Infection & Immunology

Question 1

A 32-year-old man presents to the emergency department complaining of perirectal pain and swelling. The symptoms began 24 hours earlier and have become progressively worse. The patient denies any rectal bleeding and describes the pain as very severe and localised to the area of the swelling. He relates a subjective history of fever but denies any change in bowel habits. He also denies any history of recent or chronic medical problems.

Answer 1

Anorectal abscess

Question 2

A 46-year-old man presents to the emergency department after being discovered obtunded at home. A history from family reveals complaints of progressive sinus-type headaches during the 2 weeks prior. While in the emergency department, the patient becomes unresponsive and requires intubation. Magnetic resonance imaging (MRI) scan with contrast reveals a right parietal ring-enhancing lesion.

Answer 2

Brain abscess

Question 3

A 64-year-old man presents with fever, cough productive of copious sputum with a putrid odour, and malaise. He is unable to assign the exact onset of his symptoms but claims they have developed over at least 1 month. He lives alone and is a long-time smoker with a history of chronic alcohol abuse. He also reports the occasional use of illicit drugs. Over the past year he has been admitted twice to the local emergency department after being found unconscious due to alcohol intoxication. On physical examination he looks profoundly malnourished and his dental hygiene is very poor. Auscultation of the chest reveals fixed amphoric breath sounds over the right hemi-thorax. A sputum culture grows a mixed microbial population of aerobes and anaerobes.

Answer 3

Lung abscess

Question 4

A 75-year-old woman with a long history of poorly controlled diabetes mellitus presents with fever, non-productive cough, and malaise. Her symptoms began acutely 48 hours earlier, and she self-medicated with a macrolide antibiotic. Physical and radiological examinations confirm the diagnosis of left upper lobe pneumonia. She is admitted to hospital and an aminopenicillin is added to her treatment. Although she initially shows a marginal clinical improvement (but never complete apyrexia), over the next few days her fever gradually worsens, the cough becomes productive, and her lung function deteriorates. Chest CT scan reveals spread of the existing pneumonia and development of multiple cavitating lesions with air-fluid levels. A bronchoscopy is performed, and the culture of the obtained bronchoalveolar lavage fluid grows Klebsiella pneumoniae .

Answer 4

Lung abscess

Question 5

A 50-year-old man presents to the emergency department with a 3-week history of increasing back pain. He also reports previous intravenous drug use. On examination, he has tenderness in the lumbar region, some paravertebral spasm, and a temperature of 39°C (102°F). Laboratory investigations show a white blood cell count of 16x10^9/L (16,000/microlitre), elevated erythrocyte sedimentation rate (150 mm/hour), and elevated C-reactive protein (1047.64 nanomol/L [110 mg/L]). Plain spinal x-rays are unremarkable. Computed tomography of the lumbar spine suggests discitis at the fourth lumbar interspace, and magnetic resonance imaging (MRI) reveals an enhancing epidural mass at L3 to L5.

Answer 5

Epidural abscess

Question 6

A 40-year-old woman with HIV infection presents to the accident and emergency department with a 5-day history of weakness in the lower extremities. On examination, she is afebrile. Laboratory investigations and spinal x-rays are unremarkable. MRI shows an enhancing epidural process from T10 to L5.

Answer 6

Epidural abscess

Question 7

A 14-year-old girl presents in severe respiratory distress to the emergency department. Her past medical history includes asthma and a peanut and tree nut allergy. Shortly after ingestion of a biscuit in the school cafeteria, she began complaining about flushing, pruritus, and diaphoresis followed by throat tightness, wheezing, and dyspnoea. The school nurse called an ambulance. No medications were administered and the patient did not have an epinephrine (adrenaline) auto-injector prescribed by her allergist. Her physical examination reveals audible wheezing and laryngeal oedema and an oxygen saturation of 92%.

Answer 7

Anaphylaxis

Question 8

A 65-year-old man reports being stung while working in his garden. He removed the sting and found the dying bee. In the past he tolerated insect stings on several occasions without reaction. On this occasion, within minutes, he experienced flushing, sweating, and a brief loss of consciousness. Too confused to call for help, he was found 10 minutes later by his wife. On arrival of an ambulance he was rousable, without respiratory distress or rash. Systolic BP was 75 mmHg and pulse rate was 55 bpm.

Answer 8

Anaphylaxis

Question 9

A 30-year-old woman presents with 4-month history of recurrent oral and genital ulcers. She gets the oral ulcers every other week, >5 at a time, and they resolve on their own in 7 to 10 days. They cause discomfort and occur in the inner lips and cheeks and on her tongue. The genital ulcers are fewer in number and not always painful. She has also noticed acne on her legs and on her back, but not on her face, although she never had any facial acne as a teenager. She has also had 2 episodes of painful, red, round lesions on her legs. These resolved without treatment after 1 week.

Answer 9

Behcet’s disease

Question 10

A 28-year-old man presents with a 2-month history of eye pain and blurring of vision that has been getting worse over the last several weeks. Both of his eyes are involved. He also complains of recurrent oral and genital ulcers that have been bothering him for the last 5 months. He has had facial acne for some time, but now is getting acne on his back, upper arms, and legs.

