Leprosy and plague Flashcards
How long after starting therapy is a patient non infectious with leprosy? Who gets nodules?
Almost immediately
Nodules only in lepromatous leprosy (image) (and in BL)
leprosy transmission
Respiratory droplets [not proven]
Where can leprosy be cultivated
Mouse foot pads or armadillo
Why are few bacteria cultivated in tuberculoid leprosy?
Cell mediated immunity (phagocytes / T cells) contains infection
Classic skin lesion leprosy
Anaesthetic macules with thickened nerves
Tuberculoid to lepromatotous leprosy is generally a scale with borderline in the middle.
Which has more bacteria cultivated?
Which has larger skin lesions?
Thicker nerves?
Defines borders?
- Lepromatotous are larger with more thickened nerves and bacilli. Often just global erythematous lesions.
Sensation preserved initially - Tuberculoid has more defined borders (better cell mediated immunity)
Leprosy rx? How long?
Rifampicin (monthly)
Dapsone (daily)
Clofazamine daily
and steroids for
Paucibacillary 6 months (TL, BT, B)
Multibacillary 12 months (BB, BL, LL)
Dapsone / rifampicin mechanism
- D inhibits folic acid synthesis
- R inhibits RNA polymerase
Clofazimine key side effect
- Discoloration of skin which may turn icthyotic
When do Leprosy type 1 and 2 reactions occur? What are they? Rx?
- Usually in first two months of rx but can occur any tome
Type -1 due to delayed hypersensitivity to m leprae. Erythema and tenderness of lesions and sometimes rapid nerve damage
Type 2 - Erythema nodosum leprosum. Caused by immune complex deposition. Get systemic upset
- Treat both with steroids
- Erythema nodosum leprosum will also need thalidomide
Which vaccine provides some protection from leprosy
BCG
How many lesions in pure tuburculoid leprosy
Usually 1 (may have a coupe in 1 area) erythematous macule/plaque with well defined borders
Characteristic lesions in borderline leprosy
Has a central lesion with ‘punch out’ normal skin in middle
Seen on biopsy of leprosy? Which stain?
Inflammatory Infiltrate along vessels and nerves
Mycobacteria seen on Modified Ziehl-Neelsen Stain (Wade-Fite Stain)
How do you define Paucibacillary leprosy
Negative samples for AFB
Plague distribution
Madagascar has most worldwide >60% total
Still loads wtf
Plague cause - appearance ? Temp grown at
Yersinia pestis
Gram negative bacillus, bipolar staining
(closed safety pin) - bipolar nuclei
Optimal growth rate 28 º C
Name 2 virulence factors in plague
Yersinia outer membrane proteins (Yops)
-Inhibit phagocytosis
- Downregulate pro inflammatory cytoquines
- Induce cell death
Fraction1 antigen ( 37 o C, antiphagocytic
V antigen LcrV Survive and multiply within
macrophages anti inflamatory activity
Coagulase - Blood clots in the proventriculus of the flea
-Active at 30 ºC
Plauge resevoirs
Urban - Rattus rattus
Rural - other rodents
Plague tranmission
Flea regurgitates infectious remnants (Y pestis) from a
previous blood meal into bite wound
-Ingestion of contaminated animal tissues
-Handling of contaminated animal tissues, laboratory infections
-Man to man (coughing) inhalation pneumonic
[Xenopsylla cheopis]
Where does y pestis go to (if not inhaled)?
Skin -> regional lymph nodes
->lymphatic obstruction -> lymphedema
Thrombosis in blood vessels -> haemorrhagic necrosis
Sudden onset Chills, fever, weakness, headache
Intense pain over a lymph node
Absence of ascending lymphangitis
High fever ?
Bubonic plague -Most common presentation of y pestis
Absence of ascending lymphangitis is key. Usually a single lesion
Plague usually doesnt have skin lesions (bar bubos) but what might you see?
Papules, vesicles, pustules, eschars, carbuncles
- Rarelycellulitis, abscesses Purpuric
->necrotic -> gangrene
Pneumonic plague transmission? outcomes
Inhalation
Haemategonus
100% fatal (often within 24hrs) without Rx
50% with rx
Key complication of bubonic plague with axillary bubos and incomplete rx?
Meningitis
Assoc with axillary buboes + inadequate Rx
Plague ix
Culture - Eg bubo aspirate, blood, csf…
Cary Blair medium
RDT blood
PCR etc
Plague Rx
Cipro (or doxy) + gent
co-trimox if preg
Prague rx if contact with case
Cipro again
Co-trimox if kids
Whats needed to develop sypmtoms with leprosy
Defect in specific cell-mediated immunity (specific to leprosy)
Which leprosy?
History of a few months
Macule 1-3 asymmetric
totally plane
hypochromic
ill defined margin
Sensation Normal
NERVES Normalf
Borderline
Which leprosy ?
Well defined border with central healing
hypopigmented/erythematous/coppery
dry, scaly, no hair
Anesthesia on lesions
1-2 nerves affected
Tuberculoid
Which leprosy
5-25 lesions
Decreased sensation
Mostly well defined margins
Mostly anaesthetic
Borderline tuberculoid
Multiple plaques
Well-defined / sloping margins
Erythematous punched-out margins
Decreased sensation
Mid borderline
Many small plaques
Mixed defined margins
Some infiltrated skin
Mostly normal sensation
Many nerves affected
Borderline lepromatous
Nasal stuffiness crusts
Infiltrated skin Numerous bilateral, symmetrical or diffuse
Sensation preserved
Nodules and papules
Often shiny thickened skin
Lepromatous leprosy
Which form of leprosy gets type 1 vs type 2 reactions
Leprosy on Rx
Lesions swell up, erythematous, shiny, warm
Necrosis, ulceration and New lesions
Nerves: Swelling, pain, tenderness
Paresia, paralysis, hypoesthesia, anaesthesia
Describing?
Left of image = before therapy
Right = after
Type 1 reaction
Left before, right after
**not always after starting therapy
Who gets this reaction with leprosy? what is it?
Only BL or LL
Erythema nodosum leprosum
-Can occur anywhere on the body
What is this in leprosy? Caused by? Rx?
Lucio phenomenon
Pathology: Severe necrotizing vasculitis, endothelial cells
Mycobacterium lepromatosis
prednisolone
