1. Possible diagnoses
1.1. Sjogren's Syndrome
1.1.1. Aching joints, fatigue, dry mouth, eyes, skin, and nose. Some patients experience a change in taste and smell. Increased dental caries and vaginal dryness.
1.1.1.1. The patient fits this description perfectly. Also often thyroid disease is associated with Sjorgren's Syndrome and she has hypothyroidism.
1.2. Rheumatoid arthritis
1.2.1. Joint pain, stiffness, swelling, redness, and warmth. Fatigue, malaise, and decreased appetite. Patients with RA can develop Sjogren's causing the dry mouth and eyes.
1.2.1.1. The patient does complain of aching joints but the pain is mild and there is no joint swelling or warmth. She does also have fatigue. Over time patients with RA can develop Sjogren's syndrome but usually by the time a patient has devleoped this they have had RA long enough and severe enough to have already been diagnosed. Since her other symptoms are more mild than the dry eyes and mouth this leads me away from this diagnosis.
1.3. Dehydration
1.3.1. Tachycardia, tachypnea, oliguria, increased thirst, dry mouth, eyes, and skin. Fatigue, dizziness, and hypotension.
2. Pertinent negatives
2.1. Patient denies fever, joint swelling, new medications, decreased fluid intake, excessive sweating, and increased pain in the morning or evenings.
3. VINDICATE
3.1. Vascular
3.2. Infection/inflammation
3.2.1. Sarcoidosis
3.2.2. granulomatosis with polyangeitis
3.3. Neoplasm
3.4. Drugs/degeneration
3.4.1. Some types of chemotherapy
3.4.2. Diuretics
3.4.3. Beta blockers
3.4.4. Antihistamines
3.4.5. Decongestants
3.4.6. Anticholinergics
3.4.7. Estrogen
3.4.8. Antipsychotics
3.5. Iatrogenic/idiopathic
3.5.1. Contact lenses
3.5.2. Ophthalmic surgery
3.5.3. Idiopathic sicca syndrome
3.5.4. Radiation treatment
3.6. Congenital
3.6.1. Congenital corneal anesthesia
3.6.2. Congenital alacrima
3.7. Allergy/autoimmune/anatomic
3.7.1. Sjogren's syndrome
3.7.2. Rheumatoid arthritis
3.7.3. Lupus
3.8. Trauma
3.8.1. Eye injury
3.9. Endocrine/environmental
3.9.1. Menopause
3.9.2. Thyroid disease
3.9.3. Dry climate
3.9.4. Dehydration