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Diseases » Myopia » Causes
 

Causes of Myopia

Contents
  1. Myopia: Introduction
  2. Drugs/substances (4 causes)
  3. Excerpts from book chapters
  4. Complication causes
  5. Causes of symptoms
  6. News
  7. Related cause information

Causes of Myopia (Diseases Database):

The follow list shows some of the possible medical causes of Myopia that are listed by the Diseases Database:

Source: Diseases Database

Myopia Causes: Book Excerpts

Myopia as a complication of other conditions:

Other conditions that might have Myopia as a complication may, potentially, be an underlying cause of Myopia. Our database lists the following as having Myopia as a complication of that condition:

Myopia as a symptom:

Conditions listing Myopia as a symptom may also be potential underlying causes of Myopia. Our database lists the following as having Myopia as a symptom of that condition:

Medications or substances causing Myopia:

The following drugs, medications, substances or toxins are some of the possible causes of Myopia as a symptom. This list is incomplete and various other drugs or substances may cause your symptoms. Always advise your doctor of any medications or treatments you are using, including prescription, over-the-counter, supplements, herbal or alternative treatments.

Read more about medication causes of Myopia


Medical news summaries relating to Myopia:

The following medical news items are relevant to causes of Myopia:

Related information on causes of Myopia:

As with all medical conditions, there may be many causal factors. Further relevant information on causes of Myopia may be found in:

Causes of Myopia: Online Medical Books

16 MEDICAL BOOKS ONLINE! Review excerpts from medical books online, free, without registration, for more information about the causes of Myopia.

Vision Loss: Differential Diagnosis
(In a Page: Signs and Symptoms)

Transient vision loss (<24 hours)

  • Papilledema: Lasts seconds, bilateral
  • Amaurosis fugax: Lasts minutes, unilateral
  • Vertebrobasilar artery insufficiency: Lasts minutes, bilateral
  • Migraine: Lasts 10–60 minutes
  • Impending central retinal vein occlusion
  • Ocular ischemic syndrome (carotid occlusive disease)
  • Sudden change in blood pressure; orthostatic hypotension
    • Transient acute increase in intraocular pressure (e.g., acute angle closure glaucoma, retro- or peribulbar hemorrhage)

    Vision loss >24 hours: Sudden, painless
  • Retinal artery or vein occlusion
  • Ischemic optic neuropathy (must rule out giant cell/temporal arteritis to prevent permanent bilateral vision loss)
  • Vitreous or aqueous hemorrhage (hyphema)
  • Retinal detachment
  • Other retinal or CNS disease (e.g., cortical blindness due to occipital lobe CVA)
  • Exposure (“Welder's flash”) or prolonged exposure to intense sunlight

Vision loss >24 hours: Gradual, painless
  • Cataract
  • Refractive error
  • Open angle glaucoma
  • Chronic retinopathy (e.g., age-related macular degeneration, diabetic retinopathy)
  • Chronic corneal disease (e.g., corneal dystrophy)
  • Optic neuropathy/atrophy (e.g., compressive lesion, toxic-metabolic cause, dominant optic neuropathy, radiation)
  • Retinitis pigmentosa
  • Pseudotumor cerebri

    • Vision loss >24 hours: Painful
  • Acute angle closure glaucoma
  • Optic neuritis (pain with extraocular motion)
  • Orbital apex/superior orbital fissure/ cavernous sinus syndrome
  • Uveitis
  • Corneal hydrops (keratoconus)
    • Ocular onchocerciasis (“river blindness”)
      –Common cause of blindness in developing nations due to Onchocerca volvulus worm
    • Corneal abrasion or ulcer
    • Herpes simplex or zoster infection
    '>

    » READ BOOK EXCERPT ONLINE »

    Source: In a Page: Signs and Symptoms, 2004

    Vision Loss: Differential Diagnosis
    (In A Page: Pediatric Signs and Symptoms)

    • Vascular causes
      –Amaurosis fugax: TIA of the retina lasting 5–60 minutes
      –Stroke causes loss of side vision usually to the left or right, may be interpreted as loss of vision in the right or left eye
      –Retinal vascular occlusion: Venous shows gradual decline with retinal hemorrhaging; arterial has sudden onset with minimal to no retinal hemorrhaging
      • Transient monocular blindness (TMB)
        –Lasts seconds
        –Due to positional changes in optic disc edema with increased intracranial hypertension, orthostatic hypotension, thyroid eye disease, and space-occupying lesions
    • Migraine variants are transient and may be associated with headache after presentation
    • Optic nerve edema or swelling from demyelinating disease, nonarteritic and arteritic optic neuropathy, toxicity (e.g., lead, chloramphenicol)
    • Optic atrophy
      • Retinal etiologies
        –Retinal surface wrinkling disorders
        –Idiopathic central serous retinopathy often associated with stress
        –Retinal detachment with probable history of floaters before loss of vision
    • Angle closure glaucoma
      • Postsurgical
        –Endophthalmitis: Often associated with ocular surgery and red eye
        –Cystoid macular edema may occur after ocular surgery
    • Vitreous hemorrhage
      –You will not be able to see into the eye
      • Infectious causes
        –Retinitis and/or uveitis due to toxoplasmosis, cytomegalovirus, Lyme, histoplasmosis
    • Trauma
    • Hysterical blindness
    • Cataracts
    • Hypoglycemia
    • Retinitis pigmentosa

    » READ BOOK EXCERPT ONLINE »

    Source: In A Page: Pediatric Signs and Symptoms, 2007

    Short Stature: Differential Diagnosis
    (In A Page: Pediatric Signs and Symptoms)

    • Familial short stature
    • Constitutional delay of growth and puberty
    • Hypothyroidism
    • Growth hormone deficiency (GHD)
    • GH resistance (Laron syndrome)
    • Congenital hypopituitarism
      –Secondary to brain tumors
      • Acquired hypopituitarism
        –After irradiation, surgery, and chemotherapy for neoplasms
        –Infectious
        –Infiltrative
        –Vascular
    • Cushing syndrome
    • Precocious puberty
      –Tall initially
      –Final height compromised
    • Pseudohypoparathyroidism
    • Rickets
    • Genetic syndromes
      –Turner syndrome
      –Down syndrome
      –Noonan syndrome
      –Prader-Willi syndrome
    • Intrauterine growth retardation
      –Silver-Russell syndrome
    • Disorders of bone development
      –Achondroplasia/hypochondroplasia
      –Chondrodystrophies
    • Psychosocial deprivation
    • Malnutrition
    • Chronic drug intake
      –Glucocorticoids
      –Methylphenidate
    • Infectious
      –HIV
      –Tuberculosis
    • Congenital heart disease
    • Gastrointestinal
      –Celiac disease
      –Inflammatory bowel disease
      –Chronic liver disease
    • Pulmonary
      –Cystic fibrosis
    • Chronic renal disease
      –RTA
      –Renal failure
    • Skeletal disorders

    » READ BOOK EXCERPT ONLINE »

    Source: In A Page: Pediatric Signs and Symptoms, 2007

    Scotoma: Medical causes
    (Handbook of Signs & Symptoms (Third Edition))

    Chorioretinitis

    Inflammation of the choroid and retina produces a paracentral scotoma. Ophthalmoscopic examination reveals clouding and cells in the vitreous, subretinal hemorrhage, and neovascularization. The patient may have photophobia along with blurred vision.

