Infectious Diseases Lessons

It is intresting.

I saw a patient with MRSA bacteremia, and I forgot that this patient on HD has HD Cath!!

I was looking for skin, bone, endocarditis!!

I had a patient who was admitted for pain, swelling of her leg, admitted and treated for cellulitis. She had some swelling but her main complaint was persistent pain on walking!! Because of persistent pain: we did an MRI of the leg and we found that she has ankle septic arthritis!!

Lesson: If patient complaining of pain on walking: joint involvement must be considered.

FYI: When you have pain out of propotion to skin findings, you have 2 diagnoses: Necrotizing fascitis and Septic arthritis –> Call the Surgeons.

Ciguatera:

Worldwide, ciguatera fish poisoning is the most common of the clinical syndromes associated with marine biotoxins. It is a major public health problem in the Caribbean and South Pacific regions, particularly in areas with tropical reefs.^[8-10] Illness is caused by toxins (ciguatoxins, and others) that are passed up the marine food chain; large predatory reef fish (e.g., barracuda, jacks) have the greatest risk of being toxic. Toxins are produced by the dinoflagellate Gambierdiscus toxicus, the presence of which has been associated with disruption of normal reef ecology and reef communities.

Gastrointestinal symptoms—nausea, vomiting, and diarrhea—are the first manifestation of illness and usually occur within 24 hours of eating a toxic fish. In severe cases, patients may also be acutely bradycardic and hypotensive and, in rare instances (confined almost exclusively to cases in the Pacific region), may develop respiratory difficulties. The most characteristic symptoms are headache and dysesthesias: tingling sensations in the extremities and around the mouth, cold allodynia (cold objects feeling burning hot), burning sensation in the mouth, and aching pain around the teeth. These symptoms may persist for weeks to months^[9-11] and may be linked with clinical depression. The diagnosis is clinical; other than identifying toxin in fish samples that may be left over from an implicated meal, there are no confirmatory tests. Treatment is symptomatic, including maintenance of adequate hydration, use of atropine for bradycardia, and administration of analgesics and antidepressants, as appropriate. Some literature suggests that intravenous mannitol alleviates acute symptoms, although no benefit was seen in one double-blind randomized clinical trial.^[12] Anecdotal data suggest that tocainide helps alleviate neurologic symptoms.

Prevention is difficult, as toxic fish have a normal appearance and taste. In endemic areas, this may have major economic and nutritional impact, as local populations are often reluctant to eat locally caught fish because of the risk of ciguatera. Feeding of suspect fish to the family cat to see if symptoms result is a not uncommon practice prior to human consumption in such areas.

Paralytic Shellfish Poisoning:

Paralytic shellfish poisoning is the most common cause of marine biotoxin–associated illness in the continental United States and Alaska.^[13] Illness has traditionally been associated with eating clams and mussels that contain saxitoxins produced byAlexandrium spp. and related dinoflagellates, although a variety of other vehicles have been reported.^[14] Unlike ciguatera poisoning, gastrointestinal symptoms are less prominent than neurologic manifestations: circumoral paresthesias and paresthesias of the extremities usually appear within 1 hour of ingesting toxic shellfish, and they may be accompanied by ataxia, dysphagia, and changes in mental status. Hypertension may occur and corresponds to the ingested dose, and, in the most severe cases, patients may proceed to respiratory paralysis, usually within the first 24 hours of illness. In experiments, saxitoxins can be identified in serum and urine samples from affected patients.^[15] Treatment is symptomatic. Prevention is achieved through regular monitoring of shellfish populations for saxitoxin by public health authorities, with sampling data available on state health department web pages

