Chronic bacterial skin infections - PowerPoint Presentation

Slide1

Chronic bacterial skin infections

Slide2

1- the student need know the various clinical aspects of TB of the skin & complications & how to treat

2- to know about the spectrum of leprosy ,the clinical features of each pole of the spectrum & necessary investigations required for the diagnosis

3- to learn more about the

recommendations

for treatment of leprosy & the expected adverse reaction of the anti-leprotic agents

Slide3

Tuberculosis of the skin

Slide4

types

1- localized:

a- lupus vulgaris

b- primary inoculation TB( TB chancre)

c- tuberculosis

verrucosa

cutis ( warty TB)

d-

scrofuloderma

e-

oroficial

TB

Slide5

2- generalized:

a-

miliary

TB

b- TB abscess

c- lichen

scrofulosorum

3-

tuberculide

:

a-

erythema

induratum

b-

papulonecrotic

tuberculide

Slide6

Tuberculine test

Intradermal injection of 0.1 ml of PPD ( purified protein derivative) & read after 48 hours looking for erythema & induration:

-more than 10 mm: strong +

ve

5-10 mm: moderately +

ve

less than 5 mm : weak +

ve

no reaction : -

ve

Slide7

Lupus vulgaris

It is commonest type, affect mainly children & elderly, mainly seen on the face .

T

he infection arises from distant focus, either by

hematogenous

or

lymphatic

spread in patient with high immunity against TB bacilli

Slide8

Clinical features

Asymptomatic red-brown nodules which coalesce to form well-demarcated plaque.

D

iascopy examination

: apple jelly nodules.

It is slowly progressive lesions takes sometimes years to develop & if not treated it will ulcerate & lead to scarring &deformities like ectropian of eyelids & destruction of the nose & rarely sq. cell carcinoma

Slide9

Diagnosis

Histopathology

:

epitheloid

cell granuloma:

epitheloid

cell &

Langhan

s giant cells surrounded by lymphocytes without necrosis.

Zeil

- Nelson stain

for AFB is usually negative

Slide10

treatment

Antituberculous drugs course for 9 months:

First 2 months:

ethambutol

+ INH + rifampicin

Next 7 months:

INH+ rifampicin

Slide11

Tuberculous chancre

Caused by direct inoculation of TB bacilli into the skin from infected materials in patient with

no immunity against TB

(

Tuberculine

test is negative).

It started as painless papule then enlarged to nodule which turn into painless ulceration with regional LN enlargement. Eventually heal spontaneously with scarring.

Slide12

Warty TB

result from direct inoculation of TB bacilli into the skin in patient with

high immunity against TB bacilli

. The source of infection is infected materials. physicians, pathologist & anatomist are at risk who handle infected cadavers ( called

anatomist wart

)

Clinically appear as hyperkeratotic crusted warty plaque mainly on hands & feet

Slide13

scrofuloderma

Result from

direct extension of TB bacilli

from underlying tuberculous focus such as LN, bone or joint. The skin overlying TB focus is swollen with fluctuation & pus discharging lead to painless ulceration & heal with ugly scar

Slide14

tuberculide

Skin diseases related to TB as a result of

hypersensitivity reaction to TB bacilli

. The primary TB infection is not in the skin but elsewhere & skin biopsy show no bacilli.

There are 2 types:

Slide15

1-Erythema induratum( Bazin

disease)

Deep seated nodules on posterior aspect of the lower legs with ulceration. They are seen

exclusively

in middle age women.

Slide16

2- papulonecrotic

tuberculid

Multiple necrotic papules & nodules seen mainly in lower limbs.

both respond to anti-TB drugs

Slide17

Leprosy ( Hansen`s disease)

Chronic infection caused by

Mycobacterium

leprae

: AFB, can not grow on artificial media but can be cultivated in animals like Armadillo & foot pad of mice. The micro-organism require low temperature.

Transmission

: infected air born droplet.

The bacilli pass through nasal mucosa to reach blood stream & then to target organs (

peripheral nerves & skin

)

Slide18

Fade of infection

Indeterminate leprosy

:

hypopigmented macule or patch, ill-defined border, on cold exposed area. The lesion is dry, anhidrotic ( no sweating), anesthetic or hyposthetic. It may disappear without any squale or lead to one of the

determinate type

of leprosy depending on the

state of immunity

Slide19

Spectrum of leprosy

1-

lepromatous

(L

L

)

: patient with low immunity

& large no. of bacilli….

multibacillary

2- Tuberculoid (TL)

: high immunity & few or no bacilli ……

paucibacillary

3- Borderline(B

B

): in between 2 poles, include (BL & BT ), immunologically unstable

Slide20

Lepramine test

Intra-dermal injection of 0.1 ml of dead

M.lepra

& read after 48 hrs & after 4 wks( biopsy).

It is not diagnostic test but used to assess the state of immunity against

M.lepre

:

+

ve

in normal person & TL

-

ve

in LL & BL

weak +

ve

in BT

Slide21

Tuberculoid leprosy

Because of high immunity , there is mainly skin & nerve involvement.

Skin lesions

:

they are one or few, on exposed cold areas, macules or patches, hypopigmented, loss of sensation, anhidrotic, loss of hair with slightly raised border, nerve adjacent to the lesions is thickened.

Large peripheral nerve

could be involved like median

n.Ulner

n. & area innervated by that nerve shows features of neuropathy( sensory or motor )

Slide22

Lepromatous leprosy

Because of no immunity, there is dissemination of the infection.

Skin lesions

are multiple, bilateral, symmetrical, macules, papules & nodules. In the face, the lines of skin become deeper as the skin thickened (

leonine facies

)

Slide23

Nerve involvement

: is usually late leading to peripheral neuropathy with loss of sensation in gloves & stocks, ulceration of digits.

Other features

:

lymphadenopathy, hepatosplenomegaly, keratitis , orchitis

Slide24

diagnosis

1- clinical feature

2- skin biopsy:

TL

: multiple

tuberculoid

granuloma

no bacilli , ZN stain negative

LL

: diffuse

granuloma

consist of foamy macrophages with large no. of bacilli in their cytoplasm, ZN stain positive.

Slide25

3-

slit-skin smear

:

A small skin incision is made; the site is then scraped to obtain tissue fluid from which a smear is made and examined after Ziehl-Neelsen staining. Specimens are usually

obtained from both earlobes and two other active lesions.

Slide26

4- PCR:

M. leprae DNA detected by this technique

makes the diagnosis of early Paucibacillary leprosy and identifies

M. leprae

after therapy

Slide27

Treatment

1-LL:

Dapsone

100mg / d +

rifampicin

600 mg once/ month +

clofazimine

50 mg/ d at least for 2 years.

2- TL:

D

apsone

100 mg/d +

rifampicin

600 mg once/ month for 1 year

Slide28

Lepra reactions

Type l :

C

ell mediated immunity

, occur in TL & BT .

the existing lesions become more inflamed painful & tender associated with loss of nerve function.

Treat: aspirin &

prednisolone

30-60 mg/d

Slide29

Type ll

(

erythema

nodosum

leprosum

)

Immune complex

HSR, seen in LL, development of new lesions, multiple painful nodules with or without ulceration, widespread, associated with fever, lymphadenopathy, arthropathy

Treatment: aspirin , predisolone

thalidomide 100-400mg/ d