    Macular degeneration

    Any degenerative process or disorder affecting the fovea centralis results in a central scotoma. Ophthalmoscopic examination reveals changes in the macular area. The patient may notice subtle changes in visual acuity, in color perception, and in the size and shape of objects.

    Optic neuritis

    Inflammation, degeneration, or demyelination of the optic nerve produces a central, circular, or centrocecal scotoma. The scotoma may be unilateral with involvement of one nerve, or bilateral with involvement of both nerves. It can vary in size, density, and symmetry. The patient may report severe vision loss or blurring, lasting up to 3 weeks, and pain — especially with eye movement. Common ophthalmoscopic findings include hyperemia of the optic disk, retinal vein distention, blurred disk margins, and filling of the physiologic cup.

    Retinal pigmentary degeneration

    Retinal pigmentary degeneration causes premature retinal cell changes leading to cell death. One disorder, retinitis pigmentosa, initially involves loss of peripheral rods; the resulting annular scotoma progresses concentrically until only a central field of vision (tunnel vision) remains. The earliest symptom —  impaired night vision —  appears during adolescence. Associated signs include narrowing of the retinal blood vessels and pallor of the optic disk. Eventually, with invasion of the macula, blindness may occur.

    » READ BOOK EXCERPT ONLINE »

    Source: Handbook of Signs & Symptoms (Third Edition), 2006

    Vision loss: Medical causes
    (Handbook of Signs & Symptoms (Third Edition))

    Amaurosis fugax

    With amaurosis fugax, recurrent attacks of unilateral vision loss may last from a few seconds to a few minutes. Vision is normal at other times. Transient unilateral weakness, hypertension, and elevated intraocular pressure (IOP) in the affected eye may also occur.

    Cataract

    Typically, painless and gradual visual blurring precedes vision loss. As the cataract progresses, the pupil turns milky white.

    Concussion

    Immediately or shortly after blunt head trauma, vision may be blurred, double, or lost. Generally, vision loss is temporary. Other findings include headache, anterograde and retrograde amnesia, transient loss of consciousness, nausea, vomiting, dizziness, irritability, confusion, lethargy, and aphasia.

    Diabetic retinopathy

    Retinal edema and hemorrhage lead to visual blurring, which may progress to blindness.

    Endophthalmitis

    Typically, endophthalmitis — an intraocular inflammation — follows penetrating trauma, I.V. drug use, or intraocular surgery, causing possibly permanent unilateral vision loss; a sympathetic inflammation may affect the other eye.

    Glaucoma

    Glaucoma produces gradual visual blurring that may progress to total blindness. Acute angle-closure glaucoma is an ocular emergency that may produce blindness within 3 to 5 days. Findings are rapid onset of unilateral inflammation and pain, pressure over the eye, moderate pupil dilation, nonreactive pupillary response, a cloudy cornea, reduced visual acuity, photophobia, and perception of blue or red halos around lights. Nausea and vomiting may also occur.

    Chronic angle-closure glaucoma has a gradual onset and usually produces no symptoms, although blurred or halo vision may occur. If untreated, it progresses to blindness and extreme pain.

    Chronic open-angle glaucoma is usually bilateral, with an insidious onset and a slowly progressive course. It causes peripheral vision loss, aching eyes, halo vision, and reduced visual acuity (especially at night).

    Ocular trauma

    Following eye injury, sudden unilateral or bilateral vision loss may occur. Vision loss may be total or partial and permanent or temporary. The eyelids may be reddened, edematous, and lacerated; intraocular contents may be extruded.

    Optic atrophy

    Degeneration of the optic nerve, optic atrophy can develop spontaneously or follow inflammation or edema of the nerve head, causing irreversible loss of the visual field with changes in color vision. Pupillary reactions are sluggish, and optic disk pallor is evident.

    Optic neuritis

    An umbrella term for inflammation, degeneration, or demyelinization of the optic nerve, optic neuritis usually produces temporary but severe unilateral vision loss. Pain around the eye occurs, especially with movement of the globe. This may occur with visual field defects and a sluggish pupillary response to light. Ophthalmoscopic examination commonly reveals hyperemia of the optic disk, blurred disk margins, and filling of the physiologic cup.

    Paget’s disease

    Bilateral vision loss may develop as a result of bony impingements on the cranial nerves. This occurs with hearing loss, tinnitus, vertigo, and severe, persistent bone pain. Cranial enlargement may be noticeable frontally and occipitally, and headaches may occur. Sites of bone involvement are warm and tender, and impaired mobility and pathologic fractures are common.

    Pituitary tumor

    As a pituitary adenoma grows, blurred vision progresses to hemianopia and, possibly, unilateral blindness. Double vision, nystagmus, ptosis, limited eye movement, and headaches may also occur.

    Retinal artery occlusion (central)

    Retinal artery occlusion is a painless ocular emergency that causes sudden unilateral vision loss, which may be partial or complete. Pupil examination reveals a sluggish direct pupillary response and a normal consensual response. Permanent blindness may occur within hours.

    Retinal detachment

    Depending on the degree and location of detachment, painless vision loss may be gradual or sudden and total or partial. Macular involvement causes total blindness.

    With partial vision loss, the patient may describe visual field defects or a shadow or curtain over the visual field as well as visual floaters.

    Retinal vein occlusion

    Most common in geriatric patients, retinal vein occlusion — a painless disorder — causes a unilateral decrease in visual acuity with variable vision loss. IOP may be elevated in both eyes.