Neurotoxic Shellfish Poisoning

Illness is caused by brevetoxins produced by Karenia brevis, a major cause of red tides along the Florida coast; otherKarenia species have been implicated in illness in other parts of the world. Ingestion of shellfish containing the toxin causes nausea and vomiting, as well as circumoral paresthesias and paresthesias of the extremities. In more severe cases, patients may report ataxia, slurred speech, dizziness, and, in rare cases, mild respiratory distress.^[16] Aerosolization of toxins by heavy wave action on the Atlantic coast of Florida can result in respiratory irritation and asthma-like symptoms in persons walking along affected beaches.^[17] On an experimental basis, brevetoxin metabolites have been identified in urine samples from affected patients.^[18] Treatment is symptomatic. The Florida Department of Health and other health authorities regularly monitor coastal areas for the presence of K. brevis, and they notify consumers accordingly

Scombroid:

Then patients have this symptom, fish poisoning, shellfish poisoning (Table 99-4), the so-called Chinese restaurant syndrome, and niacin poisoning are some of the major possibilities. Histamine fish poisoning (scombroid) is characterized by symptoms resembling those of a histamine reaction. Burning of the mouth and throat, flushing, headache, and dizziness are common; abdominal cramps, nausea, vomiting, and diarrhea also occur in most cases.^[81] In severe cases, urticaria and bronchospasm may also occur. Symptoms are thought to result from histamine. Histamine build-up in fish is caused by a high concentration of histidine in fish flesh being combined with a high concentration of marine bacteria, usually caused by inadequate refrigeration, which catalyze the decarboxylation of histidine to histamine.^[82,83] In an outbreak traced to tuna sashimi, a strain of Klebsiella pneumoniae capable of producing large quantities of histamine was implicated.^[84] Symptoms usually resolve in a few hours.

It is intresting I saw a patient today in the VA with red eye and he tells me he is concerned about Chlamydia because his girlfriend had it!

Conjunctivitis: DD: bacterial v/s viral - Chlamydia not to be forgotten if there is no sick contacts because it is an STD and has consequences for partners, and for checking co-infections: HIV, Hep B, RPR, Gonorhea….

I read an intresting article about case series of patients Vanc MIC was high, daptomycin MIC got higher and they combined: Dapto + oxacillin and they had good results! Go figure

It is a tricky presentation when the cultures are negative, the differential is broad, you need to:

1-Rule out Urgent treatable etiologies: such mycobacterial, HSV, fungals and other bacterias that do not grow easily.

You may have to treat empirically for Fungal or TB sometimes if the epidemiology is suggestive and patient is deteriorating.

2-Orders:

Send CSF for PCR (HSV, CMV, VZV, HSV6..)

Send CSF for fungal and mycobacterial cultures (will need 10 cc or more of CSF to get a decent yield)

Send Serologies: HIV,  WNV, Arboviruses, EBV, CMV, Influenza, Mycoplasma, Bartonella, Leptospira, Rickettsia and family(Anaplasma and Ehlrichiosis), Lyme , Syphilis

We had 2 cases today, one case an adult with AML on chemotherapy presents with:

1-necrotizing cellulitis starting from below his nail. We discuss the differential of bacterias and fungi, end up having achromobacter bacteremia

2-Pediatric 10 year old kid with cervical adenopathy that presents with CNS issues, neck stiffness, leg weakness and urine retention–> differential diagnosis: epidural abscess v/s Myelitis

She end up having myelitis of the spine, and exposures to animals reveal:  cats and turtles.

DD: viral/mycoplasma… Inclusding BARTONELLA!!! ++++ serology was positive

Trt: doxy and Rifampin

Ask about all of these exposures:

-Unpasteurised milk or foreign milk products

-Seafood

-Cats

-Dogs

-Birds

-Turtles

-Rabbits

-Fish

-Ticks

-Mosquitoes

-Fleas

-Rats

-Travel to different countries or states: East Coast – SW US – Mexico – Latin America – Africa – Middle East – Europe – Asia – Australia

-TB exposures

-Fresh or Salt Water

-Farm animals (Goats, Sheep)

I had a patient in the clinic few days ago. He has HIV and on Atripla, doing well.

He got HTN crisis and end up in the hospital where they added to him: Metoprolol and Zocor (simvastatin).

