MED: Infectious Diseases Flashcards

Question

Management recurrent episode genital herpes ?

Answer 1

>> Self-limiting **Supportive self-care only:** - Analgesia, saline bathing, ice packs. - Abstain from sexual intercourse until lesions have gone. **Episodic antiviral treatment:** - If attacks are infrequent, and self-care measures are not sufficiently controlling symptoms. **Suppressive antiviral therapy:** - At least 6 recurrences per year. - Duration of therapy is commonly 6 months to 1 year.

Answer 2

- Haemophilus influenzae type B historically the primary pathogen - Now Streptococcus pneumoniae, group A streptococci, and Staphylococcus aureus, are more frequently implicated

Answer 3

- Severe sore throat and odynophagia - painful swallowing often accompanied by drooling due to difficulty handling secretions. - Muffled voice or 'hot potato' voice - characteristic change in voice quality due to the swollen epiglottis. - Stridor - Respiratory distress - High-grade fever - Tripod or sniffing position

Answer 4

>> Usually clinical diagnosis **Lateral neck radiograph:** - The 'thumb sign' - swollen epiglottis - Only be performed if patient is stable, as manipulation of the airway can precipitate complete airway obstruction. **Flexible fiberoptic laryngoscopy:** - Only if the patient is stable, as it may trigger laryngospasm. **Blood cultures and throat swabs:** - Can help identify the causative pathogen and guide antibiotic therapy.

Answer 5

- Airway management (preferably in ICU) - endotracheal intubation or emergent tracheostomy may be necessary - Empiric broad-spectrum antibiotics, such as third-generation cephalosporins - Supportive care - IV fluids, analgesics, and antipyretics may be administered as needed

Answer 6

**Hepatitis serology:** - First line = PCR test for hepatitis A RNA. - If not available = HAV-IgM and HAV-IgG blood tests - Positive HAV-IgM and positive HAV-IgG suggests acute hepatitis A infection. - Negative HAV-IgM and positive HAV-IgG suggests past hepatitis A infection or immunity. - A high IgG reactivity and a moderate level of IgM suggests recent infection rather than acute infection. **LFTs:** - Significantly raised ALT and AST - Bilirubin may be elevated, as well as PT - ALP may be elevated but generally less than 2 times upper limit of normal

Answer 7

>> Usually mild and self-limiting and require no specific treatment >> Severely unwell patients should be admitted to hospital *Generally symptom management is all that is required* - Rest and stay hydrated. - Pain relief as required, with dose adjustment if liver impairment. - Anti-emetics as required, including metoclopramide or cyclizine unless impaired liver function. - For itch, use simple measure such as loose clothing and avoiding hot baths and showers and chlorphenamine if required unless impaired liver function. - Avoid alcohol. - Ensure good personal hygiene practices and avoid food preparation, and sexual intercourse for 7 days after symptom onset. - Patients should avoid work or school for 7 days after symptom onset. - Patients should be followed-up every 1-2 weeks, and LFTs repeated until amino-transferase levels are within normal levels.

Answer 8

**LFTs:** *ALT + AST* - Acute viral hepatitis = raised >25 times the upper limit of normal - Active chronic HBV = mildly raised (about 2x the upper limit of normal) - Acute flares/exacerbations of chronic HBV = raised >10 times the upper limit of normal - Chronic HBV carriers = usually normal - AST:ALT ratio can be raised *ALP + GGT* - In HBV infection, the ALT and AST are expected to be raised much further than the ALP and GGT **Hepatitis serology:** - HBsAg - only positive in current infection (chronic = persistently raised for >6 months) - Anti-HBs - previous infection / vaccination - Anti-HBc - only present in previous or current infective state (never post-vaccination) - IgM is the first antibody made to fight a new infection, therefore will be the predominant antibody in acute HBV - IgG is associated with a longer-term reaction and therefore will predominate in chronic HBV - It is important to note that IgM anti-HBc may be seen in acute exacerbations of chronic hepatitis B, or up to 2-years after acute HBV