    Rift Valley fever

    Rift Valley fever is a viral disease that causes inflammation of the retina and may result in some permanent vision loss. Typical signs and symptoms include fever, myalgia, weakness, dizziness, and back pain. A small percentage of patients may develop encephalitis or may progress to hemorrhagic fever that can lead to shock and hemorrhage.

    Senile macular degeneration

    Occurring in elderly patients, senile macular degeneration causes painless blurring or loss of central vision. Vision loss may proceed slowly or rapidly, eventually affecting both eyes. Visual acuity may be worse at night.

    Stevens-Johnson syndrome

    Corneal scarring from associated conjunctival lesions produces marked vision loss. Purulent conjunctivitis, eye pain, and difficulty opening the eyes occur. Additional findings include widespread bullae, fever, malaise, cough, drooling, inability to eat, sore throat, chest pain, vomiting, diarrhea, myalgias, arthralgias, hematuria, and signs of renal failure.

    Temporal arteritis

    Vision loss and visual blurring with a throbbing, unilateral headache characterize this disorder. Other findings include malaise, anorexia, weight loss, weakness, low-grade fever, generalized muscle aches, and confusion.

    Vitreous hemorrhage

    With vitreous hemorrhage, sudden unilateral vision loss may result from intraocular trauma, ocular tumors, or systemic disease (especially diabetes, hypertension, sickle cell anemia, or leukemia). Visual floaters and partial vision with a reddish haze may occur. The patient’s vision loss may be permanent.

    Other causes

    Drugs

    Chloroquine therapy may cause patchy retinal pigmentation that typically leads to blindness. Phenylbutazone may cause vision loss and increased susceptibility to retinal detachment. Digoxin, indomethacin, ethambutol, quinine sulfate, and methanol toxicity may also cause vision loss.

    » READ BOOK EXCERPT ONLINE »

    Source: Handbook of Signs & Symptoms (Third Edition), 2006

    Near drowning: Causes and incidence
    (Professional Guide to Diseases (Eighth Edition))

    Near drowning results from an inability to swim or, in swimmers, from panic, a boating accident, a heart attack or blow to the head while in the water, a fall through ice, heavy drinking prior to swimming, or a suicide attempt. Children can also suffer near drowning from swimming accidents, bathing, or falling into a container of water such as a bucket or a body of water such as a pond.

    Regardless of the tonicity of the fluid aspirated, hypoxemia is the most serious consequence of near drowning, followed by metabolic acidosis. Other consequences depend on the kind of water aspirated. If the water is contaminated, such as water from a stagnant pool or contaminated stream, bacteria, fungus, or algae may be aspirated as well, causing infection or sepsis. After fresh water aspiration, changes in lung surfactant character result in exudation of protein-rich plasma into the alveoli. This, plus increased capillary permeability, leads to pulmonary edema and hypoxemia.

    After saltwater aspiration, the hypertonicity of seawater exerts an osmotic force, which pulls fluid from pulmonary capillaries into the alveoli. The resulting intrapulmonary shunt causes hypoxemia. Also, the pulmonary capillary membrane may be injured and induce pulmonary edema. In both kinds of near drowning, pulmonary edema and hypoxemia occur secondary to aspiration.

    In the United States, drowning claims nearly 6,500 lives annually. No statistics are available for near-drowning incidents.

    » READ BOOK EXCERPT ONLINE »

    Source: Professional Guide to Diseases (Eighth Edition), 2005

    Scotoma: Medical causes
    (Professional Guide to Signs & Symptoms (Fifth Edition))

    Chorioretinitis

    Inflammation of the choroid and retina produces a paracentral scotoma. Ophthalmoscopic examination reveals clouding and cells in the vitreous, subretinal hemorrhage, and neovascularization. The patient may have photophobia along with blurred vision.

    Glaucoma

    Prolonged elevation of IOP can cause an arcuate scotoma. Poorly controlled glaucoma can also cause cupping of the optic disk, loss of peripheral vision, and reduced visual acuity. The patient may also see rainbow-colored halos around lights.

    Macular degeneration

    Any degenerative process or disorder affecting the fovea centralis results in a central scotoma. Ophthalmoscopic examination reveals changes in the macular area. The patient may notice subtle changes in visual acuity, in color perception, and in the size and shape of objects.

    Migraine headache

    Transient scintillating scotomas, usually bilateral and often homonymous, can occur during a classic migraine aura. Besides pain, characteristic associated symptoms include paresthesia of the lips, face, or hands; slight confusion; dizziness; and photophobia.

    Optic neuritis

    Inflammation, degeneration, or demyelination of the optic nerve produces a central, circular, or centrocecal scotoma. The scotoma may be unilateral with involvement of one nerve, or bilateral with involvement of both nerves. It can vary in size, density, and symmetry. The patient may report severe visual loss or blurring, lasting up to 3 weeks, and pain—especially with eye movement. Common ophthalmoscopic findings include hyperemia of the optic disk, retinal vein distention, blurred disk margins, and filling of the physiologic cup.

    Retinal pigmentary degenerations

    These disorders cause premature retinal cell changes leading to cell death. One disorder, retinitis pigmentosa, initially involves loss of peripheral rods; the resulting annular scotoma progresses concentrically until only a central field of vision (tunnel vision) remains. The earliest symptom—impaired night vision—appears during adolescence. Associated signs include narrowing of the retinal blood vessels and pallor of the optic disk. Eventually, with invasion of the macula, blindness may occur.

    » READ BOOK EXCERPT ONLINE »

    Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006

    Vision loss: Medical causes
    (Professional Guide to Signs & Symptoms (Fifth Edition))

    Amaurosis fugax

    In this disorder, recurrent attacks of unilateral vision loss may last from a few seconds to a few minutes. Vision is normal at other times. Other findings may include transient unilateral weakness, hypertension, and elevated intraocular pressure (IOP) in the affected eye.

    Cataract

    Typically, painless and gradual visual blurring precedes vision loss. As the cataract progresses, the pupil turns milky white.

    Concussion

    Immediately or shortly after blunt head trauma, the patient may develop blurred, double, or lost vision. Vision loss is usually temporary. Other findings include headache, anterograde and retrograde amnesia, transient loss of consciousness, nausea, vomiting, dizziness, irritability, confusion, lethargy, and aphasia.

    Corneal dystrophies, hereditary

    Some corneal dystrophies cause vision loss with associated pain, photophobia, tearing, and corneal opacities.

    Diabetic retinopathy

    Retinal edema and hemorrhage lead to visual blurring, which may progress to blindness.

