Toxoplasmosis is caused by the protozoan Toxoplasma gondii. It commonly infects intermediate hosts such as humans through contact with cat feces or consumption of undercooked meat containing cysts. In the eye, it most often causes retinochoroiditis which can lead to vision loss. Diagnosis is usually based on clinical findings, though serology and imaging tests provide supporting evidence. Treatment involves anti-protozoal medications such as sulfadiazine combined with pyrimethamine and corticosteroids to reduce inflammation. Recurrences are common in immunocompromised patients.
Ocular involvement in HIV could be caused by opportunistic infections, vascular abnormalities, neoplasms, neuro-ophthalmic conditions, and adverse effects of medications.
Ocular involvement in HIV infection occurs most commonly due to opportunistic infections and neoplasms. But also can be due to drug related and direct infections.
Opportunistic infections like CMV retinitis occur with a significantly reduced CD4 T-cell count and are one of the common causes of blindness in HIV patients.
Unlike other diseases, ocular infection in these immunosuppressed patients is associated with minimal inflammatory signs.
HIV has been isolated from tears, cornea, vitreous, and chorioretinal tissue in affected persons.
The ocular structures affected by HIV include the adnexa, anterior segment, posterior segment, and orbit.
Neuro ophthalmological manifestations also may be seen.
The institution of highly active antiretroviral therapy (HAART) has caused a dramatic improvement in the immune status of HIV-infected individuals and a change in the clinical presentation and course of opportunistic infections.
OCULAR TOXOPLASMOSIS the blinding disease and is classified among the torch i...BARNABASMUGABI
the disease spreads from the cats and causes retinochoroiditis and its a blinding disease aswell.its managed with spiromyscin,folinic acid and incase of retinal detachment,vitrectomy is done
Ocular involvement in HIV could be caused by opportunistic infections, vascular abnormalities, neoplasms, neuro-ophthalmic conditions, and adverse effects of medications.
Ocular involvement in HIV infection occurs most commonly due to opportunistic infections and neoplasms. But also can be due to drug related and direct infections.
Opportunistic infections like CMV retinitis occur with a significantly reduced CD4 T-cell count and are one of the common causes of blindness in HIV patients.
Unlike other diseases, ocular infection in these immunosuppressed patients is associated with minimal inflammatory signs.
HIV has been isolated from tears, cornea, vitreous, and chorioretinal tissue in affected persons.
The ocular structures affected by HIV include the adnexa, anterior segment, posterior segment, and orbit.
Neuro ophthalmological manifestations also may be seen.
The institution of highly active antiretroviral therapy (HAART) has caused a dramatic improvement in the immune status of HIV-infected individuals and a change in the clinical presentation and course of opportunistic infections.
OCULAR TOXOPLASMOSIS the blinding disease and is classified among the torch i...BARNABASMUGABI
the disease spreads from the cats and causes retinochoroiditis and its a blinding disease aswell.its managed with spiromyscin,folinic acid and incase of retinal detachment,vitrectomy is done
Thyroid eye disease is a condition in which the eye muscles, eyelids, tear glands and fatty tissues behind the eye become inflamed. Also known as:-
Graves ophthalmopathy
Thyroid associated ophthalmopathy
Thyrotoxic exophthalmos and several other terms.
This seminar is for medical graduates..it describes inflammation of posterior part of uvea i.e choroid along with retina.it describes symptoms, signs and how to diagnose such patient and treatment.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
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Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
3. • Toxoplasmosis iscaused by Toxoplasma
gondii
• an obligate intracellular protozoan.
• It infests 10%of adults in northern
temperatecountries and 50%of
adults in Mediterranean and
tropical countries.
LIFE CYCLE
• definitive host - cat
• intermediate hosts -mice, livestock,
birds& humans.
• Oocysts are excreted in cat faecesand
then ingested by intermediate hosts
via contaminated water
4.
5. SOURCES OF INFECTION
• Undercooked Lamb,Pork,Chicken
• Contamination of cat faeces in the environment –water contaminated
with cat feces
• Raw vegetables contaminated with cat feces.
• Organ transplantation
• Blood transfusion
6. Bradyzoite:
• isan inactive stage lying dormant within cystsin tissues such asthe eye,brain and skeletal
muscle
• consumption of undercooked meat (or eggs) froman intermediate host can lead to
infestation.
