The infections and the immunologicals diseases

Question 1

Polycythemia Vera

Answer 1

pruritus, typically after a hot bath
splenomegaly
hypertension
hyperviscosity
arterial thrombosis
venous thrombosis
haemorrhage (secondary to abnormal platelet function)
low ESR

full blood count/film (raised haematocrit; neutrophils, basophils, platelets raised in half of patients)
JAK2 mutation -Definitive Ix
serum ferritin
renal and liver function tests
5% are JaK2 negative-

Management
aspirin

venesection
first-line treatment to keep the haemoglobin in the normal range
chemotherapy
hydroxyurea - slight increased risk of secondary leukaemia

5-15% of patients progress to myelofibrosis
5-15% of patients progress to acute leukaemia (hydroxyurea increase risk)

Question 2

The Jarisch-Herxheimer reaction

Answer 2

The Jarisch-Herxheimer reaction is a known phenomenon following syphilis treatment (IM BENPEN) that does not require any specific treatment or investigations other antipyretics -paracetamol

fever, rash, tachycardia after the first dose of antibiotic
in contrast to anaphylaxis, there is no wheeze or hypotension

Question 3

Heamolytic aneamia causes

Answer 3

Hereditary haemolytic anaemias can be subdivided into membrane, metabolism or haemoglobin defects

Hereditary causes
membrane: hereditary spherocytosis/elliptocytosis
metabolism: G6PD deficiency
haemoglobinopathies: sickle cell, thalassaemia

Acquired haemolytic anaemias can be subdivided into immune and non-immune causes

Acquired: immune causes (Coombs-positive)
autoimmune: warm/cold antibody type
alloimmune: transfusion reaction, haemolytic disease newborn
drug: methyldopa, penicillin

Acquired: non-immune causes (Coombs-negative)
microangiopathic haemolytic anaemia (MAHA): TTP/HUS, DIC, malignancy, pre-eclampsia
prosthetic heart valves
paroxysmal nocturnal haemoglobinuria
infections: malaria
drug: dapsone
Zieve syndrome
rare clinical syndrome of Coombs-negative haemolysis, cholestatic jaundice, and transient hyperlipidaemia associated with heavy alcohol use, typically following a binge
typically resolves with abstinence from alcohol

Question 4

Warm and cold haemolytic aneamia

Answer 4

It is most commonly idiopathic but may be secondary to a lymphoproliferative disorder, infection or drugs.

warm
Warm is the most common type of AIHA. In warm AIHA the antibody (usually IgG) causes haemolysis best at body temperature and haemolysis tends to occur in extravascular sites, for example the spleen.

Causes of warm AIHA
idiopathic
autoimmune disease: e.g. systemic lupus erythematosus*
neoplasia
lymphoma
chronic lymphocytic leukaemia
drugs: e.g. methyldopa

Management
treatment of any underlying disorder
steroids (+/- rituximab) are generally used first-line

Cold AIHA

The antibody in cold AIHA is usually IgM and causes haemolysis best at 4 deg C. Haemolysis is mediated by complement and is more commonly intravascular. Features may include symptoms of Raynaud’s and acrocynaosis. Patients respond less well to steroids

Causes of cold AIHA
neoplasia: e.g. lymphoma
infections: e.g. mycoplasma, EBV

*systemic lupus erythematosus can rarely be associated with a mixed-type autoimmune haemolytic anaemia