    Endophthalmitis

    Typically, this intraocular inflammation follows penetrating trauma, I.V. drug use, or intraocular surgery, causing unilateral vision loss that may be permanent; a sympathetic inflammation may affect the other eye.

    Glaucoma

    This disorder produces gradual visual blurring that may progress to total blindness. Acute angle-closure glaucoma is an ocular emergency that may produce blindness within 3 to 5 days. It’s characterized by rapid onset of unilateral inflammation and pain, pressure over the eye, moderate pupil dilation, nonreactive pupillary response, a cloudy cornea, reduced visual acuity, photophobia, and perception of blue or red halos around lights. Nausea and vomiting may also occur.

    Chronic angle-closure glaucoma has a gradual onset and usually produces no symptoms, although blurred or halo vision may occur. If untreated, it progresses to blindness and extreme pain.

    Chronic open-angle glaucoma usually has an insidious onset, progresses slowly, and affects both eyes. It causes peripheral vision loss, aching eyes, halo vision, and reduced visual acuity (especially at night).

    Herpes zoster

    When this disorder affects the nasociliary nerve, bilateral vision loss is accompanied by eyelid lesions, conjunctivitis, skin lesions (usually on the nose), and ocular muscle palsies.

    Hyphema

    Blood in the anterior chamber can reduce vision to light perception only. Most hyphemas are the direct result of blunt trauma to the normal eye.

    Keratitis

    This inflammation of the cornea may lead to complete unilateral vision loss. Other findings include an opaque cornea, increased tearing, irritation, and photophobia.

    Ocular trauma

    Sudden unilateral or bilateral vision loss may occur after an eye injury. Vision loss may be total or partial and permanent or temporary. The eyelids may be reddened, edematous, and lacerated; intraocular contents may be extruded.

    Optic atrophy

    Degeneration of the optic nerve, optic atrophy can develop spontaneously or follow inflammation or edema of the nerve head, causing irreversible loss of the visual field with changes in color vision. Pupillary reactions are sluggish, and optic disk pallor is evident.

    Optic neuritis

    An umbrella term for inflammation, degeneration, or demyelinization of the optic nerve, optic neuritis usually produces temporary but severe unilateral vision loss, pain around the eye (especially with movement of the globe), a sluggish pupillary response to light and, possibly, visual field defects. Ophthalmoscopic examination commonly reveals hyperemia of the optic disk, blurred disk margins, and filling of the physiologic cup.

    Paget’s disease

    In this disorder, bony impingements on the cranial nerves may cause bilateral vision loss, which may be accompanied by hearing loss, tinnitus, vertigo, and severe, persistent bone pain. Cranial enlargement may be noticeable frontally and occipitally, and headaches may occur. Sites of bone involvement are warm and tender, and impaired mobility and pathologic fractures are common.

    Papilledema

    Papilledema is characterized by swelling of both optic disks from increased intracranial pressure. Acute papilledema may lead to momentary blurring or transiently obscured vision, whereas chronic papilledema may lead to vision loss.

    Pituitary tumor

    As a pituitary adenoma grows, blurred vision progresses to hemianopia and, possibly, unilateral blindness. Double vision, nystagmus, ptosis, limited eye movement, and headaches may also occur.

    Retinal artery occlusion (central)

    This painless ocular emergency causes sudden unilateral vision loss, which may be partial or complete. Pupil examination reveals a sluggish direct pupillary response and a normal consensual response. Permanent blindness may occur within hours.

    Retinal detachment

    Depending on the degree and location of detachment, painless vision loss may be gradual or sudden and total or partial. Macular involvement causes total blindness. Other effects include visual floaters, light flashes, and a sensation of a shadow or curtain over the visual field.

    Retinal Vein Occlusion

    Most common in geriatric patients, this painless disorder causes a unilateral decrease in visual acuity with variable vision loss. IOP may be elevated in both eyes.

    Rift Valley fever

    Inflammation of the retina is a complication of this viral disease that may result in some degree of permanent vision loss. Typical signs and symptoms include fever, myalgia, weakness, dizziness, and back pain. A small percentage of patients may develop encephalitis or hemorrhagic fever that can lead to shock and hemorrhage.

    Senile macular degeneration

    Occurring in elderly patients, this disorder causes painless blurring or loss of central vision. Vision loss may proceed slowly or rapidly, eventually affecting both eyes. Visual acuity may be worse at night.

    Stevens-Johnson syndrome

    Corneal scarring from associated conjunctival lesions produces marked vision loss, which may be accompanied by purulent conjunctivitis, eye pain, and difficulty opening the eyes. Additional findings include widespread bullae, fever, malaise, cough, drooling, inability to eat, sore throat, chest pain, vomiting, diarrhea, myalgia, arthralgia, hematuria, and signs of renal failure.

    Temporal arteritis

    Vision loss and visual blurring with a throbbing, unilateral headache characterize this disorder. Other findings include malaise, anorexia, weight loss, weakness, low-grade fever, generalized muscle aches, and confusion.

    Trachoma

    This rare disorder may initially produce varying degrees of vision loss and a mild infection resembling bacterial conjunctivitis. Conjunctival follicles, red and edematous eyelids, pain, photophobia, tearing, and exudation also occur. After about 1 month, conjunctival follicles enlarge into inflamed yellow or gray papillae.

    Uveitis

    Inflammation of the uveal tract may result in unilateral vision loss. Anterior uveitis produces moderate to severe eye pain, severe conjunctival injection, photophobia, and a small, nonreactive pupil. Posterior uveitis may produce insidious onset of blurred vision, conjunctival injection, visual floaters, pain, and photophobia. Associated posterior scar formation distorts the shape of the pupil.

    Vitreous hemorrhage

    This condition, which may result from intraocular trauma, ocular tumors, or systemic disease (especially diabetes, hypertension, sickle cell anemia, or leukemia), can cause sudden unilateral vision loss, visual floaters, and a reddish haze. The vision loss may be permanent.

    Other causes

    Drugs

    Chloroquine therapy may cause patchy retinal pigmentation that typically leads to blindness. Digoxin derivatives, indomethacin, ethambutol, quinine sulfate, and methanol toxicity may also cause vision loss.

    » READ BOOK EXCERPT ONLINE »

    Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006

    Near drowning: Causes
    (Handbook of Diseases)

    Near drowning results from an inability to swim or, in swimmers, from panic, a boating accident, a heart attack or a blow to the head while in the water, drinking heavily before swimming, or a suicide attempt.

