Infecto Flashcards
EBV - Overview
Most common signs and symptoms:
- Fever
- Pharyngitis
- Fatigue
- lymphadenopathy (mostly the posterior cervical chain)
- Splenomegaly
- Palatal petechiae
- Rash (maculopapular, urticarial or petechial)
EBV - Diagnosis
- Absolute or relative lymphocytosis
- Increased proportion of atypical lymphocytes
—– Elevated aminotransferases —– - Heterophile test (eg, the “Monospot” test, or Paul-Bunnell), although positivity can be delayed or absent in 10% of cases
(False positives for the Paul–Bunnell test are:
Hepatitis
Hodgkin lymphoma
Acute Leukaemia) - Diagnosis confirmed (if necessary) by EBV-specific antibodies, viral capsule antigen (VCA) antibodies—IgM, IgG and EB nuclear antigen (EBN-A)
! In addition, patients should also have a diagnostic evaluation for streptococcal infection by culture or antigen testing
EBV - resuming sports?
For athletes planning to resume noncontact sports, training can be gradually restarted three weeks from symptom onset.
For strenuous contact sports or activities associated with increased intraabdominal pressure, we suggest waiting for a minimum of FOUR WEEKS after illness onset
Q Fever - overview
Q fever is a zoonosis due to Coxiella burnetti.
Most common abattoir-associated infection in Australia and can also occur in farmers and hunters
Mode of infection – inhaled dust, animal contact, unpasteurised milk
Incubation: 1 to 3 weeks
Sudden onset fever, rigors and myalgia, muscle and joint pain, severe headache
photophobia.
Dry cough (may be pneumonia in 20%)
As the disease progresses, people can develop hepatitis (granulomatous), sometimes with jaundice.
Petechial rash(if persistant infection)
± Abdominal pain
If untreated, the acute illness usually lasts 1–3 weeks
Infection in pregnancy can result in fetal death, intrauterine growth restriction and premature delivery
TTX: doxycycline is the major treatment of choice for patients of any age with severe illness.
> Doxycycline 100 mg orally, 12-hourly for 14 days.
> If pregnant, SMT-TMP + Folic acid
Q Fever - vaccination?
Recommended for adolescents aged ≥15 years and adults who are at risk of infection with C. burnetii. These include:
abattoir workers
farmers
stockyard workers
shearers
animal transporters (of high-risk animals such as cattle, camels, sheep, goats and kangaroos)
veterinarians
wildlife and zoo workers who work with high-risk animals
Q fever vaccine is given SC, 0,5ml, as a single dose. Booster doses are not recommended.
People should receive serum antibody testing and a skin test before vaccination (together known as pre-vaccination testing).
Q Fever - fatigue syndrome and chronic form
Coxiella burnetii may cause chronic disease.
The most common complication in adults is subacute endocarditis.
Less common disease manifestations are caused by granulomatous lesions
About 10–15% of people who have had acute Q fever develop post–Q fever fatigue syndrome.
Tetanus - immunisation of adults
Tetanus toxoid as two doses 6 weeks apart with a third dose 6 months later.
Booster doses of tetanus toxoid are given every 10 years or at the time of major injury occurring 5 years after previous dose.
Tetanus prophylaxis after injury
- Tetanus immunoglobulin 250 U by IM injection - For non-immunised individuals or those of uncertain immunity IF wound is contaminated or has devitalised tissue.
(EVEN IF PREGNANT) - Tetanus toxois:
> Clean minor wounds: vaccine always if not completed before
> Contaminated wounds:
- If between 5-10y from last dose: toxoid again
- If <5y - nothing needed
! Any wound after 10y needs new toxoid
Cat-scratch disease - overview (clinical features, tx, symptoms)
Caused by a Gram negative bacterium Bartonella henselae.
An infected ulcer or papule pustule at bite site (30-50% of cases) after 3 days or so
1-3 weeks later: fever, headache, malaise regional lymphadenopathy (may suppurate) - painful
Intradermal skin test positive
Treatment is recommended in immunocompetent patients with:
- Unresolved lymphadenopathy (lasting more than 1 month);
- Lymphadenopathy associated with significant morbidity;
- Systemic disease with organ involvement (eg liver, eye, neurological); or
- Endocarditis.
eat with erythromycin or roxithromycin for 10 days OR azithromycin 500 mg on the first day and 250mg for 4 days.