Answer 10

Behcet’s disease

Question 11

A 28-year-old man presents with pain on swallowing. He has no oral symptoms, but clinically has abundant, creamy white, loosely adherent plaques throughout his mouth. Lesions are especially prominent in his buccal, palatal, and pharyngeal mucosa. HIV infection was diagnosed 2 years ago, but he has not yet started anti-retroviral treatment. His last CD4 count and viral load measurement was 8 months ago.

Answer 11

Candidiasis

Question 12

A 64-year-old man presents with a complaint of burning under his maxillary denture. He has hypertension and osteoarthritis. His medications include a thiazide diuretic, a non-selective beta-blocker, and an OTC analgesic. Intra-orally, he has severely erythematous palatal mucosa, with a distinct granular appearance. His mucosa is dry and his salivary flow is minimal.

Answer 12

Candidiasis

Question 13

A 45-year-old man presents with acute onset of pain and redness of the skin of his lower leg. Low-grade fever is present and the pretibial area is erythematous, oedematous, and tender.

Answer 13

Cellulitis

Question 14

A 6-year-old girl with no significant past medical history presents 4 days after developing a red, irritated left eye. Her mother states that she has been wiping thick whitish-yellow discharge from her eye, and the eye is matted shut in the morning. She denies any exposure to an infected person, upper respiratory tract symptoms, or contact lens use. She also denies any significant pain or light sensitivity. On examination, the patient’s pupils are equal and reactive. She does not have a tender pre-auricular lymph node. Penlight examination does not reveal any corneal opacity, but thick, whitish discharge is seen.

Answer 14

Conjunctivitis

Question 15

A 14-year-old boy with no significant past medical history presents 3 days after developing a red, irritated right eye that spread to the left eye today. He has watery discharge from both eyes and they are stuck shut in the morning. He reports recent upper respiratory tract symptoms and that several children at his day camp recently had pink eye. He denies significant pain or light sensitivity and does not wear contact lenses. On examination, his pupils are equal and reactive and he has a right-sided, tender pre-auricular lymph node. Penlight examination does not reveal any corneal opacity.

Answer 15

Conjunctivitis

Question 16

A 56-year-old man presents to the emergency department with headache, fever, blurred vision, and somnolence followed shortly by unresponsiveness to verbal commands. For the last 2 weeks he had been feeling ill and had decreased appetite and myalgias. Three days prior to presentation he experienced intermittent confusion, severe headache, and fever. Examination was limited by a generalised tonic-clonic seizure, for which he received lorazepam.

Answer 16

Encephalitis

Question 17

A 19-year-old man presents to the emergency department with a witnessed generalised tonic-clonic seizure episode. One month previously he had an upper respiratory tract infection. Over the last 2 weeks he developed headaches, blurred vision, generalised weakness, and progressive difficulty in walking. Examination revealed pain on eye movement as well as limb and gait ataxia.

Answer 17

Encephalitis

Question 18

A 21-year-old man presents with a 3-day history of worsening left-sided scrotal pain and swelling. He reports noticing a white urethral discharge over the last 24 hours. He is otherwise fit and well, and takes no regular medicine. He is heterosexual and has a single female partner, with whom he has unprotected intercourse. Examination reveals a tender, erythematous, swollen left hemiscrotum with a palpably thickened epididymis.

Answer 18

Epididymitis

Question 19

A 74-year-old man with a known history of benign prostatic enlargement and insulin-requiring type 2 diabetes presents with a 7-day history of worsening right-sided scrotal pain and swelling. Initial symptoms of dysuria and frequency have resolved since his family doctor prescribed a course of antibiotics 4 days ago. Examination reveals a tender, swollen right epididymis with an associated hydrocele.

Answer 19

Epididymitis

Question 20

A 35-year-old man comes to the emergency department with a history of nausea, vomiting, and watery diarrhoea of 1 day’s duration. The patient and his wife have just returned from a Caribbean cruise, and his wife also has mild diarrhoea. The patient denies any blood or mucus in the stool. He has chills but no fever. On examination, the patient is afebrile and anicteric, but has dry mucous membranes. His heart rate is 95 beats per minute and BP is 110/70 mmHg. His abdomen is soft and non-tender, with hyperactive bowel sounds.

Answer 20

Gastroenteritis

Question 21

A 70-year-old woman is brought to the emergency department from her nursing home with a history of nausea, projectile vomiting, and non-bloody diarrhoea of 1 day. She also complained of generalised body aches, chills, and fatigue. Her roommate in the nursing home has also had diarrhoea for 2 days. Past medical history included hypertension and coronary artery disease. Blood pressure (BP) on examination is 100/60 mmHg and heart rate is 110 beats per minute. Abdomen is non-distended and is non-tender.

