Rheumatology I Flashcards
(33 cards)
A patient has ?PMR.
You run tests for FBC, U+Es, ESR, CRP and TFTs.
Which other tests do you also need to order? [1]
The first line investigations for Polymyalgia rheumatica are indicative of the differentials which include malignancy, endocrinopathy and metabolic bone disease
A patient is dx with Sjogrens.
What medication should be commenced to address her dry mouth?
Duloxetine
Hyoscine hydrobromide
Neostigmine
Nortriptyline
Pilocarpine
Pilocarpine
- a muscarinic receptor agonist that stimulates salivary gland function, increasing saliva production to alleviate the dry mouth
Describe the pathophysiology of polyarteritis nodosa (PAN) [3]
Inflammation of Medium-sized Arteries:
- The hallmark of PAN is necrotising inflammation of the medium-sized arteries, particularly the muscular and elastic type
- Immune Complex Deposition - in cases associated with HBV, immune complexes formed by the viral antigens and corresponding antibodies are thought to be deposited in the arterial walls, leading to inflammation and damage.
Ischaemia and Infarction:
- The inflammation and damage to the arterial wall can lead to stenosis or occlusion of the vessel, resulting in ischaemia and infarction of the downstream tissues.
Aneurysm Formation:
- The weakening of the arterial wall can lead to the formation of microaneurysms, which can rupture, causing haemorrhage.
Describe the clinical features of PAN [+]
ZtF:
* Renal impairment
* Hypertension
* Cardiovascular events
* Tender skin nodules
PM:
* fever, malaise, arthralgia
* weight loss
* hypertension
* mononeuritis multiplex, sensorimotor polyneuropathy
* testicular pain
* livedo reticularis
* haematuria, renal failure
* perinuclear-antineutrophil cytoplasmic antibodies (ANCA) are found in around 20% of patients with ‘classic’ PAN
Investigations for PAN?
There is no diagnostic laboratory test for PAN.
Biopsy is performed on a clinically affected organ to confirm the diagnosis.
Arteriography (mesenteric or renal) can be used as an alternative to biopsy to confirm the diagnosis (to minimise bleeding risk). It can reveal aneurysms and irregular constrictions in the vessels.
Chest radiography may be obtained to exclude other forms of vasculitis, which have greater involvement in the lungs.
How would you differenitate PAN to atherosclerosis? [1]
Atherosclerosis can also cause infarctions in various organs, causing similar symptoms, with similar age of onset as PAN. They can be both differentiated on histology.
Tx of PAN?
Induction of Remission
* Corticosteroids - Prednisolone at a dose of 1mg/kg/day (maximum 60 mg/day) is usually recommended. Tapered
* Cyclophosphamide: For patients with severe PAN or organ-threatening disease, cyclophosphamide is usually added. The typical dose is 2 mg/kg/day orally or 15 mg/kg intravenously every 2-3 weeks.
Maintenance of Remission
* Azathioprine or Methotrexate: Once remission is induced, cyclophosphamide can be replaced with azathioprine (2 mg/kg/day) or methotrexate (15-25 mg/week) as maintenance therapy.
* Corticosteroids: Continue with a lower dose of corticosteroids and taper gradually.
On imaging, typical findings in PAN are [] and []
On imaging, typical findings in PAN are multiple aneurysms and irregular constrictions of arterial vessels.
Describe the clinical presentation of GPA
Patients typically present with:
URTI
- sinusitis
- saddle nose - due to nasal bridge collapse,
- otitis media
- nasal crusting
LRTI:
- Haemopytsis
- Dysopnea and cough
- Pleuritis
- Pulmonary infiltrates
Neurological
- Mononeuritis simplex
- Peripheral sensorimoto polyneuropathy
- Cranial neuropathy
Petechiaie, purpura
Glomerulonephritis
Consider granulomatosis with polyangiitis when a patient presents with ENT, respiratory and kidney involvement
Describe the investigations used for GPA [3]
cANCA positive in > 90%, pANCA positive in 25%
chest x-ray:
- wide variety of presentations, including cavitating lesions
renal biopsy:
- epithelial crescents in Bowman’s capsule
What is the gold standard for dx GPA? [1]
How else do you investigate? [3]
Gold standard:
- histopathological confirmation of necrotising granulomatous inflammation in a biopsy sample from an affected organ, typically the lung or kidney.
