SOAP Note: 35-Year-Old Female with Hypothyroidism
Subjective
Chief Complaint:
"I've been gaining weight, feeling exhausted all the time, and having trouble with constipation for the past 4 months."
History of Present Illness (HPI):
Patient is a 35-year-old female presenting with a 4-month history of progressive fatigue, unintentional weight gain of approximately 15 pounds, and worsening constipation. She describes the fatigue as severe and unrelenting, interfering with her ability to complete daily activities and work responsibilities 1. She reports increased cold intolerance, requiring extra layers of clothing even in warm environments. Patient notes her hair has become dry and brittle with increased shedding. She describes difficulty concentrating at work with noticeable memory problems affecting her job performance 1. Menstrual cycles have become irregular with heavier flow and longer duration (menorrhagia) 1. She denies chest pain, palpitations, shortness of breath, or recent neck surgery. No history of radiation exposure to the neck. Denies recent viral illness, medication changes, or iodine-containing contrast exposure.
Past Medical History:
None
Surgical History:
None
Family History:
Mother diagnosed with Hashimoto's thyroiditis at age 42, currently on levothyroxine. Maternal grandmother with type 1 diabetes. No family history of thyroid cancer or other autoimmune conditions.
Social History:
Works as a software engineer with sedentary lifestyle. Lives with partner in suburban home. Denies tobacco, alcohol, or illicit drug use. No recent travel. Adequate dietary iodine intake (uses iodized salt, consumes dairy products). Not currently pregnant but planning pregnancy within the next year.
Medications:
None
Allergies:
NKDA
Review of Systems:
- General: Fatigue, cold intolerance, weight gain of 15 lbs over 4 months without dietary changes
- Skin: Dry skin, brittle hair with increased shedding
- HEENT: Denies vision changes, hoarseness (though voice may sound slightly deeper)
- Cardiovascular: Denies chest pain, palpitations, orthopnea, PND, or edema
- Respiratory: Denies dyspnea, cough, or wheezing
- GI: Constipation (bowel movement every 3-4 days), denies abdominal pain, nausea, vomiting, or changes in appetite
- GU: Menorrhagia with cycles lasting 7-8 days, denies dysuria or urinary frequency
- Musculoskeletal: Generalized muscle aches, denies joint swelling
- Neurologic: Difficulty concentrating, memory problems, denies headache, dizziness, numbness, or tingling
- Psychiatric: Mild depressive symptoms secondary to fatigue, denies suicidal ideation
Objective
Vital Signs:
- BP: 118/76 mmHg
- HR: 58 bpm (bradycardia)
- RR: 14 breaths/min
- Temp: 97.4°F (36.3°C) oral
- SpO2: 98% on room air
- Height: 65 inches
- Weight: 165 lbs (BMI: 27.5)
- Weight 4 months ago: 150 lbs
Physical Examination:
General: Alert, oriented x4, appears mildly fatigued, appropriately dressed but wearing sweater in warm clinic room, cooperative, no acute distress
HEENT:
- Head: Normocephalic, atraumatic
- Eyes: Mild periorbital puffiness, conjunctiva pink, sclera white, PERRLA 3mm, EOMI intact
- Ears: TMs intact bilaterally, canals clear
- Nose: Mucosa pink, septum midline
- Throat: Oral mucosa slightly dry, tongue appears mildly enlarged, pharynx without erythema or exudate
Neck: Supple, thyroid gland diffusely enlarged (estimated 30-35 grams, normal 15-25 grams), firm, non-tender, no discrete nodules palpable, no lymphadenopathy, no JVD, trachea midline
Cardiovascular: Bradycardic regular rhythm, S1 and S2 normal, no murmurs/rubs/gallops, apical impulse at 5th ICS MCL, no peripheral edema, distal pulses +2 bilaterally, capillary refill <2 seconds
Respiratory: Respirations unlabored, lung sounds clear bilaterally, no wheezes/rales/rhonchi, symmetric chest expansion
Abdomen: Soft, non-tender, non-distended, normoactive bowel sounds x4 quadrants, no hepatosplenomegaly, no masses
Musculoskeletal: Normal gait, full ROM all extremities, no joint swelling or deformities