    Results of aspiration

    Regardless of the tonicity of the fluid aspirated, hypoxemia is the most serious consequence of near drowning, followed by metabolic acidosis. Other consequences depend on the kind of water aspirated.

    After freshwater aspiration, changes in the character of lung surfactant result in exudation of protein-rich plasma into the alveoli. This, plus increased capillary permeability, leads to pulmonary edema and hypoxemia.

    After saltwater aspiration, the hypertonicity of sea water exerts an osmotic force, which pulls fluid from pulmonary capillaries into the alveoli. The resulting intrapulmonary shunt causes hypoxemia. Also, the pulmonary capillary membrane may be injured and induce pulmonary edema. In both kinds of near drowning, pulmonary edema and hypoxemia occur secondary to aspiration.

    » READ BOOK EXCERPT ONLINE »

    Source: Handbook of Diseases, 2003

    Vision loss: Medical causes
    (Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series)

    Amaurosis fugax

    With this amaurosis fugax, recurrent attacks of unilateral vision loss may last from a few seconds to a few minutes. Vision is normal at other times. Transient unilateral weakness, hypertension, and elevated IOP in the affected eye may also occur.

    Cataract

    Typically, painless and gradual blurred vision precedes vision loss. As the cataract progresses, the pupil turns milky white.

    Concussion

    Immediately or shortly after blunt head trauma, vision may be blurred, double, or lost. Generally, vision loss is temporary. Other findings include headache, anterograde and retrograde amnesia, transient loss of consciousness, nausea, vomiting, dizziness, irritability, confusion, lethargy, and aphasia.

    Diabetic retinopathy

    Retinal edema and hemorrhage lead to blurred vision, which may progress to blindness.

    Endophthalmitis

    Typically, endophthalmitis, an intraocular inflammation, follows penetrating trauma, I.V. drug use, or intraocular surgery, causing possibly permanent unilateral vision loss; a sympathetic inflammation may affect the other eye.

    Glaucoma

    Glaucoma produces gradual blurred vision that may progress to total blindness. Findings are the rapid onset of unilateral inflammation and pain, pressure over the eye, moderate pupil dilation, nonreactive pupillary response, a cloudy cornea, reduced visual acuity, photophobia, and perception of blue or red halos around lights. Nausea and vomiting may also occur.


    ALERT: Acute angle-closure glaucoma is an ocular emergency that may produce blindness within 3 to 5 days.

    Chronic angle-closure glaucoma has a gradual onset and usually produces no symptoms, although blurred or halo vision may occur. If untreated, it progresses to blindness and extreme pain.

    Chronic open-angle glaucoma is usually bilateral, with an insidious onset and a slowly progressive course. It causes peripheral vision loss, aching eyes, halo vision, and reduced visual acuity (especially at night).

    Hereditary corneal dystrophies

    Some dystrophies cause vision loss with associated pain, photophobia, tearing, and corneal opacities.

    Herpes zoster

    When herpes zoster affects the nasociliary nerve, bilateral vision loss is accompanied by eyelid lesions, conjunctivitis, skin lesions that usually appear on the nose, and ocular muscle palsies.

    Hyphema

    Blood in the anterior chamber can reduce vision to light perception only. Most hyphemas are the direct result of blunt trauma to the normal eye.

    Keratitis

    An inflammation of the cornea, keratitis may lead to complete unilateral vision loss. Other findings include an opaque cornea, increased tearing, irritation, and photophobia.

    Ocular trauma

    Following eye injury, sudden unilateral or bilateral vision loss may occur. Vision loss may be total or partial and permanent or temporary. The eyelids may be reddened, edematous, and lacerated; intraocular contents may be extruded.

    Optic atrophy

    Degeneration of the optic nerve, optic atrophy can develop spontaneously or follow inflammation or edema of the nerve head, causing irreversible loss of the visual field with changes in color vision. Pupillary reactions are sluggish, and optic disk pallor is evident.

    Optic neuritis

    An umbrella term for inflammation, degeneration, or demyelinization of the optic nerve, optic neuritis usually produces temporary but severe unilateral vision loss. Pain around the eye occurs, especially with movement of the globe. This may occur with visual field deficits and a sluggish pupillary response to light. Ophthalmoscopic examination commonly reveals hyperemia of the optic disk, blurred disk margins, and filling of the physiologic cup.

    Paget’s disease

    Bilateral vision loss may develop as a result of bony impingements on the cranial nerves. This occurs with hearing loss, tinnitus, vertigo, and severe, persistent bone pain. Cranial enlargement may be noticeable frontally and occipitally, and headaches may occur. Sites of bone involvement are warm and tender, and impaired mobility and pathologic fractures are common.

    Papilledema

    Papilledema is characterized by swelling of the optic disk from increased intracranial pressure; both optic disks are affected. Acute papilledema may lead to momentary blurring or transiently obscured vision, whereas chimeric papilledema may lead to vision loss.

    Pituitary tumor

    As a pituitary adenoma grows, blurred vision progresses to hemianopia and, possibly, unilateral blindness. Double vision, nystagmus, ptosis, limited eye movement, and headaches may also occur.

    Retinal artery occlusion (central)

    A painless ocular emergency, retinal artery occlusion causes sudden unilateral vision loss, which may be partial or complete. Pupil examination reveals a sluggish direct pupillary response and a normal consensual response. Permanent blindness may occur within hours.

    Retinal detachment

    Depending on the degree and location of detachment, painless vision loss may be gradual or sudden and total or partial. Macular involvement causes total blindness.

    With partial vision loss, the patient may describe visual field deficits or a shadow or curtain over the visual field as well as visual floaters.

    Retinal vein occlusion (central)

    Most common in elderly patients, retinal vein occlusion is a painless disorder that causes a unilateral decrease in visual acuity with variable vision loss. IOP may be elevated in both eyes.

    Rift Valley fever

    A viral disease, Rift Valley fever causes inflammation of the retina and may result in some permanent vision loss. Typical signs and symptoms include fever, myalgia, weakness, dizziness, and back pain. A small percentage of patients may develop encephalitis or may progress to hemorrhagic fever that can lead to shock and hemorrhage.

    Senile macular degeneration

    Occurring in elderly patients, senile macular degeneration causes painless blurring or loss of central vision. Vision loss may proceed slowly or rapidly, eventually affecting both eyes. Visual acuity may be worse at night.

