NANOCEPHALIA (microcephalia; grech, mikros small + kephale the head) — the considerable reduction of the sizes of a skull and brain which is followed by mental retardation and various neurologic disturbances.
M.'s frequency makes 0,6 — 1,6 on 10 000 childbirth. Among deeply mentally retarded about 20% of cases are diagnosed M.
Razlichayut primary and secondary (embriopatichesky) M. Pervichnaya M. is caused by genetic defect and is in most cases inherited on an autosomal recessive character; however as this sign genetically and pathogenetic geterogenen, cases autosomal and dominant and recessive, linked to a floor, inheritance meet. Secondary M. results from impact on a brain of various vrednost in the anti-and perinatal periods (a hypoxia, an infection, an injury, metabolic disturbances). However accurate a wedge, there are no distinctions between genetic and embriopatichesky M.
The weight of a brain of the newborn with M. is reduced to 250 — 300 g (apprx. 350 — 400 g normal); the underdevelopment of parencephalons, especially frontal lobes is noted; crinkles can be absent completely (agiriya), can be narrow and thin (microgyria) or very wide (makrogiriya). In some cases it is observed agenesias (absence) of a corpus collosum (see. Brain, malformations ), aplasia of kernels craniocereberal (cranial, T.) nerves and conduction paths, a short front central crinkle, funneled deepenings on the surface of a brain (see. Porencephalia ), expansion of ventricles and subarachnoid spaces is noted. At microscopic examination of a brain depletion of bark is noted by nervous cells, to-rye can be insufficiently differentiated; the heterotopy of gray matter, a gliosis, laminar loss of neurons, an underdevelopment of vascular system, disturbance of myelination of nerve fibrils is observed.
Outward of the patient with M. is characteristic: the disproportion of brain and front parts of a skull (a brain part of a skull is underdeveloped), a forehead narrow, sloping, the acting superciliary arches, the large bulged ears (fig.), the Gothic sky is observed. At the newborn with M. the big fontanel is closed or is closed in the first months of life. Nevrol, symptoms vary: muscular dystonia, spastic paralyzes, paresis, an incoordination of movements, squint, spasms, an arrest of development of static and locomotory skills are possible. Nevrol, disturbances are more expressed at children from secondary M. Stepen of a delay of intellectual development fluctuates from easy moronity when training at special school, to a heavy idiocy (is possible see. Oligophrenias ), characterized motive rastormozhennostyo, netselenapravlennostyo actions, by gross violation of concentration of attention.
Diagnosis is based on data of anthropometrical inspection (the circle of the head reduced in comparison with norm), rentgenol, researches (the reduced sizes of a skull), and also a wedge, a picture of a disease. It is necessary to distinguish M. as nozol, a form from M. as symptom chromosomal diseases (see) and early post-natal injuries of a brain (exchange, traumatic, infectious, etc.); their differentiation is based on data complex rentgenol., biochemical, cytogenetic and other researches.
Treatment symptomatic. The drugs improving exchange in tissue of a brain (glutaminic to - that, Aminalonum, Cerebrolysinum), work therapy are shown. Besides, pedagogical and educational events are held.
Forecast depends on degree of an underdevelopment of a brain.
Bibliography: Badalyan L. O. Children's neurology, M., 1975; Knyazeva M. P. About neurologic disturbances at a nanocephalia, Zhurn, a neuropath, and psikhiat., t. 75, No. 10, page 1450, 1975, bibliogr.; Purine B. P., Zhukova T. P. and To about - T. I. O molova a pathogeny of a secondary nanocephalia, in the same place, t. 72, No. 9, page 1347, 1972; Chamberlin H. R. Mental retardation, in book: Pediatric neurol., ed. by T. W. Farmer, p. 90, Hagerstown a. o., 1974; Menkes J.H. Textbook of child neurology, Philadelphia, 1974; Warkany J. Congenital malformations, Chicago, 1971.
L. T. Zhurba.