Atypical pneumonia - overview
- Symptoms:
Fever, malaise
Headache
Minimal respiratory symptoms,
Non-productive cough - Findings:
Signs of consolidation absent
Chest X-ray (diffuse infiltration) - DxT: ‘flu’ + headache+ dry cough
Atypical pneumonia - most common ethiology
Mycoplasma pneumoniae (the commonest)
Adolescents and young adults: treat with roxithromycin (first line) or tetracycline (e.g. doxycycline 100 mg bd for 14 days)
Atypical pneumonia - less common ethiologies (OVERVIEW, TX)
> Legionella pneumophila (legionnaire disease)
Related to cooling systems in large buildings
Symptoms: Dry cough, influenza,
» REMEMBER: HIGH FEVER, CONFUSION AND/OR DIARRHOEA
Lymphopenia with marked leukocytosis;
Hyponatraemia
Ttx: Azithromycin (IV) or erythromycin (IV or O) plus ciprofloxacin or rifampicin for 21 days.
> Chlamydia psittaci (psittacosis)
Treat with doxycycline 100 mg 2x/D for 10 days
> Coxiella burnetti (Q fever)
EBV - Most common complications?
- Most common:
Antibiotic-induced skin rash
Thrombocytopenia
Ruptured spleen
- Other relevant:
Haematological: agranulocytosis, haemolytic anaemia, thrombocytopenia
Respiratory tract: upper airway obstruction(lymphoid hypertrophy)
Cardiac: myocarditis, pericarditis
Neurological:
cranial nerve palsies, especially facial palsy
Guillain–Barré syndrome
meningoencephalitis
transverse myelitis
Lyme Disease - cause and transmission?
A spirochaete: Borrelia burgdorferi (Borreliella)
Transmitted by Ixodes ticks
People living and working in the bush are susceptible.
Lyme Disease - clinical features (symptoms, dx, tx)
- Stage 1 (withing 1 month of the bite): erythema migrans, (characteristic pathognomonic rash, usually a doughnut shaped, well-defined rash about 6 cm in diameter at the bite site - bullseye)
+ flu-like illness (fever, chills, headache, fatigue, arthralgia) - Stage 2 (early disseminated): neurological problems such as limb weakness and cardiac problems, hearing loss
- Stage 3: arthritis (late Lyme disease)
-> Diagnosis
Clinical pattern especially rash of erythema migrans + serology and PCR of synovial fluid
-> Treatment
Remove tick
A typical regimen for adults is doxycycline 100 mg bd for 21 days or penicillin.
Rabies - overview of prophilaxy
> If exposure of intact skin to fluid - not needed
> If minor scratches without bleeding:
- Non - immune: 4 doses IM (0, 3, 7 and 14)
## - Vaccinated: 2 additional doses IM (0, 3)
> Trandermal bite or scratch OR contamination of mucous membrane or broken skin with saliva
- If vaccinated - ##
- Non-immune: HRIG (not beyong the 7th day after the dose 0 of vaccine) + Vaccine (0, 3, 7 and 14).
! If vaccinated domestic animal, observe for 15 days for signs of the disease.
! If wounded in head or neck, give Immunoglobulin even if vaccinated
Rabies - clinical overview
Causes by Lyssaviruses - single-stranded RNA viruses
Once a person is infected, the incubation period of rabies is usually 3–8 weeks. This can range from as short as 1 week to, on rare occasions, several years.
Initial symptoms: The prodromal phase lasts up to 10 days. During this phase, the person may experience non-specific symptoms such as: anorexia cough fever headache myalgia and fatigue
nausea and vomiting sore throat
Bite and clenched-fist injury - overview
For bites and clenched-fist injuries that are not infected, antibiotic therapy is usually not necessary for otherwise healthy individuals if the risk of wound infection is low (eg small wounds not involving deeper tissues that present within 8 hours and can be adequately debrided and irrigated). Give presumptive therapy if the risk of wound infection is high, including if:
presentation to medical care is delayed by 8 hours or more
the wound is a puncture wound that cannot be debrided adequately
the wound is on the hands, feet or face
the wound involves deeper tissues (eg bones, joints, tendons)
the wound involves an open fracture
the patient is immunocompromised (eg due to asplenia or immunosuppressive medications), or has alcoholic liver disease or diabetes
the wound is a cat bite.
