Bug

Helminths Bug Ascaris lumbricoides Clinical Buzz Words Man in Louisiana has CC of cough, fever, abdominal pain -CXR - pulmonary infiltrates, intestinal obstruction -CBC- increased Eos -Stool- microscopic oval eggs with rough surfaces -gives pt pyrantel pamoate Dz Asymptomatic Ascaris pneumonia Malnutrition Intestinal occlusion Common in tropics Pathophys Fecal-oral transmission or eggs in soil  hatch in small intestine  larvae invade gut wall  enter blood  land in lungs  invade alveoli  make their way to the trachea  inflammation  pneumonia Larvae go to pharynx  swallowed  larvae mature into adults in SI  swim freely in lumen and eat what the host eats  malnutrition. Adults can form a big ball that obstructs the bowels Lay eggs  eggs in stool Fecal oral transmission  ingestion  hatch in duodenum and jejunum  mature in the ileum and LI  mate in colon  at night females migrate out of rectum to perianal skin  lay eggs  perianal pruritis Scratching contaminates hands  spread infection Larvae in cow muscle  ingestion of poorly cooked beef  larvae mature and grow in SI  adults have a scolex (head) and numerous proglottids (autonomous segments)  head attach to intestinal wall, tail dangles in feces and passes eggs  cows ingest eggs Worm can cause malnutrition Dx Stool – see eggs with rough surface Eosinophilia Tx Pyrantel pamoate Mebendazole Albendazole Enterobius vermicularis Mother brings kid in with CC of “negative” behaivor. Kid scratches anus incessantly -doc does “scotch tape” test Perianal pruritis (pinworm) Scotch Tape – adhere tape to perianal region, remove and check for eggs Mebendazole, albendazole Pyrantel pamoate Taenia saginata Cow rancher has CC of “worm hanging from his anus” -stool sample- rectangular proglottid segments grossly, low power microscopy shows eggs -pt will get better in a day with drugs and should avoid undercooked beef Vietnamese immigrant has CC of severe headache and seizures -nodules everywhere -Head CT- 5 calcified cysts -CBC- high Eos -Nodule biopsy- cysts in the nodules -pt gets prazinquantel and steroids immediately Beef tapeworm Malnutrition Abdominal discomfort Asymptomatic Stool: proglottids, eggs Niclosamide + Cathartic Praziquantel Taenia solium Pork tapeworm Intestinal infection: no sx, malnutrition, abdominal discomfort Tissue infection: cysticercosis (neuro/blindness) For intestinal infection, see Taenia saginata For tissue infection: Eggs in infected feces ingested  hatch into oncospheres in SI  penetrate intestinal wall  travel to distant sites  form cysticerci containing larvae, esp in brain, muscle and eye. Cysts grow slowly  neuro defects. When cysts die there is increased inflammation which agravates sx Proglottids in stool Calcified cycticerci in muscle, brain on XRay Eosinophilia in muscle or brain Intestinal: Niclosamide + Cathartic; praziquantel Tissue: prazinquantel or albendazole + steroids Helminths Bug Trichenella spiralis Clinical Buzz Words Pig farmer presents with CC of myalgia, fever, and facial swelling -2 wks ago he had upset stomach and diarrhea -CBC- eosionphilia, inc IgE, inc muscle enzymes -if biopsy- cysts in the muscle Dz Gastroenteritis Myalgia Pathophys Pig reservoir  encysted larvae infested in raw meat  larvae mature into adults in SI  mating and eggs laid, growing into larvae  larvae penetrate gut wall  hematogenous spread, diarrhea, pain. Larvae track to muscle, esp of eye, masseters, tongue, and diaphragm  inflammation  mayalgia. larvae form fibrous cysts in muscle. Cysts persist for years, may calcify. If large inoculum of encysted larve, can infect heart and brain Eggs in dog feces  ingestion  hatch in larvae in small intestine  larvae penetrate gut wall  travel to other tissues  form hydatid cysts in liver, lung, or brain Cysts grow and divide  expansion of organ Dx Eosinophilia Muscle biopsy + for cysts with larvae Serology Tx Mebendazole / thiabendazole to kill adult worms in SI No tx for muscle cysts Steroids for severe myositis, myocarditis Ecchinococcus Woman presents with CC of abdominal discomfort granulosus Strongyloides stercoralis -RUQ pain, hepatomegaly -CT- large circular mass in liver with multiple daughter cysts with “egg shell” calcifications -South Carolina woman has CC of diarrhea -CBC shows  Eos -Stool shows larvae but no eggs -pt freq goes barefoot -doc is worried about peritonitis Dog Tapeworm Echinococcosis or hydatid cyst disease Xray or CT – cysts with daughter cysts Serology Surgery Albendazole Gastroenteritis Pneumonia