hydatid diseases
TRANSCRIPT
HYDATID DISEASES
ByDr. Sayan Chakraborty
2nd Year PGT- MD Tropical MedicineSchool of Tropical Medicine, Kolkata
E-mail: [email protected]
WHO/CDC NTDs
CASE HISTORY An 26 yrs old female presented with dull pain right side
of upper abdomen, a dragging sensation over right hypochondrium and occasional fever nearly one month
• Pain not relieved with analgesics
• Examination revealed mild hepatomegaly
• Routine blood test was normal
• Advised for imaging study of abdomen
DIFFERENTIAL DIAGNOSISHEPATIC SAPCE OCCUPYING LESIONS
Cystic/PseudocysticSpace-Occupying Lesionswith Liquid Content
Solid Space-OccupyingLesions
CONGENITAL SPACE-OCCUPYING LESIONS
Simple cyst Haemorrhagic simple cyst
VASCULAR SPACE-OCCUPYING LESIONS
Haematoma HaematomaHaemangioma
INFECTIOUS SPACE-OCCUPYING LESIONS
CE [CE1, CE2, CE3a,CE3b (mixed cystic-solid)]AE with pseudocystAbscess
CE [CE3b (mixed cystic-solid),CE4 and CE5]AETuberculoma
BENIGN SPACE-OCCUPYING LESIONS
Cystadenoma Hepatic adenomaFocal nodular hyperplasia
MALIGNANT SPACE-OCCUPYING LESIONS
CystadenocarcinomaLiver metastases with central necrosis
Metastatic liver tumoursHepatocellular carcinomaCholangiocarcinoma
INTRODUCTION• Zoonosis• 3 forms of Echinococcosis:Cystic echinococcosis (CE): Tropical and subtropical regions;
Echinococcus granulosus (Unilocular cyst) Alveolar echinococcosis (AE): Temperate northern
hemisphere; Echinococcus multilocularis (Multilocular cyst)Polycystic echinococcosis (PE): Latin America; Echinococcus
vogeli & Echinococcus oligarthus
CE eradicated in Iceland, New Zealand and Tasmania. Definitive host: Dogs and other canines Intermediate host: Sheep, goat, swine etc
GLOBAL DISTRIBUTION
Figure 1. Geographic distribution of hydatid disease. Map shows areas in which hydatid disease is endemic due to the transmission of E granulosus by means of the dog-sheep cycle (solid red areas). Red stripes indicate areas where transmission occurs by means of alternative life cycles in which carnivores such as wolves and foxes serve as definitive hosts and goats, camels, and horses serve as intermediate hosts. Transmission by means of alternative life cycles is common in North Africa, the Middle and Far East, the United States, Canada, and Iceland
LIFE CYCLE
EPIDEMIOLOGY Cystic Echinococcosis:• Highly endemic in pastoral communities• Genotypes G1–10; G1 strain of E. granulosus accounts for 95%
of human infections and has a dog-sheep transmission• Incidence rates as high as 50/100 000 person-years• Risk factors: Ownership of livestock (mainly dogs, sheep);
occupation (pastoralism, agriculture); uncontrolled slaughtering; poor water hygiene Alveolar Echinococcosis: • Definitive hosts: mainly foxes and domestic dogs• Intermediate hosts: Arvicolid and Cricetid rodents• Prevalence: 0.02% and 1.4%• Global annual incidence 18,235 cases per year
CYSTICECHINOCOCCOSIS
PATHOGENESIS• One or more spherical cysts, most frequently in liver & lungs• Tissue damage & organ dysfunction by gradual process of
space occupying compression• Cyst structure:o Outer pericyst: composed of modified host cells that form a
dense and fibrous protective zoneo Middle laminated membrane: acellular and allows the passage
of nutriento Inner germinal layer: forms brood capsule which develops
asexually into protoscolices (the larval stage of the parasite) from which daughter cysts are produced.