Neurologic: Alert and oriented x4, CNs II-XII grossly intact, motor strength 5/5 all extremities, sensation intact to light touch, deep tendon reflexes show delayed relaxation phase (characteristic "hung-up" reflexes) 2
Skin: Cool, dry, coarse texture, mild non-pitting edema of lower extremities, no rashes or lesions
Psychiatric: Flat affect, cooperative, appropriate responses, no evidence of acute psychiatric disturbance
Assessment
Primary Diagnosis:
1. Overt Primary Hypothyroidism (ICD-10: E03.9), likely secondary to Hashimoto's Thyroiditis
Clinical reasoning: This 35-year-old female presents with classic hypothyroid symptoms including severe fatigue (68-83% of cases), weight gain (24-59%), cognitive impairment (45-48%), menstrual irregularities (23%), constipation, cold intolerance, dry skin, and bradycardia 1. Physical examination reveals diffuse thyroid enlargement (goiter), delayed deep tendon reflex relaxation phase (pathognomonic for hypothyroidism), periorbital puffiness, and dry coarse skin 2. The constellation of symptoms over 4 months with progressive worsening, positive family history of Hashimoto's thyroiditis in mother, and female gender (hypothyroidism is more common in women) strongly suggests primary hypothyroidism 1, 3.
Differential Diagnoses:
1. Subclinical Hypothyroidism (ICD-10: E02)
- Defined as elevated TSH with normal free T4 and T3 4, 5
- Key differentiation: In subclinical hypothyroidism, symptoms are typically mild or absent, whereas this patient has severe, functionally limiting symptoms 3. Subclinical hypothyroidism patients have normal free T4 levels, while overt hypothyroidism shows low free T4 4. The severity and constellation of this patient's symptoms (severe fatigue interfering with daily activities, 15-pound weight gain, marked cognitive impairment, menorrhagia) strongly suggest overt rather than subclinical disease 1.
2. Chronic Fatigue Syndrome (ICD-10: G93.3)
- Can present with severe fatigue and cognitive dysfunction
- Key differentiation: Lacks the metabolic features of hypothyroidism (weight gain, cold intolerance, constipation, bradycardia, delayed reflexes, goiter) 1. Thyroid function tests will be normal in CFS.
3. Depression (ICD-10: F32.9)
- Can cause fatigue, weight changes, and cognitive impairment
- Key differentiation: Depression does not cause bradycardia, delayed deep tendon reflexes, goiter, cold intolerance, constipation, or menorrhagia 1. This patient's depressive symptoms appear secondary to her physical illness rather than primary psychiatric disease.
4. Polycystic Ovary Syndrome (ICD-10: E28.2)
- Can cause weight gain and menstrual irregularities
- Key differentiation: PCOS typically causes oligomenorrhea (infrequent periods), not menorrhagia. Does not explain fatigue, cold intolerance, bradycardia, delayed reflexes, or goiter 1.
5. Anemia (ICD-10: D50.9)
- Can cause fatigue and menorrhagia
- Key differentiation: Does not explain weight gain, cold intolerance, constipation, bradycardia, delayed reflexes, cognitive impairment, or goiter 1.
Plan
Diagnostic Testing:
Immediate Laboratory Tests (Order Today):
Thyroid Function Panel:
- TSH (thyroid-stimulating hormone) – Primary screening test with 98% sensitivity and 92% specificity for thyroid dysfunction 6. Expected to be elevated (>4.5 mIU/L) in primary hypothyroidism 6.
- Free T4 (free thyroxine) – Essential to distinguish overt hypothyroidism (low free T4) from subclinical hypothyroidism (normal free T4) 6, 4. In overt primary hypothyroidism, free T4 will be below the reference range.
- Free T3 (free triiodothyronine) – May be low-normal or low in hypothyroidism, though less sensitive than free T4 4.
Anti-Thyroid Peroxidase (Anti-TPO) Antibodies:
Anti-Thyroglobulin Antibodies:
- Additional marker for autoimmune thyroid disease, though anti-TPO is more specific 6.
Complete Blood Count (CBC):
- Rule out anemia as contributing factor to fatigue and assess for macrocytic anemia (can occur in hypothyroidism) 1.
