Infection

Question 1

Sepsis?

Answer 1

Life threatening organ dysfunction (ischaemia) due to a dysregulated (overreactive) host response to infection
Causes hypotension, resp and renal failure,
raised intracranial pressure, had/feet ischaemia
Sepsis six bundle within the hour: oxygen, blood culture, IV antibiotics, fluid challenge, lactate, urine output
Treatament: Supportive–> system relief, restoration (sepsis 6). Specific –> antimicrobials, surgery

Question 2

Bacteraemia?

Answer 2

Presence of bacteria in blood

Question 3

HIV?

Answer 3

Caused by human immunodeficiency virus (retro) -> lowers immune response
Infects cells with CD4 receptors (T helper)
Destroys cell, causes inflammation
AIDS: CD4 < 200
Transmitted via bodily fluids
Presents as: prolonged dry cough, quick loss of weight, loose motions, skin lesions, sore mouth, rapid deterioration in breathing
Features: thrush (oral candidiasis), kaposi’s sarcoma, consolidation (PCP)
Tests: HIV Ag/Ab, PCR, ‘rapid’ test
Treatment: ARVs

Question 4

Viral hepatitis?

Answer 4

Caused by hepatitis virus which replicates in hepatocytes
Presents as: abnormal LFTs, fatigue, pain, nausea, yellow eye tinge
Tests: bilirubin/ALT/ALP raised, albumin/clotting factors/INR low

Question 5

Hepatitis B?

Answer 5

Transmission: Vertical, sexual contact, drug users
Acute:
Symptoms-jaundice, fatigue, abdominal pain, anorexia, nausea, arthralgia
Incubation-6wks-months
Tests-AST/ALT > 1000s, HBsAg/Ab, HbeAg/Ab, HbcAg/Ab
Infection cleared in 6 months
Can become chronic (<10%)
-more than 6 months-> cirrhosis
-no cure (just ARVs)

Question 6

Hepatitis C?

Answer 6

Transmission: drug users, sexual contact, blood transfusion, vertical
Symptoms (20% have): fatigue, anorexia, nausea, abdominal pain
Can become chronic (80%)-> cirrhosis->hepatocelluar carcinoma
Tests: HEP C Ab, viral PCR
Treatment: ARVs (90% completely cured)

Question 7

Malaria?

Answer 7

Caused by:
Plasmodium falciparum
-most serious
-incubation period 6 to 12d
-symptoms: fever, chills, high BP/HR, diarrhoea, confusion, DIC, jaundice, hepatosplenomegaly, hypoglycaemia
-treatment: artesunate, quinine, doxycycline
P. Vivax/ovale
-incubation period upto 1y (dormant storage in liver)
-symptoms: fever, chills, sweat, malaise, headaches
-treatment: chloroquine, primaquine
Vector - female Anopheles mosquito
Tests: blood smear X3, FBC, LFTs, U&E

Question 8

Typhoid/paratyphoid (enteric fever)?

Answer 8

Caused by Salmonella typhi/paratyphi
Virulence: gram -ve endotoxin (VI antigen), invasin, fimbrae
Incubation: 1-2w
Prevalence: mainly Asia
Spread: faecal-oral contaminated food/water
Symptoms: constipation, loose motion, abdo cramps, fever, dry cough, headache, bradycardia, intestinal haemorrhage
Tests: FBC(anaemia), LFTS raised, blood/faeces cultures, serology
Treatment: ceftriaxone

Question 9

Non-typhoidal salmonella?

Answer 9

‘Food poisoning’
Caused by S. typhimurium, enteritidis
Symptoms: diarrhoea, fever, vomiting, abdo pain

Question 10

Rickettsia?

Answer 10

Spotted fever

Cases macular rash (also caused by HIV, measles, mono)

Question 11

Dengue?

Answer 11

Most common arbovirus
4 serotypes
Prevalence: sub, tropical regions (Africa, Asia, Indian SC).
Primary infection: asymptomatic - fever, rash (3-4d)
Re-infection: haemorrhagic fever, shock