquamated epithelium of the renal tubules (epithelial cylinders), as well as cells of malignant tumors.