# Clinical Cases: The Role of the Sub-Intern

## Case 1: Community-Acquired Pneumonia with Time Management Challenge

### Clinical Presentation

**Patient Demographics:** 58-year-old male

**Chief Complaint:** "I've had a cough and fever for 4 days"

**History of Present Illness:**
Mr. Thompson is a 58-year-old male with a history of type 2 diabetes mellitus and hypertension who presents to the emergency department with a 4-day history of productive cough with yellow-green sputum, fever to 38.9C at home, progressive dyspnea, and right-sided pleuritic chest pain. He reports decreased oral intake over the past 2 days and notes that his symptoms have worsened despite taking over-the-counter cough suppressants.

**Past Medical History:**
- Type 2 diabetes mellitus (A1c 7.8% three months ago)
- Hypertension
- Hyperlipidemia

**Medications:**
- Metformin 1000 mg twice daily
- Lisinopril 20 mg daily
- Atorvastatin 40 mg daily

**Social History:**
- Former smoker (quit 5 years ago, 20 pack-year history)
- No alcohol use
- Retired factory worker
- Lives with wife

**Physical Examination:**
- **Vital Signs:** Temperature 38.7C, HR 102 bpm, BP 128/78 mmHg, RR 22/min, SpO2 92% on room air
- **General:** Appears ill, mild respiratory distress
- **HEENT:** Dry mucous membranes
- **Lungs:** Decreased breath sounds at the right base with dullness to percussion; bronchial breath sounds and egophony in the right lower lobe
- **Cardiovascular:** Tachycardic, regular rhythm, no murmurs
- **Abdomen:** Soft, non-tender
- **Extremities:** No edema

### Inpatient Workup

**Laboratory Studies:**
- WBC 16,800/uL with 85% neutrophils, 8% bands
- Hemoglobin 13.2 g/dL
- Platelets 342,000/uL
- BUN 28 mg/dL, Creatinine 1.4 mg/dL (baseline 1.0)
- Sodium 136 mEq/L, Potassium 4.2 mEq/L
- Glucose 198 mg/dL
- Procalcitonin 2.4 ng/mL
- Lactate 1.8 mmol/L

**Imaging:**
- Chest X-ray: Right lower lobe consolidation with air bronchograms consistent with lobar pneumonia

**Microbiology:**
- Blood cultures x 2 obtained
- Sputum culture obtained
- Legionella urinary antigen: Negative
- Streptococcus pneumoniae urinary antigen: Positive

### Diagnosis

**Primary Diagnosis:** Community-acquired pneumonia (Streptococcus pneumoniae), right lower lobe

**Secondary Diagnoses:**
- Acute kidney injury (pre-renal, likely dehydration)
- Type 2 diabetes mellitus with hyperglycemia

### Treatment Plan

**Immediate Management:**
1. Admit to medicine floor (CURB-65 score: 2)
2. Supplemental oxygen via nasal cannula to maintain SpO2 > 92%
3. IV fluid resuscitation with normal saline
4. Ceftriaxone 1g IV daily + Azithromycin 500 mg IV daily
5. Hold metformin given AKI
6. Insulin sliding scale for glucose management
7. DVT prophylaxis with subcutaneous heparin

**Monitoring:**
- Daily weights
- Strict intake and output
- Renal function monitoring
- Respiratory status assessment

**Sub-Intern Learning Points:**
This case illustrates several key sub-intern responsibilities:
1. **Time Management:** Prioritizing this patient's admission workup while managing other patients on the team
2. **Clinical Decision-Making:** Recognizing severity markers (tachypnea, hypoxia, AKI) that warrant inpatient admission
3. **Order Writing:** Writing comprehensive admission orders including antibiotics, fluids, and prophylaxis
4. **Communication:** Staffing the case with the senior resident and attending, presenting the assessment and plan
5. **Autonomy Building:** Proposing the antibiotic regimen before asking for guidance

### Clinical Image

![Chest X-ray showing right lower lobe consolidation consistent with lobar pneumonia](case_01_image.jpg)

**Image Description:** Chest radiograph demonstrating right lower lobe consolidation with air bronchograms, characteristic of lobar pneumonia.

**Image Source:** Wikimedia Commons - "X-ray of lobar pneumonia"
- URL: https://commons.wikimedia.org/wiki/File:X-ray_of_lobar_pneumonia.jpg
- License: Creative Commons Attribution-Share Alike 4.0 International
- Author: Mikael Haggstrom, M.D.

