An Overview of the Infective Complications in Diabetics

Introduction

Diabetes mellitus (DM) is characterized by inadequate insulin secretion or action. In addition to the typical side effects of the illness, DM has been linked to abnormalities in humoral immunity, neutrophil function, and T-cell response. Consequently, DM makes a person more vulnerable to infections, both common infections and infections that almost always only affect people with DM (for example, rhinocerebral mucormycosis). Such infections can result in diabetes complications like hypoglycemia and ketoacidosis. The skin, soft tissues, urinary tract, and respiratory tract are the most frequently infected areas in diabetic patients.

What Are the Common Infections Seen in Diabetic Patients?

• Respiratory Infections- Pneumonia and tuberculosis are the most common respiratory infections that are commonly seen in diabetic patients.

  • Pneumonia - It is a common infection in people with diabetes mellitus. As per one of the studies, the causative organism is similar in people with and without diabetes mellitus, with Streptococcus pneumoniae being the most prevalent. However, individuals with diabetes mellitus (DM) have an increased prevalence of bacteria like Staphylococcus aureus and Klebsiella pneumoniae, which are linked to skin colonization and more frequent aspiration. The typical symptoms of bacterial pneumonia are purulent cough and pleuritic chest pain, but this is less prevalent in people with diabetes mellitus. It can be managed using a combination treatment with Amoxicillin/Clavulanate, Cephalosporin, and a Macrolide or Doxycycline.

  • Tuberculosis (TB) - An important risk factor for developing tuberculosis is diabetes. Diabetic patients have a greater chance of developing tuberculosis than people who are non-diabetic. There seems to be an increased risk of tuberculosis treatment failure despite sticking to the medicine prescribed. The adverse effects of drugs prescribed to treat tuberculosis are particularly relevant in diabetes. Pyridoxine should be given to reduce this risk because Isoniazid can cause peripheral neuropathy that might be mistaken for diabetic neuropathy. Rifampicin can elevate blood sugar levels. Therefore, even though the TB treatment regimen for patients with diabetes mellitus is the same as the one for patients without diabetes mellitus, special attention must be given to these diabetic-specific issues.

• Skin and Soft Tissue Infections - Skin and soft tissue infections (SSTI) are significantly more likely to occur in diabetes. In a study, it was found that the risk of SSTI complications was five times more common, and hospitalization was four times more common in patients with diabetes. The most prevalent infection-causing agent is Staphylococcus aureus. Hyperglycemia (increased glucose level), sensory neuropathy (loss of sensation), and atherosclerotic vascular disease (hardening of blood vessels due to fat deposition) are all risk factors for skin and soft tissue infections in diabetic patients. These can affect any skin surface, but the feet are the most frequently affected. The common prevalent skin and soft tissue infections are cellulitis, necrotizing fasciitis, gangrene, and sternal wound infection. Bullosis diabeticorum is a skin condition that is only seen in patients with diabetes mellitus.

  • Cellulitis - It is the most common skin and soft tissue infection seen in people with diabetes. Staphylococcus aureus is the most common causative organism for cellulitis. Abscess is frequently cultured for organism identification and resistance profiling; however, cellulitis is typically diagnosed through clinical means. In terms of oral antibiotics, Doxycycline, Clindamycin, Trimethoprim-Sulfamethoxazole, and Cephalexin are the drug of choice for out-patients.

  • Necrotizing Fasciitis - It is a condition that affects the deep fascial layers and subcutaneous fat and is life-threatening. The prognosis is poor in diabetic patients as there is a higher chance of amputation in these people. Due to the polymicrobial nature of the infection, broad-spectrum antibiotics are used. Debridement, necrosectomy, and fasciotomy are frequently used in surgical management. Klebsiella pneumoniae is the most commonly seen in microorganisms.

  • Fournier Gangrene - It is a serious skin and soft tissue infection. It is described as a necrotizing skin infection affecting the penis, vulva, and scrotum. Diabetic patients are most susceptible to skin conditions. The infection will start in the retroperitoneal or perianal area and then spread to the genitalia, or it may start as a urinary tract infection and then spread to the genitalia. There will be necrosis and crepitus, which indicate that the underlying skin and soft tissue are affected. It is caused by both aerobic and anaerobic bacteria, and the most prevalent ones are Pseudomonas and Staphylococcus aureus.

  • Sternal Wound Infection - Sternal wound infections following surgery have been strongly linked to diabetes. The presence of diabetes is one of the clearest examples of a deep sternal wound infection following coronary artery bypass surgery. It has been demonstrated that better glycemic control during the recovery period can significantly lower the incidence of sternal wound infection.

  • Bullosis Diabeticorum - It is a condition that only affects people with diabetes mellitus and causes the acral skin to blister spontaneously. It is a non-inflammatory condition. In this condition, blisters usually go away on their own after two to six weeks, but they frequently return to the same or different places. Additional infections could emerge. With a male-to-female ratio of 2:1, adult men with long-term, uncontrolled diabetes and peripheral neuropathy are more likely to develop the bullous disease.

