IgA Vasculitis (Henoch-Schonlein purpura) Flashcards
What is shown here?
Henoch Schonlein purpura - characteristic skin rash on extensor surfaces
aka IgA vasculitis
What is the tetrad of HSP?
- Rash
- Abdominal pain
- Arthritis/arthralgia
- Glomerulonephritis
(periarticular oedema is also seen)
What is the cause of HSP?
Unknown despite research
Thought to be that genetic predisposition and antigen exposure increase circulating IgA levels and disrupt IgG synthesis.
IgG and IgA interact to form complexes that activate complement and are deposited in affected organs, precipitating an inflammatory response with vasculitis
Are any investigations diagnostic of HSP?
No markers are diagnostic of HSP specifically
Investigations to consider:
- FBC
- Clotting screen
- Renal function
- Urine dipstick
When is HSP diagnosed? Who is most affected?
Can occur 6 months to adulthood, 50% in <5 years, 75% in <10 years - usually preceded by un URTI, diagnosis peaks in the winter months.
Males>females
How do you differentiate HSP from ITP?
ITP - fine petechial rash, no abdominal pain
HSP - intermittent abdominal pain, florid erythematous rash over buttocks and legs and can spread to trunk usually
List some common complications of HSP.
- Intussusception
- Acute renal impairment
- Arthritis/arthralgia, typically in ankles and knees
- Pancreatitis
Testicular/scrotal involvement reported in some boys.
Describe the presentation of HSP/IgA vasculitis including the appearance of the rash.
- Fever - present in most at presentation
- Rash - florid symmetrical erythematous rash over buttocks and extensor surfaces of arms and legs and ankles. Trunk is usually spared, May be urticarial initially but rapidly becoes maculopapular and purpuric (characteristically palpable). May recur over several weeks. Cornerstone of diagnosis and the first feature present in ~50%.
- Joint pain
- Colicky abdominal pain
- Renal involvement - features of IgA nephropathy may occur, 80% have macroscopic haematuria or mild proteinuria
Describe the joint pain in IgA vasculitis and any consequences.
- Present in two thirds of patients
- Knees and ankles affected
- Periarticular oedema present
- Symptoms usually resolve before the rash does and NO long-term damage to joints occurs
Describe the abdominal symptoms of IgA vasculitis and any complications.
Colicky in nature. If severe it is treated with corticosteroids. Complications include:
- Haematemesis and melaena
- Intusussception - can occur and be difficult to diagnose
- Ileus - rare
- Protein-losing enteropathy - rare
- CNS involvement - rare
Describe renal invovlement in IgA vasculitis and any complications. What are some indicators of progressive chronic renal disease in these patients?
Common but rarely occurs early
>80% have macroscopic haematuria or mild proteinuria but usually make a complete recovery. All children should however be monitored for 1yr to detect persisting haematuria or proteinuria.
NephrOtic syndrome may occur if proteinuria is severe
Risk of hypertension and progressive CKD in the long term.
Risk factors for chronic renal disease:
- heavy proteinuria
- oedema
- hypertension
- deteriorating renal function - renal biopsy confrms if treatment is necessary
What is the management of HSP?
Analgesia for arthralgia
Treatment of nephropathy is supportive (inconsistent evidence for use of steroids and immunosuppressants)
What is the prognosis of HSP? How common is relapse?
Usually excellent as self-limiting condition, especially in children without renal involvement
1/3 have a relapse
What are some distinguishing differences between IgA nephropathy and post-streptococcal glomerulonephritis?
- post-streptococcal glomerulonephritis is associated with low complement levels
- main symptom in post-streptococcal glomerulonephritis is proteinuria (although haematuria can occur)
- there is typically an interval between URTI and the onset of renal problems in post-streptococcal glomerulonephritis
Usually no treatment required for IgA nephropathy but if severe then ACEi can be used.