Tachyzoites:
• Releasedfrom rupture of Bradyzoitecysts
• Are the proliferating active form
• stimulate an inflammatory reaction.
7. Congenital toxoplasmosis:
• 40%of primary maternal infections result in congenital infection;
• Transplacental transmission ishighest during the third trimester.
• Therisk of severe disease developing in the fetus isinversely proportional to
gestationalage
• early pregnancy - result in spontaneous abortion, stillbirth, or severe
congenital disease
• late pregnancy - asymptomatic, normal-appearing infantwith latent
infection.
8. Theclassicpresentation (Sabin’s tetrad) includes
• retinochoroiditis,
• hydrocephalus or microcephaly,
• intracranial calcifications, and
• cognitive impairment, occurring in lessthan 10%of infected children.
• fetal death occurs in 10%of all congenital toxoplasmosis.
• Neurological and visceral involvement may be subclinical
• Retinochoroiditis occur in over 75%,leaving scarsthat are commonly alater incidental
finding
• 25%of these become blind in 1 or both eyes.
10. Retinochoroidal scars in congenital
toxoplasmosis :
(B) multiple peripheral scars on wide-feld
imaging;
(C) wide-feld autofluorescence
image of the same eye
11. Acquired toxoplasmosis in immunocompetent adults
• subclinical in 80–90%
• Cervical lymphadenopathy, fever, malaise and pharyngitis are common features in
symptomatic patients
• Earlyretinitis may occur in about 20%.
Toxoplasmosis in immunocompromised patients
• may be acquired or result from reactivation of pre-existing disease.
• constitutional symptoms + meningoencephalitis, pneumonitis, retinochoroiditis
can occur.
12. Ocular features
• Themost common causeof ocular toxoplasmosis is from intrauterine
infection
• Toxoplasmosis constitutes 20–60%of all posterior uveitis.
• Retinochoroiditis isthe most common manifestation of ocular
toxoplasmosis, but it is often accompanied by a granulomatous anterior
uveitis
• Reactivation at previously inactive cyst-containing scarsis the rule in the
immunocompetent
• Recurrent episodes of inflammation are common and occur when the cysts rupture and
release hundreds of tachyzoites into normal retinal cells
13. Symptoms
• Unilateral acute or subacute onset of floaters,
• blurring and photophobia.
SIGNS
• Spill-over’ anterior uveitis iscommon
• It may be granulomatous or resemble Fuchsuveitis
syndrome
• IOPmay
be elevated
• A single inflammatory focus of fluffy white retinitisor
retinochoroiditis associated with apigmented scar
• satellite lesion is typical.
• Lesionstend to involve the posteriorpole. Typical satellite lesion adjacent to
toxoplasma retinitis scar
14. • De novo foci not associated with an old scar
• Vitritis may be severeand impair fundus visualization.
• ‘Headlight in the fog’ isthe classicdescription of awhite
• retinal inflammatory nidus viewed through vitritis
15. • Rarely, blood vessels crossing over the active retinitis may suffer occlusion
• sheathing of vessels-common
• more commonly in the proximity of the lesion, but can also occur far from it .
• These vessels do not suffer the risk of occlusion
• sheathing disappears very quickly with therapy.
• This vascular response represents an immune mediated reaction.
• Also in the vicinity of the acute focus arteries may show multiple small deposits on
their surface, which are known as Kyrieleis plaques, are very suggestive of
toxoplasmosis .
• These vessels do not show leakage on fluorescein angiography and do not suffer
occlusion.
16. OTHER MANIFESTATIONS
• Optic disc oedema is common.
• Retinochoroiditis absent in acute phase of acquired disease,with activity
consisting of anterior uveitis,vitritis and retinal vasculitis; typical retinal scarsmay
form later.
• Neuroretinitis israre, marker of acutely acquired rather than reactivated
infection.
• Punctate outer retinal toxoplasmosis isan atypical manifestation featuring
clusters of small (25–75µm diameter) grey–white lesions.
17. • On an average, the inflammation lasts for ~4 months.
• About one-third of the patients haverecurrent attacks.
There are three main morphologic variants.
