How will you investigate her?

I. Initial Assessment & History Taking

The first step is a rapid initial assessment of vital signs (blood pressure, pulse, respiration rate, temperature, and oxygen saturation). This provides immediate information about the patient’s stability. Simultaneously, a focused history should be obtained, covering:

• Chief Complaint: Detailed description of the primary symptom(s).
• History of Present Illness (HPI): Chronological account of the symptom’s onset, duration, character, aggravating/relieving factors, and associated symptoms.
• Past Medical History: Previous illnesses, surgeries, hospitalizations, allergies, and current medications.
• Family History: Relevant medical conditions in family members.
• Social History: Occupation, lifestyle (smoking, alcohol, drug use), travel history, dietary habits, and sexual history.

II. Physical Examination

A comprehensive physical examination should be performed, including:

• General Appearance: Level of consciousness, distress, nutritional status.
• Vital Signs: Re-assessment and monitoring.
• Head, Eyes, Ears, Nose, and Throat (HEENT): Examination for signs of infection, inflammation, or structural abnormalities.
• Cardiovascular System: Auscultation for murmurs, rubs, or gallops; assessment of peripheral pulses.
• Respiratory System: Auscultation for breath sounds, percussion for resonance, and assessment of respiratory effort.
• Abdomen: Palpation for tenderness, masses, or organomegaly; auscultation for bowel sounds.
• Neurological Examination: Assessment of mental status, cranial nerves, motor strength, sensory function, and reflexes.
• Skin: Examination for rashes, lesions, or signs of infection.

III. Initial Investigations (Based on Initial Assessment)

The choice of initial investigations depends on the findings from the history and physical examination. However, a basic set of investigations is often appropriate:

• Complete Blood Count (CBC): To assess for anemia, infection, or other hematological abnormalities.
• Erythrocyte Sedimentation Rate (ESR) & C-Reactive Protein (CRP): Markers of inflammation.
• Urinalysis: To detect urinary tract infection, kidney disease, or diabetes.
• Blood Glucose: To screen for diabetes.
• Electrolytes, Blood Urea Nitrogen (BUN), Creatinine: To assess kidney function and electrolyte balance.
• Liver Function Tests (LFTs): To assess liver function.
• Chest X-ray: To evaluate for pneumonia, heart failure, or other lung abnormalities.
• Electrocardiogram (ECG): To assess cardiac rhythm and identify any ischemic changes.

IV. Further Investigations (Guided by Initial Findings)

Based on the results of the initial investigations, further investigations may be necessary. Examples include:

• Infectious Disease Workup: Blood cultures, viral serology, stool cultures, depending on suspected infection.
• Imaging Studies: CT scan, MRI, ultrasound, depending on the suspected organ system involved.
• Endoscopy/Colonoscopy: To evaluate the gastrointestinal tract.
• Pulmonary Function Tests (PFTs): To assess lung function.
• Autoimmune Workup: Antinuclear antibody (ANA), rheumatoid factor (RF), etc., if autoimmune disease is suspected.
• Specific Tumor Markers: If malignancy is suspected.

V. Differential Diagnosis & Iterative Process

Throughout the investigation process, a differential diagnosis should be maintained and refined based on new information. The investigation is an iterative process – results from one test may prompt further testing. It’s crucial to avoid premature closure and consider alternative diagnoses if the initial hypothesis is not supported by the evidence.

Symptom	Possible Investigations
Fever	Blood cultures, viral serology, chest X-ray
Abdominal Pain	Abdominal ultrasound, CT scan, endoscopy
Neurological Symptoms	MRI brain, CT scan brain, lumbar puncture