Infectious Diseases Flashcards
1
Q
What are the Baseline investigations for all patients newly diagnosed with HIV?
A
- Confirmatory HIV test: HIV ELISA
- Serum HIV rapid test/ HIV non invasive test
- CD4 count
- HIV viral load (serum RNA)
- HIV resistance profile
- Serum western blot
- HLA B*5701 status
- Serology for syphilis, hepatitis B (sAg, cAb, sAb), hepatitis C, hepatitis A
- Toxoplasma IgG, measles IgG, varicella IgG, rubella IgG
- Other bloods: FBC, U&Es, LFTs, bone profile, lipid profile
- Schistosoma serology (if has spent >1 month in sub-Saharan Africa)
- Women: pregnancy test, annual cervical cytology
2
Q
How does HIV present?
A
- Fever, night sweats > 1 month
- Skin rashes and post inflammatory scars
- Weight loss
- Oral candidiasis
- Diarrhoea > 1 month
- TB
- Karposi’s sarcoma
3
Q
What additional testing may be required on samples of bodily fluids or tissues for suspected HIV patients?
A
- TB and MAI culture
- Fungal culture and PCR, fungal stains
- Cryptococcal antigen (CRAG - commonly performed in CSF if serum CRAG positive)
- Toxoplasma PCR
- Viral PCR (e.g. EBV, CMV, HSV, VZV, JC virus)
4
Q
What are the RFs for HIV?
A
- Affected country
- IVDU
- Unprotected sex
- Perc. needle prick
5
Q
How is HIV treated?
A
- No cure
- ARVs - NRTI - tenofovir, abacavir, NNRTI, protease inhibitors of integrase inhibitor
- Patients with low CD4 counts:
- PCP prophylaxis (if CD4<200) - Co-trimoxazole 480mg PO OD
- if CD4 <50 - Azithromycin 1250mg PO once weekly - protect against MAI
6
Q
What measures should be taken for patients with low CD4 counts?
A
- If CD4<200 - Co-trimoxazole 480mg PO OD - prophylaxis against PCP.
- If the CD4 is <50 Azithromycin 1250mg PO once weekly - should also be given to protect against MAI
- CD4 <50 should - Ophthalmology with dilated fundoscopy to look for evidence of intra-ocular infections such as CMV retinitis
7
Q
What vaccinations should HIV patients be given?
A
- Hepatitis B
- Pneumococcal
- Influenza yearly
8
Q
What are some of the complications of HIV and what pharmacological agent can deal with this?
A
- TB: t: RIPE
- Karposi sarcoma;
- CMV/ CMV retinitis: ganiclovir
- Pneumocystic Jiroveci: co-trimoxazole
- Oral/ oesophageal candidiasis: fluconazole
- Meningoencephalitis
- Chronic meningitis: cryptococcus neoformans: amphotericin
- MAI: Mycobacterium avium infections
9
Q
How is HIV transmitted?
A
Blood, sexual fluids, and breast milk
10
Q
What is the pathophysiology of HIV?
A
- HIV binds, via its gp120 envelope glycoprotein, to cd4 receptors on helper t cells, monocytes, and macrophages
- These ‘CD4 cells’ migrate to lymphoid tissue where the virus replicates, producing billions of new virions.
- These are released, and in turn infect new cd4 cells.
- As infection progresses, depletion or impaired function of cd4 cells leads to ↓immune function.
11
Q
What is used for PEP HIV?
A
- 1st-line pep6 in uk - Truvada® (tenofovir/emtricitabine)
- Raltegravir for 28 days
12
Q
How does HIV present?
A
- Fever
- Lymphadenopathy
- Rash
- Cough/SOB
- Diarrhoea
- Abdominal pain
- Dysphagia
- ↑Liver enzymes
- AKI
- Headache/seizures/focal neurology
- Eye disease
13
Q
What are some of the opportunistic infections in HIV and how are they treated?