1st variant:
• lesions are larger than 1DD dense, and elevated.
• largely destructive lesions and associated with significant vitritis and anterior
chamberreaction.
• Prompt therapy isusually necessaryregardless of the location of the lesion.
Second variant :
• punctate lesions of the inner retina
• The inflammation is mild, and no therapy is necessary unless the lesion is close to the
macula and threatens vision.
Third variant :
• chr by punctate lesions on outer retina & mild vitritis.
• Lesionsslowly resolve spontaneously but also tend to recur in adjacent areas.
18. Immunocompromisedhost
• Extensiveand fulminant retinal involvement ,bilateral , may be diffcult to
distinguish from viral retinitis.
• But vitritis is still there as the patient in not as immunocompromised as in
CMV infection
• Papilloedema is another potential manifestation in the presence of encephalitis and
raised intracranial pressure.
Immunocompromised: Large area of retinitis which
is progressively enlarging in a leukaemia patient on
chemotherapy
19. Complications of toxoplasmosis retinochoroiditis include
• posterior synechiae
• macular edema,
• dragging of the macula secondary to aperipheral lesion,
• retinal detachment,
• chorioretinal vascular anastomosis,
• choroidal neovascularization,
• branch retinal artery or vein occlusions,
• optic nerve atrophy
• cataract, and
• Glaucoma
• Unilateral pigmentary retinopathy simulating retinitis pigmentosa (asa late
sequela of recurrent ocular toxoplasmosis )
20. Common complications of Toxoplasma retinitis.
(A) Macular involvement, at presentation and (B) following treatment;
21. Common complications of Toxoplasma retinitis.
(C) juxtapapillary lesion involving the optic nerve head
22. Uncommon complications of Toxoplasma retinitis. (A) Periarteritis resulting in branch
retinal artery occlusion; (B) FA shows extensive non-perfusion at the posterior pole;
23. Uncommon complications of Toxoplasma retinitis.(C) serous macular
detachment; (D) FA of (C) shows hyperfluorescence d/t pooling of
dye;
24. Uncommon complications of Toxoplasma retinitis. (E) choroidal
neovascularization adjacent to an old scar; (F) FA of (E) shows
corresponding hyperfluorescence
25. Progression of Toxoplasma retinitis. (A) Moderate activity;
(B) 3 months later, following antibiotic treatment
26. Investigations:
•Diagnosis is usually based on clinical examination findings.
Serology
• TORCH TITRE -antibody
• IgG antibodies appear after the first 2 weeks of infection, detectable throughout
life.
• IgM antibodies -acute phase of the infection, detectable upto 1 year
• newborns –IgM confirms congenital infection
Ig A first to appear after birth
• the presence of IgG antibodies may indicate passive transfer of maternal antibodies
in utero.
• IgA antibodies usually disappear by 7 months.
27. Ocular fluid
Goldmann–Witmer coefficient(GWC)
• Calculating the ratio of specifc IgG in aqueous humour to that in serum
• A ratio of greater than 3 is considered diagnostic of local antibody production.
PCR of intraocular fluid is variably sensitive but highly specific and can be
diagnostic in clinically uncertain cases
28. • Sabin Feldman dye test-
The classic gold standard serology test, uses live T.gondii tachyzoites to detect IgG
antibodies .
High sensitivity and specificity
Not frequently performed, owing to the risk for laboratory-acquired infections
Available in very few reference laboratories in North America.
• Western blot analysis –to identify cytoplasmic antigens of T.gondii
29. Imaging.
• Macular OCT will demonstrate any macular oedema if vitritis is not preventative.
• B-scan ultrasonic imaging can be used to exclude retinal detachment in the presence
of severe vitritis.