    Stevens-Johnson syndrome

    Corneal scarring from associated conjunctival lesions produces marked vision loss. Purulent conjunctivitis, eye pain, and difficulty opening the eyes occur. Additional findings include widespread bullae, fever, malaise, cough, drooling, an inability to eat, sore throat, chest pain, vomiting, diarrhea, myalgia, arthralgia, hematuria, and signs of renal failure.

    Temporal arteritis

    Vision loss and visual blurring with a throbbing, unilateral headache characterize temporal arteritis. Other findings include malaise, anorexia, weight loss, weakness, low-grade fever, generalized muscle aches, and confusion.

    Trachoma

    A rare disorder, trachoma may initially produce varying vision loss and a mild infection resembling bacterial conjunctivitis. Conjunctival follicles, red and edematous eyelids, pain, photophobia, tearing, and exudation also occur. After about 1 month, conjunctival follicles enlarge into inflamed yellow or gray papillae.

    Uveitis

    Inflammation of the uveal tract may result in unilateral vision loss. Anterior uveitis produces moderate to severe eye pain, severe conjunctival injection, photophobia, and a small, nonreactive pupil. Posterior uveitis may produce an insidious onset of blurred vision, conjunctival injection, visual floaters, pain, and photophobia. Associated posterior scar formation distorts the shape of the pupil.

    Vitreous hemorrhage

    With vitreous hemorrhage, sudden unilateral vision loss may result from intraocular trauma, ocular tumors, or systemic disease (especially diabetes, hypertension, sickle cell anemia, or leukemia). Visual floaters and partial vision with a reddish haze may occur. The vision loss may be permanent.

    Other causes

    Drugs

    Chloroquine therapy may cause patchy retinal pigmentation that typically leads to blindness. Phenylbutazone may cause vision loss and increased susceptibility to retinal detachment. Digoxin, indomethacin, ethambutol, quinine sulfate, and methanol toxicity may also cause visual disturbances and possibly vision loss.

    » READ BOOK EXCERPT ONLINE »

    Source: Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series, 2007

    Scotoma: Medical causes
    (Signs & Symptoms: A 2-in-1 Reference for Nurses)

    Chorioretinitis

    Chorioretinitis, inflammation of the choroid and retina, produces a paracentral scotoma. Ophthalmoscopic examination reveals clouding and cells in the vitreous, subretinal hemorrhage, and neovascularization. The patient may have photophobia along with blurred vision.

    Glaucoma

    With glaucoma, prolonged elevation of IOP can cause an arcuate scotoma. Poorly controlled glaucoma can also cause cupping of the optic disk, loss of peripheral vision, and reduced visual acuity. The patient may also see rainbow-colored halos around lights.

    Macular degeneration

    Macular degeneration results in a central scotoma. Ophthalmoscopic examination reveals changes in the macular area. The patient may notice subtle changes in visual acuity, in color perception, and in the size and shape of objects.

    Migraine headache

    Transient scintillating scotomas, usually bilateral and typically homonymous, can occur during a classic migraine aura. Besides pain, characteristic associated symptoms include paresthesia of the lips, face, or hands; slight confusion; dizziness; and photophobia.

    Optic neuritis

    Inflammation, degeneration, or demyelination of the optic nerve produces a central, circular, or centrocecal scotoma. The scotoma may be unilateral with involvement of one nerve, or bilateral with involvement of both nerves. It can vary in size, density, and symmetry. The patient may report severe vision loss or blurring, lasting up to 3 weeks, and pain — especially with eye movement. Common ophthalmoscopic findings include hyperemia of the optic disk, retinal vein distention, blurred disk margins, and filling of the physiologic cup.

    Retinitis pigmentosa

    Retinitis pigmentosa initially involves loss of peripheral rods; the resulting annular scotoma progresses concentrically until only a central field of vision (tunnel vision) remains. The earliest symptom — impaired night vision — appears during adolescence. Associated signs include narrowing of the retinal blood vessels and pallor of the optic disk. Eventually, with invasion of the macula, blindness may occur.

    » READ BOOK EXCERPT ONLINE »

    Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007

    Vision loss: Medical causes
    (Signs & Symptoms: A 2-in-1 Reference for Nurses)

    Amaurosis fugax

    With amaurosis fugax, recurrent attacks of unilateral vision loss may last from a few seconds to a few minutes. Vision is normal at other times. Transient unilateral weakness, hypertension, and elevated intraocular pressure (IOP) in the affected eye may also occur.

    Cataract

    With a cataract, usually, painless and gradual visual blurring precedes vision loss. As the cataract progresses, the pupil turns milky white. Night blindness and halo vision may be early signs of this disorder.

    Concussion

    Immediately or shortly after blunt head trauma, which causes a concussion, vision may be blurred, double, or lost. Generally, vision loss is temporary. Other findings include headache, anterograde and retrograde amnesia, transient loss of consciousness, nausea, vomiting, dizziness, irritability, confusion, lethargy, and aphasia.

    Diabetic retinopathy

    With diabetic retinopathy, retinal edema and hemorrhage lead to visual blurring, which may progress to blindness. The patient may also have a loss of central vision and color vision.

    Endophthalmitis

    Typically, endophthalmitis follows penetrating trauma, I.V. drug use, or intraocular surgery, causing possibly permanent unilateral vision loss; a sympathetic inflammation may affect the other eye. The patient with endophthalmitis may also experience headache, photophobia, and ocular discharge.

    Glaucoma

    Glaucoma produces gradual visual blurring that may progress to total blindness. Acute angle-closure glaucoma is an ocular emergency that may produce blindness within 3 to 5 days. Findings are rapid onset of unilateral inflammation and pain, pressure over the eye, moderate pupil dilation, nonreactive pupillary response, a cloudy cornea, reduced visual acuity, photophobia, and perception of blue or red halos around lights. Nausea and vomiting may also occur.

    Chronic open-angle glaucoma is usually bilateral, with an insidious onset and a slowly progressive course. It causes peripheral vision loss, aching eyes, halo vision, and reduced visual acuity (especially at night).

    Herpes zoster

    When herpes zoster affects the nasociliary nerve, bilateral vision loss is accompanied by eyelid lesions, conjunctivitis, skin lesions that usually appear on the nose, and ocular muscle palsies.

    Hyphema

    With a hyphema, blood in the anterior chamber can reduce vision to light perception only. Other effects include moderate pain, conjunctival injection, and eyelid edema. Most hyphemas are the direct result of blunt trauma to the normal eye.

