Infectious disease pathology Lecture - PowerPoint Presentation

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Infectious disease pathology Lecture 3

Mays Ibrahim, Arab board of pathology, CABPUniversity of Al-Mustansiriyah, college of medicine

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Syphilis

is a chronic venereal disease caused by Treponema

pallidum spirochete with multiple presentations.Mode of transmissionSexual contact is the usual mode of spread. Transplacental transmission

Syphilis

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Syphilis is divided into

Acquired syphilis

Primary Syphilis.

Secondary SyphilisTertiary Syphilis.Congenital syphilis.

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Localized

disease

Occurs about

3 weeks after contact with an infected individual. Chancre :is a characteristic sign of primary syphilis, and it is a firm, non-tender, raised, red lesion forms on the penis, cervix, vaginal wall, or anus; it will heal after 3-6 weeks even without therapy(i.e. spontaneously).

Diagnosis

:

Lesional smear( chancre) using dark field microscopy to see the micro organismTissue biopsy: reveal, ulceration, plasma cells, macrophages, and lymphocytes, with a proliferative endarteritis.

Primary syphilis

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2 to 10 weeks

after the primary chancre

Disseminated

disease with constitutional symptoms.75% of untreated primary syphilis will get secondary syphilis.

due

to

spread

and proliferation of the spirochetes within the skin and mucocutaneous tissuesSecondary syphilis

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lesions in secondary syphilis are

Maculopapular

rash

: all over the body including palms and soles of the feet, and affect the mucocutaneous tissues (especially mouth).Condylomata lata: are painless smooth, elevated plaques with a broad-based, in areas of the skin, such as the

anogenital

region, inner thighs, and axillae

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Is

highly infectious stage.

Lymphadenopathy

, mild fever, malaise, and weight loss are common The symptoms of secondary syphilis last several weeks, after which the person enters the latent phase of the diseaseTissue

biopsy

: reveal plasma cell infiltrate and

obliterative

endarteritis.

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Is

a period of time ( 5 years or more) when there are no visible sign or symptoms of syphilis but positive serology.

May

follow secondary syphilis.Patients are still contagious in the early stage of this phase.

Latent phase of syphilis

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occurs

in approximately one third of untreated

secondary syphilis patientsusually after a latent period of 5-30 years or moreHave three main manifestations

:

Cardiovascular

syphilis

NeurosyphilisGummas Tertiary syphilis

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About 80% of tertiary syphilis.It affects the followings:

Aorta

: leading to syphilitic aortitis which will end up with Aneurysm of aortic root and arch (tree barking).Aortic

valve:

causing valve incompetence.

Coronary arteries: narrowing of the coronary artery opening will cause angina pectoris.Heart (very rare): involved by gumma

.

Cardiovascular syphilis

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syphilitic

aortitis

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About

10% of tertiary syphilis.It causes:

Meningosyphilis

: characterized by involvement of the meninges by gumma or the typical syphilitic vascular changes.Tabes dorsalis: characterized by degeneration of the posterior roots and posterior column of the spinal cord.

General paralysis of insane

: characterized by encephalitis with motor & sensory dysfunction + psychiatric symptoms

.

Neurosyphilis

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Uncommon

form of tertiary syphilis.Composed of: special type of granuloma:

Central

coagulative necrosis.Surrounded by macrophage.Giant cells.Granulation tissue, heavily infiltrated by plasma cells &lymphocytes.Fibrosis.

Gumma

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The

gumma is Rubbery white-gray, occur singly or

multiple,

and vary in size from microscopic lesions resembling tubercles to large tumor-like masses.Site: They occur in most organs but particularly in skin, subcutaneous tissue, bone, and joints. When occur in liver it is called

hepar

lobatum

Gummas have become exceedingly rare, due to development of effective antibiotic e.g penicillin & reported mostly in patients with AIDS.

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Hepar

lobatum

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75% of untreated 1

30% of untreated 2

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U

sually occurs when the mother has primary or secondary syphilis.

Mode of transmission:

transplacental or trans-vaginaly during birth.Manifestation of the disease are : Intrauterine or perinatal death

(in 50% of untreated cases).

Early

(infantile) congenital syphilis

: occurs in children between 0 and 2 years old, includes nasal discharge (snuffles), rash with skin sloughing, hepatomegaly, Diffuse lung or liver fibrosis can also occur.

Late

manifestations

it

occurs in children at or greater than 2 years of age

Notched

central

incisors

known as Hutchinson's teeth

saddle nose

(collapse of the bony part of nose)

Deafness

from auditory nerve disease

Saber

shin

is a malformation of the tibia. It presents as a sharp anterior bowing

inflammation

of the cornea

known as interstitial

keratitis leading to blindness

.

Congenital syphilis

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Snuffles early congenital syphilis

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Visualizing

the spirochete in chancre or the rash of secondary syphilis using dark field microscopy.

Tissue

biopsyConfirmed by the serological test.

Serologic tests for syphilis:

Treponemal

antibody tests

measure antibodies reactive with T. pallidum.Nontreponemal tests (i.e., VDRL “venereal disease research laboratory test”, RPR “rapid plasma reagin test”) measure antibody to

cardiolipin

, a found in

treponemes

and normal tissues

.

