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Acoustic Neuroma

Acoustic neuroma, also referred to as vestibular schwannoma Schwannoma Schwannomas (also known as neurilemmomas) are benign nerve sheath tumors in the peripheral nervous system (PNS), arising from Schwann cells that encase the peripheral nerves. Schwannomas are the most common tumors in the PNS. Schwannoma, is a benign Benign Fibroadenoma tumor Tumor Inflammation arising from Schwann cells of the vestibular component of the cranial nerve VIII. Acoustic neuroma forms within the internal auditory meatus and extends into the cerebellopontine angle. Vestibular schwannoma Schwannoma Schwannomas (also known as neurilemmomas) are benign nerve sheath tumors in the peripheral nervous system (PNS), arising from Schwann cells that encase the peripheral nerves. Schwannomas are the most common tumors in the PNS. Schwannoma is mostly unilateral. Bilateral vestibular schwannomas Vestibular schwannomas A benign schwannoma of the eighth cranial nerve (vestibulocochlear nerve), mostly arising from the vestibular branch (vestibular nerve) during the fifth or sixth decade of life. Clinical manifestations include hearing loss; headache; vertigo; tinnitus; and facial pain. Bilateral acoustic neuromas are associated with neurofibromatosis 2. Neurofibromatosis Type 2 are associated with neurofibromatosis type II. Symptoms arise due to compression Compression Blunt Chest Trauma of the cranial nerves Cranial nerves There are 12 pairs of cranial nerves (CNs), which run from the brain to various parts of the head, neck, and trunk. The CNs can be sensory or motor or both. The CNs are named and numbered in Roman numerals according to their location, from the front to the back of the brain. The 12 Cranial Nerves: Overview and Functions V, VII, and VIII, and the cerebellum Cerebellum The cerebellum, Latin for "little brain," is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis. Cerebellum: Anatomy. The most common complaint is unilateral hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss but acoustic neuroma can also present with vertigo Vertigo Vertigo is defined as the perceived sensation of rotational motion while remaining still. A very common complaint in primary care and the ER, vertigo is more frequently experienced by women and its prevalence increases with age. Vertigo is classified into peripheral or central based on its etiology. Vertigo, decreased facial sensation, Bell’s palsy Bell’s palsy A syndrome characterized by the acute onset of unilateral facial paralysis which progresses over a 2-5 day period. Weakness of the orbicularis oculi muscle and resulting incomplete eye closure may be associated with corneal injury. Pain behind the ear often precedes the onset of paralysis. This condition may be associated with Human Herpesvirus 1 infection of the facial nerve. Cranial Nerve Palsies, and ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia. Diagnosis of vestibular schwannoma Schwannoma Schwannomas (also known as neurilemmomas) are benign nerve sheath tumors in the peripheral nervous system (PNS), arising from Schwann cells that encase the peripheral nerves. Schwannomas are the most common tumors in the PNS. Schwannoma is made with an 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 with contrast. Treatment depends on the size of the tumor Tumor Inflammation and symptom severity. Large tumors with severe hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss are treated with surgical excision or radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma therapy, while small tumors with mild symptoms can be observed over time.

Last updated: Oct 17, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

Overview

Definition

An acoustic neuroma is a benign Benign Fibroadenoma tumor Tumor Inflammation of Schwann cells that is most commonly found on cranial nerve VIII ( vestibulocochlear nerve Vestibulocochlear nerve The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (cochlear nerve) which is concerned with hearing and a vestibular part (vestibular nerve) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the spiral ganglion and project to the cochlear nuclei (cochlear nucleus). The fibers of the vestibular nerve arise from neurons of scarpa’s ganglion and project to the vestibular nuclei. The 12 Cranial Nerves: Overview and Functions).