Now, Atripla and Zocor are ok but WHAT if this patient was on Boosted PI regimen and the hospital staff ignored the drug drug interactions!!

At this stage even, It is wise to prevent a disaster to get rid of Zocor in case we decided to switch him to boosted PI because you may forget that he is on Zocor ourselves! We can not rely on our EHR to save us, we know computers can help but far from being reliable.

In order to evaluate osteopenia, need to search for secondary causes:

-check also TSH, PTH, P, Ca, Testosterone levels, 25-Oh Vit D

And if on Tenofovir: check Serum (P, and Cr) and Urine (Creatinine and Phosphate) and calculateL fasting fractional execretion of phosphate

traumatic abscess? What organisms and how to treat it?

Patient in the ICU do not

It is a common problem in MDA.

Patient chronically on echinocandin, break with fever and line present:

- Candida resistant like parapsilosis ++

-Trichosporon ++ Not to be forgotten: causes classically hemodynamic instability.

Ambisome is likely to work but with Trichosporon: Voricoazole is more potent.

Remember: Cancidas is only Candida and Aspergillosis.

Aspergillosis rx: Echinocandin, Itra or better Vori, Posa or Ampho.

Classic case of patient comes with ascites, abdominal pain, and pulm infiltrates found to be HIV positive.

DD: broad but classic diagnosis is Disseminated MAC. Possible diagnosis: CMV.

Many other diagnoses are possible too in AIDS.

Patient found to have MAC in ascites, stool, sputum….

The discussion was how to treat empirically and to hit broad: Not to miss Disseminated Histo, treat with broad spectrum abx, Ambisome,…. If you wait it may be too late!

Case of a man with: “‘recurrent” pneumonia & Eosinophilia. we had no definite diagnosis. DD: -Hyperinfection syndrome ( strongy)

other diagnosis were considered:

• Allergic pulm Aspegillosis.
• Churg & Strauss

To be noted: c-ANCA is associated with Wegner’s and not Churg and Strauss.

We had an interesting case presented: A black guy presented for back pain, fever, dyspnea . Found to have pulm infiltrate and bony lesions (spine) thought to be due initially as bony mets. Infection lung & bone. & Good history reveals travel to sw USA as a truck driver = Cocci. The only cause for dissemination was black race.

-Another previously healthy 3y old kid. comes for viral syndrome that progressed to severe bil pneumonia. Pcr BAL showed Adenovirus. Bec of the severity of disease and high risk of dying. He was given Cidofovir and be survived.

We had  2 great presentations today.

1) 13 year old young kid, with h/o trauma on the elbow comes for chronic osteomyelitis.

We discussed causes of chronic osteomyelitis. What was interesting is the exposures to many animals including chicken, so we had a long list of pathogens including: NTMB, Nocardia, fungi and the bacterias associated with animals from Salmonella, campylobacter, Pasteurella and Capnocytophaga

It end being a salmonella osteomyelitis in a healthy patient. ? chiken

2_ Adult case of a patient who came for abscess and sore throat end up with severe diffuse maculo, papular rash, fever and abnormal LFTs and end up being the classic DRESS syndrome but without Eo in the blood. Patient had multi-system complaints including dyspnea, rash and fever and abnl LFTs.

Bactrim related in this case.

We had a presentation in the citiwide about a person who came from Panama, he was bitten by ’shiggers’ and develops purulent skin lesions!

It seems to mimick or can be complicated by superinposed infection

Myiasis

Remember evaluating patient with HIV:

re-check Hep C if negative from time to time

re-check RPR

re-check GC/Chlamydia

1- case of fever, cough found to have a ‘chest wall mass’ contiguous with lung infiltrate and spleen lesion : contiguous not respecting the fascia–>actinomycosis : predisposing factors: poor dental health and alcoholism

2-pediatric case of recurrent MSSA: options to treat?

-issue with possible abdominal abscess, IE, retained foreign body…

-med: ? Dapto, ? Rifampin