• Gastrointestinal Infections

  • Hepatitis - Hepatitis worsens in the presence of diabetes. Diabetic patients have a worse prognosis for chronic hepatitis C infection as compared to non-diabetics. The risk of cirrhosis increases and the response to antiviral therapy decreases.

  • Emphysematous Cholecystitis - It is a condition where gas is present in the gallbladder. Patients have sudden onset of abdominal pain in the right upper quadrant. They often exhibit fever, vomiting, and jaundice. It is commonly seen in diabetic patients. Escherichia coli and Clostridium perfringens are the two most common causative agents. The surgical treatment is cholecystectomy. Although for a mild case, antibiotic therapy can be started, if there is no improvement within three to four days, then cholecystectomy is recommended.

• Head and Neck Infections - Infections of the head and neck are commonly seen in people with diabetes. Abscess formation is also very common in such patients.

  • Necrotizing External Otitis - The condition is commonly seen in diabetic patients as a result of vascular compromise. Pseudomonas aeruginosa is the common causative agent. Due to the spread of infection, temporal and nearby bones at the base of the skull are affected. Treatment includes systemic antibiotics and ear canal treatment (that is, cleaning and topical application of antimicrobials). Fluoroquinolones are the drug of choice due to their antipseudomonal action.

• Genitourinary Infection - Diabetic patients are more prone to asymptomatic pyuria and bacteriuria, cystitis, and severe upper urinary tract infections.

  • Cystitis - It is inflammation of the bladder as a result of infection. The treatment involves antibiotic management and surgical treatment. It is the same for diabetic and non-diabetic patients, except that the therapy for diabetic patients extends for a longer period.

  • Pyelonephritis - It is inflammation of the kidney as a result of the spread of urinary tract infection. It causes insulin resistance and hence makes it difficult to control diabetes. Patients are treated using antibiotics.

  • Fungal Infections - Infections from candida species are very common, causing genitourinary infections. Fluconazole is the drug of choice for such medical conditions.

  • Emphysematous Pyelonephritis - The rare necrotizing renal infection known as emphysematous pyelonephritis (EPN) is caused by Klebsiella pneumoniae, Escherichia coli, or other organisms that can ferment glucose into carbon dioxide. If the disease is not promptly diagnosed and treated, the clinical course of EPN can be serious and life-threatening.

What Are the Fungal Infections Seen in Diabetes Patients?

In diabetic patients, Candida infection is frequent, with mucosa, soft tissue, and skin being the most frequently affected sites.

• Onychomycosis - It is a very common complication of diabetes and is a fungal infection of the nails. Although topical lacquers are also used, oral medications are typically the most effective.

• Mucormycosis - It is a rare but fatal fungal infection brought on by a species of mold called mucormycetes. Classic symptoms include necrotic eschars in the nasal cavity and on the hard palate, which also point to an infection that is progressing quickly. Surgical removal of the infection is required. Isavuconazole and Amphotericin B have been used as adjunctive treatments.

  • The sinus cavity is the most common site of infection, which can result in rhinocerebral (sinus infection that spreads to the brain) and orbital infection. In these circumstances, ophthalmoplegia, cellulitis, and cranial nerve palsies are frequently present, along with symptoms of sinus congestion or inflammation, fever, and facial swelling.

  • The second commonly involved site is the respiratory tract. Endobronchial lesions are common in diabetics, and the subsequent invasion of the vasculature may cause an infection to spread at a distant site.

  • The skin is the third most frequent site. Erythematous or ulcerative necrotic lesions are the first signs of cutaneous mucormycosis, which can also cause osteomyelitis.

How Can Infections Be Prevented?

• Controlling diabetes is most important. People with uncontrolled diabetes are more likely to contract infections and have difficulty fighting infections.

• Maintaining good urinary hygiene can reduce the risk of developing urinary tract infections, particularly in women. It includes urinating right away following sexual activity, routinely emptying the bladder, and consuming enough fluids.

• Foot care is very important in preventing infections. Walking barefoot is avoided. The foot should be routinely examined for blisters, bruises, bumps, and skin problems in order to prevent them from turning into ulcerated and necrotizing infections that can spread to the bloodstream and cause serious health conditions.

Conclusion

Diabetes is a very significant risk factor for infection, increasing the risk of infection for both conditions treated as out-patients and those that require hospitalization. In addition to increasing the risk of infection, the prognosis is frequently worse for many of these conditions, which raises the incidence of uncommon and potentially fatal infectious processes in people with diabetes.

This results from immune system disturbances that have been well-described as affecting both innate and adaptive immunity. However, by enhancing immune cell function, glucose-lowering treatments seem to be able to offset some of the elevated risks of infection and worsened prognosis. It will take more research to fully understand whether and how newer diabetes medications can lower the risk of infection.