Rhizopus vs Aspergillus

[acciddropping]

Is there an easy way to differentiate Rhizopus vs Aspergillus? Rhizopus has 90 degree hyphae vs Aspergillus has V shape 45 degree hyphae. however, when i looked at slides online, those hyphae are a mess - I can see both 90' and 45' .. is there a better way to differentiate between the two? thanks in advance.

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[Modeselektor]

look at the case:
Diabetes/Leukemia w/ facial pain, black eschar on face → Rhizopus

I haven't ever seen any other way its been asked. Rest assured if they give you a slide and ask "what is this?" it's going to be the most clear and beautiful slide you have ever seen in your life.

 

[Missorleans]

Is there an easy way to differentiate Rhizopus vs Aspergillus? Rhizopus has 90 degree hyphae vs Aspergillus has V shape 45 degree hyphae. however, when i looked at slides online, those hyphae are a mess - I can see both 90' and 45' .. is there a better way to differentiate between the two? thanks in advance.

The slides of aspergillus I've seen also have the spores, not just hyphae. Check out what the fruiting bodies of aspergillus and rhizopus look like. Rhizopus's sporangium looks like a ball full of spores, while aspergillus has phialides with spores coming off the tips. Also, rhizopus/mucor hyphae tend to have a flatter, ribbon-like look on slides and have very few septa (pauci-septate), whereas you will probably notice the septa in an aspergillus example.

 

[notbobtrustme]

look at the case:
Diabetes/Leukemia w/ facial pain, black eschar on face → Rhizopus

I haven't ever seen any other way its been asked. Rest assured if they give you a slide and ask "what is this?" it's going to be the most clear and beautiful slide you have ever seen in your life.

yea, I wish Uworld was like that. Just had a question that screamed Rhizopus and the picture had both acute and 90 degree branching and sure enough, the answer was Aspergillus. Answer breakdown was like 60% Rhizopus to >20% Aspergillus.

Maybe the USMLE will be clearer, but that question was ****ing crap.

 

[Modeselektor]

yea, I wish Uworld was like that. Just had a question that screamed Rhizopus and the picture had both acute and 90 degree branching and sure enough, the answer was Aspergillus. Answer breakdown was like 60% Rhizopus to >20% Aspergillus.

Maybe the USMLE will be clearer, but that question was ******* crap.

I think I recall doing that question, swearing at the screen and pushing next.

 

[Apoplexy__]

look at the case:
Diabetes/Leukemia w/ facial pain, black eschar on face → Rhizopus.

I wouldn't say leukemia, as that implies neutropenia (primary, or secondary to Tx). I learned the following lesson from QBanks:
Facial/Orbital pain with paranasal sinus tenderness in a patient w/ neutropenia: Invasive Aspergillus
Facial/Orbital pain with paranasal sinus tenderness in a patient w/ diabetes: Mucor/Rhizopus

The presentation is literally that similar, because I got that Aspergillus question on UWorld (probably the one you guys are referring to). Now, if you get the black eschar, my understanding is that that's pretty pathognomonic when combined with the other findings.

Another good thing is using what Missorleans said. They gave me some stupid pic of Aspergillus where the pic was a bloody mess of like 90% RBC's and a couple hyphae thrown in there. You couldn't see the acute angle branching, budding spores, etc. But you could see the frequent, delineating septae of the hyphae making it look like the hyphae was a tube of little BB gun balls or something. The Mucor/Rhizopus hyphae are very different from this.

 

[ChessMaster3000]

I wouldn't say leukemia, as that implies neutropenia (primary, or secondary to Tx). I learned the following lesson from QBanks:
Facial/Orbital pain with paranasal sinus tenderness in a patient w/ neutropenia: Invasive Aspergillus
Facial/Orbital pain with paranasal sinus tenderness in a patient w/ diabetes: Mucor/Rhizopus

The presentation is literally that similar, because I got that Aspergillus question on UWorld (probably the one you guys are referring to). Now, if you get the black eschar, my understanding is that that's pretty pathognomonic when combined with the other findings.

Another good thing is using what Missorleans said. They gave me some stupid pic of Aspergillus where the pic was a bloody mess of like 90% RBC's and a couple hyphae thrown in there. You couldn't see the acute angle branching, budding spores, etc. But you could see the frequent, delineating septae of the hyphae making it look like the hyphae was a tube of little BB gun balls or something. The Mucor/Rhizopus hyphae are very different from this.

really nice summary. I also want to add that, while this is not a hard and fast rule, UW and other sources make a big deal about aspergillus's invasiveness, and therefore bloodiness. you can often see a ton of RBCs on the slide of aspergillus. If that's the case (a lot of RBCs obscuring everything), and I truly was torn, I would tend to pick aspergillus.

 

[notbobtrustme]

I wouldn't say leukemia, as that implies neutropenia (primary, or secondary to Tx). I learned the following lesson from QBanks:
Facial/Orbital pain with paranasal sinus tenderness in a patient w/ neutropenia: Invasive Aspergillus
Facial/Orbital pain with paranasal sinus tenderness in a patient w/ diabetes: Mucor/Rhizopus

The presentation is literally that similar, because I got that Aspergillus question on UWorld (probably the one you guys are referring to). Now, if you get the black eschar, my understanding is that that's pretty pathognomonic when combined with the other findings.

Another good thing is using what Missorleans said. They gave me some stupid pic of Aspergillus where the pic was a bloody mess of like 90% RBC's and a couple hyphae thrown in there. You couldn't see the acute angle branching, budding spores, etc. But you could see the frequent, delineating septae of the hyphae making it look like the hyphae was a tube of little BB gun balls or something. The Mucor/Rhizopus hyphae are very different from this.

yea, don't generalize too much. I was going the route that the pt was immunocompromised, therefore, more suspectible to Rhizo infection. The picture was **** because there were both kinds of hyphae present and I didn't know enough about fungal morphology to look for anything else. Since everything else fit Rhizopus, I went with Rhizopus even though I know that DKA = Rhizopus with those sx/symptoms.

Good explanation though and shows that generalizing concepts only goes so far. Sometimes, you just got to grind out the nitty gritty.