(From Path, Dr. Tweeddale, 30 Oct 2000, by Brian Buschman)
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Lyme disease is caused by the spirochete Borrelia. In lyme disease you have a spirochetemia with a superficial showing.
Impetigo is a skin infection. You need to be careful when viewing impetigo to determine if it is from a bacteria or from a fungus. It may be best to mix some fungoside with an antibiotic to be able to treat for either infection.
Leptospirosis is another spirochete that infects people that come into contact with urine contaminated water, often from swimming.
It develops after a week or two and when it resolves it may then come back at Wiel’s disease. Wiel’s disease is the more severe form that can show jaundice and meningitidis. Leukocyte levels are near 70%.
Listeria are the one gram positive that have endotoxin. They also travel within the system via microfilaments not blood so they can often avoid antibody formation.
Listeria is interesting in that it can grow at 4oC so it can be found on the food in the fridge. It also looks like “Chinese letters” when plated.
It invades newborns as they are born in contrast to some that invade through the placenta. Those that invade through the placenta include HSV, syphilis, CMV and syphilis. Remember syphilis is from Treponema palladium, a spirochete.
Arbovirus is a common cause of viral meningitis. It is transmitted by mice like those in his shack.
When a patient presents with meningitis it’s up to you to determine if it’s caused by viral or bacterial. Both look the same clinically but when you analyze CSF the viral meningitis will have a normal glucose level while the bacterial one will be greatly reduced. Normal CSF glucose is about 50% that of the blood. Viral meningitis may be from Arbovirus, mumps, EBV, HSV or coccivirus. ID of the viral organism is not usually important. You can treat them all the same. Bacterial you probably need to know the organism to prescribe the proper antibiotic.
Pneumonia may be viral or bacterial. There are many exceptions to the rules but in general viral pneumonia is interstitial and bacterial is lobar.
Types of intestinal pneumonia include:
|
Viral |
Non-viral |
|
Influenza |
Rheumatoid Arthritis |
|
Parainfluenza |
SLE |
|
Adenovirus |
Chlamydia |
|
RSV |
Coxiella |
|
Coxsackie |
PCP |
|
Echovirus |
|
|
Measles |
|
|
HSV |
|
|
Variecella-zoster |
|
Note that of the non-viral causes of intestinal pneumonia Chlamydia is just about the only bacteria. Chlamydia is also the world’s most common cause of blindness.
In this case we know that it is interstitial because there is scant sputum. If it were lobar there would be more sputum. You think Chlamydia because he worked with birds.
The patient presented with bradycardia which would usually be typhoid. This is an exception being another Rickettsia. This is Coxiella (Q-fever). It is seen in the U out in CA. When you think of CA you can think of Coccoidies and Coxiella. Coxiella can be differentiated from Rickettsia because it is the only member of the family that does not present with rash.
With a dog bite that you suspect might be related to rabies the first thing that you need to do it quarantine the dog. This prevents additional spread until you know if it is or not. If the dog dies you have rabies.
With rabies you get a widespread inflammatory reaction with neural degeneration. Rabies also has Negri bodies which are eosinophilic cytoplasmic inclusions.
Salmonella is an enteric that presents with headache and stupor.
The megaloblastic anemia will probably be a B12 deficiency. The question comes in as to whether there is a shortage of B12 or if there is an organism that is using it all up. One way to test is to load the patient with a large dose of labeled B12 and see if some becomes excreted in the urine. When there is an abundance of the B12/IF complex in the blood the kidneys let it go. If there is an organism metabolizing the B12 then it will metabolize this B12 causing no excretion and you need to find and treat the organism. If it becomes excreted then you need to give them B12 supplements.
One critter that can use B12 in this way is Taenia which is a tapeworm which comes from undercooked beef or pork.
Tachyzoites is a buzzword for Toxoplasma gondii as it is a rapidly growing tissue. You can look for Toxoplasma in the feces.
Trichonella causes problems with muscle pain and swelling. Trichonella likes to invade the more active muscles like the oculars and diaphragm. You will see muscle pain and periorbital swelling.
This is a case of visceral larval migrans from the kid that injests larva (eating dirt). It is similar in function to cutaneous larval migrans but is if of the viscera rather then skin.
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