TTX:
amoxicillin+clavulanate 875+125 mg orally, 12-hourly for 3 days
OR
procaine benzylpenicillin 1.5 g (child: 50 mg/kg up to 1.5 g) intramuscularly, as a single dose while awaiting oral therapy.
AND Start continuation therapy with oral amoxicillin+clavulanate (see dosage above) as soon as it is available.
! If infected wound at presentation: Amox-clav for 5 days
Toxoplasmosis - overview
Caused by Toxoplasma gondii
The definitive host is the cat (or pig or sheep)
The five major clinical forms are:
- Asymptomatic lymphadenopathy (the commonest)
- Lymphadenopathy with a febrile illness, similar to EBM
- Acute primary infection: a rash, myocarditis, pneumonitis, chorioretinitis and hepatosplenomegaly
- Neurological abnormalities - headache and neck stiffness, sore throat and myalgia
- Congenital toxoplasmosis - CNS and eye involvement - TRIAD : HYDROCEPHALUS + INTRACRANIAL CALCIFICATION + CHORIORETINITIS
Tetanus - clinical overview
Bacterial infection (Clostridium tetani)
Clinical features:
- Prodrome: fever, malaise, headache
- Trismus (patient cannot close mouth)
- Risus sardonicus
- Opisthotonos (arched trunk with hyperextended neck)
- Spasms, precipitated by minimal stimuli
Infective endocarditis without cardiac murmurs - most likely clinical scenario and pathogen?
- IV drug users who develop infection on the tricuspid valve.
- Staphylococcus aureus (causes 50% of acute form)
- Streptococcus viridans (50% of cases)
- Other responsible pathogens:
Streptococcus bovis
Staphylococcus epidermidis
Enterococcus faecalis
Candida albicans/Aspergillus
Coxiella burnetii (Q fever)
HACEK group (Gram -ve bacilli)
Giardiasis - overview (Symp, dx, tx)
+
Rapid DDx with shigellosis, amoebiasis and Enterotoxigenic E. coli
Giardia lamblia infection is usually acquired from contaminated drinking water.
Also linked to travel!!!!! And hikers in wilderness areas who drink water that has not been adequately filtered, treated, or boiled.
Often asymptomatic
Abdominal cramps, bloating, flatulence and bubbly, foul-smelling diarrhoea, which may be watery, explosive and profuse.
Diagnosis
3 specimens of faeces for analysis (cysts and trophozoites): ELISA/PCR
Treatment
Hygiene & Metronidazole 400 mg tds for 7 days or Tinidazole 2 g single dose.
- Shigellosis - bloody diarrhoea and toxemia
- Amoebiasis - bloody disentery (less whatery)
- Enterotoxigenic E. coli - symptoms within hours, toxigenic, SHU associated
Schistosomiasis (bilharzia) - overview
Cause - parasite organisms (schistosomes) whose eggs are passed in human excreta, which contaminates watercourses (notably stagnant water) and irrigation channels in Egypt, other parts of Africa, South America, some parts of South-East Asia and China.
Clinical features
The first clinical sign is a local skin reaction at the site of penetration of the parasite (it then invades liver, bowel and bladder). This site is known as ‘swimmer’s itch’.
Within a week or so there is a generalised allergic response, usually with fever (Katayama fever), malaise, myalgia and urticaria.
GIT (Nausea, vomiting, diarrhoea) and respiratory (cough)
Lymphadenopathy and hepatosplenomegaly.
Schistosomiasis (bilharzia) - Dx, Tx, prevention
Diagnosis
Serology
Detecting eggs in the stools, the urine or in rectal biopsy
Treatment
Praziquantel (adult and child) 20 mg/kg orally, for two doses, given 4 hours apart.
If Kataymama fever - prednisone + praziquantel afterwards
Prevention
Travellers should be warned against drinking from or swimming and wading in, dams, watercourses or irrigation channels, especially in Egypt and other parts of Africa.
Amoebiasis - overview
Protozoal infection – Entamoeba histolytica
More common after visiting less developed countries – India, China characterised by sever diarrhoea with blood and mucous.
Fever + blood and mucous in stools
Extraintestinal common sites of ifection are: liver, brain and lungs
Diagnosis
Specific stool E. histolytica testing (eg, cultures, antigen testing or PCR)
Treatment
Metronidazole 600 mg (child: 15 mg/kg up to 600 mg) orally, 8-hourly for 7 days
or
Tinidazole 2 g (child: 50 mg/kg up to 2 g) orally, daily for 3 days
Asymptomatic carriage of Entamoeba histolytica TTX:
Paromomycin 500 mg (child: 10 mg/kg up to 500 mg) orally, 8-hourly for 7 days
Measles - overview (Cause, incubation, transmission)
Caused by a paramyxovirus from the genus Morbillivirus, an RNA virus
The incubation period is usually 10–14 days.