---

## Case 2: Atrial Fibrillation with Rapid Ventricular Response and Supervision-Seeking

### Clinical Presentation

**Patient Demographics:** 72-year-old female

**Chief Complaint:** "My heart is racing and I feel weak"

**History of Present Illness:**
Mrs. Garcia is a 72-year-old female with a history of heart failure with preserved ejection fraction (HFpEF), hypertension, and chronic kidney disease stage 3 who presents with 2 days of palpitations, fatigue, and mild dyspnea on exertion. She notes she has not been taking her medications consistently over the past week due to running out of prescriptions. She denies chest pain, syncope, or lower extremity swelling.

**Past Medical History:**
- HFpEF (EF 55%)
- Hypertension
- CKD stage 3 (baseline creatinine 1.5 mg/dL)
- Hypothyroidism
- Osteoarthritis

**Medications (when compliant):**
- Metoprolol succinate 50 mg daily
- Losartan 50 mg daily
- Furosemide 20 mg daily
- Levothyroxine 75 mcg daily
- Acetaminophen PRN

**Physical Examination:**
- **Vital Signs:** Temperature 37.0C, HR 142 bpm (irregular), BP 156/92 mmHg, RR 18/min, SpO2 96% on room air
- **General:** Elderly female, appears fatigued but in no acute distress
- **Cardiovascular:** Irregularly irregular rhythm, tachycardic, no murmurs, JVP 10 cm H2O
- **Lungs:** Clear to auscultation bilaterally
- **Abdomen:** Soft, non-tender
- **Extremities:** Trace bilateral ankle edema

### Inpatient Workup

**Laboratory Studies:**
- WBC 7,200/uL
- Hemoglobin 11.8 g/dL
- BUN 32 mg/dL, Creatinine 1.7 mg/dL
- TSH 6.8 mIU/L (elevated)
- BNP 420 pg/mL
- Troponin I < 0.01 ng/mL (x2, 6 hours apart)
- Magnesium 1.6 mEq/L, Potassium 3.8 mEq/L

**Imaging:**
- ECG: Atrial fibrillation with rapid ventricular response (rate 138), no ST changes
- Chest X-ray: Mild cardiomegaly, no pulmonary edema
- Echocardiogram: EF 50-55%, mild left atrial enlargement, no significant valvular disease

### Diagnosis

**Primary Diagnosis:** Atrial fibrillation with rapid ventricular response, new onset vs. paroxysmal

**Secondary Diagnoses:**
- Heart failure with preserved ejection fraction (compensated)
- Subclinical hypothyroidism (contributing factor)
- Chronic kidney disease stage 3 with mild acute worsening

### Treatment Plan

**Immediate Management:**
1. Admit to telemetry for cardiac monitoring
2. Rate control: Metoprolol IV 5 mg, then restart metoprolol succinate 50 mg daily
3. Replete magnesium (2g IV)
4. Anticoagulation assessment: CHA2DS2-VASc score = 5 (age, female, HTN, HF) - initiate anticoagulation
5. Apixaban 5 mg BID (dose-adjusted for age and renal function)
6. Resume home medications with adjustment of levothyroxine
7. Gentle diuresis if symptoms of congestion

**Sub-Intern Learning Points:**
This case demonstrates critical supervision-seeking behaviors:
1. **When to Staff:** New arrhythmia requiring anticoagulation decision - staff before initiating
2. **Presenting Plans:** "My assessment is new atrial fibrillation likely triggered by medication non-adherence and thyroid dysfunction. I'd like to rate control with IV metoprolol, replete electrolytes, and discuss anticoagulation with you given her CHA2DS2-VASc score of 5."
3. **Recognizing Complexity:** Multiple comorbidities affecting drug choices (CKD affecting DOAC dosing)
4. **Building Autonomy:** Calculating risk scores independently, then confirming with the team

### Clinical Image

![ECG showing atrial fibrillation with rapid ventricular response](case_02_image.jpg)

**Image Description:** 12-lead electrocardiogram demonstrating atrial fibrillation with rapid ventricular response, showing an irregularly irregular rhythm without discrete P waves.

**Image Source:** Wikimedia Commons - "Atrial fibrillation ECG"
- URL: https://commons.wikimedia.org/wiki/File:Atrial_fibrillation_-_ECG.png
- License: Public Domain
- Author: CardioNetworks

---

## Case 3: Diabetic Ketoacidosis Requiring Prioritization Skills

### Clinical Presentation

**Patient Demographics:** 28-year-old male

**Chief Complaint:** "I've been vomiting for 2 days and feel terrible"

**History of Present Illness:**
Mr. Williams is a 28-year-old male with type 1 diabetes mellitus who presents with 2 days of nausea, vomiting, abdominal pain, and generalized weakness. He reports that he ran out of insulin 3 days ago and could not afford to refill his prescription. He has had polyuria and polydipsia for the past week with a 5-pound unintentional weight loss. He denies fever, cough, dysuria, or recent illness that may have precipitated his symptoms.