Serology:
- cANCA
- proteinase 3 (PR3)
Abnormal urinary sediement:
- microscopic haematuria or red cell casts
Pulmonary abnormalities:
- nodules, fixed infiltrates or cavities observable on chest radiograph.
How do you differentiate GPA with eGPA?
eGPA presents more with asthma and eosinophilia
mononeuritis multiplex is more common in eGPA
In EGPA, pulmonary infiltrates are more transient vs GPA
Renal involvement in EGPA tends to be less severe than in GPA, presenting as mild proteinuria or microscopic haematuria rather than rapidly progressive glomerulonephritis.
Describe the management plan for GPA in life/organ threatening disease [+]
Induction of remission:
- First-line therapy: Methylprednisolone IV for 3-5 days (followed by oral prednisolone) and cyclophosphamide for 3-6 months
- Second-line therapy: Methylprednisolone IV for 3-5 days (followed by oral prednisolone) and rituximab IV.
Maintenance of remission
* First-line therapy: Prednisolone and methotrexate (with folic acid).; Prednisolone and azathioprine
usually for 2 years following remission, but can vary.
Describe the clinical presentation of eGPA
- asthma (late onset)
- blood eosinophilia (e.g. > 10%)
- paranasal sinusitis
- mononeuritis multiplex
- pANCA positive in 60%
Mx for eGPA [3]
Induction:
- prednisolone at 0.5-1.0 mg/kg/day
- Methylprednisolone 1g daily for three days may be used for more extensive disease.
- Cyclophosphamide, which is an alkylating chemotherapeutic agent used in systemic inflammatory conditions, may be added for severe multi-system disease or an inadequate response to steroids.
Maintenance:
- This can be initiated after induction therapy to maintain disease remission over long periods of time. The choice of agents may include azathioprine or methotrexate, but there are many other options.
Epithelial crescents in Bowman’s capsule
Microscopic Polyangiitis is associated with which antibody? [1]
The major autoantigens in microscopic polyangiitis are [2]
p-ANCA
The major autoantigens in microscopic polyangiitis are MPO and PR3.
Clinical features of microscopic polyangiitis?
fever
palpable purpura
rapidly progressive glomerulonephritis
- raised creatinine, haematuria, proteinuria
Diffuse alveolar haemorrhage
Respiratory (25-55%): haemoptysis, pulmonary haemorrhage, pleural effusion, oedema
pANCA (against MPO) - positive in 50-75%
cANCA (against PR3) - positive in 40%
How do you differentiate MPA and PAN? [2]
PAN:
- usually no lung involvement, strong link with Hepatitis B, only involves small to medium arteries (not venules or capillaries)
Tx for severe MPA? [+]
Induction:
- 1st line: cyclophosphamide (CYC) with high dose steroids. Therapy is continued for 3-6 months then switched to less toxic maintenance once remission achieved
- Adjunct plasma exchange in patients with severe renal failure (creatinine >500 µmol/l) or life-threatening manifestations
Maintenance: for 24 months
- 1st line: low dose steroids with azathioprine (AZA) or MTX
- If patients refractory to AZA and MTX or contraindications to use: MMF or leflunomide
Tx for non-severe MPA? [+]
Induction:
- High dose steroids with either methotrexate (MTX) or mycophenolate mofetil (MMF)
Maintenance: for 24 months
- 1st line: low dose steroids with azathioprine (AZA) or MTX
- If patients refractory to AZA and MTX or contraindications to use: MMF or leflunomide
[Complication] patients have a nine-fold increased risk of mortality and a higher risk of relapse in MPA
Alveolar haemorrhage: patients have a nine-fold increased risk of mortality and a higher risk of relapse
In HSP, immunofluorescence studies show [3] within the walls of involved vessels.
Immunofluorescence studies show IgA, complement component 3 (C3), and fibrin deposition within the walls of involved vessels.