• Cysts modulate immune response by Th1 cell activation & impairment of macrophages
Natural Evolution of Cysts
CLINICAL FEATURES• Asymptomatic in most cases; incidental finding• Most symptomatic cysts are ≥ 5 cm• Pressure effect on liver and biliary tree• Abdominal pain , hepatomegaly, jaundice
• Pulmonary cysts: Cough with expectoration, SOB, chest pain, hemoptysis• Other sites: Pathological #, Brain SOL, Conduction
defects, Pericarditis, Pelvic mass• Leakage of cyst contents or infection of cyst• Pain, flushing and urticaria• Anaphylactic reaction• Fever and sepsis
COMPLICATION OF CYSTS• Cysts with fistulas• Biliary/bronchial obstruction (due to spillage of cyst content via cysto-biliary/cysto-bronchial fistulas)• Bacterial infection• Compression syndromesBlood vessels (leading to thrombosis, Budd–Chiari
syndrome)Biliary ductsBronchiParenchyma/muscles, nerves (leading to atrophy)• Cyst rupture• Venous/arterial embolism
OTHER DDx
• Neurocysticercosis• Cholangiocarcinoma • Imaging in NonSmall Cell Lung Cancer• Imaging in Small Cell Lung Cancer• Imaging of Benign Breast Calcifications• Lung Metastases Imaging• Metastatic Cancer With Unknown Primary Site• Pancreatic Pseudocyst Imaging• Pyonephrosis• Renal Cancer• Splenic Abscess
INVESTIGATIONS LABORATORY WORK UP:• Routine lab tests: No specific findings• Cyst rupture in biliary tree: marked & transient elevation of
cholestatic enzyme levels , often with hyperamylasemia and eosinophilia <15% (in 60% cases)
• SEROLOGY: Confirmatory role; Indirect hemagglutination test & ELISA for detection of anti-Echinococcus Antibodies [IgG]
• 10% hepatic cysts & 40% pulmonary cysts exhibit false negative results
-ve in CE1/CE2/CE4/CE5; +ve only when endocyst ruptures• Diagnostic puncture & aspiration can be performed for
histological diagnosis• PCR contribute to the differential diagnosis between CE and
AE in doubt.
INVESTIGATIONS IMAGING: USG is Inv of choice (Gharbi US classification of
1981 & WHO-IWGE 2003 classification)
OTHER INVESTIGATIONS• CT scan can detect extrahepatic smaller cysts, differentiating
parasitic from nonparasitic by measurement of cyst density & for follow up studies during chemotherapy
• MRI used in the evaluation of postsurgical residual lesions, recurrences & cardiac infections. Also superior in identifying changes of the intrahepatic and extrahepatic venous system & in identifying cystobiliary fistulas.
• Assessment of Parasite Viability: Histopathology (intact parasite-derived cyst wall including
germinal layer) Evaluation of the protoscolices (flame cell activity and
morphological integrity; eosin staining) Metabolic viability assessment using high-field H-MRS of cyst
content RT-PCR
CASONI’S TEST
MANAGEMENT Depends on the size, location and manifestations of cysts In uncomplicated cysts: “Expert consensus for the diagnosis
and treatment of cystic and alveolar echinococcosis in humans”, published by the WHO-Informal Working Group on Echinococcosis recommends four treatment modalities:
• 1. Drug treatment with benzimidazoles• 2. Percutaneous sterilization techniques• 3. Surgery• 4. ‘Watch and wait’
BENZIMIDAZOLES Indication: 1. CE 1,2,3a,3b of size 5-6 cm2. Prevention of secondary CE after interventions or after
spontaneous rupture; starting at least 4 hours before & upto 1 month after intervention
• Dosage: Albendazole 10-15 mg/kg/day in 2 divided doses or Mebendazole 40-50 mg/kg/day in 3 divided doses; with a fat-rich meal for 3-6 months
• Monitoring: Liver enzymes (upto 2-4x) & CBC at day 5, 10, then at 2 weekly intervals ,later monthly
• Contraindications: Pregnancy; cysts at risk of rupture; hepatoxicity; leucopenia; bone marrow suppression
• Follow up: 12 months after treatment completion to look for re-activation & min of 5 yrs after cysts reached inactive stage (CE4, CE5)
Puncture – Aspiration – Injection – Re-Aspiration (PAIR)
• Indication: CE1 and CE3a cysts of liver of size 5–6 to <10 cm• Principle: Sterilization of the germinal layer and protoscolices.
Only fluid is removed; all other parasitic material remains • Prerequisites: Experienced interventionalist; resuscitation set
up for severe anaphylactic reactions & surgical back-up
Puncture – Aspiration – Injection – Re-Aspiration (PAIR)
• Major steps :1. Prophylaxis of secondary echinococcosis with albendazole2. Percutaneous puncture of the cyst under US (or CT) guidance3. Aspiration of cyst fluid4. Testing for bilirubin (evaluation of aspect of fluid and test strip result) and injection of contrast medium (verification of absence of cysto-biliary communications)5. Aspiration of contrast medium6. If fistulas are reliably ruled out: injection of protoscolicidal agent – 95% ethanol or 20% NaCl to remain in the cyst for 10–15 mins7. Re-aspiration of the fluid8. Follow-up for a minimum of 5 years to detect relapses and secondary CE
SURGERY
• INDICATION:1. Any cyst >10 cm
irrespective of CE staging2. Cysts 5-6 to <10 cm in CE 2
and CE 3b3. Complicated cysts
• FOLLOW-UP: minimum of 5 years.
