Left bundle branch block on a resting 12 leads ECG is a cardiac risk factor.

True

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Non-invasive cardiac stress test is indicated pre-operatively in diabetic patients.

True

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In general, a resting 12 lead ECG does not has predictive value in patients undergoing low risk surgery. However, in patients with known ischemic heart disease undergoing high risk surgery, horizontal or downsloping ST depression greater than 0.5mm, LVH with strain pattern and LBBB on a resting ECG are clinical predictors of increased peri-operative risk.

According to ACC/AHA Shortcut to non-invasive testing in pre-operative patients, if two or more of the following three factors are present, non-invasive testing is indicated:

1. Intermediate clinical predictors are present (Canadian class 1 or 2 angina, prior MI based on history or pathological Q waves, compensated or prior failure, or diabetes);

2. Poor functional capacity (<4 METs), high surgical risk procedure (aortic repair or peripheral vascular surgery;

3. Prolonged surgical procedures with larger fluid shifts or blood loss.

Beta-blocker therapy is not an acceptable alternative to pre-operative non-invasive cardiac stress testing. Non-invasive cardiac stress testing is needed to identify patients at risk of myocardial ischemia, for which beta-blocker therapy reduces mortality.

Class I recommendations for peri-operative beta blocker use, according to ACC/AHA include:

1. Beta blockers required in the recent past to control symptoms of angina or patients with symptomatic arrhythmias or hypertension;

2. Patients at high cardiac risk owing to the findings of ischemia on pre-operative testing who are undergoing vascular surgery.

According to Boersma et al, the cardiac risk criteria for beta
blocker in the peri-operative period include:

1. High risk surgical procedures, defined as intraperitoneal, intrathoracic, or suprainguinal vascular procedures;

2. Ischemic heart disease, defined as history of MI, recurrent angina, use of nitrates, positive stress test, Q waves on ECG, patients who have undergone percutaneous transluminal coronary angioplasty or coronary artery bypass graft surgery and who have chest pain presumed to be of ischemic origin;

3. Cerebrovascular disease with history of TIA or stroke;

4. Insulin requiring DM; and

5. Chronic renal insufficiency defined as a baseline creatinine level of >2.0mg/dl.

What are the clinical diagnosis and differential diagnoses?

The clinical diagnosis is onychomycosis (OM). This patient has the white superficial onychomycosis subtype. Differential diagnoses include other causes of acquired or congenital leukonychias.

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What are the different subtypes of this condition?

OM is most frequently caused by dermatophyte. Yeast and nondermatophyte moulds are less common pathogens. The three subtypes of OM include distal lateral subungual OM (DLSO), white superficial OM (WSO) and proximal subungual OM (PSO). DLSO is the most common form in which the dermatophyte spread from plantar skin; causing onycholysis, subungual debris and discoloration beginning at the hyponychium and spread proximally. In WSO, the surface of nail plate is directly invaded, resulting in a white crumbly nail surface. PSO begins underneath the proximal nailfold and frequently associated with immunosuppressed conditions. Total dystrophic OM refers to the most advanced form of any subtype.

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What are the investigations?

Nail specimen should be examined under microscope after potassium hydroxide preparation to review the presence of septate hyphae. Identification of the species require a fungal culture. Immunosuppressed condition may need to be ruled out in case of PSO.

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What are the usual causative agents?

Trichophyton rubrum is the most common dermatophyte reported, especially for the DLSO and PSO. WSO is usually caused by Trichophyton mentagrophytes.

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What are the treatments?

The patients should be advised to avoid risk factors such as trauma to nail, communal bathing and occlusive footwear. Topical antifungal agents such as amorolfine and ciclopirox nail lacquer could be used if the nail plate involvement is less than 50% and for patients who refuse or intolerant to systemic therapy. Systemic antifungal agents including terbinafine and itraconazole have the advantage of shorter treatment course, higher cure rate and less side effects. A cure rate of up to 80% may be achieved after three months treatment.

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