Complete diagnostic flowchart for physicians and medical students

Here it is!! Welcome to our diagnostic flowchart for doctors and medical students.

The objective here is to guide you, in moments of doubt, towards more precise and safer diagnoses, so that through suspicions, you have a path to follow, differential diagnoses and avoid leaving behind what may be relevant.

Start by searching for the topic that best describes your patient's QP.

Alopecia

• Diffuse :

  • Hormonal causes :

    • Hypothyroidism → Tests: TSH, free T4.

    • Polycystic Ovary Syndrome (PCOS) → Tests: Androgenic hormones.

  • Nutritional causes :

    • Iron Deficiency Anemia → Tests: Blood count, Ferritin.

• Located :

  • Alopecia Areata → Clinical examination.

  • Tinea Capitis (ringworm) → Tests: Fungal culture.

Visual Changes

• Sudden :

  • Retinal Detachment → Symptoms: Shadow in vision, flashes of light.

    • Exams: Fundoscopy, Ocular ultrasound.

  • Central Retinal Artery Occlusion → Symptoms: Sudden, painless loss of vision.

    • Exams: Fundoscopy, Ocular angiography.

  • Optic Neuritis (common in Multiple Sclerosis) → Symptoms: Pain with eye movement, visual loss.

    • Exams: Magnetic resonance imaging, visual evoked potentials.

• Progressive :

  • Cataract → Symptoms: Blurred vision, difficulty in bright environments.

    • Examinations: Complete ophthalmological examination.

  • Glaucoma → Symptoms: Loss of peripheral vision.

    • Exams: Tonometry (measure eye pressure), Visual field.

  • Age-Related Macular Degeneration (AMD) → Symptoms: Distorted central vision.

    • Exams: Optical coherence tomography, Retinal angiography.

Anemia

• Microcytic (VGM < 80 fL) :

  • Iron Deficiency → Tests: Ferritin, Serum Iron, Transferrin.

  • Thalassemia → Tests: Hemoglobin trophoresis.

• Normocytic (VGM 80-100 fL) :

  • Chronic diseases (e.g.: Renal failure, neoplasms) → Tests: Renal function, Ferritin.

  • Hemolytic Anemia → Tests: Reticulocytes, Indirect Bilirubin.

• Macrocytic (VGM > 100 fL) :

  • Vitamin B12 or Folate Deficiency → Tests: Vitamin B12, Folic Acid, Homocysteine.

  • Megaloblastic Anemia → Tests: Blood count, Bone marrow biopsy (in some cases).

Arthritis

• Monoarthritis :

  • Gouty Arthritis (Gout) → Symptoms: Sudden pain in a joint, usually in the big toe.

    • Tests: Uric Acid, Arthrocentesis (urate crystals).

  • Septic Arthritis → Symptoms: Pain, heat, fever.

    • Exams: Arthrocentesis (analysis of synovial fluid), Blood culture.

• Polyarthritis :

  • Rheumatoid Arthritis → Symptoms: Morning stiffness, symmetrical pain in small joints.

    • Tests: Rheumatoid Factor, Anti-CCP.

  • Systemic Lupus Erythematosus (SLE) → Symptoms: Joint pain, skin lesions, photosensitivity.

    • Exams: ANA, Anti-DNA, Complement C3 and C4.

  • Rheumatic Fever → Symptoms: Migratory polyarthritis, carditis.

    • Exams: ASLO, Echocardiogram.

Cachexia (Involuntary weight loss)

• Associated with other symptoms?

  • Yes :

    • Endocrine Diseases :

      • Hyperthyroidism → Symptoms: Weight loss with increased appetite, tremors, sweating.

        • Tests: TSH, Free T4, T3.

      • Type 1 Diabetes Mellitus → Symptoms: Polydipsia, polyuria, weight loss.

        • Tests: Fasting blood glucose, Glycated hemoglobin (HbA1c).

    • Neoplasms :

      • Gastrointestinal Cancer (Ex: Stomach, pancreas, intestine) → Symptoms: Anorexia, abdominal pain, gastrointestinal bleeding.