**Past Medical History:**
- Type 1 diabetes mellitus (diagnosed age 12)
- No other medical conditions

**Medications:**
- Insulin glargine 24 units at bedtime (when available)
- Insulin lispro sliding scale with meals

**Social History:**
- Works part-time at a warehouse
- Lost health insurance 2 months ago
- Lives alone in an apartment
- No tobacco, alcohol, or drug use

**Physical Examination:**
- **Vital Signs:** Temperature 36.8C, HR 118 bpm, BP 98/62 mmHg, RR 28/min (Kussmaul respirations), SpO2 99% on room air
- **General:** Ill-appearing, appears dehydrated, fruity odor on breath
- **HEENT:** Dry mucous membranes, sunken eyes
- **Cardiovascular:** Tachycardic, regular rhythm
- **Lungs:** Clear to auscultation, deep rapid breathing
- **Abdomen:** Diffuse mild tenderness, no rebound or guarding
- **Neurologic:** Alert and oriented, no focal deficits
- **Skin:** Poor turgor, dry

### Inpatient Workup

**Laboratory Studies:**
- Glucose 486 mg/dL
- Sodium 128 mEq/L (corrected Na: 134 mEq/L)
- Potassium 5.8 mEq/L
- Chloride 94 mEq/L
- Bicarbonate 8 mEq/L
- BUN 38 mg/dL, Creatinine 1.9 mg/dL
- Anion gap: 26
- Serum ketones: Large
- Beta-hydroxybutyrate: 6.2 mmol/L
- pH 7.18, pCO2 18 mmHg
- Lactate 2.4 mmol/L
- WBC 14,200/uL
- Hemoglobin 16.2 g/dL (hemoconcentration)

### Diagnosis

**Primary Diagnosis:** Diabetic ketoacidosis (moderate severity)
- pH 7.18 (moderate: 7.0-7.24)
- Anion gap 26
- Mental status intact

**Precipitating Factor:** Insulin non-adherence due to cost/access

### Treatment Plan

**Immediate Management (First 2 hours):**
1. Admit to step-down unit or ICU depending on institutional protocol
2. IV access x 2 large bore
3. Normal saline 1L bolus, then 500 mL/hr for first 4 hours
4. Regular insulin IV infusion 0.1 units/kg/hr (no bolus needed with glucose < 500)
5. Hold potassium replacement until K < 5.2 and urine output confirmed
6. Monitor glucose hourly, BMP every 2-4 hours
7. Search for precipitating infection (UA, CXR, blood cultures)

**Ongoing Management:**
8. When glucose < 200, add D5 to fluids and reduce insulin to 0.02-0.05 units/kg/hr
9. Transition to subcutaneous insulin when anion gap closes and patient eating
10. Social work consult for insulin assistance programs
11. Diabetes education before discharge

**Sub-Intern Learning Points:**
This case emphasizes prioritization in the sub-intern role:
1. **Critical Task Recognition:** DKA is a medical emergency requiring immediate intervention
2. **Time Management:** This admission takes priority over non-urgent tasks
3. **Protocol Application:** Following DKA protocol while individualizing care
4. **Anticipating Needs:** Setting up frequent lab monitoring, calculating transition timing
5. **Patient Advocacy:** Involving social work for medication access issues
6. **Documentation:** Writing detailed admission note with clear assessment and plan

### Clinical Image

![Blood glucose meter showing elevated reading](case_03_image.jpg)

**Image Description:** Fingerstick glucose testing demonstrating significantly elevated blood glucose, as seen in diabetic ketoacidosis.

**Image Source:** Wikimedia Commons - "Glucose test"
- URL: https://commons.wikimedia.org/wiki/File:Glucose_test.JPG
- License: Creative Commons Attribution-Share Alike 3.0
- Author: David-i98

---

## Discussion Questions

1. **Time Management:** In Case 1, if you were simultaneously paged about a stable patient requesting sleep medication, how would you prioritize your tasks?

2. **Supervision Seeking:** In Case 2, at what points in the patient's care would you absolutely need to staff with your senior resident or attending before acting?

3. **Autonomy Building:** In Case 3, how might you demonstrate increasing independence over the course of managing the DKA, from initial presentation to discharge planning?

4. **Communication:** How would you present Case 1 to your attending in a focused, efficient manner while ensuring all critical information is conveyed?

5. **Professional Development:** What specific skills from these cases should you focus on improving before starting internship?