Infectious diseases

Question 1

1. Kaposi sarcoma

Answer 1

1. HHV-8

Question 2

Following treatment for syphilis, which test becomes negative and which one remains positive.

Answer 2

VDRL becomes negative

TPHA remains positive

Question 3

Causes of false positive cardiolipin tests:

Answer 3

pregnancy
SLE, anti-phospholipid syndrome
TB
leprosy
malaria
HIV

false-Positive results on VDRL with PVDRL:
Pregnancy
Viral infection (eg, EBV, hepatitis)
Drugs (eg, chlorpromazine, procainamide)
Rheumatic fever (rare)
Lupus and leprosy

Question 4

1. Pentad of symptoms in TTP
2. Which protein is most commonly inhibited deficient in TTP
3. Triggers for TTP

Answer 4

1. cerebral dysfunction, fever, AKI, thrombocytopenia and microangiopathic haemolytic anaemia
2. Acquired inhibition of the protein ADAMTS13 (deficiency) which cleaves vWF multimers
3. Pregnancy
   SLE
   tumours
   post-infection e.g. urinary, gastrointestinal
   HIV
   drugs: ciclosporin, oral contraceptive pill, penicillin, clopidogrel, aciclovir

Question 5

Beta-thalassaemia trait - what would be the MCV and Hb

Answer 5

Disproportionate microcytic anaemia - think beta-thalassaemia trait
MCV 60, disproportionally high Hb 100

Question 6

Wiskott-Aldrich syndrome 
causes primary immunodeficiency due to a combined B- and T-cell dysfunction
1. mode of inheritance
2. mutation in which gene 
3. associated symptoms 
4. deficiency in which Ig

Answer 6

1. X-linked recessive
2. mutation in the WASP gene
3. WATER: Wiskott-Aldrich:
   Thrombocytopenia,
   Eczema,
   Recurrent infections / recessive
4. W of Wiskott looks like an upside down M - IgM deficiency

Question 7

Methaemoglobinaemia

Answer 7

normal pO2 but decreased oxygen saturation