Answer 9

>>Mainly supportive **Active treatment if:** - Severe coagulopathy (INR >1.5) - Persistent symptoms for >4 weeks - Marked jaundice (bilirubin >3mg/dL) - Presence of ascites or encephalopathy **Tenofovir or entecavir:** - Liver transplant considered in all patients with fulminant hepatic failure

Answer 10

**Indications for treatment:** - Acute liver failure - Decompensated cirrhosis - Compensated cirrhosis + HBV DNA >2000IU/mL - Patients receiving concurrent immunosuppressive therapy - Hepatocellular carcinoma **Anti-viral therapy:** - First-line (no cirrhosis) = entecavir, tenofovir or peginterferon alfa 2a - First line (with cirrhosis) = entecavir or tenofovir

Answer 11

- Fulminant liver failure - Liver cirrhosis - Hepatocellular carcinoma

Answer 12

*Before initiating treatment, it's vital to:* - Confirm Diagnosis: Through HCV RNA testing - Genotype Assessment: Determines the strain of the virus, which influences treatment choice and duration. - Liver Disease Staging: Evaluate the degree of liver fibrosis and cirrhosis, which can be done via liver biopsy, elastography, or serum markers. *Co-infections: Screen for HIV and hepatitis B, as they influence management* - LFTs: Including ALT, AST, bilirubin, and albumin. - Assess for Contraindications: To DAAs and potential drug interactions.

Answer 13

**>>Direct-Acting Antivirals (DAAs)** - Combination of protease inhibitors (e.g. daclatasvir + sofosbuvir or sofosbuvir + simeprevir) with or without ribavirin - Duration ranges between 8-12 weeks, but some patients, particularly those with cirrhosis or prior treatment experience, may require extended durations. - Monitoring HCV RNA Levels to assess response to therapy

Answer 14

- Sustained Virological Response (SVR) - undetectable HCV RNA 12 weeks post-treatment. SVR12 is considered a cure in most cases. - Liver Disease - patients with advanced fibrosis or cirrhosis should continue to be monitored for hepatocellular carcinoma and complications of cirrhosis.

Answer 15

- sore throat - lymphadenopathy - malaise, myalgia, arthralgia - diarrhoea - maculopapular rash - mouth ulcers - rarely meningoencephalitis

Answer 16

TREAT ALL REGARDLESS OF CD4 COUNT **Highly active anti-retroviral therapy (HAART):** - Involves a combination of at least three drugs - Typically two nucleoside reverse transcriptase inhibitors (NRTI) and either a protease inhibitor (PI) or a non-nucleoside reverse transcriptase inhibitor (NNRTI)

Answer 17

- Oral thrush - Shingles - Hairy leukoplakia - Kaposi sarcoma

Answer 18

- Cryptosporidiosis - Cerebral toxoplasmosis - Progressive multifocal leukoencephalopathy (JCV) - PCP - HIV dementia

Answer 19

- Aspergillosis - Oesophageal candidiasis - Cryptococcal meningitis - Primary CNS lymphoma

Answer 20

- Cytomegalovirus retinitis - Mycobacterium avium-intracellulare infection

Answer 21

- males: urethral discharge, dysuria - females: cervicitis e.g. leading to vaginal discharge - rectal and pharyngeal infection is usually asymptomatic

Answer 22

- First line = single dose of IM ceftriaxone 1g - If sensitivities known and organism sensitive to ciprofloxacin - single dose of oral ciprofloxacin 500mg - If ceftriaxone is refused (e.g. needle-phobic) - single dose oral cefixime 400mg + oral azithromycin 2g

Answer 23

Gram neg diplococci

Answer 24

- tenosynovitis - migratory polyarthritis - dermatitis (lesions can be maculopapular or vesicular) >>Later complications include septic arthritis, endocarditis and perihepatitis (Fitz-Hugh-Curtis syndrome)

Answer 25

- Swimmers' itch - Acute schistosomiasis syndrome (Katayama fever) - fever, urticaria/angioedema, arthralgia/myalgia, cough, diarrhoea, eosinophilia

Answer 26

Freshwater swimming in endemic areas (most commonly Africa)