Classification of 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 tumors

Table: Classification of 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 tumors
Categories Specific tumors
Neuroepithelial tumors in the CNS
  • Astrocytomas, including glioblastoma multiforme Glioblastoma multiforme Glioblastoma multiforme is a high-grade astrocytoma, an aggressive brain tumor arising from astrocytes, with an unknown cause and a poorly understood link to risk factors. There are two main types: primary, a more aggressive form seen more commonly in older patients, and secondary, developing from lower-grade astrocytomas and seen more commonly in younger patients. Glioblastoma Multiforme
  • Oligodendroglioma Oligodendroglioma Oligodendrogliomas are malignant CNS tumors arising from neural glial cell precursors. Oligodendrogliomas often arise in the frontal lobes of the brain and have a generally favorable prognosis when compared to other gliomas. Oligodendrogliomas are the 3rd most common CNS tumor. The most frequent presenting symptom is a seizure. Oligodendroglioma
  • Ependymoma Ependymoma Ependymomas are glial cell tumors arising from CSF-producing ependymal cells lining the ventricular system. Ependymomas most commonly occur within the posterior fossa in contact with the 4th ventricle, or within the intramedullary spinal cord. Ependymoma and choroid-plexus tumors
  • Medulloblastomas (embryonal tumors)
Meningeal tumors
  • Meningiomas
  • Hemangioblastomas Hemangioblastomas A benign tumor of the nervous system that may occur sporadically or in association with von Hippel-Lindau disease. It accounts for approximately 2% of intracranial tumors, arising most frequently in the cerebellar hemispheres and vermis. Histologically, the tumors are composed of multiple capillary and sinusoidal channels lined with endothelial cells and clusters of lipid-laden pseudoxanthoma cells. Usually solitary, these tumors can be multiple and may also occur in the brain stem, spinal cord, retina, and supratentorial compartment. Cerebellar hemangioblastomas usually present in the third decade with intracranial hypertension, and ataxia. Von Hippel-Lindau Disease
Sellar region tumors
  • Craniopharyngioma Craniopharyngioma Craniopharyngiomas are rare squamous epithelial tumors with a solid and/or cystic structure that arise from the remnants of Rathke’s pouch along the pituitary stalk, in the suprasellar region. Craniopharyngiomas are histologically benign but tend to invade surrounding structures; thus, they should be treated as low-grade malignancies. Craniopharyngioma
  • Pituitary Pituitary A small, unpaired gland situated in the sella turcica. It is connected to the hypothalamus by a short stalk which is called the infundibulum. Hormones: Overview and Types adenoma
  • Pinealoma/pinealoblastoma
Primary CNS lymphoma Lymphoma A general term for various neoplastic diseases of the lymphoid tissue. Imaging of the Mediastinum Primary CNS lymphoma Lymphoma A general term for various neoplastic diseases of the lymphoid tissue. Imaging of the Mediastinum
Metastasis Metastasis The transfer of a neoplasm from one organ or part of the body to another remote from the primary site. Grading, Staging, and Metastasis to 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 (5x more common than primary 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 tumors) Most commonly arising from:
  • Lung, breast, and renal cell carcinomas
  • Melanoma Melanoma Melanoma is a malignant tumor arising from melanocytes, the melanin-producing cells of the epidermis. These tumors are most common in fair-skinned individuals with a history of excessive sun exposure and sunburns. Melanoma
Peripheral tumors
  • Schwannomas, including acoustic neuroma
  • Neuroblastoma Neuroblastoma Neuroblastoma is a malignancy that arises from the neural crest cell derivatives along the sympathetic chain (neuroblasts) and is most commonly located in the adrenal medulla. The tumor often presents in childhood with a flank mass that crosses the midline. Neuroblastoma

Epidemiology

  • Median age of diagnosis: 53 years
  • Most common tumor Tumor Inflammation of cerebellopontine angle
  • Most commonly unilateral 
  • 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: 11 per 1 million people in the United States 
  • No difference in 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 by gender Gender Gender Dysphoria
  • Higher 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 in Asian Pacific Islanders

