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Referral and warning signs
When to refer
Refer ALL suspected or confirmed cases of Echinococcosis to Specialist care (Infectious Disease, Gastroenterology, Surgery at RR) for definitive diagnosis, staging, and multidisciplinary management planning (watch/wait vs PAIR vs surgery vs medication).
Red flags
- Signs of cyst rupture (sudden pain, fever, allergic reaction/anaphylaxis).
- Jaundice.
- Signs of secondary infection.
- Large cyst size or concerning location (e.g., brain).
Signs and symptoms
- Often asymptomatic for years as cysts grow slowly.
- Symptoms depend on location, size, and number of cysts.
- Liver Cysts (Most common site ~70%):
- - Often found incidentally on imaging.
- - Right upper quadrant (RUQ) abdominal pain or discomfort.
- - Palpable abdominal mass.
- - Nausea, vomiting.
- - Jaundice (if cyst obstructs bile ducts).
- - Cholangitis (if cyst ruptures into biliary tree).
- Lung Cysts (~20%):
- - Often asymptomatic.
- - Chronic cough, chest pain, dyspnoea.
- - Haemoptysis (coughing blood) if cyst ruptures into bronchus.
- - Expectoration of cyst contents ('grape skins').
- Other Sites (Brain, Bone, Kidney, Spleen - less common): Symptoms related to mass effect or rupture in that organ (e.g., neurological deficits, pathological fractures).
- Cyst Rupture: Can cause acute abdominal/chest pain, fever, eosinophilia, allergic reactions (urticaria, pruritus), potentially life-threatening anaphylactic shock.
Risk factors
- Living in endemic pastoral areas with close contact between dogs, livestock (especially sheep), and humans.
- Raising sheep.
- Owning dogs fed raw offal from livestock.
- Poor hygiene practices allowing ingestion of dog faeces containing eggs (contaminating hands, food, water).
Diagnosis
Clinical assessment
Suspicion based on presence of cystic lesion(s) on imaging in patient from endemic area or with relevant exposure history. Often asymptomatic finding.
Differential diagnosis
- Simple liver/kidney cyst.
- Liver abscess (amoebic or pyogenic).
- Hepatocellular carcinoma / Metastatic cancer.
- Lung abscess / Tumour / TB.
- Other cystic lesions.
Investigations
- Imaging: Key diagnostic tool.
- - Ultrasound (US): Preferred initial imaging for abdominal cysts. Shows characteristic features (cyst wall, internal septations, daughter cysts, hydatid sand). WHO classification (CE1-CE5) based on US appearance.
- - CT Scan / MRI: Provide more detail, better for assessing complications, complex cysts, or extra-abdominal sites (lungs, brain).
- - Chest X-ray: May show well-defined round opacity (lung cyst).
- Serology (Antibody detection - ELISA, IHA): Supports diagnosis, especially if imaging unclear or for screening. Sensitivity varies with cyst stage/location (higher for liver, lower for lung/inactive cysts). Can have false negatives/positives.
- FBC: Eosinophilia may be present, especially after cyst leakage.
- Aspiration (Fine Needle Aspiration Biopsy - FNAB): Generally AVOIDED due to high risk of leakage -> anaphylaxis and dissemination. Done ONLY in specialized centres under specific circumstances (e.g., diagnostic uncertainty, therapeutic aspiration - PAIR technique) with precautions.
Diagnostic criteria
Compatible imaging findings +/- Positive serology + Epidemiological context.
Management
Non-pharmacological management
- Treatment strategy depends on cyst type (WHO stage), size, location, complications, patient factors. Requires specialist multidisciplinary input.
- Watch and Wait: For small, asymptomatic, inactive/calcified cysts (CE4, CE5). Regular imaging follow-up.
- PAIR Technique (Puncture, Aspiration, Injection, Re-aspiration): US-guided percutaneous drainage for selected uncomplicated liver cysts (CE1, CE3a). Instillation of scolicidal agent (e.g., hypertonic saline, ethanol). Requires peri-procedural Albendazole cover.
Pharmacological treatment
- Antiparasitic Drugs (Benzimidazoles):
- - Albendazole: Drug of choice. Used peri-operatively (before/after surgery or PAIR) to reduce recurrence/dissemination risk, OR as primary treatment for small/multiple cysts or inoperable cases.
- - Dose: 10-15 mg/kg/day PO divided BID (Max 800mg/day). Given in cycles (e.g., 1 month on, 2 weeks off) for 3-6 months or longer. (LOC: RR)
- - Mebendazole: Alternative if Albendazole unavailable/intolerated.
- - Requires monitoring of LFTs and FBC during treatment.
Surgical Management
- Surgery: Indicated for large, symptomatic, complicated (ruptured, infected, biliary communication), or superficial cysts at risk of rupture. Goal is complete removal of cyst contents/lining without spillage.
- - Techniques: Pericystectomy, Cyst evacuation with omentoplasty, Liver resection.
- - Requires peri-operative Albendazole cover. (LOC: RR)
Monitoring
Regular imaging (US/CT) to monitor cyst size/activity. Monitor LFTs/FBC during Albendazole therapy. Monitor for recurrence after treatment.
Complications
- Cyst rupture -> Anaphylaxis, dissemination (secondary echinococcosis).
- Secondary bacterial infection of the cyst.
- Compression of adjacent structures (bile ducts -> jaundice; blood vessels).
- Communication with biliary tree or bronchus.
- Complications of surgery or PAIR.
- Drug toxicity (Albendazole).
Prevention
- Regular deworming of domestic dogs (with Praziquantel).
- Preventing dogs from accessing raw offal of livestock.
- Good personal hygiene (handwashing after contact with dogs/soil, before eating).
- Safe disposal of infected livestock carcasses/organs.
- Health education in endemic communities.
- Meat inspection.
Patient education
- Explanation of hydatid disease as a parasitic cyst from dog tapeworm eggs.
- Transmission cycle involving dogs and livestock.
- Treatment options and rationale.
- Importance of adherence to medication (Albendazole) if prescribed.
- Need for long-term follow-up.
- Prevention measures (dog deworming, hygiene).
Uganda-specific notes
Endemic, particularly in pastoralist communities (e.g., Karamoja) with close dog-livestock-human interaction. Diagnosis often relies on Ultrasound. Access to specialist care (PAIR, surgery, Albendazole) is limited.
References
- Uganda Clinical Guidelines (UCG) 2023
Chapter 2, Section 2.4.2