Answer 27

Schistosoma haematobium: Eggs deposit in the bladder - local skin hypersensitivity reaction e.g. small, itchy maculopapular lesions - classic urogenital symptoms - bladder calcification - can cause an obstructive uropathy and kidney damage

Answer 28

- Asymptomatic = serum schistosome antibodies - Symptomatic = gold standard is urine or stool microscopy looking for eggs

Answer 29

- single oral dose of praziquantel - often needs to be repeated after a few weeks as it is more effective when the worms have grown. - steroids may be used for symptomatic relief

Answer 30

- profuse, bloody diarrhoea - may be a long incubation period - stool microscopy may show trophozoites if examined within 15 minutes or kept warm (known as a 'hot stool')

Answer 31

- oral metronidazole - a 'luminal agent' (to eliminate intraluminal cysts) is recommended usually as well e.g. diloxanide furoate

Answer 32

- usually a single mass in the right lobe (may be multiple) - contents are often described as 'anchovy sauce' - fever, RUQ pain, systemic symptoms e.g. malaise, hepatomegaly - associated with erythema multiforme

Answer 33

anaemia, raised LDH, raised unconjugated bilirubin → autoimmune haemolytic anaemia

Answer 34

- diagnosis by Mycoplasma serology - positive cold agglutination test → peripheral blood smear may show red blood cell agglutination - chest X-ray shows bilateral consolidation

Answer 35

doxycycline or a macrolide (e.g. erythromycin/clarithromycin)

Answer 36

- patches of hypopigmented skin typically affecting the buttocks, face, and extensor surfaces of limbs - sensory loss

Answer 37

**Lepromatous leprosy ('multibacillary'):** - extensive skin involvement - symmetrical nerve involvement **Tuberculoid leprosy ('paucibacillary'):** - limited skin disease - asymmetric nerve involvement → hypesthesia - hair loss

Answer 38

triple therapy: rifampicin, dapsone and clofazimine

Answer 39

- flu-like symptoms including fever (present in > 95% of patients) - dry cough - relative bradycardia - confusion - lymphopaenia - hyponatraemia - deranged liver function tests - pleural effusion: seen in around 30% of patients

Answer 40

treat with erythromycin/clarithromycin

Answer 41

- sewage workers, farmers, vets or people who work in an abattoir - common in the tropics so should be considered in the returning traveller

Answer 42

*Early phase is due to bacteraemia and lasts around a week:* - may be mild or subclinical - fever / flu-like symptoms - subconjunctival suffusion (redness)/haemorrhage *second immune phase may lead to more severe disease (Weil's disease)* - acute kidney injury (seen in 50% of patients) - hepatitis: jaundice, hepatomegaly - aseptic meningitis

Answer 43

- serology: antibodies to Leptospira develop after about 7 days - PCR - culture - growth may take several weeks so limits usefulness in diagnosis - blood and CSF samples are generally positive for the first 10 days - urine cultures become positive during the second week of illness

Answer 44

high-dose benzylpenicillin or doxycycline

Answer 45

- combination tests (HIV p24 antigen and HIV antibody) are now standard for the diagnosis and screening of HIV - if the combined test is positive it should be repeated to confirm the diagnosis - testing for HIV in asymptomatic patients should be done at 4 weeks after possible exposure - after an initial negative result when testing for HIV in an asymptomatic patient, offer a repeat test at 12 weeks

Answer 46

Ground-glass hepatocytes

Answer 47

- IV access → take bloods and blood cultures - Lumbar puncture - if cannot be done within first hour, IV antibiotics should be given after blood cultures have been taken - IV antibiotics - cefotaxime/ ceftriaxone (if >50yrs / <3m, + amoxicillin/ampicillin) - Consider IV dexamethasone - preferably starting before or with first dose of antibacterial, but no later than 12 hours after starting antibacterial - Avoid dexamethasone in septic shock, meningococcal septicaemia, or if immunocompromised, or in meningitis following surgery' - CT scan if signs of raised ICPManagem

