Gout differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Shivam Singla, M.D.[2]

Overview

Gout needs to be differentiated from other Crystal arthropathies and also from the diseases that present with similar symptoms. List of diseases that present with similar symptoms include cellulitis, Rheumatoid arthritis, trauma, Septic arthritis and tophaceous gout from Osteomyelitis, Dactylitis and other Autoimmune Arthritis like Reactive arthritis, sarcoidosis. Gout must also be differentiated from other causes of rash and Arthritis. Synovial fluid aspiration and analysis including Gram staining,culture and different types of microscopic examination is the Diagnostic for differentiating gout from other diseases. X-rays when combined with effective History and Physical examination also help in differentiating diseases.

Differentiating Gout from other Diseases

Gout must be differentiated from other causes of acute and chronic inflammatory Joint Disease such as Pseudogout or Calcium pyrophosphate Dihydrate deposition disease, Calcium apatite deposition disease.

	gout	pseudogout	Calcium apatite deposition disease	Calcium Oxalate deposition disease
Cause	Urate crystal deposition in joints	Calcium Pyrophosphate dihydrate deposition in joints	Calcium apatite deposition in joints	Calcium oxalate deposition in joints
Most frequently involved	First metatarsal bone	Knee-joint	Shoulder-joint { Milwaukee Shoulder} in elderly	Shoulder Joint
Diagnosis	Needle shaped negatively birefringent Monosodium urate crsytals on synovial fluid analysis	Blunt rods, rhomboid shaped Calcium pyrophosphate dihydrate positively birefringent crsytals on Synovial fluid analysis	Calcium apatite crystals that stains purplish on Wright's stain and red with Alizarin. Definitive diagnosis needs Electron microscopy.	Extremely rare. Calcium oxalate depositions seen in the joints .
Treatment	Analgesia, NSAIDs, Colchicine, xanthine oxidaseXanthine inhibitors and Uricosuric drugs.	NSAIDs, Intravascular Glucocorticosteroids.	NSAIDS, repeat Aspiration of affected joints, and rest.	Identifying the etiology of primary vs secondary oxalosis and treating the cause.

Certain diseases can present with similar symptoms like

• Cellulitis
• Rheumatoid arthritis
• Septic arthritis
• Sarcoidosis

Gout must be differentiated from other diseases that cause bone pain, edema, and erythema.

Disease	Findings
Soft tissue infection (Commonly cellulitis)	History of skin warmness, swelling and erythema. Bone probing is the definite way to differentiate them.
Osteonecrosis (Avascular necrosis of bone)	Previous history of trauma, radiation, use of steroids or biphosphonates are suggestive to differentiate osteonecrosis from ostemyelitis. MRI is diagnostic.
Charcot joint	Patients with Charcot joint commonly develop skin ulcerations that can in turn lead to secondary osteomyelitis. Contrast-enhanced MRI may be diagnostically useful if it shows a sinus tract, replacement of soft tissue fat, a fluid collection, or extensive marrow abnormalities. Bone biopsy is the definitive diagnostic modality.
Bone tumors	May present with local pain and radiographic changes consistent with osteomyelitis. Tumors most likely to mimic osteomyelitis are osteoid osteomas and chondroblastomas that produce small, round, radiolucent lesions on radiographs.
Gout	Gout presents with joint pain and swelling. Joint aspiration and crystals in synovial fluid is diagnostic for gout.
SAPHO syndrome (Synovitis, acne, pustulosis, hyperostosis, and osteitis)	SAPHO syndrome consists of a wide spectrum of neutrophilic dermatosis associated with aseptic osteoarticular lesions. It can mimic osteomyelitis in patients who lack the characteristic findings of pustulosis and synovitis. The diagnosis is established via clinical manifestations; bone culture is sterile in the setting of osteitis.
Sarcoidosis	It involves most frequently the pulmonary parenchyma and mediastinal lymph nodes, but any organ system can be affected. Bone involvement is often bilateral and bones commonly affected include the middle and distal phalanges (producing “sausage finger”), wrist, skull, vertebral column, and long bones.
Langerhans' cell histiocytosis	The disease usually manifests in the skeleton and solitary bone lesions are encountered twice as often as multiple bone lesions. The tumours can develop in any bone, but most commonly originate in the skull and jaw, followed by vertebral bodies, ribs, pelvis, and long bones.

Gout must be differentiated from other causes of rash and arthritis

Disease	Findings
Nongonococcal septic arthritis	Presents with an acute onset of joint swelling and pain (usually monoarticular) Culture of joint fluid reveals organisms
Acute rheumatic fever	Presents with polyarthritis and rash (rare presentation) in young adults. Microbiologic or serologic evidence of a recent streptococcal infection confirm the diagnosis. Poststreptococcal arthritis have a rapid response to salicylates or other antiinflammatory drugs.
Syphilis	Presents with acute secondary syphilis usually presents with generalized, pustular lesions at the palms and soles with generalized lymphadenopathy Rapid plasma reagin (RPR), Venereal Disease Research Laboratory (VDRL) and Fluorescent treponemal antibody absorption (FTA-ABS) tests confirm the presence of the causative agent.
Reactive arthritis (Reiter syndrome)	Musculoskeletal manifestation include arthritis, tenosynovitis, dactylitis, and low back pain. Extraarticular manifestation include conjunctivitis, urethritis, and genital and oral lesions. Reactive arthritis is a clinical diagnosis based upon the pattern of findings and there is no definitive diagnostic test
Hepatitis B virus (HBV) infection	Presents with fever, chills, polyarthritis, tenosynovitis, and urticarial rash Synovial fluid analysis usually shows noninflammatory fluid Elevated serum aminotransaminases and evidence of acute HBV infection on serologic testing confirm the presence of the HBV.
Herpes simplex virus (HSV)	Genital and extragenital lesions can mimic the skin lesions that occur in disseminated gonococcal infection Viral culture, polymerase chain reaction (PCR), and direct fluorescence antibody confirm the presence of the causative agent.
HIV infection	Present with generalized rash with mucus membrane involvement, fever, chills, and arthralgia. Joint effusions are uncommon
Gout and other crystal-induced arthritis	Presents with acute monoarthritis with fever and chills Synovial fluid analysis confirm the diagnosis.
Lyme disease	Present with erythema chronicum migrans rash and monoarthritis as a later presentation. Clinical characteristics of the rash and and serologic testing confirm the diagnosis.