Answer 21

Gastroenteritis

Question 22

A 24-year-old woman presents with a 3-day history of painful sores in the genital area, dysuria, fever, and headache. She is sexually active with men and has a new partner within the past month. She does not use condoms. Physical examination reveals a temperature of 38.3°C (100.9°F), stable vital signs, slight nuchal rigidity (implying aseptic meningitis), bilateral tender inguinal lymphadenopathy, and multiple tender 1- to 2-cm erythematous ulcerations without labial crusts. The cervix is oedematous with pustules and clear discharge. Cervical motion tenderness is also present.

Answer 22

HSV

Question 23

A 25-year-old man presents for STD screen. He is sexually active with men, has had 4 partners in the past year, and uses condoms ‘most of the time’. He was HIV-negative 6 months ago and denies a history of urethral discharge, dysuria, or genital ulcers. He does have occasional genital itching and mild sores on the penile shaft. Genitourinary examination reveals a circumcised male with no inguinal lymphadenopathy, no lesions on the penile shaft or perianal area, and no urethral discharge.

Answer 23

HSV

Question 24

A 32-year-old male taxi driver was recently hospitalised for a pneumonic illness. Compatible chest x-ray findings and confirmatory sputum culture were positive for Mycobacterium tuberculosis , resulting in a diagnosis of pulmonary tuberculosis (TB). In the outpatient clinic, history obtained from the patient confirmed some months of deteriorating health. He had lost approximately 10 kg in weight and had experienced fevers, night sweats, loss of appetite, and intermittent bouts of diarrhoea. In addition, 4 weeks prior to admission he had developed a productive cough and pleuritic chest pain. He had also noted a scaly skin condition at the hair line. His medical history is non-significant, but he nursed his mother with TB approximately 6 years ago. His current medicine includes anti-tuberculous therapy and pyridoxine. He has recently completed 1 week of topical mycostatin for oral candidiasis. On examination he is thin, with evidence of oral thrush and mild seborrhoeic dermatitis. He has mild bronchial breathing in his right upper chest, with mild tracheal deviation to the right. His neurological, cardiovascular, and abdominal examinations are normal. A CD4 count performed while the patient was still in the hospital was 186 cells/microlitre.

Answer 24

HIV

Question 25

A 26-year-old female bank clerk is 24 weeks pregnant She explains that she has been very well with only pregnancy-related nausea and mild fatigue. This is her first pregnancy. On examination, she looks well, with mild generalised lymphadenopathy only. She has been married for 2 years and had only 1 sexual partner in the last 4 years.

Answer 25

HIV

Question 26

A 16-year-old student presents with fever, sore throat, and fatigue. She started feeling ill 1 week ago. Her symptoms are gradually getting worse, and she has difficulty swallowing. She has had a fever every day, and she could hardly get out of bed this morning. She does not remember being exposed to anybody with a similar illness recently. On physical examination she is febrile and looks ill. Enlarged cervical lymph nodes, exudative pharyngitis with soft palate petechiae and faint erythematous macular rash on the trunk and arms are found.

Answer 26

Infectious mononucleosis

Question 27

A 31-year-old woman presents with a 1-week history of fever, chills, fatigue, and unilateral ankle pain. Her past medical history includes mitral valve prolapse and hypothyroidism. She admits to infrequent intravenous heroin use and has a 10-pack-year history of smoking. Physical examination reveals temperature of 39°C (102°F), regular heart rate 110 beats per minute, blood pressure 110/70 mmHg, and respiration rate of 16 breaths per minute. Her cardiovascular examination reveals a grade 2/4 holosystolic murmur that is loudest at the right upper sternal border. Her right ankle appears red and warm, and is very painful on dorsiflexion.

Answer 27

Infective endocarditis

Question 28

A 42-year-old Nigerian woman presents to her primary care physician with a 2-day history of fever, chills, and sweats with associated headache and myalgia. She is febrile (38.6°C [101.4°F]) and tachycardic, but examination is otherwise unremarkable. A presumptive diagnosis of influenza is made, and she is advised to return if she does not improve. Two days later she presents to the emergency department with similar symptoms and frequent vomiting. On examination she appears ill, with a temperature of 38.8°C (101.8°F), pulse rate 120 bpm, blood pressure 105/60 mmHg, and mild jaundice. Further history reveals that she recently visited family in Nigeria for 2 months, returning 1 week before presentation.

Answer 28

Malaria

Question 29

A 28-year-old man presents to his physician with a 5-day history of fever, chills, and rigors, not improving with paracetamol (acetaminophen), along with diarrhoea. He had been travelling in Central America for 3 months, returning 8 weeks ago. He had been bitten by mosquitoes on multiple occasions, and although he initially took malaria prophylaxis, he discontinued it due to mild nausea. He does not know the specifics of his prophylactic therapy. On examination he has a temperature of 38°C (100.4°F), and is mildly tachycardic with a blood pressure of 126/82 mmHg. The remainder of the examination is normal.