        • Exams: Upper Digestive Endoscopy, Abdominal Tomography, Colonoscopy.

      • Lung Cancer → Symptoms: Chronic cough, hemoptysis.

        • Exams: Chest CT scan, Bronchoscopy with biopsy.

    • Chronic Infectious Diseases :

      • Tuberculosis → Symptoms: Prolonged cough, fever, night sweats, weight loss.

        • Exams: Chest X-ray, Sputum smear microscopy, Culture for Mycobacterium tuberculosis.

      • HIV infection → Symptoms: Chronic diarrhea, opportunistic infections, weight loss.

        • Tests: HIV serology, CD4 count, viral load.

    • Gastrointestinal Diseases :

      • Inflammatory Bowel Disease (e.g. Crohn's Disease, Ulcerative Colitis) → Symptoms: Chronic diarrhea, abdominal pain.

        • Exams: Colonoscopy, Biopsy.

  • No (no associated symptoms):

    • Psychiatric causes :

      • Anorexia Nervosa → Symptoms: Refusal to eat, distortion of body image.

        • Examinations: Clinical and psychiatric evaluation.

    • Depression → Symptoms: Depressed mood, loss of appetite.

      • Examinations: Psychiatric evaluation.

Headache

• Acute :

  • Common causes :

    • Migraine → Symptoms: Pulsating pain, nausea, photophobia.

      • Treatment: Analgesics, triptans.

    • Tension Headache → Symptoms: Band-like pain, bilateral.

      • Treatment: Common painkillers, relaxation techniques.

  • Serious causes to be ruled out :

    • Subarachnoid Hemorrhage → Symptoms: Sudden headache, "worst pain in life".

      • Exams: Cranial tomography, Lumbar puncture (if necessary).

    • Meningitis → Symptoms: Fever, stiff neck, confusion.

      • Exams: Lumbar puncture, blood culture, cerebrospinal fluid PCR.

• Chronic (+ 15 days per month, for at least 3 months) :

  • Common causes :

    • Chronic Migraine → Symptoms: Recurrent episodes of pain, aura (in some cases).

    • Chronic Tension Headache → Symptoms: Mild to moderate pain, neck tension.

    • Cluster headache → Symptoms: Intense unilateral pain, tearing.

      • Treatment: Oxygen, triptans.

  • Investigate if there are warning signs (change in pain pattern, neurological deficit):

    • Brain Tumors → Exams: Tomography or Magnetic Resonance Imaging.

    • Intracranial Hypertension → Exams: Fundoscopy, MRI.

Mental Confusion

• Acute (delirium):

  • Metabolic causes :

    • Hypoglycemia → Symptoms: Sweating, tremors, confusion.

      • Tests: Capillary blood glucose.

    • Hyponatremia → Tests: Serum sodium.

  • Infectious causes :

    • Urinary Tract Infection in the Elderly → Symptoms: Confusion, fever.

      • Exams: EAS (urine test), Urine culture.

    • Sepsis → Symptoms: Fever, hypotension, confusion.

      • Exams: Blood count, Blood culture, PCR.

• Chronic (Dementia) :

  • Alzheimer's disease → Symptoms: Memory loss, difficulty with orientation.

    • Exams: Neuropsychological tests (See: MiniMental ), Tomography or MRI of the skull.

  • Vascular Dementia → Symptoms: Cognitive impairment after vascular events.

    • Exams: Carotid Doppler, Cranial tomography.

  • Vitamin B12 deficiency → Tests: Serum B12 dosage.

Seizures

• Isolated seizure (first episode) :

  • Provoked epileptic seizure (e.g. high fever, hypoglycemia, head trauma) → Symptoms: Loss of consciousness, tonic-clonic movements.

    • Exams: Blood glucose, Electroencephalogram (EEG), Cranial Tomography.

  • CNS infections (e.g. Meningitis, Encephalitis) → Symptoms: Fever, stiff neck, headache.

    • Exams: Lumbar puncture, CSF PCR, Blood culture.

• Recurrent seizures :

  • Epilepsy → Symptoms: Repetitive seizures, with no apparent triggering factors.

