What is the diagnosis?

Complete heart block. The ventricular rate was 35/min. There was complete AV dissociation with constant P waves intervals and R waves intervals.

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What may be the underlying causes?

The differential diagnoses include degenerative causes and acute myocardial infarction (inferior) causing conduction block. Drugs with negative chronotropic effects, electrolytes disturbance or hypothyroidism may also induce heart block but they usually exacerbate preexisting heart block and seldom directly induce complete heart block.

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The escape ventricular rhythm may not be stable and cardiogenic shock and syncope may follow. All drugs with potential negative chronotropic effect should be stopped. Any electrolyte or metabolic disturbance should be corrected. If no reversible elements can be found, permanent pacemaker implantation is indicated. Temporary pacemaker placement would be needed if permanent pacemaker implantation is delayed. External transcutaneous pacemaker should be available before temporary pacemaker placement is available. Intravenous atropine may be helpful before any external or transvenous pacing is available. For complete heart block due to acute myocardial infarction, successful revascularization of the blocked coronary vessel may resolve the heart block.

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What are the differential diagnoses?

The differential diagnoses are dyshidrotic eczema (pompholyx), contact dermatitis, tinea manuum, palmar pustulosis, "id" reaction to active tinea pedis and bullous impetigo.

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What is the most likely clinical diagnosis?

The most likely diagnosis is dyshidrotic eczema. It is an idiopathic recurrent deep-seated, pruritic vesicular eruption of the palms and soles. Vesicles may coalesce to form bullae. It is most common in adults between the ages of 20 and 40 and is rare before puberty and elderly. Sex incidence is equal. It is recurrent with episodes of spontaneous remissions.

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What are laboratory investigations?

Bacterial culture and KOH preparation may be needed to rule out staphylococcal and fungal infection. Biopsy is usually not indicated.

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What is the pathophysiology? What are the precipitating factors?

Dyshidrosis is a misnomer as the sweat ducts are not primarily involved. Half of the patients may have an atopic background. It may be precipitated by emotional stress, contact allergens or irritants and sometimes by hot and humid weather.

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What is the treatment?

All precipitating factors and aggravating contactants should be avoided. Mild cases often respond to intermediate strength topical steroids and oral antihistamine. Ultrapotent topical steroid ointment or intralesional steroid injection may be necessary for severe cases. For very severe cases, systemic corticosteroid may be necessary. Any secondary bacterial infection or concomitant fungal infection should be treated. PUVA may be tried for severe and recalcitrant cases.

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