Answer 29

Malaria

Question 30

A 43-year-old man with no significant medical history presents with 3 days of progressive fatigue, dyspnoea on exertion and while lying in the supine position, and lower-extremity swelling. He reports having a flu-like illness consisting of fevers, myalgias, fatigue, and respiratory symptoms 2 weeks prior that resolved spontaneously. On examination the patient has an elevated jugular venous pressure, bilateral pulmonary rales, and a heart rate of 104 bpm with an audible left ventricular S3 gallop. He is mildly dyspnoeic at rest but becomes markedly dyspnoeic with minimal exertion.

Answer 30

Myocarditis

Question 31

A 49-year-old man originally from Argentina with a 3-year history of congestive heart failure presents to the emergency department with syncope while at work. He reports speaking with a co-worker then suddenly awaking on the floor of the office. The patient’s wife states that the patient has had 2 similar episodes in the past. The patient is euvolaemic with non-distended neck veins and a normal lung examination. Cardiac examination reveals a laterally displaced apex, and regular rate and rhythm without murmur or gallop but frequent ectopy.

Answer 31

Myocarditis

Question 32

A 1-month-old girl presents to her general practitioner with a high fever, feeding difficulties, and irritability for the past 24 hours. Examination reveals altered mental status and a bulging fontanelle.

Answer 32

Bacterial meningitis

Question 33

An 18-year-old male student presents with severe headache and fever that he has had for 3 days. Examination reveals fever, photophobia, and neck stiffness.

Answer 33

Bacterial meningitis

Question 34

A 19-year-old man presents with a 2-day history of headache and associated nausea. He says that bright light hurts his eyes. He has no significant past medical history, is not currently taking any medicine, and reports no drug allergies. He works as a librarian and has not travelled overseas for the past year. He lives with his girlfriend whom he has been seeing for 2 years. They have a pet hamster.

Answer 34

Viral meningitis

Question 35

Parents bring their 2-year-old child who has been ill for 1 day with irritability, vomiting, and fever. The child has a widespread maculopapular rash.

Answer 35

Viral meningitis

Question 36

A 28-year-old woman in her second post-partum week presents with recent-onset breast pain and a tender wedge-shaped area in one breast that feels firm, warm, and swollen, and appears erythematous. She has decreased milk output, flu-like symptoms, pyrexia of 38°C (100.4°F), and myalgia, in addition to feeling fatigued.

Answer 36

Mastitis and breast abscess

Question 37

A 30-year-old woman with a history of mastitis presents with sharp shooting breast pain and an exquisitely tender, swollen, red, and warm fluctuant peri-areolar breast mass.

Answer 37

Mastitis and breast abscess

Question 38

A 35-year-old woman is admitted to hospital because of pain and swelling of the right thigh. The patient has been in excellent health until the morning before admission, when she observed a pimple on her right thigh. During the course of the day, the lesion enlarged, with increasing pain, swelling, and erythema, and was accompanied by nausea, vomiting, and delirium. Her temperature is 37.5°C (99.5°F), pulse is 128 bpm, and respirations are 20 breaths/minute. BP is 85/60 mmHg. On physical examination, the patient appears ill and in pain. A small, indurated area of skin breakdown with surrounding erythema and warmth is present on the right thigh; no fluctuance is detected. She is unable to flex or extend the right hip because of pain and reports pain on passive extension of the right ankle. The temperature soon rises to 38.4°C (101°F), and the BP drops to 70/40 mmHg. Haematocrit is 42, WBC count 5900/mm³ (with 64% neutrophils, 19% band forms), serum creatinine 168 micromol/L (1.9 mg/dL), and serum urea 7.8 millimol/L (22 mg/dL). Contrast-enhanced CT shows a diffuse, non-enhancing, honeycomb pattern within the subcutaneous tissue of the right thigh. Subcutaneous stranding and thickening of the skin are prominent in the posterolateral aspect of the thigh; there is also thickening of the posterolateral deep fascia.

Answer 38

Necrotising fasciitis

Question 39

A 78-year-old woman presents to hospital for an elective right hemicolectomy. She has a past medical history of hypertension, angina on exertion, and diabetes mellitus. She is independently mobile, does her own shopping, and has a 30-pack-a-year history of smoking. The operation was uncomplicated. On day 5 post-surgery, she becomes confused. On examination, she has a Glasgow Coma Scale score of 14/15. She has a temperature of 38.5°C (101.3°F), a respiratory rate of 28 breaths/minute, and oxygen saturations of 92% on 2 L of oxygen per minute. She is tachycardic at 118 bpm, and her BP is 110/65 mmHg. On chest auscultation, she has coarse crackles in the right lower zone. Her surgical wound appears to be healing well and her abdomen is soft and not tender.

Answer 39

Sepsis

Question 40

A 40-year-old man who suffered an open tibial fracture in a motor vehicle accident 6 months ago presents with swelling and pain in his lower leg.

Answer 40

Osteomyelitis

Question 41

A 5-year-old boy fell off his bicycle 2 weeks ago and has stopped walking and complains of non-specific pain in his leg. His mother reports that he apparently has had flu, with fever and chills.

