Sandbox:jsoujanya

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

The diagnosis of gout is based upon the identification of intracellular monosodium urate (MSU) crystals in the synovial fluid aspirate of an affected joint, under polarizing light microscopy. But when this is not possible, a clinical diagnosis can be deduced with the help of classical clinical features, including the history and physical examination, laboratory findings, and various imaging studies.

Diagnosis of acute gout

• While the favored approach is to find MSU crystals in the synovial fluid aspirate of an affected joint, in clinical practice a crystal evaluation is routinely not done.
• When a patient is presenting with classic symptoms of rapid onset (within 24 hours), podagra, swelling, and erythema, supported by the presence of hyperuricemia, a clinical diagnosis of gout can easily be concluded.
• When an arthrocentesis is done, synovial fluid should be examined readily under routine light and polarizing light microscopy and looked for negatively birefringent needle-shaped MSU crystals.
• In addition, testing for cell counts with differential, gram staining and culture should also be done on the aspirate.
• The sensitivity of this technique in demonstrating negatively birefringent intra- and extracellular crystals in patients with gout flares is at least 85 percent, and the specificity for gout is 100 percent. . The sensitivity of can be further improved by examination of the sediment in a centrifuged specimen.

Accuracy of diagnostic criteria for gout among patients who had synovial fluid analysis

	Criteria	Sensitivity	Specificity
ARA (ACR)	6 of 12 criteria	70%	79%
Rome	2 of 4 criteria: • Painful joint swelling, abrupt onset, Clearing in 1-2 weeks initially • Serum uric acid: >7 in males; >6 in females • Presence of tophi • Urate crystals in synovial fluid or tissues	70%	83%
New York	2 of 5 criteria: • 2 attacks of painful limb joint swelling • Abrupt onset and remission in 1—2 weeks initially • First MTP attack • Presence of a tophus • Response to colchicine-major reduction in inflammation within 48 h	67%	89%

Several sets of diagnostic criteria exit (see table).

The serum uric acid level during an attack of gout

	Sensitivity	Specificity
> 5.88 mg/dl	95%	53%
≥ 6 mg/dl	86%	?
≥ 8 mg/dl	68%	?

A clinical prediction rule (online link) found that the following predicted urate crystals by aspiration:

• Male
• Onset within one day
• Joint redness
• First metatarsaophalangeal joint
• Previous arthritis attack per patient
• History of hypertension or 1 or more cardiovascular diseases
• Serum uric acid level > 5.88 mg/dl

However, among patients with high scores, 20% did not have crystals. Only one of 381 patients had bacterial arthritis.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]; Associate Editor(s)-in-Chief:

HISTORICAL PERSPECTIVE:

• There is limited historical perspective for shock.

Definition:

Shock is defined as decrease in the oxygen delivery to the cells and tissues due to either increase in oxygen demand, decrease in oxygen consumption, inadequate oxygen utilization or a combination of these processes.

Classification:

• Distributive shock
• Obstructive shock

• cardiogenic shock
• Hypovolemic shock

Causes:

• Distributive shock can be from Septic Shock, Systemic inflammatory response syndrome, endocrine, toxin and drug induced, Anaphylactic shock and Neurogenic shock.
• Obstructive shock can be mechanical, pulmonary or Vascular causes.
• Cardiogenic shock can be from cardiomyopathy, Arryhthmias or mechanical.
• Hypovolemic shock can be hemorrhagic or non -hemorrhagic.

Pathophysiology:

Characteristics of forms of shock

Types of shock	CVP	PCWP	CARDIAC OUTPUT	SYSTEMIC VASCULAR RESISTANCE
Distributive	decrease	decrease	increase	decrease
cardiogenic	increase	increase	decrease	increase
obstructive	increase	may increase or decrease	decrease	increase
hypovolemic	decrease	decrease	decrease	increase

shock

cold clammy extremities

warm bounding extremities

Low cardiac output

high cardiac output

inc JVP,crackes

Dec JVP,orthostasis

septic shock,liver failure

cardiogenic shock

hypovolemic shock

antibiotics,IV fluids

evaluate for MI

IV fluids

OVERVIEW