Answer 48

IV amoxicillin (or ampicillin) + gentamicin

Answer 49

IV benzylpenicillin or cefotaxime (or ceftriaxone)

Answer 50

Abx prophylaxis with oral ciprofloxacin (or rifampicin)

Answer 51

amoxicillin or cefalexin

Answer 52

Cryptosporidium parvum

Answer 53

stool: modified Ziehl-Neelsen stain (acid-fast stain) of the stool may reveal the characteristic red cysts of Cryptosporidium

Answer 54

Staph aureus

Answer 55

- Combination of oral antiretrovirals for 4 weeks - Can be administered up to 72 hours post-exposure

Answer 56

- annual influenza vaccine - one-off pneumococcal vaccine

Answer 57

Caused by the spirochaete Borrelia burgdorferi and is spread by ticks

Answer 58

*Erythema migrans:* - 'bulls-eye' rash is typically at the site of the tick bite - typically 1-4 weeks after initial bite but may present sooner - usually painless, more than 5 cm in diameter and slowly increases in size *systemic features:* - headache - lethargy - fever - arthralgia

Answer 59

- cardiovascular - heart block, peri/myocarditis - neurological - facial nerve palsy, radicular pain, meningitis

Answer 60

>>Diagnosed clinically if erythema migrans is present **First line = ELISA antibodies to Borrelia burgdorferi:** - if negative and Lyme disease still suspected in people tested within 4 weeks from symptom onset, repeat the ELISA 4-6 weeks after the first ELISA test. - If still suspected in people who have had symptoms for 12 weeks or more then an immunoblot test should be done - if positive or equivocal then an immunoblot test should be done

Answer 61

- If the tick is still present, the best way to remove it is using fine-tipped tweezers, grasping the tick as close to the skin as possible and pulling upwards firmly - The area should be washed following. - NICE guidance does not recommend routine antibiotic treatment to patients who've suffered a tick bite

Answer 62

- Doxycycline if early disease - Amoxicillin if contraindicated (e.g. pregnancy) - People with erythema migrans should be commenced on antibiotic without the need for further tests - Ceftriaxone if disseminated disease - Jarisch-Herxheimer reaction is sometimes seen after initiating therapy: fever, rash, tachycardia after first dose of antibiotic (more commonly seen in syphilis, another spirochaetal disease)

Answer 63

*Classic triad:* - sore throat - lymphadenopathy - pyrexia *Also:* - malaise, anorexia, headache - palatal petechiae - splenomegaly - hepatitis, transient rise in ALT - lymphocytosis: presence of 50% lymphocytes with at least 10% atypical lymphocytes - haemolytic anaemia secondary to cold agglutins (IgM) - maculopapular, pruritic rash develops following ampicillin/amoxicillin

Answer 64

- Heterophil antibody test (Monospot test) - FBC and Monospot in the 2nd week of the illness to confirm a diagnosis of glandular fever.

Answer 65

- rest during the early stages, drink plenty of fluid, avoid alcohol - simple analgesia for any aches or pains - avoid playing contact sports for 4 weeks after having glandular fever to reduce the risk of splenic rupture

Answer 66

Campylobacter

Answer 67

- prodrome: headache malaise - diarrhoea: often bloody - abdominal pain: may mimic appendicitis

Answer 68

- usually self-limiting - treatment if severe or patient is immunocompromised - antibiotics if severe symptoms (high fever, bloody diarrhoea, or >8 stools/d) or symptoms have last >1w - first-line antibiotic is clarithromycin - ciprofloxacin is an alternative

Answer 69

- GBS - reactive arthritis - septicaemia, endocarditis, arthritis

Answer 70

- most common neurological infection seen in HIV - constitutional symptoms, headache, confusion, drowsiness - CT: usually single or multiple ring enhancing lesions, mass effect may be seen - management: sulfadiazine and pyrimethamine