Etiology

  • Many cases have no known etiology.
  • Sometimes associated with mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations in long arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy of chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 22:
    • NF2 NF2 Neurofibromatosis type 2 is a neurocutaneous disorder that can arise from mutations in the NF2 gene located in chromosome 22 and may be inherited in an autosomal dominant fashion or occur from de novo mutations. The main clinical features are bilateral vestibular schwannomas, intracranial/spinal meningioma, and intramedullary and extramedullary spinal tumors. Neurofibromatosis Type 2 gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics produces schwannomin Schwannomin A membrane protein homologous to the erm (ezrin-radixin-moesin) family of cytoskeleton-associated proteins which regulate physical properties of membranes. Alterations in neurofibromin 2 are the cause of neurofibromatosis 2. Neurofibromatosis Type 2, or merlin Merlin A membrane protein homologous to the erm (ezrin-radixin-moesin) family of cytoskeleton-associated proteins which regulate physical properties of membranes. Alterations in neurofibromin 2 are the cause of neurofibromatosis 2. Neurofibromatosis Type 2, a tumor Tumor Inflammation suppressor.
    • Inactivated gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics has been found in some acoustic neuromas.
  • Associated with loud noises, head and neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma therapy, and neurofibromatosis type 2 Neurofibromatosis type 2 Neurofibromatosis type 2 is a neurocutaneous disorder that can arise from mutations in the NF2 gene located in chromosome 22 and may be inherited in an autosomal dominant fashion or occur from de novo mutations. The main clinical features are bilateral vestibular schwannomas, intracranial/spinal meningioma, and intramedullary and extramedullary spinal tumors. Neurofibromatosis Type 2

Clinical Presentation

Symptoms of acoustic neuroma are divided into early and late phases.

Early phase

Tumor Tumor Inflammation expansion in the internal auditory meatus exerting pressure on vestibulocochlear nerve Vestibulocochlear nerve The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (cochlear nerve) which is concerned with hearing and a vestibular part (vestibular nerve) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the spiral ganglion and project to the cochlear nuclei (cochlear nucleus). The fibers of the vestibular nerve arise from neurons of scarpa’s ganglion and project to the vestibular nuclei. The 12 Cranial Nerves: Overview and Functions (CN VIII):

  • Vestibular nerve compression Compression Blunt Chest Trauma:
  • Cochlear nerve compression Compression Blunt Chest Trauma:
    • Unilateral sensorineural hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss (most common symptom)
    • Tinnitus Tinnitus A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of cochlear diseases; vestibulocochlear nerve diseases; intracranial hypertension; craniocerebral trauma; and other conditions. Cranial Nerve Palsies

Late phase Late Phase Sepsis in Children

Compression Compression Blunt Chest Trauma of adjacent structures in the cerebellopontine angle:

  • Facial nerve Facial nerve The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and salivary glands, and convey afferent information for taste from the anterior two-thirds of the tongue and for touch from the external ear. The 12 Cranial Nerves: Overview and Functions compression Compression Blunt Chest Trauma:
    • Ipsilateral facial weakness or complete facial paralysis ( Bell’s palsy Bell’s palsy A syndrome characterized by the acute onset of unilateral facial paralysis which progresses over a 2-5 day period. Weakness of the orbicularis oculi muscle and resulting incomplete eye closure may be associated with corneal injury. Pain behind the ear often precedes the onset of paralysis. This condition may be associated with Human Herpesvirus 1 infection of the facial nerve. Cranial Nerve Palsies)
    • May also present with:
      • Xerophthalmia Xerophthalmia Dryness of the eye surfaces caused by deficiency of tears or conjunctival secretions. It may be associated with vitamin A deficiency, trauma, or any condition in which the eyelids do not close completely. Sjögren’s Syndrome
      • Xerostomia Xerostomia Decreased salivary flow. Sjögren’s Syndrome
      • Episodic lacrimation
  • Trigeminal nerve Trigeminal nerve The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the trigeminal ganglion and project to the trigeminal nucleus of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication. The 12 Cranial Nerves: Overview and Functions compression Compression Blunt Chest Trauma:
    • Decreased ipsilateral facial sensation or numbness
    • Ipsilateral facial pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Ipsilateral cerebellar compression Compression Blunt Chest Trauma
    • Ataxia Ataxia Impairment of the ability to perform smoothly coordinated voluntary movements. This condition may affect the limbs, trunk, eyes, pharynx, larynx, and other structures. Ataxia may result from impaired sensory or motor function. Sensory ataxia may result from posterior column injury or peripheral nerve diseases. Motor ataxia may be associated with cerebellar diseases; cerebral cortex diseases; thalamic diseases; basal ganglia diseases; injury to the red nucleus; and other conditions. Ataxia-telangiectasia
    • Dysdiadochokinesia Dysdiadochokinesia Difficulty with rapid alternating movements Cerebellar Disorders (impaired performance of rapid alternating movements)
    • Dysmetria Dysmetria Cerebellar Disorders