Measles is spread by respiratory secretions, including by aerosols.
It is infectious from the beginning of the prodromal period (typically 2 to 4 days before rash onset) and for up to 4 days after the rash appears.
Measles - symptoms and most common complications
- Symptoms of measles
The prodrome lasts 2–4 days. It is characterised by:
fever
malaise
cough
coryza
conjunctivitis
A maculopapular rash typically begins on the face and upper neck, and then becomes generalised.
- Complications of measles
otitis media (in around 9% of people)
pneumonia (in around 6%)
diarrhoea (in around 8%)
Acute encephalitis occurs in 1 per 1000 cases, and has a mortality rate of 10–15%.
Measles is a notifiable disease in all states and territories in Australia, and is an urgent public health priority.
Measles - vaccination and prophylaxis
All children aged ≥12 months are recommended to receive 2 doses of measles-containing vaccine.
12 months of age — MMR
18 months of age — MMRV
People who receive MMR vaccine may develop a fever 7–10 days (range 5–12 days) after vaccination. This can last 2–3 days. The fever may be associated with malaise and/or a non-infectious rash.
MMRV (measles, mumps, rubella, varicella) vaccine is not recommended as the 1st dose of measles-containing vaccine in children <4 years of age. This is due to a small but increased risk of fever and febrile seizures when MMRV vaccine is given as the 1st dose of measles-containing vaccine in this age group.
MMR-containing vaccines are contraindicated in pregnant women and immunocompromised individuals.
Vaccinated women should avoid pregnancy for 28 days after vaccination
- Immunoglobulin (NIHG) indication within 72 hours of 1st exposure:
Immunocompromised
Birth to 5 months - the mother is IgG Negative (no 2 vaccinations or history of measles)
Pregnant women - if IgG negative
Varicella - overview (Cause, incubation, transmission)
Caused by Varicella-zoster virus (VZV) which is a DNA virus in the herpesvirus family. After primary infection, VZV establishes latency in the dorsal root ganglia. Reactivation of the latent virus manifests as herpes zoster (shingles)
The average incubation period is 14–16 days.
The period of infectivity is from 48 hours before the onset of the rash until all lesions have crusted over
Varicella is a notifiable disease in most states and territories in Australia.
What’s Breakthrough varicella?
A case of wild-type varicella occurring more than 42 days after vaccination.
Most breakthrough varicella cases are mild, with fewer lesions than natural infection.
However, breakthrough varicella infections can be contagious, especially if many lesions are present.
Varicella - symptoms and most common complications
A short prodromal period of 1–2 days may precede the onset of the rash, especially in adults.
- Acute varicella may be complicated by:
secondary bacterial skin infection
pneumonia
acute cerebellar ataxia (1 in 4000 cases)
aseptic meningitis
transverse myelitis
encephalitis (1 in 100,000 cases)
thrombocytopenia
Congenital varicella syndrome - overview
Varicella infection in pregnancy may result in congenital varicella syndrome in the infant. These infants may have:
skin scarring
limb defects
ocular anomalies
neurological malformations
The fetus has a higher risk of developing congenital varicella syndrome if the mother is infected during the 2nd trimester compared with the 1st trimester
Infants born to mothers who have perinatal varicella infection can have severe neonatal varicella infection
Varicella - post-exposure prophylaxis, contact management
Significant exposure to varicella-zoster virus is defined as:
living in the same household as a person with active varicella or herpes zoster
direct face-to-face contact with a person with varicella or herpes zoster for at least 5 minutes
being in the same room with a person with varicella or herpes zoster for at least 1 hour
- For post-exposure vaccination, people should receive varicella vaccine within 5 days after exposure, and preferably within 3 days
- High-risk groups that should receive ZIG (high-titre zoster immunoglobulin):
Scheme: 0-10kg=200ui; 11-30=400UI; >30KG=600UI
Pregnant women who are presumed to be susceptible to varicella infection — if practical, test them for varicella-zoster antibodies before they receive ZIG
Neonates whose mothers develop primary varicella infection within 7 days before delivery to 2 days after delivery — these neonates must receive ZIG, as early as possible in the incubation period, because neonatal mortality without ZIG is up to 30%60,66
Neonates exposed to varicella in the 1st month of life, if the mother has no personal history of infection with varicella virus and is seronegative15 — these neonates should receive ZIG, because of the increased risk of severe varicella in newborns of seronegative women
Premature infants (<28 weeks gestation or birth weight <1000 g) exposed to varicella while still hospitalised — these infants should receive ZIG regardless of maternal history of varicella
Patients with primary or acquired diseases associated with cellular immune deficiency, and people receiving immunosuppressive therapy
If a person is exposed to varicella again >3 weeks after the 1st dose of ZIG, repeat the ZIG dose.