Answer 41

Osteomyelitis

Question 42

An otherwise healthy 30-year-old man presents with a several-day history of progressive, severe, retrosternal chest pain that is sharp and pleuritic in nature. The pain is worse on lying down and improved with sitting forward. There is radiation to the neck and shoulders and specifically to the trapezius muscle ridges. The pain is constant and unrelated to exertion. On physical examination, a pericardial friction rub is heard at end-expiration with the patient leaning forward

Answer 42

Pericarditis

Question 43

A 53-year-old man with a history of hepatitis C presents with a complaint of abdominal distention, fever, vomiting, and blood in his stool. He has presented numerous times previously with abdominal distention and has received paracenteses, which have improved the symptoms.

Answer 43

Peritonitis

Question 44

A 46-year-old woman with a history of long-standing alcoholism and previous episodes of hepatic encephalopathy presents with altered mental status and worsening abdominal distention.

Answer 44

Peritonitis

Question 45

A 55-year-old man with a history of peripheral vascular disease, who presents with a complaint of a left foot ulcer and pain when walking short distances, is found to have a popliteal stenosis and admitted for re-vascularisation. Four days after admission, on postoperative day 3, he develops SOB, hypoxia, and a productive cough. Auscultation of his chest reveals decreased breath sounds at the lower aspect of the right side of his chest. His morning leukocyte count is slightly higher than the day before at 11,000 cells/mL^3. An anterior-posterior bedside CXR reveals right lower lobe opacity.

Answer 45

HAP

Question 46

An 88-year-old female resident of a nursing home, who typically does not present to the acute care hospital, has frequent UTIs that are managed by the nursing home physician. In the nursing home, she develops a UTI due to multi-drug-resistant pathogens. On admission to hospital, she has poor mental status and her bed is left with the head elevated to only a 5° angle. On hospital day 4, a CXR reveals a right lower lobe opacity.

Answer 46

HAP

Question 47

A 54-year-old smoker with multiple comorbidities (diabetes, hypertension, coronary artery disease) presents with a 2-day history of a productive cough with yellow sputum, chest tightness, and fever. Physical examination reveals a temperature of 38.3°C (101°F), BP of 150/95 mmHg, heart rate of 85 bpm, and a respiratory rate of 20 breaths per minute. His oxygen saturation is 95% at rest; lung sounds are distant but clear, with crackles at the left base. CXR reveals a left lower lobe infiltrate.

Answer 47

CAP

Question 48

A 10-year-old female Pacific Islander presents with a 2-day history of fever and sore joints. Further questioning reveals that she had a sore throat 3 weeks ago but did not seek any medical help at this time. Her current illness began with fever and a sore and swollen right knee that was very painful. The following day her knee improved but her left elbow became sore and swollen. While in the waiting room her left knee is now also becoming sore and swollen.

Answer 48

Rheumatic fever

Question 49

A 55-year-old woman presents with a 1-week history of pain and swelling in her left wrist. She was diagnosed with rheumatoid arthritis at the age of 36 years but the rest of her joints are currently asymptomatic. Her rheumatoid arthritis is well controlled on her current medication. On examination her left wrist is found to be hot, swollen, tender, and highly restricted in its range of movement. There is no sign of inflammation in any of her other joints. She has a temperature of 37.5˚C (99.5˚F).

Answer 49

Septic arthritis

Question 50

A 25-year-old man who is a known intravenous drug abuser presents with a 5-day history of pain and swelling in his right leg. On examination there are multiple sites of intravenous puncture. His right leg is swollen from the knee downwards. There is a large effusion on the right knee together with significant cellulitic changes of the overlying skin.

Answer 50

Septic arthritis

Question 51

A 45-year-old woman presents with fatigue and a history of positive ANAs. She has had recurrent sensation of sand/gravel in eyes and dry mouth every day for more than 3 months.

Answer 51

Sjogren syndrome

Question 52

A 38-year-old white woman presents to the accident and emergency department with 24 hours of dyspnoea and pleuritic chest pain. On further questioning, she reports a 3-year history of Raynaud’s disease, polyarthralgia, and intermittent migraine. Physical examination reveals hypoxia, tachycardia, and normal blood pressure. Ventilation perfusion scanning confirms a pulmonary thromboembolism.

Answer 52

SLE

Question 53

A 16-year-old black female presents to her general practitioner with symptoms of fatigue, musculoskeletal pain, and a facial rash. On examination she is noted to be thin with malar skin changes. No other abnormality is found.

Answer 53

SLE

Question 54

A 38-year-old woman presents with Raynaud’s phenomenon for the past 5 years. She also has a history of digital ulcers and GORD. Physical examination reveals telangiectasias on the hands. She has sclerodactyly. Digital pits are present with no active ulcers. Serology tests reveal a high-titre ANA by indirect immunofluorescence, at a titre of >1:640 in a centromere pattern.

Answer 54

Systemic sclerosis

Question 55

A 35-year-old woman presents complaining of puffy hands and feet for the past 3 months. She noted the onset of Raynaud’s phenomenon 6 months ago. Examination confirms the presence of puffy hands and feet, with subtle skin thickening of the fingers and dorsum of the hands. Serology tests reveal a positive ANA with both speckled and nucleolar patterns at a titre of >1:1280. Anti-topoisomerase (anti-Scl 70) antibody is strongly positive. Pulmonary function tests are normal (although this does not preclude the possibility of the development of fibrosis at a later date).