Diagnosis

Cranial nerve testing

  • Vestibulocochlear nerve Vestibulocochlear nerve The 8th cranial nerve. The vestibulocochlear nerve has a cochlear part (cochlear nerve) which is concerned with hearing and a vestibular part (vestibular nerve) which mediates the sense of balance and head position. The fibers of the cochlear nerve originate from neurons of the spiral ganglion and project to the cochlear nuclei (cochlear nucleus). The fibers of the vestibular nerve arise from neurons of scarpa’s ganglion and project to the vestibular nuclei. The 12 Cranial Nerves: Overview and Functions: audiometry Audiometry The testing of the acuity of the sense of hearing to determine the thresholds of the loWest intensity levels at which an individual can hear a set of tones. The frequencies between 125 and 8000 hz are used to test air conduction thresholds and the frequencies between 250 and 4000 hz are used to test bone conduction thresholds. Ménière Disease
    • Sensorineural hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss
    • Difficulty perceiving high-frequency sounds
  • Facial nerve Facial nerve The 7th cranial nerve. The facial nerve has two parts, the larger motor root which may be called the facial nerve proper, and the smaller intermediate or sensory root. Together they provide efferent innervation to the muscles of facial expression and to the lacrimal and salivary glands, and convey afferent information for taste from the anterior two-thirds of the tongue and for touch from the external ear. The 12 Cranial Nerves: Overview and Functions:
    • Ipsilateral facial weakness
    • Ipsilateral facial twitching
  • Trigeminal nerve Trigeminal nerve The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the trigeminal ganglion and project to the trigeminal nucleus of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication. The 12 Cranial Nerves: Overview and Functions
    • Ipsilateral decreased facial sensation
    • Ipsilateral decreased corneal reflex

Imaging studies

  • 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 with contrast:
    • Initial imaging test of choice
    • Performed in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with abnormal audiometry Audiometry The testing of the acuity of the sense of hearing to determine the thresholds of the loWest intensity levels at which an individual can hear a set of tones. The frequencies between 125 and 8000 hz are used to test air conduction thresholds and the frequencies between 250 and 4000 hz are used to test bone conduction thresholds. Ménière Disease results and high suspicion for vestibular schwannoma Schwannoma Schwannomas (also known as neurilemmomas) are benign nerve sheath tumors in the peripheral nervous system (PNS), arising from Schwann cells that encase the peripheral nerves. Schwannomas are the most common tumors in the PNS. Schwannoma
    • Findings:
      • Enhanced circular lesion in internal auditory meatus
      • Expansion into the cerebellopontine angle
      • Cystic Cystic Fibrocystic Change and fat degeneration are often seen.
  • CT 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 with contrast:
    • Performed in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship not eligible for MRI (e.g., patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with a pacemaker Pacemaker A device designed to stimulate, by electric impulses, contraction of the heart muscles. It may be temporary (external) or permanent (internal or internal-external). Bradyarrhythmias or metal implant)
    • Findings similar to those of MRI scan

Histopathology

  • Strongly reactive for S100
  • Hypercellular areas with spindle cells (referred to as Antoni A) alternating with hypocellular myxoid stroma (referred to as Antoni B)

Management

Large tumor Tumor Inflammation with severe hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss

  • Surgical excision:
    • Surgery cannot restore hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss but can prevent further loss.
    • Intraoperative monitoring of cranial nerves Cranial nerves There are 12 pairs of cranial nerves (CNs), which run from the brain to various parts of the head, neck, and trunk. The CNs can be sensory or motor or both. The CNs are named and numbered in Roman numerals according to their location, from the front to the back of the brain. The 12 Cranial Nerves: Overview and Functions to reduce risk of nerve injury Nerve Injury Surgical Complications
    • Complications:
      • Tinnitus Tinnitus A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of cochlear diseases; vestibulocochlear nerve diseases; intracranial hypertension; craniocerebral trauma; and other conditions. Cranial Nerve Palsies
      • Hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss
      • Facial paralysis
      • Taste changes
      • Headaches
  • Radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma therapy:
    • Stereotactic radiosurgery, proton beam therapy, or fractionated stereotactic radiotherapy
    • Goal of radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma is to control the tumor Tumor Inflammation, prevent further growth, and sometimes cause a reduction in tumor Tumor Inflammation size.
    • Complications:

Small tumor Tumor Inflammation with minor hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss

Serial monitoring:

  • MRI scan every 6–12 months to track tumor Tumor Inflammation progression
  • Hearing aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS for hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss (about 50% of patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship who are observed for a decade lose functional hearing)