    • Exams: EEG, Cranial Magnetic Resonance Imaging.

  • Brain Tumors → Symptoms: Headache, seizures, neurological deficits.

    • Exams: Magnetic Resonance Imaging, Cranial Tomography.

  • Neurodegenerative diseases (e.g.: advanced Alzheimer's, vascular dementia) → Symptoms: Cognitive deficits, seizures.

    • Exams: Tomography, Magnetic Resonance Imaging, Neuropsychological assessment.

Diarrhea

• Acute Diarrhea (less than 2 weeks) :

  • Infectious causes :

    • Viral Gastroenteritis → Symptoms: Vomiting, fever, watery diarrhea.

      • Treatment: Hydration, symptomatic.

    • Bacterial Infection (Ex: Salmonella, Shigella) → Tests: Stool culture, Blood culture.

  • Non-infectious causes :

    • Food Poisoning → Symptoms: Diarrhea, vomiting, abdominal pain.

• Chronic Diarrhea (more than 4 weeks) :

  • Inflammatory causes :

    • Inflammatory Bowel Disease (Crohn's, Ulcerative Colitis) → Exams: Colonoscopy, Biopsy.

    • Irritable Bowel Syndrome (IBS) → Symptoms: Abdominal pain, changes in bowel habits.

  • Chronic infectious causes :

    • Giardiasis → Examination: Parasitological stool test.

    • Intestinal tuberculosis → Tests: Stool culture, Intestinal biopsy.

Dyspnea

• Acute :

  • It can be caused by:

    • Pulmonary Embolism → Tests: CT angiography, D-dimer.

    • Pneumonia → Tests: Chest X-ray, PCR, Blood count.

    • Acute Pulmonary Edema (Cardiogenic) → Tests: Echocardiogram, BNP.

    • Exacerbation of chronic cause (see below)

• Chronicle :

  • Possible diagnoses:

    • Chronic Obstructive Pulmonary Disease (COPD) → Symptoms: Chronic cough, progressive dyspnea.

    • Asthma → Symptoms: Wheezing, history of allergies.

    • Chronic Heart Failure → Symptoms: Orthopnea, dyspnea on exertion.

    • Interstitial Lung Diseases → Exams: High-resolution tomography.

Dysphagia

• Oropharyngeal :

  • Neurological Diseases (Ex: Stroke, Myasthenia Gravis) → Symptoms: Difficulty in starting to swallow, frequent choking.

    • Exams: Electroneuromyography, Videofluoroscopy, Cranial Tomography/Magnetic Resonance Imaging.

  • Muscle Disorders (Ex: Myopathies) → Symptoms: Generalized muscle weakness, difficulty swallowing.

    • Exams: Electromyography, CPK, Laboratory tests of muscle enzymes.

• Esophageal :

  • Esophageal stricture (eg, chronic post-gastroesophageal reflux) → Symptoms: Difficulty swallowing solid foods first, then liquids.

    • Exams: Upper Digestive Endoscopy (EDA), Esophageal Manometry.

  • Achalasia (lower esophageal sphincter dysfunction) → Symptoms: Difficulty swallowing both solids and liquids, regurgitation.

    • Exams: Esophageal manometry, EDA.

  • Esophageal Neoplasms → Symptoms: Progressive dysphagia, weight loss.

    • Exams: Endoscopy with biopsy, CT scan of the chest and abdomen.

  • Reflux or Infectious Esophagitis → Symptoms: Heartburn, pain when swallowing (odynophagia).

    • Examinations: EDA with biopsy, Culture of esophageal lesions (in cases of infectious esophagitis).

Abdominal Pain

• Acute :

  • Investigate:

    • Acute Appendicitis → Symptoms: Pain in the right lower quadrant.

      • Exams: Ultrasound, Tomography.

    • Acute Pancreatitis → Symptoms: Epigastric pain radiating to the back.

      • Exams: Amylase, Lipase, Tomography.

    • Cholecystitis → Symptoms: Right upper quadrant pain, fever.

      • Exams: Abdominal ultrasound.