A
- Pneumocystis jirovecii - progressive sob on exertion, malaise, dry cough. Haemoptysis and pleuritic pain rare. co-trimoxazole + prednisalone
- Tuberculosis - RIPE - rifampacin, isoniazid 300mg/ day
- Oral Candidiasis
- CMV Retinitis
- CMV
- Cryptosporidium: acute or sub-acute non-bloody, watery diarrhoea. Also cholangitis, pancreatitis
- Kaposi’s sarcoma: cutaneous or mucosal lesions: patch, plaque, or nodular. Visceral disease less common
- Lymphoma
14
Q
What things should be considered when assessing patients with infection?
A
- Evidence
- Severity
- Patient factors
- Micro organisms
- Antimicrobial therapy
- Route of administration
- Any other treatment
- Risk of transmission to others
- Planning follow up and discharge
15
Q
What questions should be asked for those with a fever in a returned traveller?
A
- Geographic region of travel
- Travel and duration
- Careful documentation
- Types of accomodation + rural vs urban stays
- Recreational activities + exposures
- Food and water consumed
- Sexual history, sexual exposure while abroad.
- PMH and predisposition to infection
16
Q
What infectious diseases do you expect in the following time frames?
- 0-10 days
- 10-21 days
- >21 days
A
- 0-10 days: Dengue, rickettsia, viral
- 10-21 days: Malaria, typhoid, primary HIV infections
- >21 days: Malaria, chronic bacterial infections, TB, parasitis infections (helminths, protozoa)
17
Q
What pre-travel immunizations and chemoprophylaxis should be given/ noted in a history?
A
- Vaccination: Hep A, B, typhoid, tetanus, childhood vaccinations (e.g. MMR) + yellow fever and rabies
- Malaria chemoprophylaxis (as directed).
- Personal protective measures e.g. insect repellent and bed-net use
18
Q
What should be examined in clinical examination?
A
- Vital signs: HR
- Skin:
- A maculopapular rash
- Rose spots
- Necrotic ulcer
- Petechiae, ecchymoses, haemorrhagic lesions
- Eyes
- Splenomegaly
- Neurological system
19
Q
What do each of the things examined in clinical examination indicate?
A
- Vital signs: HR
- Skin:
- A maculopapular rash: dengue fever, leptospirosis, rickettsia, infectious mononucleosis (EBV, CMV), childhood viruses (rubella, parvovirus B19), primary HIV infection
- Rose spots: pink macules, 2 to 3 mm in diameter) on chest or abdomen (typhoid fever)
- Necrotic ulcer: rickettsia (tick exposure)
- Petechiae, ecchymoses, haemorrhagic lesions
- Eyes: conjunctival suffusion - leptospirosis.
- Splenomegaly: mononucleosis, malaria, visceral leishmaniasis, typhoid fever, brucellosis.
- Neurological system: fever and altered mental status: meningo-encephalitis
20
Q
What suggested investigations should be performed in patients with fever from unknown traveller?
A
- FBC, LFTs, U+E, electrolytes
- Malaria smears ± antigen detection dipstick: at least 3 times over 24-48 hours
- Blood cultures x2 (must have biohazard labels/travel documented)
- Urinalysis (± urine culture)
- Stool culture +/- stool for ova, cysts and parasites (OCP)
- CXR
- HIV, Hep B, Hep C and Syphillis (treponema) serology (white top)
- Acute serology tube to be saved in lab (white top)
21
Q
What is malaria?
A
- Blood protozoa/parasite (plasmodium species) that is transmitted by night-biting Anopheles mosquitoes.
- P. falciparum results in the most serious illness.
- Approximately 90 percent of malaria cases originate in Africa.
- Other common species: P. vivax, P. ovale (mostly SE Asia)
22
Q
How does malaria present?
A
- Abrupt onset of rigors
- High fevers, malaise, severe headache and myalgia, vague abdominal pain, nausea, vomiting.
- Diarrhea: 25 percent of patients
- Jaundice and hepatosplenomegaly
- Bloods: anaemia, thrombocytopenia, leukopenia, and abnormal LFTs
23
Q
What are the complications of malaria?
A
- Hypoglycemia
- Renal failure
- Pulmonary edema
- Neurologic deterioration
- Leading to death