Answer 55

Systemic sclerosis

Question 56

A 40-year-old woman with no prior thyroid history presents with 7 days of fevers to 40°C (104°F), shaking, chills, myalgias, and pharyngitis. On the last day she has developed a severe neck pain that radiates to her ear and jaw. She has noted rapid heartbeat, palpitations, tremor, and feeling hot. The neck pain is severe and has changed from the left side of her neck to the right side in the last 24 hours. She cannot eat or drink anything because it exacerbates the pain. She indicates that the pain is not in her pharynx but over her lower neck and radiates to her ear and jaw. She is mildly distressed and will not let you touch her neck because it hurts so much. On examination, her thyroid is enlarged, firm, and very tender to palpation.

Answer 56

Thyroiditis (subacute granulomatous)

Question 57

A 62-year-old man presents with atrial fibrillation. He has not noticed any tremulousness, heat intolerance, or weight loss. His thyroid gland is non-nodular, non-tender, and slightly enlarged. Serum thyroid-stimulating hormone (TSH) is undetectable, free T4 and T3 are modestly elevated, and thyroid peroxidase antibodies are positive with a low titre. A 24-hour radioiodine uptake is 0.2%.

Answer 57

Thyroiditis (painless lymphocytic)

Question 58

A 31-year-old woman is 4 months postnatal, breastfeeding, and found to have a resting heart rate of 92 bpm. She has a slightly enlarged non-nodular, non-tender thyroid and no proptosis. Serum TSH is undetectable, free T4 and T3 are modestly elevated, and thyroid peroxidase antibodies are positive. The ratio of total serum T3 to T4 is 12.

Answer 58

Thyroiditis (painless lymphocytic)

Question 59

A 6-year-old previously healthy boy presents with acute onset of fever of 39°C (102°F), severe throat pain that is exacerbated by swallowing, headache, and malaise. On examination his tonsils are symmetrically enlarged and red, with purulent exudate. He has multiple enlarged, painful anterior neck lymph nodes, but no other lymphadenopathy and no splenomegaly. He has no runny nose or cough, and no difficulty breathing.

Answer 59

Tonsilitis

Question 60

A 34-year-old man presents to his primary care physician with a 7-week history of cough that he describes as non-productive. He has had a poor appetite during this time and notes that his clothes are loose on him. He has felt febrile at times, but has not measured his temperature. He denies dyspnoea or haemoptysis. He is originally from the Philippines. He denies any history of TB or TB exposure. Physical examination reveals a thin, tired-appearing man but is otherwise unremarkable.

Answer 60

Pulmonary TB

Question 61

A 42-year-old Asian woman presents to her primary care physician with a 7-week history of an enlarging mass on the left side of her neck. She denies pain or drainage. The mass failed to respond to antibiotics. She denies cough, fever, night sweats, or anorexia. She is originally from Vietnam but has lived in the US for 15 years. She denies any history of TB or TB exposure. Physical examination reveals a well-appearing woman. There is a 2 x 4 cm left neck mass consistent with a lymph node in the anterior cervical chain. There is no tenderness; the node is firm and mobile. There are smaller subcentimetre lymph nodes in the left supraclavicular fossa. The physical examination is otherwise unremarkable.

Answer 61

Extrapulmonary TB

Question 62

A 66-year-old black man presents to the emergency department with a history of fever and weight loss. He reports that he has had little appetite for the last 3 months and has lost 11 kg during that time. He has noted tactile fevers over the last 6 weeks but has not had access to a thermometer. He has been having headaches for the last week but denies cough, haemoptysis, or chest pain. He has been intermittently homeless over the last 2 years and has a history of heavy alcohol use but recently stopped. On examination, he is a thin man with a temperature of 38.8°C (101.9°F) and a respiratory rate of 20 breaths per minute. Physical examination is notable for temporal wasting and hepatomegaly without tenderness.

Answer 62

Extrapulmonary TB

Question 63

A 59-year-old man complains of urinary frequency, urgency, and dysuria for several days. He denies the presence of haematuria or penile discharge, but does have 3 episodes of nocturia most nights. His past medical history includes benign prostatic hyperplasia (BPH). The patient is in a monogamous relationship with his wife.

Answer 63

UTI

Question 64

A 70-year-old man, who has been an inpatient for 4 days with an exacerbation of congestive heart failure, is now complaining of unilateral back pain. He has had an indwelling urinary catheter to strictly monitor urine output since admission. He also relates a history of increasing suprapubic discomfort for the last 24 hours. Examination confirms fever, suprapubic tenderness, and costovertebral angle tenderness.

Answer 64

UTI

Question 65

A 27-year-old, healthy, sexually active woman presents with pain on urination and recent onset of urinary frequency and urgency. She has no costovertebral angle tenderness on examination.

