Chiari malformations (CMs) are a group of central nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification (CNS) conditions characterized by the underdevelopment of the posterior cranial fossa Cranial fossa The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface. Skull: Anatomy with subsequent protrusion of neural structures through the foramen magnum. There are 4 types of CM, with type I being the most common. Headaches are the most common symptom. Diagnosis is made by clinical findings and confirmed by magnetic resonance imaging (MRI). Treatment is surgical, based on decompression of the posterior fossa and restoration of CNS flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure. Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual's condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas depends on the type of malformation.
Last updated: 8 Jan, 2021
Chiari malformations (CMs) are a group of disorders defined by structural deficits in the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification and spinal cord Spinal cord The spinal cord is the major conduction pathway connecting the brain to the body; it is part of the CNS. In cross section, the spinal cord is divided into an H-shaped area of gray matter (consisting of synapsing neuronal cell bodies) and a surrounding area of white matter (consisting of ascending and descending tracts of myelinated axons). Spinal Cord: Anatomy leading to limited space in the posterior fossa, which forces cerebellar structures to protrude through the foramen magnum.
Chiari type I and II
Chiari malformations are characterized by and underdeveloped posterior
cranial fossa
Cranial fossa
The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface.
Skull: Anatomy, with subsequent protrusion of neural structures through the foramen magnum.
Type 1
Type 1
Spinal Muscular Atrophy is characterized by
herniation
Herniation
Omphalocele of the cerebellar
tonsils
Tonsils
Tonsillitis only, while
type 2
Type 2
Spinal Muscular Atrophy involves more structures.
Chiari II malformation showing the points of potential obstruction that yield different subtypes of hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage
Image: “Chiari2” by Rekate HL HL Hodgkin lymphoma (HL) is a malignancy of B lymphocytes originating in the lymph nodes. The pathognomonic histologic finding of HL is a hodgkin/reed-sternberg (HRS) cell (giant multinucleated B cells with eosinophilic inclusions). The disease presents most commonly with lymphadenopathy, night sweats, weight loss, fever, splenomegaly and hepatomegaly. Hodgkin Lymphoma. License: CC BY 2.0Magnetic resonance imaging (MRI) findings suggestive of Arnold–Chiari II malformation
Sagittal
Sagittal
Computed Tomography (CT) T2W whole-spine MRI (A) shows a
meningomyelocele
Meningomyelocele
Congenital, or rarely acquired, herniation of meningeal and spinal cord tissue through a bony defect in the vertebral column. The majority of these defects occur in the lumbosacral region. Clinical features include paraplegia, loss of sensation in the lower body, and incontinence. This condition may be associated with the arnold-chiari malformation and hydrocephalus.
Neural Tube Defects (arrow) opposite the L5 and
S1
S1
Heart Sounds vertebrae.
Sagittal
Sagittal
Computed Tomography (CT) T2W MRI of the
brain
Brain
The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem.
Nervous System: Anatomy, Structure, and Classification (B) shows a small posterior
cranial fossa
Cranial fossa
The inferior region of the skull consisting of an internal (cerebral), and an external (basilar) surface.
Skull: Anatomy, with
herniation
Herniation
Omphalocele of the cerebellar vermis and
tonsils
Tonsils
Tonsillitis (arrow) through the foramen magnum with tectal beaking (arrowhead).
Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency:
Associated conditions:
Neurologic symptoms are caused by:
Syrinx seen with Chiari malformation
Cavities filled with
cerebrospinal fluid
Cerebrospinal Fluid
A watery fluid that is continuously produced in the choroid plexus and circulates around the surface of the brain; spinal cord; and in the cerebral ventricles.
Ventricular System: Anatomy (CSF) are commonly seen with CMs. They cause
symptomatology
Symptomatology
Scarlet Fever commonly associated with the malformation by putting pressure on the surrounding neural tissue.
Symptoms:
Physical signs:
Symptoms:
Physical signs:
There is high infant mortality Mortality All deaths reported in a given population. Measures of Health Status with this type.
Symptoms:
Physical signs:
Magnetic resonace imaging scan showing a type I CM. Notice the tonsillar herniation Herniation Omphalocele.
Image: “ Sagittal Sagittal Computed Tomography (CT) MRI scan of brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification of patient with Chiari malformation” by Raymond F Sekula Jr et al AL Amyloidosis. License: CC BY 2.0