1. A patient presents in clinic with an extremely painful foot. On examination you note that the left second toe is extremely inflamed and the inflammation is spreading to the dorsal aspect of the foot. What is the most likely type of infection to cause these symptoms? If left untreated, describe and explain how the symptoms may progress. What treatment strategy would you undertake for this condition? You are not expected to discuss specific drug therapies.
2. Bacterial infections commonly affect the foot. Describe and explain the possible outcomes of a Streptococcal infection affecting the dorsal aspect of the foot.
3.Define cellulitis. Outline the causes, risk factors and clinical signs and symptoms.
4.Give a definition of each for the following conditions and discuss their signs and symptoms (cellulitis and lymphangitis).

Definition and who it affects
A bacterial infection usually occurs when bacteria successfully invade the soft tissues through small wounds/abrasions on the skin surface or through existing conditions, e.g. leg ulceration or tinea pedis. Cellulitis arises following bacterial infection of the skin. It can frequently occur where there has been no break in the skin at all. Patients who are particularly prone to developing cellulitis are patients with diabetes, impairment of the immune system (e.g. HIV/AIDS), peripheral vascular disease and circulatory disease.

Bacterium which cause it
The most common cause of superficial cellulitis is the bacterium Streptococcus Pyogenes which is a spherical, Gram-positive bacterium and is the cause of group A streptococcal infections. Enzymes produced by the organism break down cellular components that otherwise would contain and localize the inflammation.

Where does it occur
Cellulitis can occur anywhere on the body, but is most commonly encountered on the lower legs, especially near the shins and ankles. Ascending cellulitis typically starts at the foot, with inflammation on the dorsum of the foot, or spreading to the dorsum of the foot. It may affect only the skin's surface or it can be more severe, affecting both the skin and the subcutaneous tissues beneath.

Symptoms
First symptoms include redness, pain, and tenderness over an area of skin. As this red area begins to spread, the person may develop a fever, sometimes with chills and sweats, and swollen lymph nodes near the area of infected skin. Infected skin becomes hot and slightly swollen - may look slightly pitted, like an orange peel. Fluid-filled blisters, which may be small (vesicles) or large (bullae), sometimes appear on the infected skin.

If untreated?
An untreated infection may spread to the lymphatic system causing Lymphangitis, the lymph nodes (lymphadenitis), the bloodstream (bacteremia) or into deeper tissues. In rare cases, streptococcal infection can spread to the deep layers of the fascial lining around muscles, resulting in necrotising fasciitis.

Treatment
1. Determine whether it is cellulitis or some other infection.
2. Check the white blood cell count - if it is elevated this is an indication of a bacterial infection.
3. Identification of causative organism via the microbiology department. Analysis of bacterial wound swabs and blister aspirate to determine bacterial culture and sensitivity. Mycology samples from tinea pedis.
4. Treatment is dependent upon whether the cellulitis is wet or dry and on the causative organism.
In both instances the patient will require systemic antibiotic therapy. Antibiotics may be given intravenously initially and then orally once they begin to take effect. If the cellulitis is dry , keep the skin dry until the oedema resolves itself. After which the skin should be moisturised. For wet cellulitis, an appropriate dressing (foam, alginate) should be applied to control exudate.
5. For oedema, the limb should be kept elevated.It is useful to mark the boundary of the erythema with an pen to monitor progress or regressing of the redness. Exercise will aid drainage of the oedema.
6. Analgesics given for pain relief.

Lymphangitis - definition and cause
Is inflammation of the subcutaneous lymphatic channels. It is commonly caused by streptococci which enters the lymphatic channels from an abrasion, wound or infection (cellulitis) on an extremity. Lymphangitis may suggest that an infection is progressing and should raise concerns of spread of bacteria to the bloodstream, which can cause life-threatening infections. Lymphangitis may be confused with a clot in a vein.

Signs and symptoms
Red streaks from infected area to the armpit, popliteal region or groin, which may be faint or obvious. Throbbing pain along the infected area. Fever or chills. Individuals may have a general malaise.

Lymphadenitis - definition and cause
Inflammation of the lymph nodes. Any pathogen, bacterial, viral, protozoal or fungal can cause lymphadenitis. Lymph node involvement may be generalised, with systemic infection, or it can be confined to regional lymph nodes.

Symptoms
Lymph nodes may be swollen, tender and hard.
Lymph nodes feel smooth or irregular to touch, or soft and rubbery if an abscess has formed.
The skin over a node may be reddened and hot.

Signs and tests for both
Examination
May be evidence of trauma around enlarged or swollen nodes
Biopsy and blood cultures to reveal the cause of the inflammation and to establish if the infection has spread to the bloodstream.

Treatment
Should begin promptly as both conditions may spread within hours.
Specific antibiotics are used to control infection.
Analgesics may be needed to control plain.
Anti-inflammatory medications to reduce inflammation and swelling.
An abscess may require surgical drainage.

	Created by Morgan Morgan over 10 years ago

University Pod Year 1 Note on Bacterial - essay, created by Morgan Morgan on 10/04/2014.