• Chronicle :

  • Possible diagnoses:

    • Gastroesophageal Reflux Disease (GERD) → Symptoms: Burning, regurgitation.

    • Irritable Bowel Syndrome (IBS) → Symptoms: Abdominal pain with bowel changes.

    • Inflammatory Bowel Disease → Tests: Colonoscopy, PCR.

Chest Pain

• Acute :

  • Suspect:

    • Acute Myocardial Infarction → Symptoms: Tight pain, radiating to the left arm, sweating.

      • Exams: Electrocardiogram (ECG), Troponin.

    • Pulmonary Embolism → Symptoms: Pleuritic pain, tachypnea, sudden dyspnea.

      • Exams: D-dimer, chest Angio-CT.

    • Aortic Dissection → Symptoms: Sudden, intense, migratory pain.

      • Exams: Angio-CT of Aorta.

• Chronicle :

  • Possible diagnoses:

    • Angina Pectoris → Exams: ECG, Exercise Stress Test.

    • Chronic Lung Disease (Ex: COPD) → Tests: Spirometry, X-ray.

    • Pericarditis → Tests: ECG, Echocardiogram.

Edema

• Located :

  • Deep Vein Thrombosis → Exam: Doppler Ultrasound

  • Lymphedema → Exam: Lymphoscintigraphy

  • Other localized edema (Ex: Infections, trauma)

    
    

• Generalized :

  • Signs of heart failure ?

    • Yes → Heart Failure

      • Associated symptoms: Dyspnea, orthopnea, jugular venous distention.

      • Exams: Echocardiogram, Chest X-ray.

  • No cardiac signs but renal signs (proteinuria, hematuria)?

    • Yes → Nephrotic or Nephritic Syndrome

      • Tests: EAS (urine test), Creatinine, Urea.

  • No cardiac or renal signs, but liver signs ( jaundice, ascites)?

    • Yes → Liver Failure or Cirrhosis

      • Tests: Liver function (TGO, TGP), Albumin, Abdominal Ultrasound.

Prolonged Fever (>3 weeks)

• Infectious causes :

  • Tuberculosis → Tests: Chest X-ray, PPD, Sputum culture.

  • Infectious Endocarditis → Symptoms: Fever, heart murmur.

    • Exams: Blood cultures, Echocardiogram.

  • Malaria (if exposed in an endemic area) → Tests: Thick smear, Rapid Test.

• Non-infectious causes :

  • Autoimmune Diseases (Ex: Systemic Lupus Erythematosus, Rheumatoid Arthritis) → Tests: FAN, Anti-DNA, Rheumatoid Factor.

  • Neoplasms (Ex: Lymphoma, Leukemia) → Tests: Complete blood count, Lymph node biopsy.

Hepatosplenomegaly

Accompanied by other symptoms?

• Yes :

  • Infectious Diseases :

    • Infectious Mononucleosis (Epstein-Barr Virus) → Symptoms: Fever, lymphadenopathy, fatigue.

      • Tests: Serology for Epstein-Barr, Hemogram with lymphocytosis.

    • Visceral Leishmaniasis → Symptoms: Fever, paleness, weight loss.

      • Tests: Serology, PCR for Leishmania.

    • Malaria → Symptoms: Periodic fever, anemia.

      • Tests: Thick smear, Rapid malaria test.

  • Hematological Diseases :

    • Leukemias → Symptoms: Paleness, tiredness, frequent infections.

      • Exams: Blood count, Myelogram, Bone marrow biopsy.

    • Lymphomas → Symptoms: Fever, night sweats, lymphadenopathy.

      • Exams: Lymph node biopsy, chest and abdominal tomography.

  • Liver Cirrhosis → Symptoms: Ascites, jaundice, edema.

    • Tests: Liver function (ALT, AST, Bilirubin), Abdominal ultrasound.

• No :

  • Metabolic Diseases :

    • Gaucher disease → Symptoms: Splenomegaly, anemia, bone pain.

      • Tests: Lysosomal enzymes, Genetic tests.

    • Hemochromatosis → Symptoms: Hepatomegaly, skin changes.

