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Mycobacterial Diseases

Terms in this set (52)

Epidemiology of mycobacterial diseases
-increase in # of TB cases due to
-immigraton from countries with high rates of TB
-HIV infection- coinfection, higher susceptibility for infection, activation of latent Tb
-dense low income population living as homeless shelters or prisons
-Africa has the highest rate of TB cases (30%)
-currently India has the highest infection rate among health care workers!!
-TB has become increasingly resistant to standard tx
-MDR TB- resistant to isoniazid or rifampin
-EDR TB- resistant (extensive drug resistant) to isoniazid or rifampin, all fluoroquinolones adn one of the following: capreomycin, kanamycin, amikacin
-aggressive tx with drugs x 2 years +/- surgical resection can cure 60% of EDR TB cases
Cutaneous Tb accounts for ___% of cases worldwide
2%
Cutaneous TB
-cutaneous disease most often caused by M. tuberculosis or M bovis
-cutaneous presentation depends on host factors:
-age-25% of scrofuloderma and lichen scrofuloderma occur in children
-gender- women are 10x more likely to develop erythema induratum (men 2-3x more likely to develop all other forms of cutaneous TB)
-anatomic location- lupus vulgaris occurs most often on the face adn extremities- TB verrucosa cutis most often occurs on the soles and foot
-nutritional status- TB abscesses and scrofuloderma are associated with poor nutrition
-Tuberculids are the fast growing type of cutaneous TB indicating that disease is reactivation rather than new infection
-among HIV pts, miliary tb is the more frequent cutaneous TB disease
-between 3-12% of cutaneous TB cases have pulmonary and lymph node involvement
What is the fastest type of cutaneous TB that represents a reactivation of TB rather than new infection?
Tuberculids
Among HIV pts, _____ TB is the most frequent cutaneous TB disease
miliary TB
Two forms of Tuberculin testing include..
-TST (tuberculin skin test) or PPD (Mantoux test)
-IGRA (Interferon y release assay) aka QuantiFERON TB GOLD
TST/ PPD test
-detect memory cell mediated immune response
-positive 2-4 weeks post infection
-intradermal injection read for induration after 48-72 hours
-5mm positive for HIV, high risk ,close contacts, + CXR, possible exposed children
-10mm positive in IVDU, born in endemic country, lab personnel, residents in high risk facilities, predisposing medical conditions
-15mm positive in all others without risk factors
-TST test is not as sensitive to latent TB, bcg vaccination, other medical conditions that may affect cellular immunity
QuantiFERON -TB Gold
-interferon y released by T cells
-only slightly more sensitive detecting latent Tb
-more specific for BCG immunization
-combo is optimal testing to assess for latent or active Tb infection
BCG (bacille Calmette-Guerin) Vaccine
-live attenuated strain of Mycobacterium bovis
-used in most parts of the world except Northern America and Western Europe
-protection from neonates from TB
-depending on age and frequency of immunization, PPD can remain positive
-any child immunized with TB test > 10mm is considered to have active TB infection
-dermatologic complications are rare- localized abscess, ulcerations, papular and papulonecrotic tuberculids
-disseminated diseases only occurs in setting of immunodeficiency
-bcg has been used to treat bladder ca- disseminated disease can occur with pneumonitis, hepatitis, prostatitis, abdominal aneurysms
Tuberculin testing for biologics
-screen for active TB by history and physical (CXR when suspicious)
-administer a TST/IGRA
-interpret test results with caution in pts already on significant iatogenic immunosuppression or anti-TNF treatments
-regular monitorng of pts on anti-TNF agents for the development of TB with appropriate hx, physical, lab testing
-suspect and screen for TB if clinical symptoms indicate infection
How are cutaneous TB lesions classified?
-classified by the mechanism of disease acquisition
4 major categories of Cutaneous TB
- inoculation from an exogenous source (primary inoculation TB and tuberculosis verrucosa cutis)