SURGERY1. Partial Cystectomy: Removal of the parasite-derived cyst components (endocyst) & part of the pericyst (host-derived connective tissue capsule).2. Total cystectomy and Resectiona. Total cystectomy: endocyst and the entire pericystb. Resection: additional removal of part of the organ where CE-cyst is embedded
‘Watch and Wait’
• Cyst allowed to progress along its natural course if asymptomatic
• Indicated in CE 4 & CE 5 Stages
• Follow-up patients with CE4 and CE5 cysts for a min of 5 years
Management of Complicated Cyst
Cysto-biliary and cysto-bronchial fistulas: ERCP, if possible, followed by early surgery under albendazole cover
Bacterial Infection: Initially, abscess management with drainage and antibiotics followed by specific management of residual CE cyst/cavity & albendazole therapy
Compression Syndromes: Rapid decompression of blood vessels, bile ducts, bronchi, parenchyma, muscle, nerves
Cyst Rupture: Allergic Reactions and Secondary CE:• standard approach to allergic reactions including anaphylactic
shock followed by CE-specific treatment• To prevent secondary CE, surgical intervention to clear CE cyst
material and benzimidazole therapy
PREVENTION 4 phases: (1) planning; (2) attack; (3) consolidation; and (4)
maintenance of eradication
Horizontal approaches: Slow-track (>25 yrs)• reduction of disease transmission through primary healthcare
interventions, including health education, general husbandry improvements, upgrading of abattoirs & meat inspection
• regular deworming of dogs by their owners
Vertical or fast-track approach: 3-5 yrs• Mass treatment of dogs, dog registration and reduction of
stray dog numbers• EG95 vaccine 95% effective against ovine hydatidosis
ALVEOLARECHINOCOCCOSIS
INTRODUCTION Organism: Echinococcus multilocularis Global distribution: Temperate northern hemisphere Epidemiology: • Definitive hosts: mainly foxes and domestic dogs• Intermediate hosts: Arvicolid and Cricetid rodents• Prevalence: 0.02% and 1.4%• Global annual incidence: 18,235 cases per year Site of infection:• E. multilocularis metacestode (larva) develops primarily in the
liver. • In advanced stages, other sites may become metastasized
such as retroperitoneum, lungs, brain and bones
PATHOLOGY• Conglomerate of scattered vesicles, each ranging from a few
mm to cm in size• Germinal layer represents the proliferating metacestode
generating new vesicles, which leads to the tumour-like behaviour of the parasite.
• A granulomatous host reaction surrounds the metacestode, including a vigorous synthesis of fibrous and germinative tissue.
• 3 immune mediated clinical outcome:(1) resistance as shown by the presence of ‘dying out’ or ‘aborted’ metacestodes; (2) controlled susceptibility by a slowly growing metacestode tissue – presents 5–15 years after infection;(3) Uncontrolled hyperproliferation of the metacestode due to an impaired immune response
DIAGNOSIS• Serology: Em2, Em2+, Em18 antigens• Imaging: USG/CT/MRI/PET• Diagnostic puncture and aspiration of parasitic material• Histology• RT-PCR
• PNM Classification: Resemblance to malignant diseasesP primary mass in the liverN involvement of neighbouring organs (lymph nodes)M metastases
MANAGEMENT• Curative treatment is possible with combination of radical
surgery with 2 cm liver margin & subsequent drug treatment (benzimidazoles) for at least 2 years.
• Life long follow up• Recurrences have been observed almost 20 years after surgery• After successful surgery, anti-Em18 or anti-Em2+ antibodies
decline rapidly, and seroconversion to undetectable levels correlates well with curative resection
• Advanced stage lesions: life long benzimidazole therapy & management of acute problems such as obstruction of bile ducts, abscess formation and thrombosis of major blood vessels
• Liver transplantation
ATYPICAL CASES
PUBLICATIONS
PUBLICATIONS
PUBLICATIONS
HYDATID CYST OF BRAIN
HYDATID CYST OF BONE
HYDATID CYST OF SEMINAL VESICLE
HYDATID CYST OF SPINE
REFERENCES1. Manson’s Tropical Diseases (23rd Ed)2. Harrison’s Principles of Internal Medicine 19th edition3. Mandell Douglas and Bennett Principles and Practice of
Infectious Diseases 7th Edition 4. WHO | Echinococcosis; www.who.int/echinococcosis/en/5. CDC – Echinococcosis;
www.cdc.gov/parasites/echinococcosis/6. Links:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3716240/ http://europepmc.org/abstract/med/593481 http://pmj.bmj.com/content/79/928/113.full