    Keratitis

    Keratitis (inflammation of the cornea) may lead to complete unilateral vision loss. Other findings include an opaque cornea, increased tearing, irritation, and photophobia.

    Ocular trauma

    Following eye injury, sudden unilateral or bilateral vision loss may occur. Vision loss may be total or partial and permanent or temporary. The eyelids may be reddened, edematous, and lacerated; intraocular contents may be extruded.

    Optic atrophy

    Optic atrophy (degeneration of the optic nerve) can develop spontaneously or follow inflammation or edema of the nerve head, causing irreversible loss of the visual field with changes in color vision. Pupillary reactions are sluggish, and optic disk pallor is evident.

    Optic neuritis

    Optic neuritis usually produces temporary but severe unilateral vision loss. Pain around the eye occurs, especially with movement of the globe. This may occur with visual field defects and a sluggish pupillary response to light. Ophthalmoscopic examination commonly reveals hyperemia of the optic disk, blurred disk margins, and filling of the physiologic cup.

    Paget’s disease

    With Paget’s disease, bilateral vision loss may develop as a result of bony impingements on the cranial nerves. This occurs with hearing loss, tinnitus, vertigo, and severe, persistent bone pain. Cranial enlargement may be noticeable frontally and occipitally, and headaches may occur. Sites of bone involvement are warm and tender, and impaired mobility and pathologic fractures are common.

    Papilledema

    Papilledema is characterized by swelling of the optic disk from increased intracranial pressure; both optic disks are affected. Acute papilledema may lead to momentary blurring or transiently obscured vision, whereas chimeric papilledema may lead to vision loss.

    Pituitary tumor

    As a pituitary adenoma grows, blurred vision progresses to hemianopia and, possibly, unilateral blindness. Double vision, nystagmus, ptosis, limited eye movement, and headaches may also occur.

    Retinal artery occlusion (central)

    Retinal artery occlusion is a painless ocular emergency that causes sudden unilateral vision loss, which may be partial or complete. Pupil examination reveals a sluggish direct pupillary response and a normal consensual response. Permanent blindness may occur within hours.

    Retinal detachment

    Depending on the degree and location of retinal detachment, painless vision loss may be gradual or sudden and total or partial. Macular involvement causes total blindness.

    With partial vision loss, the patient may describe visual field defects or a shadow or curtain over the visual field as well as visual floaters.

    Retinal vein occlusion (central)

    Most common in geriatric patients, retinal vein occlusion is a painless disorder that causes a unilateral decrease in visual acuity with variable vision loss. IOP may be elevated in both eyes.

    Senile macular degeneration

    Occurring in elderly patients, senile macular degeneration causes painless blurring or loss of central vision. Vision loss may proceed slowly or rapidly, eventually affecting both eyes. Visual acuity may be worse at night.

    Temporal arteritis

    Vision loss and visual blurring with a throbbing, unilateral headache characterize temporal arteritis. Other findings include malaise, anorexia, weight loss, weakness, low-grade fever, generalized muscle aches, and confusion.

    Uveitis

    Inflammation of the uveal tract may result in unilateral vision loss. Anterior uveitis produces moderate to severe eye pain, severe conjunctival injection, photophobia, and a small, nonreactive pupil. Posterior uveitis may produce insidious onset of blurred vision, conjunctival injection, visual floaters, pain, and photophobia. Associated posterior scar formation distorts the shape of the pupil.

    Vitreous hemorrhage

    With vitreous hemorrhage, sudden unilateral vision loss may result from intraocular trauma, ocular tumors, or systemic disease (especially diabetes, hypertension, sickle cell anemia, or leukemia). Visual floaters and partial vision with a reddish haze may occur. The patient’s vision loss may be permanent.

    Other causes

    Drugs

    Chloroquine therapy may cause patchy retinal pigmentation that typically leads to blindness. Phenylbutazone may cause vision loss and increased susceptibility to retinal detachment. Cardiac glycoside derivatives, indomethacin, ethambutol, quinine sulfate, and methanol toxicity may also cause vision loss.

    » READ BOOK EXCERPT ONLINE »

    Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007

    Scotoma: Medical causes
    (Nursing: Interpreting Signs and Symptoms)

    Chorioretinitis.Inflammation of the choroid and retina produces a paracentral scotoma. Ophthalmoscopic examination reveals clouding and cells in the vitreous, subretinal hemorrhage, and neovascularization. The patient may have photophobia along with blurred vision.

    Macular degeneration.Any degenerative process or disorder affecting the fovea centralis results in a central scotoma. Ophthalmoscopic examination reveals changes in the macular area. The patient may notice subtle changes in visual acuity, in color perception, and in the size and shape of objects.

    Optic neuritis.Inflammation, degeneration, or demyelination of the optic nerve produces a central, circular, or centrocecal scotoma. The scotoma may be unilateral with involvement of one nerve, or bilateral with involvement of both nerves. It can vary in size, density, and symmetry. The patient may report severe vision loss or blurring, lasting up to 3 weeks, and pain—especially with eye movement. Common ophthalmoscopic findings include hyperemia of the optic disk, retinal vein distention, blurred disk margins, and filling of the physiologic cup.

    Retinal pigmentary degeneration.Retinal pigmentary degeneration causes premature retinal cell changes leading to cell death. One disorder, retinitis pigmentosa, initially involves loss of peripheral rods; the resulting annular scotoma progresses concentrically until only a central field of vision (tunnel vision) remains. The earliest symptom—impaired night vision—appears during adolescence. Associated signs include narrowing of the retinal blood vessels and pallor of the optic disk. Eventually, with invasion of the macula, blindness may occur.

    » READ BOOK EXCERPT ONLINE »

    Source: Nursing: Interpreting Signs and Symptoms, 2007

    Vision loss: Medical causes
    (Nursing: Interpreting Signs and Symptoms)

    Amaurosis fugax.With amaurosis fugax, recurrent attacks of unilateral vision loss may last from a few seconds to a few minutes. Vision is normal at other times. Transient unilateral weakness, hypertension, and elevated intraocular pressure (IOP) in the affected eye may also occur.

    Cataract.With a cataract, painless and gradual visual blurring typically precede vision loss. As the cataract progresses, the pupil turns milky white.

    Concussion.Immediately or shortly after blunt head trauma, vision may be blurred, double, or lost. Generally, vision loss is temporary. Other findings include headache, anterograde and retrograde amnesia, transient loss of consciousness, nausea, vomiting, dizziness, irritability, confusion, lethargy, and aphasia.