-endogenous cutaneous spread contiguously or by autoinoculation (scrofuloderma, tuberculosis cuta orificialis)

-hematogenous spread to the skin (lupus vulgaris, acute miliary tub, tuberculosis ulcer, gumma or abscess, tuberculosis cellulitis)
-lupus vulgaris can also occur adjacent to lesions of scrofuloderma, suggesting that both hematogenous and local spread is capable of triggering this reaction pattern

-tuberculids- erythema induratum, papulonecrotic tuberculid, lichen scrofulosorom
Inoculation cutaneous tuberculosis from an exogenous source
-Primary inoculation TB (primary tb, tuberculosis chancre)

-Paucibacillary cutaneous tb from an exogenous or endogenous source in persons with high immunity (tb verrucosa cutis and lupus vulgaris)
Primary inoculation TB
-Tuberculosis Chancre--> TB develops at site of inoculation in an uninfected person
-occurs mostly in children on the face or extremities
-inoculation by piercing, injections, trauma or tattoo
-2-4 post infection, a painless, brown to red papule develops into an indurated nodule or plaque that can ulcerate
-prominent regional LAD 3-8 weeks post infection +/- cold, suppurative, draining lesions or nodes

Primary tb complex- occurs on mucous membranes
-spontaneous healing of lesion and LAD within 1 year- skin heals first, then lymph node which is often enlarged and calcified
-lupus vulgaris may develop over node
-disseminated disease not uncommon with this form of cutaneous TB
Histology of primary inoculation tb
1-2 weeks- PMN leukocyted and tubercle bacilli
2-4 weeks- lymphocytes and epitheliod cells to replace leukocytes with decrease in tubercle bacilli
Ddx for primary inoculation TB
-deep fungal or bacterial origin
-pyogenic granuloma
-cat scratch disease
Paucibacillary cutaneous tuberculosis from an exogenous or endogenous source in persons with high immunity includes which two diseases?
-Tuberculosis verrucosa cutis
-Lupus vulgaris
Tuberculosis verrucosa cutis
-exogenous inoculation into the skin of a previously sensitized person with high immunity
-TBT is strong positive
-small, solitary papule that becomes hyperkeratotic, growing circumferentially, up to several cm with fissuring of lesion +/- purulent discharge at center
-adults- fingers and hands; children- butocks and ankles
-histo- hyperkeratosis, granulomatous inflammation and very few bacilli
-cannot use biopsy to r/o dx
-culture will be positive only in 50%
-ddx- blastomycosis, chromoblastomycosis, verrucous epidermal nevus, hypertrophic licehn planus, halogenoderma, verruca vulgaris
Lupus vulgaris
-slowly progressing single plaque made of small brown/red papules called "lupomes" which whern blanched appear as an "apple jelly" color
-destructive disease that causes deformity scars or hypertrophy depending on the area
-lesions of the head, face form destructive scars
-earlobes and lips are hyperplastic
-lesions of the head and neck can be associated with lymphangitis
-SCC can develop in long standing lesions
What can develop in long standing lesions of lupus vulgaris?
SCC
Lupus vulgaris postexanthematicus
-follows measles or another significant illness
-1 mo post illness, multiple erythematous papules in generalized distribution appear
-prior TBT will be negative
-after papules appear, TBT will be positive
-histology- hallmark is classic tubercle
-bx and cultures may be required for dx
Cutaneous TB from endogenous source by direct extension includes..
-scrofuloderma
-perianal tb
-periorifical tb
Scrofuloderma
-direct extension of underlying infection
-subcutaneous masses which enlarge to form nodules most commonly over the cervical lymph nodes but also bones and joints
-necrotic cavities filled with liquified debris and PMN leukocytes from infection to nodule can ulcerate and discharge material
-reddish granulation tissue present at ulcerated base
-in the armpit can look like hidradenitis suppurativa
Perianal TB (tuberculosis fistulosa subcutanea)
