What is the diagnosis for a 59-year-old female presenting with acute onset of small joint pains, morning stiffness, and recent history of mosquito bites and radiation (rad) exposure?

Differential Diagnosis for 59-year-old Female with Joint Pains

Single Most Likely Diagnosis

• Rheumatoid Arthritis (RA): The patient presents with joint pains involving all small joints, morning stiffness, and no other symptoms. These are classic symptoms of RA, which is a common autoimmune disorder that can cause joint inflammation and pain.

Other Likely Diagnoses

• Osteoarthritis (OA): Although OA typically affects larger joints, it can also involve smaller joints, especially in older adults. Morning stiffness is less common in OA, but it's still a possibility.
• Viral Arthritis: The patient mentions being bitten by mosquitoes, which could potentially transmit viral infections like Chikungunya or Zika virus, both of which can cause arthritis.
• Lyme Disease: Although less common, Lyme disease can cause arthritis, especially if the patient has been exposed to ticks (not just mosquitoes).

Do Not Miss Diagnoses

• Septic Arthritis: This is a medical emergency that requires prompt diagnosis and treatment. Although the patient doesn't have other symptoms like fever or redness, septic arthritis can still occur without these classic signs.
• Gout: Gout is a type of arthritis that can cause sudden, severe joint pain, often without other symptoms. It's essential to consider gout, especially if the patient has a history of kidney stones or other risk factors.
• Lupus: Systemic lupus erythematosus (SLE) is an autoimmune disorder that can cause arthritis, among other symptoms. Although the patient doesn't have other classic lupus symptoms, it's crucial to consider SLE in the differential diagnosis.

Rare Diagnoses

• Psoriatic Arthritis: This is a type of arthritis that occurs in people with psoriasis, a skin condition. Although the patient doesn't mention skin symptoms, psoriatic arthritis can still occur without obvious skin lesions.
• Reactive Arthritis: This is a type of arthritis that occurs after a bacterial infection, often in the gastrointestinal tract or urinary tract. Although the patient doesn't have other symptoms, reactive arthritis is still a possibility.
• Hemochromatosis: This is a genetic disorder that can cause arthritis, among other symptoms, due to iron overload. Although rare, hemochromatosis is essential to consider in the differential diagnosis, especially if the patient has a family history or other risk factors.