Answer 65

UTI

Question 66

A 74-year-old post-menopausal woman with diabetes mellitus presents with pain on urination and urinary frequency.

Answer 66

UTI

Question 67

A 50-year-old man with a past medical history of HTN and a recent diagnosis of osteoarthritis presents to his primary care physician with complaints of hives over the past 2 weeks. He reports red and raised lesions that are intensely pruritic and involve his torso and bilateral extremities. He denies any swelling or pain associated with the episodes. The patient also denies any unusual food ingestions or recent changes in his environment (e.g., soaps, detergents). However, he has recently started using scheduled ibuprofen for osteoarthritis.

Answer 67

Urticaria

Question 68

A 33-year-old woman with a past medical history of hypothyroidism presents with complaints of hives for the past 4 months. She describes red, raised, itchy lesions that involve her entire body, including her face. She also reports 2 episodes of face and tongue swelling, each of which prompted her to report to the nearest emergency department. In addition to itching, the lesions sometimes cause a burning sensation. The lesions and symptoms resolve over 24 to 36 hours. Despite countless attempts, she has not been able to associate the hives with any specific triggers. The patient voices extreme frustration and feelings of depression, which she attributes to her recent condition.

Answer 68

Urticaria

Question 69

A 6-year-old boy presents with fever, headache, and a diffuse, pruritic, vesicular rash, which is most prominent on the face and chest. He has had generalised malaise and low-grade fever for a few days prior to presentation. He developed high fever and a rash in the last 48 hours. Physical examination demonstrates a temperature of 39°C (102°F) and heart rate of 140 beats/minute. He has a few scattered vesicular lesions in his oropharynx and his lung fields are clear. The lesions are prominent on the face and chest, but all extremities are also involved. In some areas the lesions are crusted, while in others they appear newly formed. He has no nuchal rigidity or other meningeal signs.

Answer 69

Varicella zoster

Question 70

A 36-year-old man undergoing chemotherapy for non-Hodgkin’s lymphoma presents with fever, shortness of breath, haemoptysis, and a diffuse rash. His family recalls that he had a fever the previous day, and that the rash started on his chest and progressed rapidly. His current medications are levofloxacin and an antidepressant. On examination he has a temperature of 40.1°C (104.2°F), a heart rate of 145 bpm, and an O2 saturation of 83%. Lung examination demonstrates bilateral crackles, and the patient has diffuse vesicular lesions, some of which appear to be haemorrhagic. Initial laboratory testing indicates a low haematocrit and platelets, a low absolute lymphocyte count (<100 cells/mL), and mild transaminitis. A chest x-ray demonstrates ground glass opacities or diffuse small nodular infiltrates.

Answer 70

Varicella zoster

Question 71

A 34-year-old woman with a 2-year history of poorly controlled asthma and allergic rhinitis presents with new right lower extremity weakness. Electromyogram indicates mononeuritis multiplex.

Answer 71

Churg-Strauss syndrome (vasculitis)

Question 72

A 72-year-old white woman presents with partial vision loss in the right eye. She reports bitemporal headache for several weeks, accompanied by pain and stiffness in the neck and shoulders. Review of systems is positive for low-grade fever, fatigue, and weight loss. On physical examination, there is tenderness of the scalp over the temporal areas and thickening of the temporal arteries. Fundoscopic examination reveals pallor of the right optic disc. Bilateral shoulder range of motion is limited and painful. There is no synovitis or tenderness of the peripheral joints. There are no carotid or subclavian bruits, and the blood pressure is normal and equal in both arms. The remainder of the examination is unremarkable.

Answer 72

Giant cell arteritis (vasculitis)

Question 73

A previously healthy 61-year-old woman presents with a 3-month history of sinusitis and nasal drainage. She has noted only marginal, temporary improvement despite multiple courses of antibiotics. The nasal drainage is purulent and frequently haemorrhagic. She also has a 2-week history of migratory joint pain, mainly affecting wrists, knees, and ankles. She does not describe joint swelling. She reports having less energy and has lost 10 pounds in weight over the past 2 months. She has no respiratory, urinary, neurological, or other symptoms. Bleeding and inflammation of the nasal mucosa is noted, along with tenderness to percussion over both maxillary sinuses. The remainder of the physical examination is unremarkable. In-office urinalysis reveals 3+ microscopic haematuria and 2+ proteinuria.

Answer 73

Wegener’s granulomatosis (vasculitis)

Question 74

A 5-year-old boy is brought in by his mother. He presents with a 4-day history of a rash on his lower extremities, mild abdominal cramping, and diffuse joint pain. His mother reports that he was recently treated for a URTI.