-cutaneous tb from endogenous source by direct extension
-perianal TB mostly affects men 30-60
-chronic fistula indicating involvement of the GI tract
Perioficial TB (tuberculosis cutis orifialis)
-ulcerations that are soft, punched out with undermined edges on the mucocutaneous borders of the mouth, nose and tongue
-caused by autoinoculation from underlying active tb, particularly the GI tract
-TBT is positive but variable
-deep and lateral to the ulcer, AFB are plentiful
Cutaneous tb from hematogenous spread- miliary (disseminated tb)
-fulminant TB of the lung or meninges
-most common in children, AIDs, following infectious illness such as measles
-TB test is negative
-genearlized macules, papules, pustules, subq nodules, purpuric vasculitic lesions, painful ulcerations and other signs of systemic TB
-skin bx shows suppurative inflammation, PMNs, caseating granulomas with abundant AFB
Metastatic tb abscess, ulceration or cellulitis
-firm, non tender erythematous plaques resembling cellulitis, or nodules which can evolve to form draining abscesses, ulcers or draining sinus tracts
-most common in kids, malnourished and immunosuppressed
-debridement of lesions can cause infection to healthfcare staff
-numerous AFB are found in the lesions
Sporotrichoid tuberculosis
-lymphatic spread of TB- usually begins with a distal lesion and forms a proximal lesion
-however, retrograde lymphatic spread does occur
-string of lupus vulgaris like lesions is most common or a string or deep fluctuant, draining nodules that appear as linear scrofuloderma
-TBT is positive, no underling foci of systemic TB found
-AFB stains are negative in biopsy
Tuberculosis mastitis (Tb of the breast)
-subq nodules of the breast destroying fat tissue and forming sinus tracts
-can resemble breast cancer
-axillary LNs are enlarged and matted
-most common in females but can affect males
-TST is positive, AFB stain negative, culture neg, but biopsy shows granulomatous inflammation
-dx by biopsy!! granulomas
-tx is anti-TB drugs
-mastectoym only in resistant cases
Tuberculids
-erupt from hematogenous dissemination of TB from a silent site in a person with strong immunity
-PPD will be positive
-diagnosed by clinical features, histo, positive IGRA/TST, and resolution of the eruption with tx
-lupus vulgaris may develop in tuberculids
Types of tuberculids
-papulonecrotic tuberculid
-lichen scrofulosorum
-induratum and vascular reactions due to tuberculosis (nodular tuberculid, nodular granulomatous phlebitis)
Papulonecrotic tuberculid
-symmetrically distributed 2-8mm inflammatory papules that become pustular and necrotic (HIV esp)
-usually asymptomatic, chronic, affecting the extensor surfaces and appear in crops and resolve with scarring
-females 3:1, winter months worse, TST positive
-may appear in association with erythema induratum and scrofuloderma
-histo- small chronic granulomatous vasculitis
Lichen scrofuloderma (tuberculosis cutis lichenoides)
-2-4mm yellow pink, hyperkeratotic papules with flat tops in groups, scattered on the trunk
-unchanged for months, and asymptomatic that may or may not involute
-95% cases are in children <20
-active TB distant site usually at bones or LNs
-TST positive
-histo- noncaseating tb granulomas
Erythema induratum (Bazin disease) and other vascular reactions
-1-2cm erythematous violaceous tender nodules on the posterior lower calf occurring in middle aged women (80%)
-lesions spontaneously resolve over months +/- ulceration
-nodular granulomatous phlebitis- similar, affects saphenous vein on women on the upper and lower posterior leg
-TST is positive
-histo- affects subq fat causing necrosis
-granulomatous vasculitis
-can look similar to polyarteritis nodosa or Sweet syndrome
-dddx is EN, nodular vasculitis, polyarteritis nodosa, tertiary syphilis, inflammatry panniculitis
How to dx Tb
-biopsy with acid fast staining
-PCR
-culture remains the gold standard!!
TB Tx
