MSK Flashcards
(234 cards)
Define giant cell arteritis
Granulomatous inflammation of large arteries, particularly branches of the external carotid artery, most commonly the temporal artery.
One of the aorta + medium to large artery vasculitides
Explain the aetiology / risk factors of giant cell arteritis
Unknown.
Genetic: Associated with HLA-DR4 and HLA-DRB1
Viral infection: parvovirus b19
Both the humoral and cellular immune systems have been implicated in the pathogenesis of GCA.
Pathphysiology:
- Inflammation (dendritic cells recruit monocytes, which differnetiate the macrophages and giant cells)
- Local vascular damage (macrophages produce MMPs)
- Concentric intimal hyperplasia (macrophages and giant cell produce PDGF and VEGF which stimulate intimal proliferation leading to reduced blood flow and ischaemia)
Association with polymyalgia rheumatica (PMR): 40–50% of patients with giant cell arteritis also have PMR.
Summarise the epidemiology of giant cell arteritis
Peak onset 65-70 y/o. Female: male= 2-4:1. Norther european women
Recognise the presenting symptoms of giant cell arteritis
Subacute, over a few weeks
Constitutional symptoms
Fever, weight loss, night sweats
Symptoms of anemia: fatigue and malaise
Headache: scalp and temporal tenderness (pain on combing hair. Jaw and tongue claudication (when eating!).
Visual disturbances : Blurred vision, sudden blindness in one eye (amaurosis fugax=painless temporary loss of vision in one or both eyes and scintillating scotoma ).
Systemic features : Malaise, low-grade fever, lethargy, weight loss, depression.
Symptoms of polymyalgia rhuematica (PMR): Early morning pain and stiffness of the muscles of the shoulder and pelvic girdle (40– 60% of cases are associated with PMR).
Recognise the signs of giant cell arteritis on physical examination
Swelling and erythema overlying the temporal artery.
Scalp and temporal tenderness.
Thickened non-pulsatile temporal artery.
Reduced Visual acuity.
Identify appropriate investigations for giant cell arteritis and interpret the results
ACR criteria (3 of 5 required):
- Age AT ONSET >50
- Headaches
- Abnormalities of temporal arteyr
- Elevated ESR (>50mm/h)
- Histopathaological abnormalities of temporal artery
Blood : raised ESR, FBC (normocytic anaemia of chronic disease).
Temporal artery biopsy : Within 48h of starting corticosteroids. Note that a negative biopsy does not exclude the diagnosis, because skip lesions occur.
Generate a management plan for giant cell arteritis
High dose oral prednisolone (40-60mg/day) to prevent VISUAL LOSS. Begin treatment as soon as temporal arteritis is suspected. Do not wait for a biopsy.
Reduce pred dose gradally according to symptoms adn ESR. Can require for 1-2 years
Low dose aspirin (+PPIs) to prevent ischaemic complications e.g. reduce risk of visual loss, TIAs or stroke.
Osteoporosis prevention (adequate dietary calcium and vitamin D intake, bisphosphonates).
If GCA is complicated by visual loss: IV pulse methylprednisolone (1 g for 3 days) followed by oral prednisolone (60 mg/day, as above).
Annual CXR for up to 10 years to identify thoracic aortic aneurysms. If detected, monitor with CT every 6– 12 months.
Identify the possible complications of giant cell arteritis and its management
Permanent vision loss: ∼ 20–30% if giant cell arteritis is left untreated
Cerebral ischemia (e.g., transient ischemic attack and stroke): < 2% of cases
Aortic aneurysm and/or dissection: ∼ 10–20% of patients
Summarise the prognosis for patients with giant cell arteritis
In most cases the condition lasts for ~2 years before complete remission.
Define sarcoidosis
Multisystem granulomatous inflammatory disorder
an immunologic disorder that results in lots of small nodules forming throughout the body.
Explain the aetiology / risk factors of sarcoidosis
Unknown.
PATHOLOGY/PATHOGENESIS The unknown antigen is presented on the MHC Class II complex of dendritic cells to CD4 (Th1) lymphocytes, which accumulate and release cytokines (e.g. IL-1/IL-2).
This results in formation of non-caseating granulomas in a variety of organs.
RISK FACTORS:
- Environmental risk factors include a prior infection with Mycobacterium tuberculosis and Borrelia burgdorferi (which causes lyme disease), but to be specific, these pathogens are long gone when the autoimmune problem sets in.
- Genetic: African American/family member with sarcoidosis
Summarise the epidemiology of sarcoidosis
Uncommon. More common in 20– 40 year olds, Africans and females. The prevalence is variable worldwide. Prevalence in UK is 16 in 100 000 (highest in Irish women).
Recognise the presenting symptoms of sarcoidosis
Where does it most commonly involve?
Sarcoidosis can involve nearly every organ, but they most often involves hilar lymph nodes which are lymph nodes that are near the point where the bronchi meets the lung.