• FAF may facilitate monitoring of inflammatory activity
Toxoplasma –active –full thickness involvement
Healed- full thickness atrophy
30. • Usually self –resolving in Immunocompetent patients –resolves in 4- 8 weeks
INDICATIONS FOR TREATMENT
• Lesions threatening fovea or optic nerve
• Lesions within temporal arcades
• Lesions with moderate to severe vitritis
• Lesions greater than 1 DD
• Persistent disease for > 1 month
• Presence of multiple active lesions
• 2 line drop in visual acuity
• Immunocompromised
32. • Trimethoprim –Sulfamethoxazole (160/800mg) combination is now preferred
Can cause bone marrow suppression
CBC,Serum Creatinine and Liver enzymes should be tested at baseline and at 7
days
Contraindicated in pediatric patients <2 years
Risk of SJS and TEN
Hypersensitivity to sulphonamides – fever, maculopapular
rash
• If hypersensitivity, can switch to Clindamycin 300 mg QID alone OR
Azithromycin(500 mg/day) alone or in combination with pyrimethamine
(50md/day) –Has less side effects also –is accepted for sight threatening toxo
• QUADRUPLE THERAPY –Triple therapy + Clindamycin 300 mg qid
33. • Spiramycin 400 mg 3 times /day
• Atovaquone 750mg qid for 3 months –also very effective in CNS toxoplasmosis
• Treatment of congenital toxoplasmosis in neonateswith antimicrobials (pyrimethamine
and sulfonamides plus folinic acid)for one year may reduce the frequency of subsequent
development of retinochoroidal scars.
34. • Prednisolone (1 mg/kg)
given initially and tapered according to clinicalresponse
should alwaysbe used in conjunction with aspecific anti Toxoplasmaagent
Most frequently pyrimethamine combined with sulfadiazine (‘classic’ or
‘triple’ therapy, sometimes supplemented with clindamycin)
Systemic steroids should be avoided in immunocompromised
patients
• In AIDS pyrimethamine is avoided or used at alower dosage because of possible pre-existing bone
marrow suppression and the antagonistic effect of zidovudine when the drugs are combined.
• In AIDS Initial dose BACTRIM DS BD for 6 weeks ,then BACTRIM DS OD lifelong
• For recurrent infection –prophylaxis BACTRIM DS alternate / BACTRIM DS twice a week for 21 months
35. Pregnancy.
• Treatment of recurrent ocular toxoplasmosis during pregnancy should be chosen
carefully and only started if clearlynecessary
• Management should be multidisciplinary.
• Severalof the drugs discussed above have the potential to harm the fetus.
• Intravitreal therapy for reactivated disease,or systemic treatment with azithromycin,
clindamycin and possibly prednisolone may be appropriate.
• Specifc treatment to prevent transmission to the fetus isnot generally given except
in newly acquired infection.
• Spiramycin (treatment dose, 400 mg 3 times daily) reduces the rate of tachyzoite
transmission to the fetus and may be used safely without undue risk of
teratogenicity
37. HISTORY
• Donald Gass
• Described as ‘Unilateral wipe out syndrome’
• Young adults
• Visual loss accompanied by optic atrophy, retinal vascular
attenuation and pigmentary retinopathy in one eye
• clusters of grey-white lesions that migrated to different
areas of the fundus over time.
• Noted a small curvilinear glistening white structure
approximately 400 microns in length with tapered ends in
the vicinity of the active lesions.
• The white worm like structure moved with the crops of
grey-white lesions.
38. WORM
• Ancylostoma caninum (dog hookworm)
• Baylisascaris procyonis (raccoon round worm)-can
cause neural larva migrans –
(neurodegenerative)devastating.
LARVA MIGRANS
• Patient gives a significant history of cutaneous larva
migrans (few months to upto a year back from the
presenting ocular feature.)
• The nematode burrows through the skin and may
cause an eruption on the dorsum of the foot
The small DUSN worm coiled into a ring
(arrow) in the vicinity of the active lesions
39. PATHOGENESIS
• White lesions appears to be a reaction of the local tissue to the presence of the
worm.
• The byproducts or waste products of the worm presumably incite a toxic reaction in
the retinal receptors causing the inflammatory response in the form of vitreous cells
and retinal vasculitis and loss of the vision.
• Consecutive optic atrophy ensues secondary to destruction of retinal elements
40. CLINICAL FEATURE
• Young
• Male
• c/o diminution of vision,floater
• Characteristic retinal lesion ,mild disc edema, mild vitritis
• Vision loss is out of proportion to the fundus appearance
• The white lesions are clustered within a small zone and fade over a few weeks leaving
pigment mottling.
• As the disease progresses, there may be an increase in the number of vitreous cells and
the retinal vessels begin to narrow with some amount of sheathing.
