Hydatid Cyst

Hydatid cyst is a parasitic disease caused by the larval stage of Echinococcus granulosus, a tapeworm transmitted primarily through dogs and livestock. Humans become accidental intermediate hosts after ingesting parasite eggs through contaminated food, water, or direct animal contact. Once ingested, the larvae penetrate the intestinal wall and migrate via the bloodstream, most commonly lodging in the liver (approximately 60–70%) and lungs (20–30%). Less frequently, cysts may develop in the spleen, brain, bones, or peritoneum.

The disease progresses slowly and may remain asymptomatic for years. Clinical manifestations depend on cyst size, location, and complications. Hepatic hydatid cysts may present with right upper quadrant pain, hepatomegaly, nausea, or obstructive jaundice. Pulmonary cysts can cause cough, chest pain, and dyspnea. Rupture of the cyst may lead to anaphylaxis or secondary dissemination.

Diagnosis is established through imaging modalities such as ultrasonography and contrast-enhanced CT scan, supported by serological tests. Management includes anti-parasitic therapy with albendazole and definitive surgical intervention. Procedures range from cystectomy and pericystectomy to minimally invasive techniques such as PAIR (Puncture, Aspiration, Injection, Re-aspiration). Early diagnosis and structured surgical planning are essential to prevent recurrence and life-threatening complications.