General: fever, malaise, weight loss, bilateral parotid swelling, lymphadenopathy, hepatosplenomegaly
Lungs: breathlessness, cough (usually unproductive) , chest discomfort. Fine inspiratory crepitations
MSK: Bone cysts (e.g. dactylitis in phalanges), polyarthralgia, myopathy
Eyes: keratoconjuctivitis sicca (dry eyes), uveitis, papilloedema
Skin : Lupus pernio (red– blue infiltrations of nose, cheek, ears, terminal phalanges), erythema nodosum, maculopapular eruptions.
Neurological : Lymphocytic meningitis, space-occupying lesions, pituitary infiltration, cerebellar ataxia, cranial nerve palsies (e.g. bilateral facial nerve palsy), peripheral neuropathy.
Heart : Arrhythmia, bundle branch block, percarditis, cardiomyopathy, congestive cardiac failure.
Recognise the signs of sarcoidosis on physical examination
General: fever, malaise, weight loss, bilateral parotid swelling, lymphadenopathy, hepatosplenomegaly
Lungs: breathlessness, cough (usually unproductive) , chest discomfort. Fine inspiratory crepitations
MSK: Bone cysts (e.g. dactylitis in phalanges), polyarthralgia, myopathy
Eyes: keratoconjuctivitis sicca (dry eyes), uveitis, papilloedema
Skin : Lupus pernio (red– blue infiltrations of nose, cheek, ears, terminal phalanges), erythema nodosum, maculopapular eruptions.
Neurological : Lymphocytic meningitis, space-occupying lesions, pituitary infiltration, cerebellar ataxia, cranial nerve palsies (e.g. bilateral facial nerve palsy), peripheral neuropathy.
Identify appropriate investigations for sarcoidosis and interpret the results
Why would you do a 24-hr urine collection for sarcoidosis?
Stage 0, 1, 2 and 3 on CXR?
What happens to CD4:CD8 ratio on broncheoalveiolar lavage
Blood: SERUM ACE (is a measure of granuloma burden in tissues, product of macrophages), Ca2+ (elevated)
ESR, FBC (WCC may be reduced because of lymphocyte sequestration in the lungs), immunoglobulins (polycloncal hyperglobulinaemia), LFT (raised alkaline phosphatase and GGT)
24hr urine collection for: hypercalcuria
CXR: Stage 0 : May be clear. Stage 1 : Bilateral hilar lymphadenopathy. Stage 2 : Stage 1 with pulmonary infiltration and paratracheal node enlargement. Stage 3 : Pulmonary infiltration and fibrosis.
High-resolution CT scan: For diffuse lung involvement.
67 Gallium scan: Shows areas of inflammation (classically parotids and around eyes).
Pulmonary function tests: # FEV 1 , FVC and gas transfer (showing restrictive picture).
Bronchoscopy and bronchoalveolar lavage: increased lymphocytes with increased CD4: CD8 ratio.
Transbronchial lung biopsy (or lymph node biopsy): Non-caseating granulomas composed of epithelioid cells (activated macrophages), multinucleate Langhans cells and mononuclear cells (lymphocytes).
What happens to WCC in sarcoidosis
WCC may be reduced because of lymphocyte sequestration in the lungs
What are the normal components of synovial fluid analysis
Colour
Leukocytes
%PMNs
Total protein
Glucose
Crystals
Culture
What would you expect to see in a gouty arthritis synovial fluid analysis
Colour- yellow
Leukocytes- raised
%PMNs: raised
Total protein: slightly raised
Glucose: reduced
Crystals: -vely birefringent needle-shaped crysals
Culture: negative
Interpret this synovial fluid analysis:
Color: Yellow/opaque Leukocytes: 100,000 mm3 %PMNs: 75 Total Protein: 4g/dL Glucose: 20g/dL Crystals: None Culture: Gram+ cocci in clusters
This is a typical synovial fluid analysis for septic arthritis or septic bursitis.
Where are the common sites of bursitis
Common sites of bursitis include trochanteric (as in the vignette above) subacromial, olecranon, prepatellar, and infrapatellar bursae.
Outline what happens to the bursa in bursitis
Trauma or repetitive use can irritate the bursa, leading to inflammation and proliferation of the mesothelial cells lining the sac.
Inflammation of the bursa results in the effusion of a clear fluid within the bursal sac.
With prolonged inflammation, the sac gets thickened and may cause erosion on the adjacent bone due to the pressure exerted by the sac.
What might radiographs of bursitis around the greater trochanter show
Radiographs may show some calcification arising from the apex of the greater trochanter.
What is the current vignette typical for
Gradual, dull, and nocturnal pain with poor response to salicylates. Radiograph shows a well-circumscribed, lytic lesion (> 2 cm) with a rim of reactive sclerosis.
Is this benign or malignant?
Osteoblastoma
Benign
This type of tumor is usually a solitary lesion and tends to affect the axial skeleton (m.c., posterior column of the cervical spine). Osteoblastoma is more common in males between 20 to 30 years. Patients present with gradual, dull, and nocturnal pain with poor response to salicylates. In the physical exam, findings may include decreased range of motion and tender and swollen affected area. Patients may also progress to develop a neurological deficit as a result of cord compression.
Differentiate osteoblastoma with an osteoid osteoma
Osteoid osteoma is basically same as osteoblastoma, but >1cm