• As disease progresses- white lesion disappear without any sequele or sometimes
pigmentation.
• Disc pallor may progress.
• Sometimes, anterior uveitis, hemorhages ,vascular sheathing.
41. • Careful observation in the vicinity of the
white lesion shows a small white nematode
which is gently tapered at both ends.
• The disease is believed to be caused by two
worms, the smaller worm measuring 400 to
500 microns in length and the larger worm
measuring approximately 1500 to 2000
microns in length.
• The smaller worm propels itself by slow
coiling and uncoiling movements and moves
rather slowly in the subretinal space
• the larger worm moves at a faster pace.
C/o floaters and decline in vision 6/12.
Afferent pupillary defect, relative central scotoma
and small white lesions in the posterior pole.
History of travel to Mexico 6 months prior with
cutaneous
larva migrans at that time
42. • A careful history will reveal travel of the affected individual to an endemic area.
• Endemic in United states, unusual cases reported from France, UK,Germany
• Repeated examination in the vicinity of the greywhite lesions may be required to
identify the worm.
• When the worm hasn’t been found with multiple examinations, a 50 micron laser
burn placed in the vicinity of the suspected site of the worm often stimulates
movement of the worm. This confirms the location of the worm which can then
be treated.
43. • Vitritis
• Papillitis
• One must search for the worm when these gray white
outer retinal lesions are present
• Rates of nematode identification range from 33%-52% !!!!
44. Late stages
• Dense scotomas
• RAPD
• Progressive optic atrophy
• Degenerative RPE
• Marked narrowing of the
arteries.
Diffuse and focal pigmentation Of the
RPE
45. • increased internal limiting membrane
reflex (Oréfice’ssign),
• subretinal tunnels (Garcia’ssign)
• the most common features seen in
early and late DUSN are
• subretinal tracks (91.7%),
• focal RPE changes (89.3%),
• small white subretinal spots (80.2%)
46.
47.
48.
49. FFA -EARLY STAGES
• Early hypoflourescence
• Late hyperflourescence with
staining
• Leakage of dye from ONH
• LATE STAGES
• Hyperflourescence
from RPE window
defects
• Delay in retinal perfusion
50. • ICGA in Late stages shows
hypocyanescence corresponding to the
hypopigmented lesions in fundus and a
hypercyanescence at the macula
51. FFA
• Lesions –initial hypo-hyper
• Hot disc
• Pigment mottling-window defect
Showing initial hypofluorescence (A) and late staining of the lesions(B)
52. • OCT
• Shows diffuse retinal thinning and
RNFL atrophy
• Focal retinal edema in areas affected by
the worm
53. DUSN OTHER PARASITIC INFECTIONS
OUTER RETINA IS AFFECTED INNER RETINA IS AFFECTED
NO RPE CHANGES AND SCARRING SCARRING
DUSN MEWDS
NO SUCH HISTORY HISTORY OF FLU LIKE
ILLNESS
CHILDREN AND
YOUNG ADULTS
YOUNG ADULT WOMEN
HYPOFLOURESCENT HYPERFLOURESCENT
DOTS IN EARLY PHASES
OF FFA
DUSN APMPPE AND OTHER
WHITE DOT
SYNDROMES
NO SCARRING SCARRING
UNILATERAL BILATERAL
55. TREATMENT
• Laser photocoagulationto the worm - Confluent laser burns approximately 100 to 200
microns in size can be placed over the worm, which causes minimal inflammatory
response- New lesions cease to occur and the old lesions fade.
Confluent 200 microns argon laser burns applied
directly to the worm seen
The small DUSN worm coiled into a ring (arrow) in
the vicinity of the active lesions
56. Scatter laser applied to the quadrant with
active lesions to disrupt the blood retinal
barrier
Mid-peripheral fundus showing both active and
inactive lesions. Repeated examinations failed to
find the worm
If worm couldn’t be localized- if active inflammation (means retinal blood barrier
disrupted) –give oral anti-helmith Albendazole 400 mg BD for 3 days - see patient again
after 5 days - worm staggers in the subretinal space and die - causing white
inflammatory reaction.
