Five patients, five medical problems

Correct answer: A. 15 g of oral carbohydrate, such as half a glass of juice or three glucose tablets

• A. CORRECT. This is the RULE OF 15. If capillary glucose is below 70 mg/dL in a CONSCIOUS patient with an intact swallow, give 15 g of rapidly absorbed carbohydrate — about half a cup of juice or regular soda, three or four glucose tablets, or a tablespoon of sugar or honey. Recheck after 15 minutes and repeat if still below 70. Once glucose is normal, give a snack containing complex carbohydrate and protein to prevent recurrence. Note that juice and glucose tablets work whereas chocolate and other fatty confectionery are poor choices, because the fat delays gastric emptying.
• B. Insulin would deepen the hypoglycaemia and could be fatal. It is the classic distractor in this item and the one that must never be selected.
• C. Intravenous dextrose is the definitive treatment for an unconscious hypoglycaemic patient where intravenous access exists, which in most dental settings means waiting for the emergency medical team.
• D. Intramuscular glucagon 1 mg is for the UNCONSCIOUS patient, or anyone who cannot protect their airway or swallow safely. It mobilises hepatic glycogen and takes 10 to 15 minutes to act, and it is far less effective in a starved or alcohol-dependent patient whose glycogen stores are depleted.

Note: The single most useful rule: if you cannot measure the glucose and cannot tell whether a diabetic patient is hyper- or hypoglycaemic, TREAT AS HYPOGLYCAEMIA. Hypoglycaemia causes irreversible neurological damage within minutes; hyperglycaemia takes hours to days. Prevention matters too — morning appointments, confirm the patient has eaten and taken medication as usual, and keep oral glucose in the emergency kit.

Correct answer: B. Chronic bronchitis is a CLINICAL diagnosis (productive cough on most days for 3 months in each of 2 consecutive years); emphysema is a PATHOLOGICAL diagnosis (permanent enlargement and destruction of airspaces distal to the terminal bronchiole)

• A. COPD obstruction is by definition INCOMPLETELY REVERSIBLE, and that is exactly what distinguishes it from asthma.
• B. CORRECT. Both definitions are worth carrying verbatim. CHRONIC BRONCHITIS is defined CLINICALLY — a productive cough on most days for at least three months in each of two consecutive years. Its phenotype is the ‘blue bloater’: overweight and cyanotic, with peripheral oedema, wheeze and an elevated haemoglobin from chronic hypoxaemia. EMPHYSEMA is defined PATHOLOGICALLY — permanent enlargement of the airspaces distal to the terminal bronchiole with destruction of their walls. Its phenotype is the ‘pink puffer’: older and thin, severely dyspnoeic, with a quiet chest and a hyperinflated film showing flattened diaphragms. Most real patients have elements of both.
• C. This reverses the two definitions.
• D. Post-bronchodilator spirometry showing an FEV1/FVC ratio below 0.70 CONFIRMS airflow obstruction and grades its severity, but it does not define either component.

Note: The oral and dental consequences of smoking to list alongside COPD: nicotinic stomatitis, smoker's melanosis, oral squamous cell carcinoma, accelerated periodontal breakdown with a BLUNTED bleeding response that masks disease severity, delayed healing and dry socket, implant failure, staining and halitosis. For treatment: short appointments, an upright chair position, caution with rubber dam if it worsens dyspnoea, avoid nitrous oxide in severe disease, and remember that in a CO₂ retainer high-flow oxygen is not automatically benign.

Correct answer: B. Fludrocortisone

• A. Triamcinolone is a GLUCOCORTICOID. In dentistry it is best known as triamcinolone acetonide in an adhesive oral paste for ulcerative and erosive mucosal disease.
• B. CORRECT. FLUDROCORTISONE is the mineralocorticoid used clinically. It acts on the aldosterone receptor in the distal nephron to retain sodium and water and excrete potassium, and it is the replacement given in ADDISON DISEASE alongside a glucocorticoid.
• C. Dexamethasone is a long-acting, high-potency GLUCOCORTICOID with essentially NO mineralocorticoid activity — which is what makes it the agent of choice for reducing post-operative oedema and trismus after third molar surgery, where sodium retention would be an unwanted effect.
• D. Prednisone is a GLUCOCORTICOID and the standard oral agent; it is a prodrug converted to prednisolone in the liver. Note that HYDROCORTISONE (cortisol itself) has substantial mineralocorticoid activity as well as glucocorticoid activity, which is exactly why it is the drug given intravenously for adrenal crisis.

Note: Glucocorticoid adverse effects to expect and to distinguish from the mineralocorticoid ones: HYPERglycaemia (not hypo — a common exam trap), adrenal suppression, osteoporosis, posterior subcapsular cataract and raised intraocular pressure, thin fragile skin, impaired wound healing, immunosuppression, peptic ulceration, mood change and the cushingoid habitus. ADRENAL SUPPRESSION is the one that determines whether supplemental steroid cover is needed before a surgical procedure.

Correct answer: D. Immunity through vaccination

• A. Immunity from resolved natural infection shows anti-HBs POSITIVE and anti-HBc POSITIVE together, with HBsAg negative — because the person encountered the entire virus, including its core protein, rather than just the surface antigen.
• B. Acute infection is HBsAg positive with IgM anti-HBc positive, often during the window period when anti-HBs has not yet appeared.
• C. Chronic infection is defined by HBsAg positive for more than six months, with anti-HBc positive and anti-HBs negative. HBsAg is negative here.
• D. CORRECT. Anti-HBs is the antibody to the SURFACE ANTIGEN and it signifies IMMUNITY. The vaccine contains recombinant surface antigen ONLY, so a vaccinated person develops anti-HBs and nothing else. The NEGATIVE anti-HBc is the discriminator that settles it — core antibody is produced only in response to the whole virus and is never generated by the vaccine.

Note: The employer MUST make the hepatitis B vaccine series available at NO COST within 10 working days of assignment to a role with occupational exposure; offering it is mandatory for the employer, accepting it is voluntary for the employee. Post-vaccination testing is performed one to two months after the final dose, and an anti-HBs titre of 10 mIU/mL or above indicates protection. No booster is currently recommended for immunocompetent responders.

Correct answer: D. The causative organism is Staphylococcus aureus

• A. This IS true. Transmission is by direct contact and respiratory droplet, which is why it moves rapidly through schools and households.
• B. This IS true and is exactly what is described. The sequence runs from a WHITE coating through which swollen hyperplastic fungiform papillae project — the white strawberry tongue — which sloughs after a few days to leave a deep red surface with prominent papillae, the red or raspberry strawberry tongue.
• C. This IS true. The incubation period is short, roughly one to three days, which contributes to the speed of spread.
• D. CORRECT as the exception. SCARLET FEVER is caused by GROUP A BETA-HAEMOLYTIC STREPTOCOCCUS (Streptococcus pyogenes), specifically strains producing an erythrogenic (pyrogenic) exotoxin, which is what produces the rash. Staphylococcus aureus causes a different toxin-mediated illness, staphylococcal scalded skin syndrome, in which the skin blisters and peels rather than developing a sandpaper rash.

Note: Scarlet fever matters in dentistry mainly for what follows untreated group A streptococcal infection: ACUTE RHEUMATIC FEVER, which damages heart valves and creates a lifelong cardiac concern, and post-streptococcal glomerulonephritis. Treatment is penicillin. Keep the other causes of a strawberry tongue in the differential — KAWASAKI DISEASE and toxic shock syndrome — since both are serious and neither responds to antibiotics.