      • Tests: Serum ferritin, Transferrin saturation.

Jaundice

• Pre-hepatic (causes of hemolysis):

  • Hemolytic Anemia → Tests: Complete blood count, Bilirubin (increased indirect), Haptoglobin.

  • Thalassemia or Spherocytosis → Tests: Hemoglobin Electrophoresis, Osmotic Fragility Test.

• Hepatic Origin :

  • Viral Hepatitis (A, B, C) → Tests: Serology for hepatitis (Anti-HAV, HBsAg, Anti-HCV).

  • Alcoholic Hepatitis → Tests: Liver function (TGO, TGP), Gamma GT.

  • Cirrhosis → Symptoms: Ascites, esophageal varices.

    • Exams: Abdominal Ultrasound, Elastography.

• Biliary Origin :

  • Cholelithiasis (Gallstones) → Symptoms: Pain in the right upper quadrant, fever, choluria.

    • Exams: Abdominal Ultrasound, Cholangioresonance.

  • Cholangitis or Pancreatic Cancer → Symptoms: Jaundice, fever, abdominal pain.

    • Exams: Abdominal ultrasound, ERCP (cholangiopancreatography).

Low back pain

• Acute :

  • Mechanical Low Back Pain (Ex: Physical exertion) → Treatment: Rest, anti-inflammatories.

  • Herniated Disc → Symptoms: Pain radiating to the leg (sciatica).

    • Exams: Spine Magnetic Resonance Imaging.

  • Vertebral Fracture (in osteoporosis) → Exams: Spine X-ray, Bone densitometry.

• Inflammatory Pain :

  • Ankylosing Spondylitis → Symptoms: Prolonged morning stiffness, improves with exercise.

    • Exams: Pelvic X-ray, HLA-B27.

  • Vertebral Fracture (in the elderly or patients with osteoporosis) → Exams: Spine X-ray, Bone densitometry.

  • Metabolic Diseases (Ex: Osteoporosis) → Tests: Bone densitometry, Serum calcium.

  • Neoplasia (vertebral metastasis) → Symptoms: Persistent pain, weight loss.

    • Exams: Tomography, Biopsy.

Myasthenia

• Generalized :

  • Neuromuscular Diseases (Ex: Myasthenia Gravis) → Tests: Electroneuromyography, Tensilon Test.

  • Polyneuropathy (Ex: Guillain-Barré Syndrome) → Exams: Electroneuromyography, CSF examination.

• Located :

  • Parkinson's disease → Symptoms: Tremors, stiffness.

  • Stroke → Exams: Cranial Tomography, Magnetic Resonance Imaging.

Palpitations

Paresthesia/Paralysis

• Sudden :

  • Stroke → Symptoms: Unilateral weakness, difficulty speaking.

    • Exams: Cranial tomography, Magnetic resonance imaging.

  • Bell's palsy (facial paralysis) → Examinations: Clinical examination, Electroneuromyography test (if necessary).

• Progressive :

  • Amyotrophic Lateral Sclerosis (ALS) → Exams: Electroneuromyography, Clinical exams.

  • Multiple Sclerosis → Symptoms: Paresthesia, visual disturbances.

    • Exams: Cranial magnetic resonance imaging, evoked potentials.

  • Charcot-Marie-Tooth disease (hereditary neuropathy) → Tests: Electroneuromyography, Genetic testing.

  • Polyneuropathy (Ex: Guillain-Barré Syndrome) → Exams: Electroneuromyography, CSF examination.

Itching

• Located :

  • Common causes :

    • Contact Dermatitis → Tests: Contact test (patch test).

    • Fungal Infection (Tinea) → Tests: Skin scraping culture.

• Generalized :

  • Systemic causes :

    • Chronic Renal Failure → Tests: Creatinine, Urea.

    • Liver Disease (Ex: Cirrhosis) → Tests: Bilirubin, Liver function.

    • Hematological Disorders (Ex: Polycythemia Vera) → Tests: Complete blood count, Hemoglobin.

