Urinary Tract Infection (UTI) Lecture Notes PDF

Restricted and Non- Sensitive Urinary Tract This Photo by Unknown Author is licensed under CC BY-SA-NC Infection Restricted and Non- Sensitive Learning outcomes 1. Describe the pathophysiology...

Restricted and Non- Sensitive Urinary Tract This Photo by Unknown Author is licensed under CC BY-SA-NC Infection Restricted and Non- Sensitive Learning outcomes 1. Describe the pathophysiology of urinary tract infections. 2. Discuss the clinical manifestations and antibiotic regimens of urinary tract infection. Restricted and Non- Sensitive Case study A 75-year-old male patient admitted to the hospital with a stroke 2 days earlier has developed a urinary tract infection (UTI). His Foley catheter is draining urine that is cloudy and dark yellow-orange with a strong odour. He is receiving an intravenous heparin infusion and has a history of type 2 diabetes. The physician ordered co-trimoxazole* for his UTI. 1. Identify the risk factors for developing UTI in this patient. 2. Are there any potential drug interactions? 3. Why was this particular antibiotic chosen for UTI? *Co-trimoxazole is a combination of sulfamethoxazole and trimethoprim Restricted and Non- Sensitive Urinary tract infection (UTI) An inflammation of the urinary epithelium usually caused by bacteria from gut flora Can occur anywhere along the urinary tract Urethra (urethritis) Prostate (prostatitis) Bladder (cystitis) Ureter Kidney (pyelonephritis) This Photo by Unknown Author is licensed under CC BY Restricted and Non- Sensitive Spectrum of UTI Uncomplicated UTI Mild, no complications Individuals with normal urinary tract Complicated UTI Abnormality in urinary tract Immunocompromised E.g. HIV, renal transplant, diabetes, spinal cord injury Restricted and Non- Sensitive Pathophysiology of UTI Urinary tract is usually sterile Protected by several mechanisms that prevent bacteria from ascending UTI occurs when bacteria Gain access, overwhelm defenses and ascend Restricted and Non- Sensitive Host defence mechanisms Most bacteria are washed out of the urethra during micturition Low pH of urine High concentration of urea Tamm-Horsfall proteins which are secreted by tubular cells in the distal loop of Henle are bactericidal Closure of Vesico-ureteric junction prevents reflux into ureters Prostatic secretions and longer urethra in males Restricted and Non- Sensitive Mechanisms of UTI Ref: Understanding Restricted and Non- Sensitive Bacterial factors Capsular antigens resist phagocytosis Haemolysin causes damage to epithelium Urease bacteria (e.g., Proteus & Klebsiella) promote infection E. coli have fimbriae that bind to receptors in uroepithelium and resist flushing during micturition Restricted and Non- Sensitive Host groups for UTI 1. Renal stones 2. Diabetes 3. Immunosuppression 4. Pregnancy 5. Postmenopausal women 6. Neurogenic bladder Neurologic impairment interferes normal bladder contraction, with residual urine and ascending infection 7. Catheterization 8. Shorter urethra in women Restricted and Non- Sensitive Female Reproductive Model Restricted and Non- Sensitive Types of UTI Acute cystitis Acute pyelonephritis Chronic pyelonephritis Restricted and Non- Sensitive Acute cystitis An inflammation of the urinary bladder The most common site of UTI Causal organisms Uropathic strains of Escherichia coli (the most common) Staphylococcus saprophyticus (the 2nd most common) Klebsiella, Proteus, Pseudomonas, fungi, viruses, parasites (less common) Restricted and Non- Sensitive Different types of acute cystitis 1. Hyperemic mucosa in mild inflammation 2. Advanced cases Diffuse haemorrhage (haemorrhagic cystitis) Pus or suppurative exudates (suppurative cystitis) 3. Prolonged infection Sloughing of the bladder mucosa with ulcer formation (ulcerative cystitis) 4. The most severe infections Necrosis of the bladder wall (gangrenous cystitis) Restricted and Non- Sensitive E. coli Restricted and Non- Sensitive Clinical features of acute cystitis Acute onset Frequency of micturition Urgency Dysuria (pain during micturition) Suprapubic pain during and after voiding Intense desire to pass more urine after micturition due to spasm of the inflamed bladder wall (strangury) Cloudy urine with an unpleasant odour Microscopic or visible haematuria Systematic symptoms are slight or absent Restricted and Non- Sensitive Pyelonephritis An infection of one or both upper urinary tracts (ureter, renal pelvis, and interstitium) Acute or chronic Risk factors Renal stones * Vesicoureteral reflux* Pregnancy Neurogenic bladder Instrumentation * the most common risk factors Restricted and Non- Sensitive Acute pyelonephritis Usually due to Instrumentation or urinary tract surgery May also occur as the blood-borne Causal organisms E.coli Proteus Pseudomonas Restricted and Non- Sensitive Pathology of acute pyelonephritis  Progressive infection results in  Inflammation, fibrosis, scarring  Acutely inflamed renal pelvis with small cortical abscesses & streaks of pus in medulla Restricted and Non- Sensitive Clinical Features of acute pyelonephritis Acute onset A classic triad of Loin pain Fever Tenderness over the kidney Urinary frequency Dysuria Restricted and Non- Sensitive Chronic pyelonephritis ( Reflux Nephropathy ) Usually associated with urinary obstructions such as renal stones and vesicoureteral reflux A persistent or recurrent infection of the kidney  scarring Gradual onset with tiredness, fatigue Often asymptomatic initially Hypertension and proteinuria on routine check- up Progressive deterioration in renal function results in Symptoms of chronic renal failure Restricted and Non- Sensitive Investigations Urine dipstick test Urine microscopy Urine culture and antibiotic sensitivity Urine specimen must be collected before initiation of any antibiotic therapy Identification of risk factors urinary obstruction by imaging e.g. X-ray, USG, CT Restricted and Non- Sensitive Management Antibiotics for all cases of confirmed UTI Duration of therapy Uncomplicated UTI- 3-7 days Complicated UTI – 7-14 days A fluid intake of at least 2 L/day Urinary alkalinising agent (potassium citrate) may help symptomatically Restricted and Non- Sensitive Antibiotic regimens for UTI Trimethoprim is the choice for initial treatment Other antibiotics Nitrofurantoin Quinolone antibiotics such as ciprofloxacin, norfloxacin Cefalexin Co-amoxiclav Amoxicillin Restricted and Non- Sensitive Ref: Davidson’s Principle and Practice of Restricted and Non- Sensitive Case study (Refer to the recorded lecture for the answers) A 75-year-old male patient admitted to the hospital with a stroke 2 days earlier has developed a urinary tract infection (UTI). His Foley catheter is draining urine that is cloudy and dark yellow-orange with a strong odour. He is receiving an intravenous heparin infusion and has a history of type 2 diabetes. The physician ordered co-trimoxazole* for his UTI. 1. Identify the risk factors for developing UTI in this patient. 2. Are there any potential drug interactions? 3. Why was this particular antibiotic chosen for UTI? *Co-trimoxazole is a combination of sulfamethoxazole and trimethoprim Restricted and Non- Sensitive Key Terms Urinary tract infection Cystitis Pyelonephritis Antibiotic regimens for UTI Restricted and Non- Sensitive Review Question 1. After studying this lesson, students should answer two short answer questions. 2. Scan the QR code or use the link to get access to the question. https://forms.office.co m/r/idTkEGV32T Restricted and Non- Sensitive References 1. Huether & McCance (2015), Understanding Pathophysiology, 6th Edition 2. Davidson’s Principles and Practice of Medicine (2016), 23rd Edition