Varicella - vaccination
VARICELA 3-18
Varicella-containing vaccine is recommended for:
children aged 12 months to <14 years
adolescents aged ≥14 years and adults who have not received 2 doses of varicella-containing vaccine
Varicella-containing vaccine is recommended for children at 18 months of age as MMRV (measles-mumps-rubella-varicella) vaccine AND a second dose of varicella vaccine ≥4 weeks after the first dose (BUT NOT COVERED IN NIP).
! If parents or carers wish to minimise the risk of breakthrough varicella in children <14 years of age, a 2nd dose of varicella-containing vaccine is recommended
Shingles - overview (clinical features, epidemiology, complication, TTX)
Herpes zoster, or shingles, occurs when latent VZV reactivates.
Most cases present with a unilateral vesicular rash in a dermatomal distribution.
80% of cases have a prodromal phase 48–72 hours before the rash appears.15 Associated symptoms may include:
headache
photophobia
malaise
itching, tingling or severe pain in the affected dermatome
In most people, herpes zoster is an acute and self-limiting disease.
!!The rash usually lasts 10–15 days.
Post-herpetic neuralgia (PHN) is the most frequent debilitating complication of herpes zoster.
- TTX: Antiviral therapy can reduce the severity and duration of herpes zoster if therapy starts within 3 days of onset.
> valaciclovir 1 g (child older than 2 years: 20 mg/kg up to 1 g) orally, 8-hourly for 7 days OR
> famciclovir 500 mg orally, 8-hourly for 7 days. For immunocompromised patients, the duration is 10 days
> aciclovir 800 mg (child: 20 mg/kg up to 800 mg) orally, 5 times daily for 7 days.
! If immunocompromised with disseminated disease - admit and aciclovir EV
Antiviral therapy may also reduce the risk of developing PHN.
Herpes zoster occurs most commonly in people who:
are older — particularly >50 years
are immunocompromised
had varicella in the 1st year of life
Shingles - vaccination
Zoster vaccines are recommended for:
- people aged ≥50 years who are immunocompetent
- people aged ≥18 years who are immunocompromised
- people aged ≥50 years who are household contacts of a person who is immunocompromised
There are 2 vaccines: one single and other double dosed. No booster resquired
Post-herpetic neuralgia and Acute pain associated with shingles - TTX
Acute pain associated with shingles
Antiviral treatment started within 72 hours accelerates pain resolution.
Neuropathic shingles pain can be treated with lidocaine 5% patches; however, they cannot be used on broken skin or lesions, which are common in the acute phase of infection.
> lidocaine 5% patch, up to 3 patches applied at the same time to the painful area (after shingles has healed). Wear for up to 12 hours, followed by a patch-free interval
Gabapentinoids may be used in addition to, or as an alternative to
Mild nociceptive shingles pain can be treated with oral paracetamol or nonsteroidal anti-inflammatory drugs (NSAIDs)
Moderate to severe nociceptive shingles pain can be treated with an oral corticosteroid, in addition to oral paracetamol and NSAIDs.
> Prednisolone 50 mg orally, in the morning for 7 days.
Postherpetic neuralgia is difficult to manage, but successful management is more likely if commenced early. It mostly affects the elderly, and comorbidities may influence analgesic choic
Lidocaine 5% patches are a suitable first-line analgesic option.
If lidocaine 5% patches are ineffective or not tolerated, consider trialling an oral adjuvant (gabapentinoid, tricyclic antidepressant, or serotonin and noradrenaline reuptake inhibitor). Alternatively, add an oral adjuvant if lidocaine 5% patches are partially effective.