If no significant inflammation- apply laser burns over the seemingly apparent lesion –
causes disruption of blood retinal barrier-give antihelmith-exam again after 5 days and
few weeks later to check arrest of visual loss and resolution of active lesion
3 days post-laser and albendazole, 3
new active lesions are seen. The
lesions are believed to be sited where
the worm staggered before death
58. INTRODUCTION
• Cause-larvae of the adult tapeworm Taenia solium (Pig)and Taenia saginata(cow)
• LIFE CYCLE- Human definitive host –eggs excreted in stools—contaminate food
and water –pig/cow is intermediate host---pig consume this contaminated food--
-hematogenous dessimination occurs and cyst are formed in multiple tissue –
cytecercosis in human occur by consumption of this undercooked pork/beef
• Cysticerci may be found in almost any tissue. most frequently-are skin, skeletal
muscle, heart, eye, CNS
59.
60. Modes of infestation:
• 1) contaminated food and water with the Taenia solium eggs (hetero-infection);
• 2) reinfection by ingestion ova of the existing parasite (external auto-infection)- feco –
oral route;
• 3) retrograde peristalsis causing the transport of mature proglottids bearing eggs
from bowel to stomach (internal auto-infection).
61. • Parasite reaches the posterior segment via
the short ciliary arteries.
• The macular region being thinnest and
vascularized,
• the larvae lodges itself in the subretinal space from where it
perforates and enters into the vitreous cavity.
MACULAR
HOLE
RETINAL
DETACHME
NT
62. SYMPTOMS
• Depend on the location
• Loss of vision, mass lesions, motility disorders and other
orbital or neuro-ophthalmic symptoms.
• Visualization of cysts via fundoscopy - diagnostic of the
disease.
• The cyst is seen as a spherical, and translucent cavity
associated with dense white scolex
• A living cysticercus usually induces mild inflammation in
the eye.
• However, when it dies, it is accompanied by marked
acute granulomatous inflammation.
• This severe inflammation is associated with disruption
and scarring of retina, retinal pigment epithelium and
choroid
A large cysticercosis with the dense
white area of protoscolex
63. 3 stages
• 1)The vesicular cyst is
the living cyst with a well- defined
scolex . It causes minimal or no
inflammation in the tissue.
• 2)Colloidal vesicular stgae - As larva begins to
die the cyst wall becomes leaky, releasing
toxins and causing inflammation. The cyst
becomes less translucent with a surrounding
inflammatory membrane.
• 3)Calcified nodular stage - Larvae die and
totally resorbed or calcified.
64. Posterior segment manifestations
• Vitreous cysts are more common than retinal or subretinal cysts
• Inferotemporal subretinal cyst is most frequently encountered
• Exudative RD
• Focal Chorio-retinitis
• Rarely, vitreous hemmorhage(if cyst migrates from retina into vitreous cavity)
• Translucent white cyst with dense white spot formed by the invaginated scolex with typical
undulating movements
65. Live submacular
cysticercosis
One week later, cyst migrated to
intravitreal cavity
Patient underwent pars plana
vitrectomy with complete
removal of the cyst.
Postoperative fundus
photograph shows subfoveal
scarring in the area of rupture
into the vitreous cavity
66. INVESTIGATIONS
• Opaque media- BSCAN
• Orbital and neurological manifestation need CT scan
• AC Tap-raised eosinophils
• ELISA –detect antigen, sensitivity directly linked to number of
parasitic lesions and the stage of lesions
(Only 50% of ocular cysticercosis cases test positive on ELISA,
whereas 80% of neurocysticercosis cases test positive.)
• Single lesions and calcification are more likely to be associated
with a false-negative assay result.
• Sensitivity is more if associated with multiple cysts or CSF is
analysed
• False-positive results may be caused by other parasitic
infections.
BSCAN -dead and calcified cyst throwing back
shadow (red arrow) and a
subretinal live cysticercosis with hyper-
reflective scolex (yellow arrow) with total
retinal detachment
67. Lesion superior to the nasal appeared to be a subretinal
cyst with adjacent subretinal fluid surrounding it with
chorioretinal scaring and atrophy surrounding the cyst
Outline of the cyst is captured on OCT -double-layered
cyst wall is evident .
The scolex, which represents the knoblike anterior end of
the tapeworm difficult to visualize. (Possibly, the
honeycomb invagination within the cyst is the intestine of
the larvae)
68.