Comprehensive Metabolic Panel (CMP):
- Assess for hyponatremia (can occur in severe hypothyroidism), evaluate renal function before initiating levothyroxine, and check glucose (hypothyroidism can cause insulin resistance and hyperglycemia in diabetics) 1.
Lipid Panel (Total Cholesterol, LDL, HDL, Triglycerides):
Morning Cortisol and ACTH (8 AM):
- Critical safety measure: Rule out concurrent adrenal insufficiency before starting levothyroxine, as thyroid hormone replacement can precipitate life-threatening adrenal crisis if adrenal insufficiency is present 6. This is especially important given family history of autoimmune disease (mother with Hashimoto's, grandmother with type 1 diabetes), as autoimmune polyglandular syndrome can cause both thyroid and adrenal failure 6.
No Imaging Required:
There is no role for thyroid ultrasound, CT, MRI, FDG-PET, or radioiodine uptake scan in the initial workup of primary hypothyroidism in adults 7. Imaging does not help differentiate among causes of hypothyroidism, and all causes will show decreased radioiodine uptake 7.
Treatment Plan:
Levothyroxine Monotherapy (First-Line Treatment):
Initial Dosing Strategy:
For this patient (35 years old, no cardiac disease, no multiple comorbidities): Start with full replacement dose of approximately 1.6 mcg/kg/day 6.
- Calculation: 165 lbs = 75 kg → 75 kg × 1.6 mcg/kg = 120 mcg daily
- Prescribe: Levothyroxine 125 mcg tablets, take 1 tablet by mouth once daily on an empty stomach, 30-60 minutes before breakfast 6.
- Dispense: 90 tablets, Refills: 3
Rationale for full-dose initiation: Young patients without cardiac disease can safely start at full replacement dose, which achieves target TSH more rapidly and improves symptoms sooner 6, 4. Lower starting doses (25-50 mcg) are reserved for patients >70 years, those with coronary artery disease, atrial fibrillation, or long-standing severe hypothyroidism 6, 4.
Critical Safety Precaution:
- Do NOT initiate levothyroxine until morning cortisol and ACTH results are available and adrenal insufficiency is excluded 6. If morning cortisol is low (<5 mcg/dL) or ACTH is elevated (suggesting primary adrenal insufficiency), start hydrocortisone 20 mg AM + 10 mg afternoon for at least 1 week BEFORE starting levothyroxine 6.
Administration Instructions:
- Take levothyroxine on empty stomach, 30-60 minutes before breakfast, with full glass of water 6, 4.
- Separate from other medications by at least 4 hours: iron supplements, calcium supplements, multivitamins containing iron or calcium, antacids, proton pump inhibitors, sucralfate, bile acid sequestrants (cholestyramine), soy products 6, 4.
- Take at same time each day for consistent absorption 4.
- Do not switch between brand-name and generic formulations without retesting TSH, as bioavailability may differ 4.
Monitoring Protocol:
Initial monitoring (6-8 weeks after starting levothyroxine):
Dose titration (if needed):
Long-term monitoring (once stable):
Expected Timeline for Symptom Improvement:
- Fatigue and cognitive symptoms: Begin improving within 2-3 weeks, significant improvement by 6-8 weeks 4.
- Weight: Stabilization within 6-8 weeks, gradual weight loss over 3-6 months 4.
- Constipation: Improvement within 2-4 weeks 4.
- Menstrual irregularities: Normalization within 2-3 cycles (2-3 months) 1, 4.
- Hair and skin changes: Improvement within 3-4 months 4.
- Deep tendon reflexes: Normalization within 4-8 weeks 4.
Patient Education:
Disease Education:
Explain diagnosis: "You have hypothyroidism, which means your thyroid gland is not producing enough thyroid hormone. This hormone controls your body's metabolism—how your body uses energy. When levels are low, everything slows down, causing your fatigue, weight gain, constipation, cold intolerance, and other symptoms" 1, 3.
Likely cause: "Based on your family history (mother with Hashimoto's thyroiditis) and your symptoms, you most likely have Hashimoto's thyroiditis, an autoimmune condition where your immune system attacks your thyroid gland. This is the most common cause of hypothyroidism in the United States, affecting up to 85% of patients with hypothyroidism" 1, 3.