Differential Diagnosis

  • Meningioma Meningioma Meningiomas are slow-growing tumors that arise from the meninges of the brain and spinal cord. The vast majority are benign. These tumors commonly occur in individuals with a history of high doses of skull radiation, head trauma, and neurofibromatosis 2. Meningioma: benign Benign Fibroadenoma tumor Tumor Inflammation arising from the meninges Meninges The brain and the spinal cord are enveloped by 3 overlapping layers of connective tissue called the meninges. The layers are, from the most external layer to the most internal layer, the dura mater, arachnoid mater, and pia mater. Between these layers are 3 potential spaces called the epidural, subdural, and subarachnoid spaces. Meninges: Anatomy 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 or the 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. Risk factors include radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma exposure. Meningioma Meningioma Meningiomas are slow-growing tumors that arise from the meninges of the brain and spinal cord. The vast majority are benign. These tumors commonly occur in individuals with a history of high doses of skull radiation, head trauma, and neurofibromatosis 2. Meningioma presents with headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess, vision Vision Ophthalmic Exam disturbances, and possible seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures. 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 imaging and biopsy Biopsy Removal and pathologic examination of specimens from the living body. Ewing Sarcoma are the main diagnostic tools. Meningioma Meningioma Meningiomas are slow-growing tumors that arise from the meninges of the brain and spinal cord. The vast majority are benign. These tumors commonly occur in individuals with a history of high doses of skull radiation, head trauma, and neurofibromatosis 2. Meningioma is treated with surgical excision or radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma
  • Neurofibromatosis type II: autosomal dominant Autosomal dominant Autosomal inheritance, both dominant and recessive, refers to the transmission of genes from the 22 autosomal chromosomes. Autosomal dominant diseases are expressed when only 1 copy of the dominant allele is inherited. Autosomal Recessive and Autosomal Dominant Inheritance neurocutaneous syndrome caused by NF2 NF2 Neurofibromatosis type 2 is a neurocutaneous disorder that can arise from mutations in the NF2 gene located in chromosome 22 and may be inherited in an autosomal dominant fashion or occur from de novo mutations. The main clinical features are bilateral vestibular schwannomas, intracranial/spinal meningioma, and intramedullary and extramedullary spinal tumors. Neurofibromatosis Type 2 gene mutation Gene Mutation Myotonic Dystrophies on chromosome Chromosome In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. Basic Terms of Genetics 22. NF2 NF2 Neurofibromatosis type 2 is a neurocutaneous disorder that can arise from mutations in the NF2 gene located in chromosome 22 and may be inherited in an autosomal dominant fashion or occur from de novo mutations. The main clinical features are bilateral vestibular schwannomas, intracranial/spinal meningioma, and intramedullary and extramedullary spinal tumors. Neurofibromatosis Type 2 gene Gene A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms. Basic Terms of Genetics codes for the merlin Merlin A membrane protein homologous to the erm (ezrin-radixin-moesin) family of cytoskeleton-associated proteins which regulate physical properties of membranes. Alterations in neurofibromin 2 are the cause of neurofibromatosis 2. Neurofibromatosis Type 2 protein. Symptoms depend on the tumors and their locations. These tumors include bilateral cataracts, bilateral acoustic neuromas, meningiomas, ependymomas, and neurofibromas. Diagnosis is made with genetic patient history, physical examination, imaging, and genetic testing Genetic Testing Detection of a mutation; genotype; karyotype; or specific alleles associated with genetic traits, heritable diseases, or predisposition to a disease, or that may lead to the disease in descendants. It includes prenatal genetic testing. Myotonic Dystrophies. Management includes surgical excision or radiation Radiation Emission or propagation of acoustic waves (sound), electromagnetic energy waves (such as light; radio waves; gamma rays; or x-rays), or a stream of subatomic particles (such as electrons; neutrons; protons; or alpha particles). Osteosarcoma for the tumors and hearing aids AIDS Chronic HIV infection and depletion of CD4 cells eventually results in acquired immunodeficiency syndrome (AIDS), which can be diagnosed by the presence of certain opportunistic diseases called AIDS-defining conditions. These conditions include a wide spectrum of bacterial, viral, fungal, and parasitic infections as well as several malignancies and generalized conditions. HIV Infection and AIDS for any functional hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss.
  • Meniere’s disease: typically, a unilateral inner ear Inner ear The essential part of the hearing organ consists of two labyrinthine compartments: the bony labyrinthine and the membranous labyrinth. Ear: Anatomy disorder causing a periodic sensation of spinning, tinnitus Tinnitus A nonspecific symptom of hearing disorder characterized by the sensation of buzzing, ringing, clicking, pulsations, and other noises in the ear. Objective tinnitus refers to noises generated from within the ear or adjacent structures that can be heard by other individuals. The term subjective tinnitus is used when the sound is audible only to the affected individual. Tinnitus may occur as a manifestation of cochlear diseases; vestibulocochlear nerve diseases; intracranial hypertension; craniocerebral trauma; and other conditions. Cranial Nerve Palsies, and fullness in the ear. Symptoms seem to be caused by fluid accumulation in the inner ear Inner ear The essential part of the hearing organ consists of two labyrinthine compartments: the bony labyrinthine and the membranous labyrinth. Ear: Anatomy’s labyrinth. The disease is considered progressive and may cause hearing loss Hearing loss Hearing loss, also known as hearing impairment, is any degree of impairment in the ability to apprehend sound as determined by audiometry to be below normal hearing thresholds. Clinical presentation may occur at birth or as a gradual loss of hearing with age, including a short-term or sudden loss at any point. Hearing Loss. Diagnosis is based on clinical symptoms and hearing examination. Treatment is with antiemetics Antiemetics Antiemetics are medications used to treat and/or prevent nausea and vomiting. These drugs act on different target receptors. The main classes include benzodiazepines, corticosteroids, atypical antipsychotics, cannabinoids, and antagonists of the following receptors: serotonin, dopamine, and muscarinic and neurokinin receptors. Antiemetics and anxiolytics (acute episodes) and includes physical therapy Physical Therapy Becker Muscular Dystrophy, dietary changes (low-salt diet), and counselling (chronic management). Unlike acoustic neuroma, there is no mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast seen on imaging in Meniere’s disease.

References

  1. Park, J.K., Vernick, D.M. (2020). Vestibular schwannoma (acoustic neuroma). UpToDate. Retrieved May 23, 2021, from https://www.uptodate.com/contents/vestibular-schwannoma-acoustic-neuroma
  2. Martin, K.A. (n.d.). Patient education: Vestibular schwannoma (acoustic neuroma). UpToDate. Retrieved May 23, 2021, from https://www.uptodate.com/contents/vestibular-schwannoma-acoustic-neuroma-the-basics
  3. Kutz, J.W. (2020). Acoustic neuroma. Medscape. Retrieved May 23, 2021, from https://emedicine.medscape.com/article/882876-overview

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