Home
Keys to Success in Medicine
Cardiovascular System
Respiratory System
Locomotor System
Endocrine and Metabolic System
Kidneys and Urinary System
Gastrointestinal Tract
Central Nervous System
Haematological System
Integumental System
Reproductive and Genital System
Recommended Reading
Forum
Links

amazon astore

ydr

aces for paces

Leishmaniasis

Title                    

Ñ    Leishmaniasis      

Definition

Ñ    A group of diseases caused by protozoa of the genus Leishmania

Aetiology

Ñ    Various species of the protozoan genus Leishmania

Pathogenesis

Vectors

Ñ    Sandflies:

·          Phlebotomous:

Old World

·          Lutzomyia:

New World

Reservoir of Infection

Ñ    Humans

Ñ    Animals:

Canines, rodents, sloths, anteaters

Rarely

Ñ    Spread by blood transfusion, congenital, sexual contact

Life cycle

Ñ    In the vertebrate host the protozoa are found as amastigotes:

Leishman-Donovan bodies

Ñ    They multiply within macrophages and cells of the reticuloendothelial system

Ñ    Released into the circulation when cells rupture

Ñ    Taken up into the gut of feeding sandfly

Ñ    Develop into flagellated promastigotes

Ñ    Migrate to salivary glands

Ñ    Inoculated into new host

 

 

Visceral Leishmaniasis

Title

Ñ    Visceral Leishmaniasis (Kala-Azar)

Aetiology

Parasites of Leishmania donovani complex:

Ñ    Leishmania donovani

Ñ    Leishmania infantum

Ñ    Leishmania chagasi

Vector

Ñ    Sandfly:      

Genus Phlebotomous

Pathogenesis

Ñ    Parasites inoculated by sandfly bite

Ñ    Migrate to reticuloendothelial system and multiply

Clinical Features

History

Incubation Period

Ñ    2 weeks to 1 year:

Usually 1-2 months

E&M

Ñ    Fever

Ñ    Emaciation

Examination

E&M

Ñ    Emaciation

IS                           

Ñ    Primary lesion at the site of inoculation is small and usually not apparent

Ñ    Skin rough

Ñ    Pigmentation

HS

Ñ    Hepatosplenomegaly

Ñ    Lymphadenopathy:

African kala-azar

Ñ    Pancytopaenia

Ñ    Polyclonal hypergammaglobulinaemia

Complications

IS

Ñ    1-2 years after apparent cure nodular cutaneous lesions full of parasites may develop

Ñ    This is known as Post Kala-Azar Dermal Leishmaniasis (PKDL)

Investigations

Fluids

Smears

Ñ    Parasites may be demonstrated in Giemsa stained smears of aspirates from:

Bone marrow, lymph nodes, spleen, liver

Culture

Ñ    Organisms may be cultured from aspirates of the:

Bone marrow, lymph nodes, spleen, liver

Blood

Haematology

Ñ    Pancytopaenia

Biochemistry

Ñ    Hypoalbuminaemia

Ñ    Hypergammaglobulinaemia

Immunology

Ñ    Specific serology:

Positive in 95% of patients

Tissue diagnosis

Ñ    Leishmanin (Montenegro) Skin Test (intradermal injection of Leishmania antigen):

Negative, indicating poor cell mediated immune response

Management

Cure

Drugs

Ñ    Pentavalent antimony salts:

Sodium stibogluconate

Ñ    Amphotericin B

Ñ    Pentamidine

Ñ    Miltefosine

Prevention

Drugs

Ñ    Mass treatment of patients

Biological agents

Ñ    Vector reduction

Equipment

Ñ    Insect screens

Ñ    Insect repellents

Prognosis

Ñ    Without treatment emaciation and death occur in 80-90% of untreated patients

 

 

Cutaneous Leishmaniasis                       

Title               

Ñ    Cutaneous Leishmaniasis                     

Aetiology

Ñ    Leishmania major, L. tropica, L. aethiopica

Southern Europe, Asia and Africa

Ñ    Leishmania mexicana complex

Mexico, Central and South America

Ñ    Leishmania braziliensis complex

Central and South America

Pathogenesis

Ñ    Sandfly bite

Ñ    Amastigotes multiply in dermal macrophages

Response depends on

Ñ    Species

Ñ    Size of inoculum

Ñ    Host response

Clinical Features

History

Incubation Period

Ñ    1 week to 3 months

IS

Ñ    Painless ulcer:

This generally heals over several months leaving a depressed scar

In the New World skin lesions may be followed by metastatic mucocutaneous lesions

Examination

IS

Ñ    Single lesion

Ñ    Multiple lesions:

Caused by:

·          Multiple bites

·          Accidental autoinoculation

·          Metastatic spread

Ñ    The lesion begins as a papule that enlarges and ulcerates centrally

Ñ    Border raised, hyperpigmented

Complications

IS

Ñ    Diffuse cutaneous leishmaniasis (rare):

Diffuse infiltration of the skin

Investigations

Fluids

Smear

Ñ    Giemsa stain of split skin smear

Tissue Diagnosis

Ñ    Leishmanin Test:

Positive

Does not help to distinguish between active and resolved infection

Ñ    Biopsy:

Histology

PCR

Management

Ñ    Cutaneous leishmaniasis may be divided into that of the Old World (Africa, Mediterranean, Afghanistan) and cutaneous leishmaniasis of the New World (Central and South America)

Ñ    Cutaneous leishmaniasis of the Old World heals in 4 to 18 months leaving a scar

·          No serious sequelae occur

·          It may be left alone

·          It could be frozen with liquid nitrogen

·          A pentavalent antimonial such as sodium stibogluconate may be administered intralesionally

Ñ    Cutaneous leishmaniasis of the New World runs a more protracted course and should be treated

 

Cure

Drugs

Ñ    Topical antiparasitic agents:

Intralesional antimonials

Ñ    Systemic treatment:

Sodium stibogluconate

Pentamidine

Amphotericin B

Surgery

Ñ    Curettage

Ñ    Cryotherapy

 

 

Mucocutaneous Leishmaniasis                       

Title               

Ñ    Mucocutaneous Leishmaniasis                     

Aetiology

Ñ    Leishmania braziliensis

Clinical Features

History

Incubation Period

Ñ    2-3months

IS

Ñ    Cutaneous sores

RS

Ñ    Ulcerating lesions of the mucosa or cartilage of the nose (espundia) occur months or years after the cutaneous lesions

GIT

Ñ    Ulcerating lesions of the lips may occur months or years after the cutaneous lesions

Complications

RS

Ñ    Gross mutilation of the nose

GIT

Ñ    Gross mutilation of the palate

Investigations

Ñ    As for cutaneous leishmaniasis but parasites difficult to isolate

Management

Cure

Drugs

Ñ    Amphotericin B:

Treatment of choice

Ñ    Systemic antimony compounds

[ Back ] [ Up ] [ Next ]

[Up]