Prognosis: "The good news is that hypothyroidism is highly treatable with daily thyroid hormone replacement (levothyroxine). With proper treatment, your symptoms will improve significantly within 6-8 weeks, and you can expect to return to your normal energy level and quality of life. The prognosis is excellent with treatment" 3, 4.
Medication Instructions:
How to take levothyroxine:
- Take every morning on an empty stomach, 30-60 minutes before breakfast 6, 4.
- Swallow tablet whole with full glass of water 4.
- Wait at least 4 hours before taking iron, calcium, multivitamins, or antacids 6, 4.
- Take at same time each day for consistent absorption 4.
- Do not stop taking medication even when you feel better—this is lifelong therapy 4.
What to expect:
Pregnancy Planning:
- Critical information: "Since you are planning pregnancy within the next year, it is essential to have your thyroid function optimized BEFORE conception" 6, 4.
- Target TSH for pregnancy: "We need to get your TSH below 2.5 mIU/L before you try to conceive, as untreated or inadequately treated hypothyroidism during pregnancy increases risk of miscarriage, preeclampsia, low birth weight, and impaired cognitive development in your baby" 6, 1, 4.
- Levothyroxine dose in pregnancy: "Your levothyroxine dose will need to increase by 25-50% as soon as you become pregnant, so notify me immediately when you have a positive pregnancy test" 6, 4.
- Monitoring in pregnancy: "We will check your TSH every 4 weeks during pregnancy to ensure optimal levels for your baby's brain development" 6, 4.
Warning Signs (When to Seek Immediate Care):
Severe symptoms requiring emergency evaluation:
- Severe chest pain, shortness of breath, or palpitations (could indicate cardiac complications) 1.
- Severe confusion, extreme lethargy, or difficulty staying awake (could indicate myxedema coma, a life-threatening complication with 30% mortality) 1.
- Hypothermia (body temperature <95°F) or severe hypotension 1.
Symptoms of overtreatment (iatrogenic hyperthyroidism):
Lifestyle Modifications:
Dietary considerations:
Exercise:
Long-Term Management:
- Lifelong treatment: "Hypothyroidism is typically a permanent condition requiring lifelong daily levothyroxine therapy" 3, 4.
- Regular monitoring: "Once your TSH is stable, you will need blood tests every 6-12 months to ensure your dose remains appropriate" 6, 4.
- Medication consistency: "Do not switch between brand-name and generic levothyroxine without retesting TSH, as absorption may differ" 4.
Follow-Up Plan:
1. Initial Follow-Up (6-8 Weeks):
- Schedule appointment in 6-8 weeks for repeat TSH and free T4 to assess response to levothyroxine 6, 4.
- Labs to order 1 week before appointment: TSH, free T4 6, 4.
- Assess symptom improvement: Fatigue, weight, constipation, menstrual regularity, cognitive function 1, 4.
- Adjust levothyroxine dose if needed: Increase by 12.5-25 mcg if TSH remains elevated; decrease by 12.5-25 mcg if TSH is suppressed (<0.5 mIU/L) 6, 4.
2. Subsequent Follow-Ups (Every 6-8 Weeks Until Stable):
- Continue dose adjustments every 6-8 weeks until TSH reaches target range (0.5-4.5 mIU/L, ideally 0.5-2.0 mIU/L) 6, 4.
- Recheck TSH and free T4 6-8 weeks after each dose change 6, 4.
3. Long-Term Follow-Up (Once Stable):
- Annual visits once TSH is stable on consistent levothyroxine dose 6, 4.
- Annual labs: TSH (free T4 only if TSH is abnormal) 6, 4.
- Recheck sooner if:
4. Preconception Counseling (Before Pregnancy Attempt):
- Optimize TSH to <2.5 mIU/L before conception 6, 4.
- Educate on need for immediate dose increase (25-50%) upon positive pregnancy test 6, 4.
- Plan for TSH monitoring every 4 weeks during pregnancy 6, 4.
