Day 10: tape worms, echinococcus
Tapeworms:
Today we
discussed tapeworms, fish tape worm D. latum, pork Tape worm (T. Solium), beef
tape worm (T. saginata). Of all of them, probably the most significant is the
pork tape worm, not so much because infection with it causes disease, but
ingestion of its eggs causes neurocysticercosis. http://www.nejm.org/doi/full/10.1056/NEJM199209033271004
The article
often quoted to demonstrate this point with orthodox Jews in New York who
acquired it because their South American workers who were preparing the food
had the tape worm themselves. Having tapeworms can be difficult to diagnose, we
were told of one patient who was actually given anti-pscyh medications, the
take home point being to document (picture and or bring in the worm or
proglottids), to help identify it. Thereis a stool antigen (ELISA) for T.
solium.
Hymenolepsis
nana (not to be confused with E. nana) is a dwarf tapeworm causing abdo pain
and possibly pruritis, the one reason to check stool O&P in patient with
anal pruritis.
Liver
flukes:
We reviewed
a case of katayama fever, classically from someone swimming in a river (the
Nile is often mentioned in test question), then presenting several weeks later
with fever, cough, diarrhea (possibly pulm nodules on cxr) and eosinophilia. It
is felt to be due to immune response to antigens during Schistosoma maturation (strongyloides being a differential... maybe toxocara)
Treatment
is generally with steroids, praziquantal can be given after acute stage. The
life cycle of flukes reveals that an intermediate host (snails), is needed for
miracidium (from eggs) to develop into cercariae which can penetrate human skin
and make their way to the bowel or bladder (S. heamtobium). The paired adults migrate
to the mesenteric venules. We discussed that this can seed the spine or brain
via batsons plexus. Cirrhosis from Schisto is pre-sinusoidal, and thus often
not associated with jaundice.
A great
point brought up, are these individuals infective if they go to a public pool?
No, the intermediate host is needed to make cercariae.
S.
Hamatobium – in a nut shell, hematuria, associated with renal/bladder calcification
and possibly obstruction. Long term risk appears to be SCC of bladder due to
chronic inflammation of eggs.
Echinococcosis:
A very interesting disease, humans act as intermediate hosts (like sheep), and
issues arise when dogs get the worm when they ingest viscera from a dead
infected animal (sheep), humans ingest dogs feces with ova - from there cysts can form in the human, most
commonly in the liver. Treatment is carefully decided based on stages. A simple
cyst that is <5 cm will get albendazole vs a cyst filled with solid material
(stage 4 or 5) will receive no treatment. Patients with stage CE3b will
generally undergo surgery to completely resect this. However, many
complications can arise. Need to ensure there are no connections to the biliary
tree or vascular supply, also, need to be very careful to not have any leakage
of fluid, as this can lead to secondary echinococcosis.
Take home
point: cyst in the liver from an endemic place, think about the diagnosis…. Then
call someone who knows about the disease, US is used to stage not CT or MRI.
Cases on
rounds:
1. A child presenting with fever for
several days, muscle aches. His labs showed Hb 15, liver enzymes in the 100s,
and platelet count of 40. Patient’s with dengue often have 3 phases – febrile,
critical (plasma leak) and convalescence (resorption). Patient’s are to be
admitted if they warning signs which may suggest impending severe dengue (abdo
pain, nausea, vomiting, rectal bleeding, etc.). Patient’s have a classic rash
as seen below, islands of white in a sea of red which is actually often seen in
the convalescent phase (as in our kid). They also get erythroderma which is
non-blanching.
2. Patient was a 13 year old female
with 1 week of fever, high grade, fatigue, and abdo pain, her labs showed WBC
of 4000, normal hemoglobin and platelets were <150. She had blood cultures
positive for salmonella typhi. Patient was on ceftriaxone, as there is
increased resistance in India, generally susceptible in Africa. For adults,
typically patients get high dose azithromycin ~10 mg/kg per day AND ceftriaxone.
Generally, patients will have fever for ~4-5 days but will feel better. Dr.
Parry had also discussed a particular drowsiness he’s noticed with typhoid
fever.
3.
Patient was a 10 year old female
with previous TB meningitis, and now TB peritonitis (diagnosed by peritoneal
biopsy).
Comments
Post a Comment