0071643192.pdf

ORTHOPEDICS

DIFFERENTIAL

Septic hip, psoas abscess, sciatic, herniated disc, pyelonephritis, ankylosing

spondylitis

DIAGNOSIS

■ X-rays show symmetric erosion and sclerosis of the SI joint.

■ MRI of SI joint

■ Aspiration and blood cultures if infection suspected

TREATMENT

Depends on underlying cause (eg, anti-inflammatory agents for inflammatory

causes, antibiotics if infection suspected)

COMPLICATIONS

May be a part of a larger inflammatory arthritis, ie, ankylosing spondylitis,

which is a seronegative spondyloarthropathy typically found in young males

with prolonged (>3 months) back pain

RHABDOMYOLYSIS

Breakdown of muscle that leads to a cascade of events, including: hypo-

volemia (fluid build-up in injured myocytes); hyperkalemia (from release of the

intracellular stores in the injured myocytes); and renal failure (from clogging of

glomeruli with myoglobin and toxic effects of myocyte breakdown products);

accounts for about 10% of all cases of acute renal failure

SYMPTOMS/EXAM

■ Symptoms are often very subtle; must maintain a high index of suspicion.

■ Only half of patients complain of muscle pain.

■ Only a small fraction of patients complain of dark urine.

■ Tender or focal muscle swelling is rare. If present, must consider compart-

ment syndrome!

ETIOLOGY

■ Trauma (most common)

■ Ischemia

■ Polymyositis

■ Toxins/drugs

■ Excessive muscle activity

■ Seizures

■ Burns

■ Sepsis

■ Viral illness

DIAGNOSIS

■ CK>5–10x above normal. However, if CK levels >2–3x normal, repeat

CK level—it peaks about 24 hours from initial insult.

■ Urine dipstick test is positive for blood (globin) but there are no RBCs

in the urine microscopic exam.

■ LDH and AST are elevated.

■ Check serum for elevated potassium, phosphate, creatinine. Serum calcium

may be low.