Gastrointestinal Bleeding

• Upper Gastrointestinal Bleeding (hematemesis or melena):

  • Common causes :

    • Peptic Ulcer → Exams: Upper Digestive Endoscopy.

    • Esophageal Varices → Exams: Endoscopy, Liver Doppler.

  • Less common causes :

    • Mallory-Weiss (tears in the esophagus after intense vomiting) → Tests: Endoscopy.

• Lower Gastrointestinal Bleeding (Hematochezia):

  • Common causes :

    • Diverticulitis → Symptoms: Abdominal pain, fever.

      • Exams: Abdominal CT scan, Colonoscopy.

    • Hemorrhoidal Disease → Symptoms: Bright red bleeding when defecating.

      • Exams: Anoscopy, Colonoscopy (if necessary).

  • Other causes :

    • Polyps or Colorectal Cancer → Exams: Colonoscopy, Biopsy.

Abnormal Vaginal Bleeding

• Of reproductive age :

  • Ectopic Pregnancy → Symptoms: Severe abdominal pain, delayed menstruation, bleeding.

    • Tests: Beta-hCG, Transvaginal ultrasound.

  • Abortion → Symptoms: Vaginal bleeding, severe cramping, ovular products.

    • Tests: Beta-hCG, Transvaginal ultrasound.

  • Uterine Fibroids → Symptoms: Heavy menstrual bleeding, pelvic pain.

    • Exams: Transvaginal ultrasound, Hysteroscopy (if necessary).

  • Hormonal Disorders (Ex: Polycystic Ovary Syndrome - PCOS) → Symptoms: Irregular menstrual cycles, acne, hirsutism.

    • Exams: Sex hormone dosage, Ovarian ultrasound.

• Post-menopause :

  • Endometrial Cancer → Symptoms: Vaginal bleeding.

    • Exams: Endometrial biopsy, Transvaginal ultrasound.

  • Endometrial Atrophy → Symptoms: Light bleeding, vaginal dryness.

    • Exams: Transvaginal ultrasound, Biopsy (if necessary ).

Syncope

Associated with effort, position, or emotional stress?

• Yes → Vasovagal syncope .

• No :

  • Was it during physical activity?

    • Yes → Heart disease (Arrhythmia, Aortic Stenosis).

      • Exams: ECG, Echocardiogram, Stress Test.

  • Are there associated neurological signs (seizures, weakness)?

    • Yes → Seizure or Stroke .

      • Exams: Cranial Tomography, Electroencephalogram (if seizure).

Cough

• Acute Cough (less than 3 weeks) :

  • It can be caused by:

    • Viral or Bacterial Infection (Ex: Common cold, pneumonia).

      • Exams: Chest X-ray (if necessary), PCR.

    • Asthma Exacerbation → Symptoms: Wheezing, dyspnea.

• Subacute Cough (3 to 8 weeks) :

  • Suspect:

    • Whooping cough → Tests: PCR for Bordetella pertussis.

    • Bronchitis → Tests: X-ray (if necessary), PCR.

• Chronic cough (more than 8 weeks) :

  • Possible diagnoses:

    • COPD → Tests: Spirometry.

    • Gastroesophageal reflux (GER) → Symptoms: Heartburn, regurgitation.

    • Chronic Asthma → Symptoms: Nocturnal cough, wheezing.

    • Tuberculosis → Tests: Chest X-ray, Bacilloscopy, Culture for BK.

Vertigo

• Peripheral (inner ear) :

  • Benign Paroxysmal Positional Vertigo (BPPV) → Symptoms: Dizziness when changing position.

    • Exams: Dix-Hallpike maneuver, Vestibular tests.

  • Ménière's disease → Symptoms: Dizziness, tinnitus, hearing loss.

    • Exams: Audiometry, Electronystagmography.

• Central (CNS) :

  • Stroke → Symptoms: Vertigo associated with other neurological deficits (e.g., slurred speech, weakness).

    • Exams: Cranial tomography, Magnetic resonance imaging.

  • Multiple Sclerosis → Symptoms: Vertigo with visual disturbances, muscle weakness.

    • Exams: Magnetic resonance imaging of the skull.