Intestinal Nematodes Lecture

Introduction

• Focus on high-yield information about intestinal nematodes.
• Common issue: students often prioritize bacteria and viruses, neglecting helminthic infections.
• Goal: Cover high-yield information and provide a mnemonic (a poem) for better recall.

Overview of Intestinal Nematodes

• Intestinal nematodes are helminthic organisms (parasitic worms).
• Tubular digestive systems with openings at both ends.
• Commonly reside in topsoil, transmission often through contact with contaminated soil.
• Human immune system fights them using eosinophils.
  • Type I hypersensitivity reaction: involves histamine.
  • Type II hypersensitivity reaction: involves eosinophilic attachment via IgE.

Key Nematodes

Enterobius Vermicularis (Pinworm)

• Transmission: Fecal-oral, ingestion of pinworm eggs.
• Symptoms: Perianal pruritus (itching around the anal area).
• Diagnosis: Cellophane tape test (eggs on tape).
• Treatment: Bendazoles.
• Key Buzzwords: Perianal pruritus, cellophane tape test.

Ascaris Lumbricoides

• Transmission: Fecal-oral.
• Symptoms: Obstruction of tubular structures (pancreas, gallbladder), pneumonitis, eosinophilia.
• Diagnosis: Stool exam for ova and parasites.
• Treatment: Bendazoles.
• Key Buzzwords: Obstruction of tubular structures, stool exam for ova and parasites.

Strongyloides Stercoralis

• Transmission: Transcutaneous (larvae in contaminated soil).
• Symptoms: GI symptoms (diarrhea, abdominal pain), respiratory symptoms (cough), Loeffler syndrome (eosinophilic pneumonia).
• Risk Factors: Immunosuppressed patients, HIV, HTLV-1, alcoholism, occupational exposure (farmers, miners).
• Treatment: Bendazoles, ivermectin.
• Key Buzzwords: Transcutaneous infection, soil exposure, Loeffler syndrome.

Ancylostoma Duodenale and Necator Americanus

• Transmission: Transcutaneous from contaminated soil.
• Symptoms: Cutaneous larvae migrans (itchy snake-like rash), anemia, protein loss.
• Pathogenesis: Worms attach to intestinal capillaries, causing rupture.
• Treatment: Bendazoles, pyrantel pamoate.
• Key Buzzwords: Itchy snake-like rash (cutaneous larvae migrans), anemia, protein loss.

Trichinella Spiralis

• Transmission: Consumption of raw or undercooked pork.
• Phases:
  • Intestinal phase: release of larvae.
  • Systemic phase: larvae travel to muscle tissue (myocardium, brain, skeletal muscle).
• Symptoms: Myalgia, periorbital edema, non-specific GI symptoms (fever, chills).
• Treatment: Bendazoles.
• Key Buzzwords: Myalgia, periorbital edema, pork consumption.

Trichuris Trichiura

• Transmission: Fecal-oral, often in warm, humid climates.
• Symptoms: Rectal bleeding, rectal prolapse, nocturnal passage of stools, painful defecation, mucusy stools.
• Severe Symptoms: Anemia, poor nutrition, failure to thrive.
• Treatment: Bendazoles.
• Key Buzzwords: Rectal prolapse, rectal bleeding.

Mnemonic Poem

• Enter eggs in the anus will make it itchy
• Pork makes you spiral, the muscle gets glitchy
• Strong from the soil causes poops and coughs
• The Ankle of America makes capillary sloth
• Trichuris indeed, the prolapse protrudes
• Them lumber in the tubes, this will elude
• The nematode poem, that is all
• Treat all these worms with bendazole

Conclusion

• Key high-yield points and mnemonics covered for intestinal nematodes.
• Focus on symptoms, diagnosis, transmission, and treatment.
• Use the mnemonic poem for quick recall on exam day.