Hydatid disease (cystic echinococcosis) caused by Echinococcus granulosus. The hydatid sand in aspirated cyst fluid consists of:
- A Sporocysts containing cercariae
- B Proglottids with characteristic lateral genital pores
- C Microfilariae in embryonic sheath
- D Free hooklets, scolices, and daughter cyst membrane fragments ✓
Explanation
Hydatid sand refers to the granular material that settles at the bottom of a hydatid cyst aspirate. Microscopically it contains free scolices (with suckers and hooklets), scattered protoscolices, calcareous corpuscles, brood capsule fragments, and free hooklets. These elements are derived from the inner germinal layer of the cyst. If viable scolices are demonstrated, it confirms the diagnosis of cystic echinococcosis. Aspiration carries risk of anaphylaxis from cyst fluid leakage; PAIR (percutaneous aspiration-injection-re-aspiration) with hypertonic saline is the current interventional approach.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.