Diffuse autoinfection None Fecal-cutaneous trans  infectious larvae penetrate skin of feet  itching. Itching opens cuts so bug goes to blood, tracking to the lungs infecting alveoli and the trachea  respiratory inf, possibly pneumonia Larvae go from trachea to pharynx  swallowed  larvae mature into adults in SI  mate, invade mucosa and lay eggs. Eggs hatch  inflammation (gastroenteritis). Tunneling action can introduce gut bacteria to peritoneum  peritonitis Larve exit via feces to restart life cycle or reenter blood to infect lungs and UR system Detect larvae in stool Eosinophilia String test – swallow string, pull out larvae Ivermectin Thiabendazole Helminths Bug Necator americanus, Ancylostoma duodenale Clinical Buzz Words Child from rural Alabama has CC of severe weakness and pallor -CBC shows  hematocrit with hyopchromic microcytic RBC with increased EOS. -Stool sample shows lots of eggs -the child may have gotten the illness by walking barefoot Dz Pneumonia Gastroenteritis Anemia [Hookworm] Pathophys Fecal-cutaneous trans  infectious larvae penetrate skin of feet  itching  enter blood  track to lungs  enter alveoli and ascend towards trachea  respiratory tract inf (possible pneumonia) Larvae go from trachea to pharynx  swallowed  larvae mature into adults. Adults use teeth to attach to mucosa and release anticoagulant, then they suck blood from the host  anemia Mating produces eggs that are passed in feces and then hatch in soil Larvae live in snails, then get released into freshwater. Penetrate skin  blood  track to portal vein, where they mature into adults. Migrate to various venous plexi GI venous plexus  mate  release eggs  acute inf response that produces a syndrome called Katayama fever (fever, chills, nodes). Eggs get into lumen  passed via feces Eggs enter portal circulation  chronic inf  periportal fibrosis  HTN, splenomegaly, esophageal varices Eggs in GI wall  chronic inf  GI inf  polyps Bladder venous plexus  mate  eggs  acute inf (katayama fever), eggs get into bladder lumen and passed in urine Eggs that lodge in bladder wall  chronic inf  hematuria, CA. Eggs hatch and the larvae infect snails Dx Detect eggs, not larvae, in stool Eosinophilia Tx Mebendazole Pyrantel Pamoate Fe and Folic acid to tx anemia Schistosoma African man as CC of vomiting blood. species -says stool has been dark for years -denies EtOH and says he likes to freshwater fish -Endoscopy shows esophageal varices -stool shows eggs African woman has CC of bloody urine -works in freshwater rice fields Schistosomiasis Blood fluke Katayama fever Acute: Itchiness at site of infection, fever, chills, nodes Chronic: periportal fibrosis, intestinal polyps, bladder inf, hamaturia, Squamous bladder CA Adults coat themselves with host antigens, allowing then to live in the host for years. The eggs however are very offensive Eggs in urine or feces Eosinophilia Prazinquantel Helminths Bug Onchorcerca volvulus Clinical Buzz Words The elders in a village in S. America are blind. -villagers have skin nodules and hyperpigmented rashes -the blindness can be prevented with invermectin and mosquito control Dz Skin nodules Thick, dark, pruritic rash River Blindness Pathophys Black fly near rivers  bite host  release larvae into skin. Larvae move through tissue and mature into adults  fibrotic nodule encloses bug  skin nodule. Adults mate and release micrifiliare into subcutaneous tissue Microfiliarie disseminate  inf  thick, dark rash. If reach eye  inf  blindness Microfiliare need to be ingested by mosquito to become larvae and complete the lifecycle. Transmitted via mosquito. Bite puts larvae into blood  carried to lymph nodes of genitals and lower extremities  mature into adults over the course of 1 yr. Adults mate and release larvae into blood. Adults trigger inf  fever, swollen nodes Repeated infection  fibrosis around dead adults worms in the nodes  obstruction  edema and scaly skin in legs and scrotum Dx Skin biopsy shows microfiliare (adults in nodules) Tx Ivermectin – kills microf, not adults Excision of nodules Wuchereria bancrofti Pt from tropical village has CC of massively swollen scrotum and lower extremities -skin around swelling is scaly and thick -pt felt nodules in groin mos ago -Blood draw at night shows worm-like bugs -mosquito nets are prescribed to villagers Filiarasis, Elephantiasis Fever, edema, scaly skin and scaly genitalia Detect blood in nocturnal blood draw Diethylcarbamazine (only effective against microfiliare, not adults)