Trachoma - overview, epidemiology, TTX
Trachoma is a form of chronic C. trachomatis conjunctivitis caused by repeated infections with C. trachomatis serotypes A, B, Ba or C.
It is the leading cause of preventable infectious blindness in the world, especially in developing countries, and is still common in remote Aboriginal and Torres Strait Islander communities in Australia.
Without treatment, recurrent infection can lead to scarring of the eyelids, corneal ulceration, corneal scarring and loss of vision.
Suspect trachoma in all cases of conjunctivitis in endemic areas.
Treatment is with azithromycin 1 g (child: 20 mg/kg up to 1 g) orally, as a single dose.
(Approximately 50% of neonates with chlamydial conjunctivitis have associated chlamydial pneumonia)
In areas where trachoma is prevalent, regular face washing and treatment of household contacts is recommended.
Routinely recommended vaccinations for travelers?
Diphtheria, tetanus and pertussis
Hepatitis B
Influenza and pneumococcal disease
Measles, mumps and rubella
Varicella
Meningococcal disease
Poliomyelitis
Vaccines based on travel itinerary, activities and likely risk of disease exposure
Japanese encephalitis - recommended for travellers spending a month or more in endemic areas in Asia, Papua New Guinea or the outer islands of Torres Strait during the JE virus transmission season (Wet).
Tuberculosis - Vaccination with BCG (bacille Calmette–Guérin) vaccine is generally recommended for tuberculin-negative children <5 years of age who will be staying in high-risk countries for an extended period (3 months or longer).
Typhoid - Typhoid vaccine may be recommended for travellers ≥2 years of age travelling to endemic regions, including:
the Indian subcontinent
most Southeast Asian countries
several South Pacific nations, including Papua New Guinea
Cholera - vaccine is not recommended by WHO
Yellow fever - Yellow fever vaccine is recommended for all people ≥9 months of age travelling to, or living in, an area with a risk of yellow fever virus transmission.19
Requirements for travellers to Mecca - MenACWY vaccination is mandatory
Botulism - overview
Sexual assault - regime of prophylaxis and testing?
Offer emergency contraception to women of reproductive age presenting within 5 days of a sexual assault
Screen for the following sexually transmitted pathogens: Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum (syphilis), Trichomonas vaginalis, hepatitis B virus (HBV) and HIV.
Give prophylaxis against HIV and hepatitis B virus
> If not immune: Start a course of hepatitis B vaccination as soon as possible, preferably within 24 hours of exposure + Administer hepatitis B immunoglobulin within 72 hours of exposure
> For HIV: lamivudine 300 mg orally, daily for 4 weeks
PLUS
tenofovir disoproxil fumarate 300 mg orally, daily for 4 weeks
PLUS
dolutegravir 50 mg orally, daily for 4 weeks
Presumptive antimicrobial therapy for people who have been sexually assaulted is generally not required. If needed:
Ceftriaxone - 250mg IM
Azithromycin - 1g - one dose
Metronidazole - 2g - single dose
Prophylaxis ttx in HIV/AIDS according to CD4
- PPJ - If CD4 < 200: SMT-TMP
- Toxoplasmosis - If CD4 < 100: SMT-TMP
- Mycobacterium avium complex - if CD4 < 50: Azithromycin 1200mg/weekly
(Dapsone can replace it if CI or not tolerated)
Congenital toxoplasmosis - overview + ttx
Triad:
- Chorioretinitis
- Hydrocephalus
- Diffuse Intracranial calcifications
Also: seizures, hepatosplenomegaly
Dx: Toxoplasma serology or PCR
Ddx: CMV - both can have microcephaly and retinitis, but only Toxo causes macrocephaly
Tx: Pyrimethamine + sulfadiazine + folinic acid
Patients receiving solid organ transplantations require high-dose immunosuppressive medication to prevent organ rejection. They’re at risk for which opportunistic infections?
Pneumocystis pneumonia (PCP) and cytomegalovirus (CMV).
Prophylaxis for PCP (trimethoprim-sulfamethoxazole) and CMV (valganciclovir) is needed.
Tissue-invasive CMV disease - overview (features, dx, tx)
Tissue-invasive CMV disease causes pneumonitis, gastroenteritis, and hepatitis):
- Pulmonary symptoms (dyspnea on exertion, dry cough)
- Gastrointestinal symptoms (abdominal pain, diarrhea, hematochezia)
- Pancytopenia,
- Mild hepatitis
- Interstitial infiltrates on chest x-ray.
