Haemolytic disease of the Newborn and HSP

Question 1

What is haemolytic disease of the newborn?

Answer 1

An immune haemolytic anaemia due to antibodies against blood group antigens

e.g. Anti D, Anti-A, Anti-B, Anti-Kell

Question 2

How do you diagnose HDoN?

Answer 2

Coombs test positive

Biochemistry- raised BR, raised reticulocytes, low Hb/ Hct

Question 3

What clinical features may occur in HDN?

Answer 3

Anaemia symptoms
Raised reticulocyte count
Jaundice
Hepatosplenomegaly
Respiratory distress

Question 4

What is the treatment of HDN?

Answer 4

Phototherapy
IVIG
Exchange transfusion

Question 5

What is Henoch-Schonlein Purpura?

Answer 5

• Most common vasculitis of childhood
• Affects small vessels
• Involves tissue deposition of IgA-containing immune complexes within affected organs

Question 6

What is HSP characterised by?

Answer 6

o Characteristic purpuric rash over extensor surfaces (esp buttocks and legs)
o Arthralgia
o Abdominal pain
o Periarticular oedema
o Glomerulonephritis

Question 7

What is the epidemiology of HSP?

Answer 7

o Usually affects ages 3-10 years
o More common in boys (2:1)
o Peaks during winter months, often preceded by an upper RTI

Question 8

What is the pathophysiology of HSP?

Answer 8

o Underlying aetiology is unknown – thought to be an immune-mediated vasculitis
o Possible theory: genetic predisposition and antigen exposure increase circulating IgA
levels and disrupt IgG synthesis → the IgA and IgG interact to produce complexes
that activate complement and are deposited in affected organs precipitating an
inflammatory response and vasculitis
o Similar pathophysiology to IgA nephropathy

Question 9

What is a fun way to remember the characteristic features of HSP?

Answer 9

Ÿ Haematuria
Ÿ Surface rash on extensors (nonblanching raised palpable
purpura), Scrotal Swelling
Ÿ Polyarthritis, Pain (Abdo)

Question 10

What investigations do you do for HSP?

Answer 10

• Urinalysis → RBCs, proteinuria, casts
• 24-hour urine collection for protein
• Serum creatinine and electrolyte levels – to assess for renal failure
• Serum IgA – raised
• Coagulation studies – normal
• Skin biopsy – IgA deposition
• Renal biopsy – IgA, C3 and fibrin deposition in the mesangial region

Question 11

What is the management of HSP?

Answer 11

• Most cases will resolve spontaneously within 4 weeks
• Admit if inability to maintain adequate hydration with oral intake, severe abdominal pain,
severe renal involvement etc
o If dehydrated → IV fluids
o If significant anaemia → may need RBC transfusion
• Joint pain can be managed using paracetamol or ibuprofen
• If there is scrotal involvement or severe oedema or severe abdominal pain, oral prednisolone
may be given
• IV corticosteroids are recommended in patients with nephrotic-range proteinuria and those
with declining renal function
• Renal transplant may be considered in end-stage renal disease