-HIV test recommended for all- need longer course of tx
-multidrug chemo recommended 3-4 drug regimen (RIPE therapy)
-surgical excison
-no change in cutaneous lesions in 6 weeks then reassess your dx
Atypical mycobacterial infections
-acid fast bacilli that do not cause Hansen's or Tb
Atypical Mycobacteriosis
-found in soil and animals
-increasing # of cases due to improved culture and ID as well as increasing immunocompromised populations
Classification of mycobacterium
-Group 1-photochromogens (Mycobacterium marinum)
-Group 2- scotochromogens
-Group 3-non chromogens (M avium, Mycobacterium heamophilum)
-Group IV- rapid growers (M fortuitum, chelonae, abscessus)
Swimming pool granuloma is caused by what organism?
Mycobacterium marinum
-fresh and salt water
Who acquires swimming pool granuloma with M marinum?
-persons involved in aquariums, fishing, fish handling
-3 weeks post exposure, small papule or nodule on the hand, knees, elbow and feet develop with warty surface
-in immunocompromised, plaque can ulcerate
-deep infection present if tenosynovitis, bursitis, arthritis, OA occur
-histo- tissue culture positive, TST positive
Tx for M. marinum infection
-optimal unknown
-multiple vs singular regimen
-reoccurence prevalent
-mino or doxy alone or in combo
-immunosuppressed needs longer tx
-refer to ID
Buruli ulcer
-due to mycobacterium ulcerans
-Australia, Africa, Asia, Brazil, Mexico, Peru, French Guyana
-M ulcerans produces toxin, mycolactone which causes necrosis and ulceration
-creates a biofilm in the human which makes tx difficult
-transmission via carnvirous insects
-children and elderly most affected
-those working in swampy areas are protected from pathogen
-dx- clinical +AFB, culture, PCR
-up to 7% of cases will have all 3 negative tests
-tx--> streptomycin and rifampin for 8 week +/- surgical resection
-severe scars with contractures can occur
-multiple metastatic skin lesions can occur within lesions
Mycobacterium haemophilum
-affects immunocompromised- AIDs, transplant, leukemia, lymphoma
-acral sites develop papules/plaques that develop into painful ulcers, septic arthritis, osteo, pulmonary nodules may occur
-if infection with m haemophilum is suspected, lab must be notified to prepare mediums for growth- difficult to isolate
-tx 1 year of cipro, clarithro, amikacin, rifampin, rifabutin
Rapidly growing mycobacterium includes
M fortuitum
M chelonae/abscessus
Rapidly growing mycobacterium
-due to M. fortuitum, M chelonae/abscessus
-subcutaneous abscess or cellulitis
-usually resistant to Tb meds
-infections occur after trauma in immunocompetent pts
-whirpool foot bath infection by M. fortuitum- erythematous papules, fluctuant abscesses which are painful and can ulcerate (shaving legs prior to tx is a risk factor!!)
-immunocompromised can develop disseminated disease
-renal transplant pts--> tender, nodular lesions of the legs are common
Young healthy 25 year old girl develops erythematous papules, fluctuant abscesses, which are painful. She recalls getting a pedicure a few days earlier. Dx?
M. fortuitum
-due to shaving legs prior to going in whirpool foot bath
Tx for M. chelonae/abscessus
clarithromycin BID x 6 months
Tx for M. fortuitum
amikacin plus cefoxitin or imipenem or quinolone
Other tx options for rapidly growing mycobacterium besides abx
-surgical excision
-debridement and drainage
Mycobacterium avium-intraceullulare complex
-AIDS and children with chronic pulmonary infections at risk
-nodules, ulcer, pustules, cellulitis of the skin via hematogenous dissemination
-tx--> clarithromycin or azithromycin +ethambutol and rifampin
-antiretroviral for HIV load
Mycobacterium kansasii
-rare cause of cutaneous infection
-can follow trauma in immunosuppressed
-lesions are papules, pustules, cellulitis, or sporotrichoid
-tx--> isoniazid, rifampin, ethambutol for 12 month after lesions have cleared
-surgical excision can be helpful
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