    Diabetic retinopathy.With diabetic retinopathy, retinal edema and hemorrhage lead to visual blurring, which may progress to blindness.

    Endophthalmitis.Typically, endophthalmitis follows penetrating trauma, I.V. drug use, or intraocular surgery, causing possibly permanent unilateral vision loss; a sympathetic inflammation may affect the other eye.

    Glaucoma.Glaucoma produces gradual visual blurring that may progress to total blindness. Acute angle-closure glaucoma is an ocular emergency that may produce blindness within 3 to 5 days. Findings are rapid onset of unilateral inflammation and pain, pressure over the eye, moderate pupil dilation, nonreactive pupillary response, a cloudy cornea, reduced visual acuity, photophobia, and perception of blue or red halos around lights. Nausea and vomiting may also occur.

    Chronic angle-closure glaucoma has a gradual onset and usually produces no symptoms, although blurred or halo vision may occur. If untreated, it progresses to blindness and extreme pain.

    Chronic open-angle glaucoma is usually bilateral, with an insidious onset and a slowly progressive course. It causes peripheral vision loss, aching eyes, halo vision, and reduced visual acuity (especially at night).

    Ocular trauma.Following eye injury, sudden unilateral or bilateral vision loss may occur. Vision loss may be total or partial and permanent or temporary. The eyelids may be reddened, edematous, and lacerated; intraocular contents may be extruded.

    Optic atrophy.Optic atrophy can develop spontaneously or follow inflammation or edema of the nerve head, causing irreversible loss of the visual field with changes in color vision. Pupillary reactions are sluggish and optic disk pallor is evident.

    Optic neuritis.An umbrella term for inflammation, degeneration, or demyelinization of the optic nerve, optic neuritis usually produces temporary but severe unilateral vision loss. Pain around the eye occurs, especially with movement of the globe. This may occur with visual field defects and a sluggish pupillary response to light. Ophthalmoscopic examination commonly reveals hyperemia of the optic disk, blurred disk margins, and filling of the physiologic cup.

    Paget's disease.With Paget's disease, bilateral vision loss may develop as a result of bony impingements on the cranial nerves. This occurs with hearing loss, tinnitus, vertigo, and severe, persistent bone pain. Cranial enlargement may be noticeable frontally and occipitally, and headaches may occur. Sites of bone involvement are warm and tender and impaired mobility and pathologic fractures are common.

    Pituitary tumor.As a pituitary adenoma grows, blurred vision progresses to hemianopsia and, possibly, unilateral blindness. Double vision, nystagmus, ptosis, limited eye movement, and headaches may also occur.

    Retinal artery occlusion (central).Retinal artery occlusion is a painless ocular emergency that causes sudden unilateral vision loss, which may be partial or complete. Pupil examination reveals a sluggish direct pupillary response and a normal consensual response. Permanent blindness may occur within hours.

    Retinal detachment.Depending on the degree and location of retinal detachment, painless vision loss may be gradual or sudden and total or partial. Macular involvement causes total blindness.

    With partial vision loss, the patient may describe visual field defects or a shadow or curtain over the visual field as well as visual floaters.

    Retinal vein occlusion (central).Retinal vein occlusion causes a unilateral decrease in visual acuity with variable vision loss. IOP may be elevated in both eyes.

    Rift Valley fever.Rift Valley fevercauses inflammation of the retina and may result in some permanent vision loss. Typical signs and symptoms include fever, myalgia, weakness, dizziness, and back pain. A small percentage of patients may develop encephalitis or may progress to hemorrhagic fever that can lead to shock and hemorrhage.

    Senile macular degeneration.Senile macular degeneration causes painless blurring or loss of central vision. Vision loss may proceed slowly or rapidly, eventually affecting both eyes. Visual acuity may be worse at night.

    Stevens-Johnson syndrome.With Stevens-Johnson syndrome, corneal scarring from associated conjunctival lesions produces marked vision loss. Purulent conjunctivitis, eye pain, and difficulty opening the eyes occur. Additional findings include widespread bullae, fever, malaise, cough, drooling, inability to eat, sore throat, chest pain, vomiting, diarrhea, myalgias, arthralgias, hematuria, and signs of renal failure.

    Temporal arteritis.Vision loss and visual blurring with a throbbing, unilateral headache characterize temporal arteritis. Other findings include malaise, anorexia, weight loss, weakness, low-grade fever, generalized muscle aches, and confusion.

    Vitreous hemorrhage.With vitreous hemorrhage, sudden unilateral vision loss may result from intraocular trauma, ocular tumors, or systemic disease (especially diabetes, hypertension, sickle cell anemia, or leukemia). Visual floaters and partial vision with a reddish haze may occur. The patient's vision loss may be permanent.

    Other causes

    Drugs.Chloroquine therapy may cause patchy retinal pigmentation that typically leads to blindness. Phenylbutazone may cause vision loss and increased susceptibility to retinal detachment. Digoxin, indomethacin, ethambutol, quinine sulfate, and methanol toxicity may also cause vision loss.

    » READ BOOK EXCERPT ONLINE »

    Source: Nursing: Interpreting Signs and Symptoms, 2007

    Near Drowning: Near Drowning - risk factors
    (The 5-Minute Pediatric Consult)

    • Children <5 years of age, especially toddlers and boys, who cannot swim and have direct access to swimming pools, are at highest risk.
    • Use of alcohol and illicit drugs
    • Inadequate adult supervision
    • Children with seizure disorders
    • Children with primary cardiac arrhythmias such as long QT syndrome

    Near Drowning - pathophysiology

    • Grossly, the lungs are edematous, but not filled with aspirated fluid, with focal hemorrhages.
    • Microscopically, there is thinning of the alveolar septum with emphysematous changes and frothy fluid in the airways.

    Near Drowning - etiology

    • Drowning begins with a loss of the normal breathing pattern as panic ensues.
    • Reflex inspiratory gasps lead to hypoxemia by aspiration or reflex laryngospasm:
    • “Dry drowning” was thought to occur through laryngospasm alone without aspiration of water; whether this occurs is controversial and the term has fallen out of favor.
  • Water is aspirated into the trachea and lungs, washing out surfactant, and leading to atelectasis, intrapulmonary shunting, and hypoxemia.
  • Hypoxemia resulting in multisystem organ failure is the final common pathway.
    • >

    » READ BOOK EXCERPT ONLINE »

    Source: The 5-Minute Pediatric Consult, 2008


     » Next page: Risk Factors for Myopia

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