Name four conditions that predispose patients to osteoporosis.
- Inflammatory diseases (RA, AS, lupus)
- Multiple myeloma
- Celiac disease
What is the best way to diagnose gout? How are gout crystals recognized on polarized microscopy? How are pseudogout crystals recognized on polarized microscopy?
Gout is best diagnosed by visualization of crystals in a joint aspirate. Gout (monosodium urate) crystals have a needle-shaped appearance under light microscopy. Under a polarizing light microscope, these needle-shaped crystals are strongly negatively birefringent. This means that when the compensator portion of the microscope is positioned parallel to the long axis of the crystal, the crystal appears bright yellow. When the compensator is turned perpendicular to the crystal, the crystal appears bright blue.
Pseudogout (or calcium pyrophosphate) crystals are rhomboid-shaped and weakly positively birefringent. This means that when the compensator is parallel to the long axis of a pseudogout crystal, the crystal has a faint blue colour. When the compensator is perpendicular to the crystal, the crystal is faintly yellow.
What are the symptoms of giant cell arteritis (temporal arteritis)?
GCA symptoms are variable and may include any of the following.
- New onset headache (occurs in two-thirds of patients)
- Constitutional symptoms
- Jaw claudication
- Tongue claudication
- Scalp tenderness
- Arm claudication
- Visual disturbance including amaurosis fugax, diplopia or permanent vision loss.
- Symptoms of polymyalgia rheumatica (including aching of the shoulder or hip girdle)
A markedly elevated ESR is usually seen, although giant cell arteritis is occasionally seen in patients with a normal ESR. Frequency of PMR and GCA increase with age and the conditions are essentially not seen in individuals under 50 years of age.
What are antiphospholipid antibodies? What is their clinical significance?
Antiphospholipid antobodies are antibodies directed against against epitopes on plasma proteins that are uncovered by the binding of these proteins to phospholipids.
The presence of these antibodies in high titers predisposes to venous and arterial thrombus formation, as well as spontaneous abortion. A patient with persistently elevated levels of these antibodies and associated clotting is considered to have the antiphospholipid antibody syndrome. This can occur as a primary phenomenon or secondary to systemic lupus.
Three different antiphospholipid antibodies can be measured clinically:
- anti-cardiolipin antibodies
- lupus anticoagulant
In a patient complaining of back pain, what are the “red flags” on history that suggest a need for urgent surgical intervention? What historical features suggest an underlying medical cause for the pain (such as a tumor, infection or an inflammatory problem)?
Surgical emergencies in patients presenting with back pain include the cauda equina syndrome (usually due to a tumor or massive disc herniation) and aortic aneurysmal dissection or rupture.
Historical features that should raise suspicion of these conditions include:
- Numbness (particularly “saddle anesthesia”)
- Focal weakness
- Progressive neurological compromise in the lower extremities
- Bladder or bowel incontinence
- Complaints suggestive of heart failure or ischemia (aortic aneurysm)
An underlying medical cause for back pain is suggested by the following features:
- Weight loss
- Known history of malignancy
- Recent infection
- Intravenous drug use
- Night pain
Inflammatory back pain is more likely to occur in patients with IBD, psoriasis or uveitis. The following 5 questions are particularly useful in assessing patients for inflammatory back pain. The presence of four of these five features provide a sensitivity of 0.95 and a specificity of 0.85 for spondylitis:
- Presence of morning stiffness
- Improvement of pain with exercise
- Onset before age 40
- Insidious onset
- Duration of symptoms longer than three months
Do not forget to consider visceral causes of back pain, such as pancreatitis, pyelonephritis, renal colic, or a penetrating duodenal ulcer.