A myriad of disorders may cause the inability of the kidneys to perform their respective function, and the term renal impairment encompasses two major disorders - acute and chronic kidney failure:

• Acute renal failure (ARF) can stem from diseases of pre-renal (severe bleeding, hypovolemia, extensive burns, renal hypoperfusion, heart failure, liver cirrhosis, etc.), intrinsic renal (the glomeruli, the tubules, the interstitium, and/or the renal blood vessels), and post-renal systems (obstructive uropathy arising from blood clots, tumors, or congenital defects) [1] [2]. Patients in the intensive care unit who are critically ill are most susceptible to ARF [1] [3], who present with symptoms of shock due to the severe effects of hyperkalemia, metabolic acidosis and diminished glomerular filtration rate (GFR) [2].
• Chronic renal failure - Contrary to ARF, a slowly progressing course of symptoms is seen in chronic renal impairment. At first, patients may be completely asymptomatic, but signs such as alterations in urinary habits (nocturia), generalized weakness, and fatigue eventually ensue [4] [5]. As chronic renal failure is an irreversible and progressive process, further deterioration of kidney function leads to neuromuscular symptoms (hyperreflexia, cramping, neuropathies, or even convulsions), weight loss, nausea, pruritus, and anorexia [4] [5]. The last stage of chronic renal failure, termed end-stage renal disease (ESRD), can include all of the mentioned symptoms, as well as muscle wasting, depression, anxiety, constipation, sleep disturbances, restless legs, and dyspnea [2] [4] [6].

• Nocturia

  At first, patients may be completely asymptomatic, but signs such as alterations in urinary habits (nocturia), generalized weakness, and fatigue eventually ensue. [symptoma.com]

  Symptoms of ESRD include: 1 nocturia malaise anorexia/nausea/vomiting pruritus restless legs dyspnoea Patients with acute renal failure from glomerulonephritis caused by viral infection and immune reaction can present with proteinuria and “nephritic sediment [myhivclinic.org]

  Nocturia is often noted, principally due to failure to concentrate the urine. Lassitude, fatigue, anorexia, and decreased mental acuity often are the earliest manifestations of uremia. [merckmanuals.com]

  Chronic Kidney Disease Symptoms Effects and symptoms of chronic kidney disease include: need to urinate frequently, especially at night (nocturia); swelling of the legs and puffiness around the eyes (fluid retention); high blood pressure; fatigue and [emedicinehealth.com]

  […] symptoms is termed uraemia. [16] Symptoms of kidney failure include the following: [16] [17] [18] [19] High levels of urea in the blood, which can result in: Vomiting or diarrhea (or both) may lead to dehydration Nausea Weight loss Nocturnal urination ( nocturia [en.wikipedia.org]

Renal impairment, both in the form of acute and chronic renal failure, could be severely harmful and even life-threatening for the patient in the absence of an early diagnosis [1]. For this reason, physicians must obtain a thorough patient history and determine the presence of underlying disorders that may induce renal impairment, whereas a complete physical examination assesses the signs and symptoms and determine the next steps in workup [2]. In fact, the clinical examination can lead to a prompt diagnosis in some cases, examples being prostate hypertrophy and cervical cancer, where the physician might be able to palpate the masses during rectal and vaginal examinations, respectively [1]. As soon as a presumptive diagnosis is made, a meticulous laboratory workup needs to be performed. A complete blood count (CBC), kidney function tests (urea and creatinine), urinalysis, serum glucose levels, complete coagulation panel, serum electrolytes (sodium, potassium, bicarbonate, calcium, and phosphate), inflammatory parameters (erythrocyte sedimentation rate, C-reactive protein), liver transaminases, and in most severe patients, arterial blood gasses must be included [1] [2] [5]. Imaging studies are equally important in determining the cause of kidney failure, with abdominal ultrasonography being the gold standard for evaluation of kidney anatomy and structure [1] [5]. To assess the degree of kidney failure, determination of GFR using creatinine and specific calculations is vital in establishing the severity of renal impairment [1] [5].

• Abnormal Renal Function

  renal function has been shown to be an independent predictor of mortality in people living with HIV (PLWHIV). 6 The higher prevalence of RI in HIV-infected patients has been demonstrated in a study in which RI prevalence was higher in women, older patients [myhivclinic.org]

  Both have low urine concentrations and are not indicated in the treatment of UTI in patients with normal or abnormal renal function. In contrast, ciprofloxacin and levofloxacin achieve high urine concentrations with oral or parenteral therapy. [cjasn.asnjournals.org]

  Background There is a high prevalence (30%) of abnormal renal function among patients with HIV disease. CKD is increasingly a cause of morbidity among people with HIV infection. [hiv.va.gov]

1. Fry AC, Farrington K. Management of acute renal failure. Postgrad Med J. 2006;82(964):106-116.
2. Hilton R. Acute renal failure. BMJ : British Medical Journal. 2006;333(7572):786-790.
3. Schrier RW, Wang W, Poole B, Mitra A. Acute renal failure: definitions, diagnosis, pathogenesis, and therapy. J Clin Invest. 2004;114(1):5-14.
4. Parmar MS. Chronic renal disease. BMJ. 2002;325(7355):85-90.
5. Porter RS, Kaplan JL. Merck Manual of Diagnosis and Therapy. 19th Edition. Merck Sharp & Dohme Corp. Whitehouse Station, N.J; 2011.
6. Murtagh FE, Addington-Hall J, Higginson IJ. The prevalence of symptoms in end-stage renal disease: a systematic review. Adv Chronic Kidney Dis. 2007;14(1):82-99.