- Dx: tissue biopsy is the gold standard.
-Tx: discontinuing antimetabolite immunosuppression (eg, mycophenolate) and initiating antiviral therapy. Intravenous ganciclovir is used for patients with severe disease (eg, pneumonitis, meningoencephalitis, high viral loads, significant gastrointestinal disease). Patients with minimal signs and symptoms can take oral valganciclovir.
Common causes of esophagitis in patients with HIV - Ddx
> Candida albicans:
Oral thrush usually present
White plaques throughout esophagus
Biopsy: pseudohyphae
> Herpes simplex virus
Orolabial lesions usually present
Vesicular or ulcerative round/ovoid lesions (“volcano-like”)
Biopsy: multinucleated giant cells
> Cytomegalovirus
Large, linear ulcers in distal esophagus
Biopsy: intranuclear/intracytoplasmic inclusions
The most common cause of esophagitis in patients with HIV is Candida albicans (>60% of cases);
Symptomatic patients (especially with visible thrush) can be treated empirically for Candida esophagitis with fluconazole; endoscopy is usually performed in those failing treatment.
VIRAL esophagitis is more likely than candidal esophagitis in patients who have:
> > Severe odynophagia (pain with swallowing) as the predominant symptom
NO DYSPHAGIA (difficulty swallowing)
NO THRUSH
Legionnaire’s disease - overview
Legionella pneumonia
A gram-negative intracellular rod
- Epidemiology
Contaminated water
Hospital
Travel (cruise, hotel)
- Clinical features
Fever >38.8 C
Relative bradycardia
Gastrointestinal: diarrhea, vomiting, cramps
Pulmonary: delayed symptoms
Neurologic symptoms: confusion, ataxia
- Diagnosis
Hyponatremia
Chest x-ray: lobar infiltrate
Sputum Gram stain: PMNs, few/no organisms (intracellular rod)
Urine Legionella antigen
- Treatment
Respiratory fluoroquinolone or newer macrolide
What’s the most likely diagnosis in a transplant recipient with meningeal irritation?
Clinical signs suggest meningeal irritation. 🏥
CSF analysis reveals monocytosis, decreased glucose (60% of simultaneous plasma levels), and elevated protein, indicating fungal meningitis. 💉
In transplant recipients, invasive fungal infections are common, with cryptococcosis being the third most frequent in immune-compromised patients. 🦠
Confirming the diagnosis typically involves a Cryptococcus assay of the CSF. 🧫
When is a person with hepatitis A considered infectious?
Hepatitis A is most contagious just before the onset of jaundice, with the highest viral load in the stool. Infected individuals are considered infectious from a few days before prodromal symptoms appear to a few days after jaundice onset. They become non-infectious one week after the onset of jaundice (if it occurs) or two weeks (14 days) after the onset of prodromal symptoms, whichever comes first. 🤢👁️🤧📅
What are the guidelines for pneumococcal vaccination in adults, and who should receive it?
Vaccination against pneumococcus with the 20-valent pneumococcal conjugate vaccine (PCV20) or with the 15-valent pneumococcal conjugate vaccine (PCV15) followed by the 23-valent pneumococcal polysaccharide vaccine (PPSV23) is recommended for all adults aged ≥65. (aborigenous >50y) 💉
Additionally, vaccination is recommended for those under age 65 who have specific comorbid conditions that increase their risk for pneumococcal disease, such as chronic liver, lung, heart disease, diabetes mellitus, and smoking. 🫁🫀🩺
What should be the next steps if a Tuberculin Skin Test (TST) or Interferon-Gamma Release Assay (IGRA) is positive?
If TST or IGRA is positive, the next step is to exclude active tuberculosis (TB) with a chest X-ray 📸
If the chest X-ray is normal, active TB is excluded, and the patient should be treated for latent TB infection (LTBI) with Isoniazid (INH) and pyridoxine for 6-9 months 🩺💊
What should be done if the chest X-ray shows abnormalities in a patient with a positive TST or IGRA?
If the chest X-ray shows abnormalities, sputum should be examined for acid-fast bacilli (AFB) stain and culture 🔬
An abnormal chest X-ray and 3 negative sputum smears exclude active TB, and the patient should be treated for LTBI with INH (300mg/day) and pyridoxine for 6-9 months 🌡️
What malignancy is associated with asbestosis?
Mesothelioma