Answer 71

**Patient has had a full course of tetanus vaccines, with the last dose < 10 years ago:** - no vaccine nor tetanus immunoglobulin is required, regardless of the wound severity **Patient has had a full course of tetanus vaccines, with the last dose > 10 years ago:** - if tetanus prone wound: reinforcing dose of vaccine - high-risk wounds (e.g. compound fractures, delayed surgical intervention, significant degree of devitalised tissue): reinforcing dose of vaccine + tetanus immunoglobulin **If vaccination history is incomplete or unknown:** - reinforcing dose of vaccine, regardless of the wound severity - for tetanus prone and high-risk wounds: reinforcing dose of vaccine + tetanus immunoglobulin

Answer 72

- schizonts on a blood film - parasitaemia > 2% - hypoglycaemia - acidosis - temperature > 39 °C - severe anaemia

Answer 73

artemisinin-based combination therapies (ACTs)

Answer 74

- intravenous artesunate - if parasite count > 10% then exchange transfusion should be considered

Answer 75

fever, hepatosplenomegaly, diarrhoea and jaundice

Answer 76

>>Usually managed in primary care, as disease is generally mild and self-limiting - Rehydration - Antibiotic therapy if - malnourished, immunocompromised, elderly, food handlers, healthcare workers, severe disease (bloody diarrhoea with cramping while systemically unwell) - ciprofloxacin

Answer 77

*Early syphilis is defined as the first 2 years after infection and includes 3 stages:* **(1) Primary syphilis:** - Painless chancre - highly infectious, hard anogenital ulcer - Local lymphadenopathy **(2) Secondary syphilis:** - Symmetrical maculopapular rash, typically on the trunk, face, palms or soles, might be scaly - Constitutional symptoms - fever, malaise, myalgia, fatigue, and arthralgia - Lymphadenopathy - Tonsillitis - Condylomata lata (flat papules around/ beyond the genitals) - Oral snail-track ulcers - Also - Alopecia, Hepatitis, Hepatosplenomegaly, Rhinitis, Uveitis, Optic neuritis, Meningism, Glomerulonephritis, Periosteitis **(3) Early latent syphilis:**Confirmed infection in the absence of any current clinical features. - If untreated, might progress to tertiary or late syphilis (defined as more than 2 years after infection). - In the late stage, the disease may damage the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints

Answer 78

- Positive serological treponeme specific antibody testing (which will remain positive for life) - Positive non-treponeme specific antibody testing (to confirm active infection).

Answer 79

*If diagnosis is confirmed:* - Benzathine benzylpenicillin IM 2-3 doses, 1 week apart - Alternative: Doxycycline 100mg/12h (14 days for early syphilis, 28 days for late syphilis) - In pregnancy: Erythromycin 500mg/6h PO >>Follow up at 3, 6, and 12 months in specialist GUM clinic

Answer 80

all patients with a CD4 count < 200/mm³

Answer 81

Co-trimoxazole IV pentamidine in severe cases

Answer 82

U&Es, LFTs, vision testing, FBC

Answer 83

Tetracyclines

Answer 84

- causes painless black eschar (cutaneous 'malignant pustule', but no pus) - typically painless and non-tender - may cause marked oedema - anthrax can cause gastrointestinal bleeding

Answer 85

ciprofloxacin

Answer 86

- rounded opacity - crescent sign may be present

Answer 87

Bartonella henselae

Answer 88

**NAATs are investigation of choice:** - women: vulvovaginal swab is first-line - men: urine (first void urine sample) is first-line - should be carried out two weeks after a possible exposure

Answer 89

- doxycycline (7 day course) if first-line - if contraindicated / not tolerated then azithromycin (1g od for one day, then 500mg od for two days) - if pregnant then azithromycin, erythromycin or amoxicillin *partner notification:* - for men with urethral symptoms: all contacts since, and in the four weeks prior to, the onset of symptoms - for women and asymptomatic men all partners from the last six months or the most recent sexual partner should be contacted

Answer 90

profuse 'rice water' diarrhoea dehydration hypoglycaemia

Answer 91

oral rehydration therapy antibiotics: doxycycline, ciprofloxacin

Answer 92

prodrome fever, lethargy, headache trismus (lockjaw) risus sardonicus: facial spasms opisthotonus (arched back, hyperextended neck) spasms (e.g. dysphagia)