Critical Pitfalls to Avoid:
Never start levothyroxine before ruling out adrenal insufficiency in patients with suspected central hypothyroidism or autoimmune polyglandular syndrome, as thyroid hormone can precipitate life-threatening adrenal crisis 6.
Do not treat based on single elevated TSH value—confirm with repeat testing after 3-6 weeks, as 30-60% of elevated TSH levels normalize spontaneously 6.
Avoid overtreatment—approximately 25% of patients on levothyroxine are unintentionally maintained on doses that suppress TSH (<0.1 mIU/L), increasing risk of atrial fibrillation (3-5 fold), osteoporosis, fractures, and cardiovascular mortality 6, 4.
Do not use thyroid imaging (ultrasound, CT, MRI, nuclear medicine) for initial hypothyroidism workup—imaging does not help differentiate causes of hypothyroidism and is not indicated 7.
Avoid starting elderly patients (>70 years) or those with cardiac disease at full replacement dose—use lower starting dose (25-50 mcg) to prevent unmasking cardiac ischemia or precipitating arrhythmias 6, 4.
Do not recheck TSH before 6-8 weeks after dose initiation or adjustment—levothyroxine requires this interval to reach steady state 6, 4.
Never assume hypothyroidism is transient without reassessment—most cases (especially Hashimoto's thyroiditis) require lifelong treatment 3, 4.
Differentiating Overt Hypothyroidism from Subclinical Hypothyroidism
Biochemical Differentiation:
| Parameter | Overt Hypothyroidism | Subclinical Hypothyroidism |
|---|---|---|
| TSH | Elevated (>4.5 mIU/L, often >10 mIU/L) [4,5] | Elevated (typically 4.5-10 mIU/L) [4,5] |
| Free T4 | Low (below reference range) [4,5] | Normal (within reference range) [4,5] |
| Free T3 | Low or low-normal [4] | Normal [4] |
Key biochemical distinction: The presence of low free T4 defines overt hypothyroidism, while normal free T4 with elevated TSH defines subclinical hypothyroidism 4, 5.
Clinical Differentiation:
Overt Hypothyroidism:
Subclinical Hypothyroidism:
Progression Risk:
- Subclinical hypothyroidism progresses to overt hypothyroidism in approximately 2-5% of cases annually 4, 5.
- Risk factors for progression:
Treatment Approach Differences:
Overt Hypothyroidism:
- Treat immediately with levothyroxine regardless of TSH level or symptoms 6, 4.
- Start with full replacement dose (1.6 mcg/kg/day) in young patients without cardiac disease 6.
- Treatment is mandatory to prevent serious complications (heart failure, myxedema coma) 1, 3.
Subclinical Hypothyroidism:
- Treatment algorithm based on TSH level 6, 4, 5:
- Confirm diagnosis with repeat testing after 3-6 weeks, as 30-60% of elevated TSH levels normalize spontaneously 6.
Cardiovascular and Metabolic Consequences:
Overt Hypothyroidism:
- Significant cardiovascular dysfunction: Delayed myocardial relaxation, reduced cardiac output, increased systemic vascular resistance, risk of heart failure 1, 3, 4.
- Severe dyslipidemia: Markedly elevated LDL cholesterol and triglycerides 4.
- Insulin resistance and hyperglycemia in diabetic patients 1.
Subclinical Hypothyroidism:
- Mild cardiovascular effects: Possible increased risk of heart failure and cardiovascular events, though evidence is less consistent than in overt disease 3, 5.
- Mild dyslipidemia: Modest elevation in LDL cholesterol 5.
- Metabolic effects are less pronounced than in overt hypothyroidism 5.
Summary Algorithm for Differentiation:
- Measure TSH and free T4 in all patients with suspected hypothyroidism 6, 4.
- If TSH elevated AND free T4 low → Overt hypothyroidism → Treat immediately with levothyroxine 4.
- If TSH elevated AND free T4 normal → Subclinical hypothyroidism → Confirm with repeat testing in 3-6 weeks, then treat based on TSH level and clinical factors 6, 4, 5.
- Assess symptom severity: Severe, functionally limiting symptoms suggest overt disease even before lab confirmation 1, 3.
- Check anti-TPO antibodies to identify autoimmune etiology and predict progression risk 6, 5.