69. • It is important to do MRI or CT scan in case of ocular cysticercosis to rule out neurocysticercosis
• Neurocysticercosis can co-exist in upto 24% of the cases of ocular cysticercosis
70. TREATMENT
• Localized ocular or adnexal cysticercosis generally is treated by surgical removal because
death of the organism is associated with marked inflammation and severe damage to the
eye.
• Posterior segment involvement- PPV + cyst removal via sclerotomy site or aspirated with
vitrectomy cutter
• If ruptured cyst-complete vitrectomy should be done to remove all the vitreous debris.
• Subretinal cyst- can be removed through retinotomy site with the help of soft tip cannula.
• Subretinal cyst-poor prognosis as it can be associated with retinal detachment and fibrosis
• Orbital lesions can be treated with medical therapy under the cover of steroids to avoid
any inflammatory damage around the dying cyst
74. Symptoms
• Usually unilateral involvement
• 2-9 years of age with an average age of 7.5 years at the time of diagnosis
• Can present in adults also
• Decrease in visual acuity
• Leukocoria
• Strabismus
77. Posterior pole Granuloma
• Occurs when the stage 2 larva gets
encysted in the choroid
• Raised lesion –whitish
• Vitritis
• Accounts for 44% of
toxocariasis
A.67 years/F Optic disc toxocara
granuloma, RPE atrophy and
hyperplasia
B. B-SCAN shows hyperechogenicity
of the granuloma
78. Peripheral Granuloma
• Focal white elevated nodule
• Associated with traction bands and
retinal folds extending from the lesion to
the disc
Peripheral toxocara granuloma,
retinal pigment epithelial atrophy
and hyperplasia
79. Nematode endophthalmitis
• Panuveitis with a chronic
endopthalmitis with hypopyon
• Not very painful and red
• Occurs in very young patients
• Retinal granulomas are visible once the uveitis
clears
• Can mimic retinoblastoma
• USG B Scan –Can demonstrate traction bands
and highly reflective peripheral mass
80.
81. Atypical presentation
• Neuroretinitis
• Optic neuritis
• Optic nerve granuloma
• Mobile living larvae in the eye
• Severe Anterior uveitis
• Inflammatory mass in the iris
• Scleritis
82. D/D
• Coats disease –presents unilaterally but no uveitis is seen.
• PHPV-Unilateral and eye may be microophthalmic .Presents earlier
• ROP –history of prematurity and presents early.
RETINO BLASTOMA OCULAR TOXOCARIASIS
Mean age at presentation is
23 months
Mean age ais 7 years
No intra-ocular inflammation Intra-ocular inflammation
Family history No family history
MRI T1 HYPER
T2 HYPO
MRI T1 HYPER
T2 HYPER
CT scans may reveal calcification in retinoblastoma, but are not useful in discreminating toxocara granuloma
and noncalcified retinoblastoma.
83. • Intraocular migration is a feature of toxocara that may help clinche the diagnosis
COMPLICATIONS
• Epi-Retinal membrane
• Macular hole
• Tractional RD
• Combined RD
• Detachment of the ciliary body and anterior choroid with hypotony,
• phthisis bulbi
• Cataract
• glaucoma
84. INVESTIGATIONS
• Serum ELISA is the gold standard for the diagnosis
• A serum titre of 1:8 is taken as evidence of toxocara
• ELISA has a sensitivity and specificity of 91%
• ELISA detects the exo-antigen of the organism
• Cytologic examination of the aqueous and vitreous shows Eosinophils as opposed to
lymphocytes and malignant cells(RB)
85. Posterior pole toxocara granuloma involving macula, epiretinal membranes
in a 29-year-old female patient (Fundus photo and Bscan)
86.
87. TREATMENT
In active vitritis
• Systemic steroids -1mg/kg/day + Albendazole 800mg BD for adults and 400mg
BD for children for 2 weeks.
• Thiabendazole -2g/day for 5 days (Maximum 3 g)
• DEC –(3-4mg/kg/day for 21 days ) with a starting minimum dose of 25mg/day for
adults
The risk of hypersensitivity reaction after the death of larvae post treatment is
less with toxocara unlike other helminths