Answer 74

Henoch-Schonlein purpura (vasculitis)

Question 75

A 55-year-old man presents with tingling of the left hand and loss of sensation in both lower limbs. He gives a 6-week history of a 5-kg weight loss and fevers. Examination shows mononeuritis multiplex affecting both the common peroneal nerves and the left radial nerve. Investigation reveals a normocytic, normochromic anaemia (haemoglobin 93 d/L [9.3 g/dL]), neutrophilia (WBC count 11.5 x 10^9/L [11,500/microL]), a raised creatinine (2.48 mg/dL), and elevated inflammatory markers (ESR 89 mm/hour, CRP >15.2 nanomol/L [1.6 mg/L]) but normal urinary sediment. Tests are negative for anti-neutrophil cytoplasmic antibodies (ANCA), with no evidence of hepatitis B infection. His blood pressure is 193/103 mmHg. Sural nerve biopsy demonstrates a transmural vascular inflammatory infiltrate with a mixture of macrophages, lymphocytes, and neutrophils plus evidence of focal and segmental necrotising vasculitis with fibrinoid necrosis. Multiple aneurysms are seen on renal angiography.

Answer 75

Polyarteritis nodosa (vasculitis)

Question 76

A 44-year-old woman presents with a 3-month history of abdominal pain, fever, and weight loss. The abdominal pain is cramping in nature and occurs 30 minutes after eating. Abdominal examination is unremarkable. She has widespread purpuric lesions on her lower limbs. Blood tests reveal elevated inflammatory markers (ESR 93 mm/hour, CRP >15.2 nanomol/L [1.6 mg/L]) and raised transaminases (ALT 300 units/L). ANCA is negative. HbeAg and HbsAg are positive, with raised hepatitis B DNA. A liver ultrasound examination is normal. A full-thickness skin biopsy of the purpuric lesions is reported as showing segmental necrotising vasculitis of medium vessels with fibrinoid necrosis. A mesenteric angiogram demonstrates multiple aneurysms involving the superior and inferior mesenteric arteries.

Answer 76

Polyarteritis nodosa (vasculitis)

Question 77

A 58-year-old woman presents with a 2-week history of fatigue, anorexia, fevers, and bilateral pain and stiffness in the shoulder and hip girdles. These symptoms are worse at night. Upon awakening in the morning, she feels as if she has a bad flu. She reports difficulty getting out of bed in the morning due to stiffness. Her wrists and finger joints are also painful and swollen.

Answer 77

Polymyalgia rheumatica (vasculitis)

Question 78

A 28-year-old woman presents with new left-arm pain. She was previously well but for 2 months has had episodes of low-grade fever, night sweats, and arthralgia. She works as a shop assistant and has noticed left-arm pain when she stocks shelves. Her only medication is an oral contraceptive. She does not smoke cigarettes. On examination, her blood pressure is 126/72 in her right arm, but it cannot be measured in her left arm. The left radial pulse cannot be detected. There is a bruit over the left subclavian artery. Carotid pulses are normal but there is a bruit over the right carotid artery. Femoral and pedal pulses are normal and no abdominal bruits are heard. The left hand is cool but has no other evidence of ischaemia.

Answer 78

Takayasu’s arteritis (vasculitis)

Question 79

A 39-year-old woman presents with headaches of insidious onset over 3 months. She has lost 3 kilograms during this time but feels otherwise well. On examination, bilateral blood pressures taken in the arms are 190/110 on the right and 200/110 on the left. She is taking a multivitamin but no other medications. For the past 20 years she has smoked 10 cigarettes a day. Urinalysis reveals estimated protein of 360 mg/24 hour.

Answer 79

Takayasu’s arteritis (vasculitis)

Question 80

A 34-year-old man presents 2 weeks after returning from a month-long trip to India. He denies attending pre-travel vaccination clinic and did not take prophylaxis of any sort while in India. He reports a 6-day history of malaise, anorexia, abdominal pain, nausea with emesis, and dark urine. He admits to dietary indiscretion and consumed salad at a road-side vendor 3 weeks before onset of symptoms. On examination there is icterus. His alanine transaminase (ALT) is 5660 units/L, and total bilirubin 153.9 micromols/L (9 mg/dL).

Answer 80

Viral hepatitis (A)

Question 81

A 60-year-old man presents with several months of gradually worsening abdominal swelling, intermittent haematemesis, and dark stool. He denies chest pain or difficulty breathing. Past medical and family history are not contributory. Past surgical history is significant for back surgery requiring blood transfusion in 1990. Social history is significant for occasional alcohol use. BP is 110/80 mmHg. Physical examination is significant for spider angiomata on the upper chest, gynaecomastia, caput medusae, and a fluid wave of the abdomen. The rest of the examination is normal.

Answer 81

Viral hepatitis (C)

Question 82

A 62-year-old man presents for a routine initial visit in New York. He has occasional arthralgia or myalgia, and takes an ACE inhibitor and a thiazide diuretic for hypertension. A retired accountant and non-smoker, he drinks 1 or 2 beers per week and denies current drug use. Physical examination is normal except for being overweight.

Answer 82

Viral hepatitis (C)

Question 83

A 40-year-old asymptomatic man presents for a routine visit with elevated alanine aminotransferase (ALT) level (55 international units [IU]/mL). His mother died of hepatocellular carcinoma and he has a middle-aged sister with “liver infection”. He has a normal physical examination and has no stigmata of chronic liver disease.

Answer 83

Viral hepatitis (B)