Diagnosis:

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LeishmaniasisAmoebiasisGiardiasis

Hydatid cystSchistosomiasis (bilhariziasis)

Parasitic

infections

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is a chronic inflammatory disease of the skin, mucous membranes, or viscera

caused by intracellular Leishmania species, an obligate intracellular parasites transmitted by sandfly bites

With 3 different clinical presentations

Visceral leishmaniasis: Cutaneous leishmaniasisMucocutaneous leishmaniasisLeishmaniasis

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called

kala-azar or “black fever”

L

. donovani parasites invade macrophages throughout the mononuclear phagocyte system.

Hepatosplenomegaly

, lymphadenopathy, pancytopenia, fever, and weight loss

.

Biopsy from the lesion or bone marrow aspirate shows L-D bodies,(leishmania donovani)

Sometimes

patient will have bleeding lead to death.

V

isceral

leishmaniasis

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LEISHMANIA DONOVANI

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The lesion is called

Baghdad boil or oriental sore.

Caused

by leishamania tropica.The disease is a localized & self-limited.

It

starts as a papule which gradually turned into an ulcer which will heal by

fibrosis

.Heal in 6-18 months without treatment.Microscopically

: the lesion is granulomatous, usually with many giant cells and few parasites.

Cu

t

aneous

leishmaniasis

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Caused

by leishmania

braziliensis

The lesions are at the mucocutaneous junction e.g nose, upper lip.The lesion doesn’t heal spontaneously

, but it progresses and erodes the

skin, mucous

membrane and even the cartilage causing a

gross disfigurement.Mic.: granuloma formation.Mucocutaneous leishmaniasis

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Cause: Entamoeba histolytica.

Site: 1. Colon: amoebic dysentery.2. Extraintestinal: liver and lung abscesses.

Amoebiasis

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Intestinal

AmoebiaisMode of transmission:Contaminated food and water WITH FRESH STOOL contain the Entamoeba

histolytica cystFlask shape ulcer in the colon caused by the trophozoite of parasites.Mic.: Mucosal necrosis, invasion of the submucosa

& spread laterally.

Diagnosis

:

GSE (general stool exam)……to see the trophozoite in case of active disease, or the cyst in healthy carrier. Clinically: Fever &

diarrhea.

Complications

: Perforation & peritonitis.

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Passage

of the trophozoite from the colon to the liver via the portal vein will cause Amoebic liver abscess

.

Grossly: The abscess is pale , shaggy with necrotic rim and contains red-brown thick fluid composed of dead hepatocytes+ blood+ fibrin…..giving the characteristic Anchovy sauceClinically : Fever, hepatosplenomegaly, high WBC titer.

Complications

:

Rupture of the abscess to the: Peritoneum,

Pleura, Pericardium.Hepatic Amoebisis

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Cause

: Giardia Lamblia.

Route of infection: Contaminated food and water by giardia

cyst.Site: Duodenum & small intestine.The cyst will hatch into a trophozoite that adheres to the mucosal surface without penetrating it.

Mic

.:

Villous atrophy

& chronic inflammatory cells infiltrating the area (lymphocytes and plasma cells).Trophozoite can be detected near the mucosal surface as pear shaped.Clinically: most patients are Asymptomatic, 10% develop chronic diarrhea.

Diagnosis

: -

G

S

E…..to detect the

c

yst.

-

Intestinal

b

iopsy ……. To detect the

tro

p

hozoite

.

Giardiasis

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Cause

: Echinococcus Granulosus

.

Man is considered as the intermediate host, dog is the final host having the adult worm & shed the eggs onto the grass or green plants, the eggs will be ingested by man which will hatch and pass from the intestine through the portal system to the liver and other organs.About two thirds of human E. granulosus cysts are found in the liver

, 5% to 15% in the lung, and the rest in bones and brain or other organs

Histopathology

of

hydatid cyst: The cyst is composed of:Outer fibrous capsule.Acellular white laminated layer.Thin cellular (germinal) layer which give rise to

scolices

.

Hydatid

cyst

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Rupture

of the cyst will; release the scolices which will form new cyst from each scolex

.

Complications:Organ compression by cyst. Rupture of the cyst which will cause sever allergic (Anaphylactic ) reaction.

Infection of the cyst e.g. by

aspergillus

.

Diagnosis:Imaging modalities range from simple to complex and invasive. Ultrasonography (US) is the screening method of choice.Serological and immunological test: Casoni skin test

High

eosinophilic

titer

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caused by:Schistosoma

hematobium give urinary diseases.Schistosoma mansoni and schistosoma japanicum

give

liver and intestinal disease.Schistosomiasis is transmitted by freshwater snails that live in the slow-moving water.Infectious schistosome is the larva (cercariae).Larvae (cercariae) penetrate human skin, migrate through the vasculature, to the lungs and the liver where the adult worm live, then to a specific organs where they can stay for many years and can lay thousands of eggs per dayIf they settle in the urinary bladder (S. haematobium) or portal venous systems (all others).Schistosomiasis (bilhariziasis

)

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Early

presentationitchy rash (swimmer’s rash) at site of penetration through the skin.

Constitutional symptoms: fever, diarrhea, cough….etc.

Late presentation depending on the organ they affectUrinary bladder: hematuria, bladder hardening due to fibrosisIntestine: abdominal pain, diarrhea, blood in stool.

Liver: A granuloma formation around the implanted eggs which will heal by fibrosis , this will cause obstruction of the portal system causing the shift of blood to the systemic circulation ending in esophageal

varices

and

hematamesis (vomiting of blood).Microscopically: calcified egg deposition and granulomas formation or fibrosis around the eggs.Note: Urinary schistosomiasis

is also associated with

urinary bladder

surface

epithelial squamous metaplasia then dysplasia and squamous cell carcinoma.

Clinical presentation

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